/*
 * Copyright © 2012 Intel Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice (including the next
 * paragraph) shall be included in all copies or substantial portions of the
 * Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 *
 * Authors:
 *    Eugeni Dodonov <eugeni.dodonov@intel.com>
 *
 */

#include <linux/module.h>
#include <linux/pm_runtime.h>

#include <drm/drm_atomic_helper.h>
#include <drm/drm_fourcc.h>
#include <drm/drm_plane_helper.h>

#include "display/intel_atomic.h"
#include "display/intel_atomic_plane.h"
#include "display/intel_bw.h"
#include "display/intel_de.h"
#include "display/intel_display_trace.h"
#include "display/intel_display_types.h"
#include "display/intel_fb.h"
#include "display/intel_fbc.h"
#include "display/intel_sprite.h"
#include "display/skl_universal_plane.h"

#include "gt/intel_llc.h"

#include "i915_drv.h"
#include "i915_fixed.h"
#include "i915_irq.h"
#include "intel_pcode.h"
#include "intel_pm.h"
#include "vlv_sideband.h"
#include "../../../platform/x86/intel_ips.h"

/* Stores plane specific WM parameters */
struct skl_wm_params {
        bool x_tiled, y_tiled;
        bool rc_surface;
        bool is_planar;
        u32 width;
        u8 cpp;
        u32 plane_pixel_rate;
        u32 y_min_scanlines;
        u32 plane_bytes_per_line;
        uint_fixed_16_16_t plane_blocks_per_line;
        uint_fixed_16_16_t y_tile_minimum;
        u32 linetime_us;
        u32 dbuf_block_size;
};

/* used in computing the new watermarks state */
struct intel_wm_config {
        unsigned int num_pipes_active;
        bool sprites_enabled;
        bool sprites_scaled;
};

static void gen9_init_clock_gating(struct drm_i915_private *dev_priv)
{
        enum pipe pipe;

        if (HAS_LLC(dev_priv)) {
                /*
                 * WaCompressedResourceDisplayNewHashMode:skl,kbl
                 * Display WA #0390: skl,kbl
                 *
                 * Must match Sampler, Pixel Back End, and Media. See
                 * WaCompressedResourceSamplerPbeMediaNewHashMode.
                 */
                intel_uncore_write(&dev_priv->uncore, CHICKEN_PAR1_1,
                           intel_uncore_read(&dev_priv->uncore, CHICKEN_PAR1_1) |
                           SKL_DE_COMPRESSED_HASH_MODE);
        }

        for_each_pipe(dev_priv, pipe) {
                /*
                 * "Plane N strech max must be programmed to 11b (x1)
                 *  when Async flips are enabled on that plane."
                 */
                if (!IS_GEMINILAKE(dev_priv) && intel_vtd_active(dev_priv))
                        intel_uncore_rmw(&dev_priv->uncore, CHICKEN_PIPESL_1(pipe),
                                         SKL_PLANE1_STRETCH_MAX_MASK, SKL_PLANE1_STRETCH_MAX_X1);
        }

        /* See Bspec note for PSR2_CTL bit 31, Wa#828:skl,bxt,kbl,cfl */
        intel_uncore_write(&dev_priv->uncore, CHICKEN_PAR1_1,
                   intel_uncore_read(&dev_priv->uncore, CHICKEN_PAR1_1) | SKL_EDP_PSR_FIX_RDWRAP);

        /* WaEnableChickenDCPR:skl,bxt,kbl,glk,cfl */
        intel_uncore_write(&dev_priv->uncore, GEN8_CHICKEN_DCPR_1,
                   intel_uncore_read(&dev_priv->uncore, GEN8_CHICKEN_DCPR_1) | MASK_WAKEMEM);

        /*
         * WaFbcWakeMemOn:skl,bxt,kbl,glk,cfl
         * Display WA #0859: skl,bxt,kbl,glk,cfl
         */
        intel_uncore_write(&dev_priv->uncore, DISP_ARB_CTL, intel_uncore_read(&dev_priv->uncore, DISP_ARB_CTL) |
                   DISP_FBC_MEMORY_WAKE);
}

static void bxt_init_clock_gating(struct drm_i915_private *dev_priv)
{
        gen9_init_clock_gating(dev_priv);

        /* WaDisableSDEUnitClockGating:bxt */
        intel_uncore_write(&dev_priv->uncore, GEN8_UCGCTL6, intel_uncore_read(&dev_priv->uncore, GEN8_UCGCTL6) |
                   GEN8_SDEUNIT_CLOCK_GATE_DISABLE);

        /*
         * FIXME:
         * GEN8_HDCUNIT_CLOCK_GATE_DISABLE_HDCREQ applies on 3x6 GT SKUs only.
         */
        intel_uncore_write(&dev_priv->uncore, GEN8_UCGCTL6, intel_uncore_read(&dev_priv->uncore, GEN8_UCGCTL6) |
                   GEN8_HDCUNIT_CLOCK_GATE_DISABLE_HDCREQ);

        /*
         * Wa: Backlight PWM may stop in the asserted state, causing backlight
         * to stay fully on.
         */
        intel_uncore_write(&dev_priv->uncore, GEN9_CLKGATE_DIS_0, intel_uncore_read(&dev_priv->uncore, GEN9_CLKGATE_DIS_0) |
                   PWM1_GATING_DIS | PWM2_GATING_DIS);

        /*
         * Lower the display internal timeout.
         * This is needed to avoid any hard hangs when DSI port PLL
         * is off and a MMIO access is attempted by any privilege
         * application, using batch buffers or any other means.
         */
        intel_uncore_write(&dev_priv->uncore, RM_TIMEOUT, MMIO_TIMEOUT_US(950));

        /*
         * WaFbcTurnOffFbcWatermark:bxt
         * Display WA #0562: bxt
         */
        intel_uncore_write(&dev_priv->uncore, DISP_ARB_CTL, intel_uncore_read(&dev_priv->uncore, DISP_ARB_CTL) |
                   DISP_FBC_WM_DIS);

        /*
         * WaFbcHighMemBwCorruptionAvoidance:bxt
         * Display WA #0883: bxt
         */
        intel_uncore_write(&dev_priv->uncore, ILK_DPFC_CHICKEN, intel_uncore_read(&dev_priv->uncore, ILK_DPFC_CHICKEN) |
                   DPFC_DISABLE_DUMMY0);
}

static void glk_init_clock_gating(struct drm_i915_private *dev_priv)
{
        gen9_init_clock_gating(dev_priv);

        /*
         * WaDisablePWMClockGating:glk
         * Backlight PWM may stop in the asserted state, causing backlight
         * to stay fully on.
         */
        intel_uncore_write(&dev_priv->uncore, GEN9_CLKGATE_DIS_0, intel_uncore_read(&dev_priv->uncore, GEN9_CLKGATE_DIS_0) |
                   PWM1_GATING_DIS | PWM2_GATING_DIS);
}

static void pnv_get_mem_freq(struct drm_i915_private *dev_priv)
{
        u32 tmp;

        tmp = intel_uncore_read(&dev_priv->uncore, CLKCFG);

        switch (tmp & CLKCFG_FSB_MASK) {
        case CLKCFG_FSB_533:
                dev_priv->fsb_freq = 533; /* 133*4 */
                break;
        case CLKCFG_FSB_800:
                dev_priv->fsb_freq = 800; /* 200*4 */
                break;
        case CLKCFG_FSB_667:
                dev_priv->fsb_freq =  667; /* 167*4 */
                break;
        case CLKCFG_FSB_400:
                dev_priv->fsb_freq = 400; /* 100*4 */
                break;
        }

        switch (tmp & CLKCFG_MEM_MASK) {
        case CLKCFG_MEM_533:
                dev_priv->mem_freq = 533;
                break;
        case CLKCFG_MEM_667:
                dev_priv->mem_freq = 667;
                break;
        case CLKCFG_MEM_800:
                dev_priv->mem_freq = 800;
                break;
        }

        /* detect pineview DDR3 setting */
        tmp = intel_uncore_read(&dev_priv->uncore, CSHRDDR3CTL);
        dev_priv->is_ddr3 = (tmp & CSHRDDR3CTL_DDR3) ? 1 : 0;
}

static void ilk_get_mem_freq(struct drm_i915_private *dev_priv)
{
        u16 ddrpll, csipll;

        ddrpll = intel_uncore_read16(&dev_priv->uncore, DDRMPLL1);
        csipll = intel_uncore_read16(&dev_priv->uncore, CSIPLL0);

        switch (ddrpll & 0xff) {
        case 0xc:
                dev_priv->mem_freq = 800;
                break;
        case 0x10:
                dev_priv->mem_freq = 1066;
                break;
        case 0x14:
                dev_priv->mem_freq = 1333;
                break;
        case 0x18:
                dev_priv->mem_freq = 1600;
                break;
        default:
                drm_dbg(&dev_priv->drm, "unknown memory frequency 0x%02x\n",
                        ddrpll & 0xff);
                dev_priv->mem_freq = 0;
                break;
        }

        switch (csipll & 0x3ff) {
        case 0x00c:
                dev_priv->fsb_freq = 3200;
                break;
        case 0x00e:
                dev_priv->fsb_freq = 3733;
                break;
        case 0x010:
                dev_priv->fsb_freq = 4266;
                break;
        case 0x012:
                dev_priv->fsb_freq = 4800;
                break;
        case 0x014:
                dev_priv->fsb_freq = 5333;
                break;
        case 0x016:
                dev_priv->fsb_freq = 5866;
                break;
        case 0x018:
                dev_priv->fsb_freq = 6400;
                break;
        default:
                drm_dbg(&dev_priv->drm, "unknown fsb frequency 0x%04x\n",
                        csipll & 0x3ff);
                dev_priv->fsb_freq = 0;
                break;
        }
}

static const struct cxsr_latency cxsr_latency_table[] = {
        {1, 0, 800, 400, 3382, 33382, 3983, 33983},    /* DDR2-400 SC */
        {1, 0, 800, 667, 3354, 33354, 3807, 33807},    /* DDR2-667 SC */
        {1, 0, 800, 800, 3347, 33347, 3763, 33763},    /* DDR2-800 SC */
        {1, 1, 800, 667, 6420, 36420, 6873, 36873},    /* DDR3-667 SC */
        {1, 1, 800, 800, 5902, 35902, 6318, 36318},    /* DDR3-800 SC */

        {1, 0, 667, 400, 3400, 33400, 4021, 34021},    /* DDR2-400 SC */
        {1, 0, 667, 667, 3372, 33372, 3845, 33845},    /* DDR2-667 SC */
        {1, 0, 667, 800, 3386, 33386, 3822, 33822},    /* DDR2-800 SC */
        {1, 1, 667, 667, 6438, 36438, 6911, 36911},    /* DDR3-667 SC */
        {1, 1, 667, 800, 5941, 35941, 6377, 36377},    /* DDR3-800 SC */

        {1, 0, 400, 400, 3472, 33472, 4173, 34173},    /* DDR2-400 SC */
        {1, 0, 400, 667, 3443, 33443, 3996, 33996},    /* DDR2-667 SC */
        {1, 0, 400, 800, 3430, 33430, 3946, 33946},    /* DDR2-800 SC */
        {1, 1, 400, 667, 6509, 36509, 7062, 37062},    /* DDR3-667 SC */
        {1, 1, 400, 800, 5985, 35985, 6501, 36501},    /* DDR3-800 SC */

        {0, 0, 800, 400, 3438, 33438, 4065, 34065},    /* DDR2-400 SC */
        {0, 0, 800, 667, 3410, 33410, 3889, 33889},    /* DDR2-667 SC */
        {0, 0, 800, 800, 3403, 33403, 3845, 33845},    /* DDR2-800 SC */
        {0, 1, 800, 667, 6476, 36476, 6955, 36955},    /* DDR3-667 SC */
        {0, 1, 800, 800, 5958, 35958, 6400, 36400},    /* DDR3-800 SC */

        {0, 0, 667, 400, 3456, 33456, 4103, 34106},    /* DDR2-400 SC */
        {0, 0, 667, 667, 3428, 33428, 3927, 33927},    /* DDR2-667 SC */
        {0, 0, 667, 800, 3443, 33443, 3905, 33905},    /* DDR2-800 SC */
        {0, 1, 667, 667, 6494, 36494, 6993, 36993},    /* DDR3-667 SC */
        {0, 1, 667, 800, 5998, 35998, 6460, 36460},    /* DDR3-800 SC */

        {0, 0, 400, 400, 3528, 33528, 4255, 34255},    /* DDR2-400 SC */
        {0, 0, 400, 667, 3500, 33500, 4079, 34079},    /* DDR2-667 SC */
        {0, 0, 400, 800, 3487, 33487, 4029, 34029},    /* DDR2-800 SC */
        {0, 1, 400, 667, 6566, 36566, 7145, 37145},    /* DDR3-667 SC */
        {0, 1, 400, 800, 6042, 36042, 6584, 36584},    /* DDR3-800 SC */
};

static const struct cxsr_latency *intel_get_cxsr_latency(bool is_desktop,
                                                         bool is_ddr3,
                                                         int fsb,
                                                         int mem)
{
        const struct cxsr_latency *latency;
        int i;

        if (fsb == 0 || mem == 0)
                return NULL;

        for (i = 0; i < ARRAY_SIZE(cxsr_latency_table); i++) {
                latency = &cxsr_latency_table[i];
                if (is_desktop == latency->is_desktop &&
                    is_ddr3 == latency->is_ddr3 &&
                    fsb == latency->fsb_freq && mem == latency->mem_freq)
                        return latency;
        }

        DRM_DEBUG_KMS("Unknown FSB/MEM found, disable CxSR\n");

        return NULL;
}

static void chv_set_memory_dvfs(struct drm_i915_private *dev_priv, bool enable)
{
        u32 val;

        vlv_punit_get(dev_priv);

        val = vlv_punit_read(dev_priv, PUNIT_REG_DDR_SETUP2);
        if (enable)
                val &= ~FORCE_DDR_HIGH_FREQ;
        else
                val |= FORCE_DDR_HIGH_FREQ;
        val &= ~FORCE_DDR_LOW_FREQ;
        val |= FORCE_DDR_FREQ_REQ_ACK;
        vlv_punit_write(dev_priv, PUNIT_REG_DDR_SETUP2, val);

        if (wait_for((vlv_punit_read(dev_priv, PUNIT_REG_DDR_SETUP2) &
                      FORCE_DDR_FREQ_REQ_ACK) == 0, 3))
                drm_err(&dev_priv->drm,
                        "timed out waiting for Punit DDR DVFS request\n");

        vlv_punit_put(dev_priv);
}

static void chv_set_memory_pm5(struct drm_i915_private *dev_priv, bool enable)
{
        u32 val;

        vlv_punit_get(dev_priv);

        val = vlv_punit_read(dev_priv, PUNIT_REG_DSPSSPM);
        if (enable)
                val |= DSP_MAXFIFO_PM5_ENABLE;
        else
                val &= ~DSP_MAXFIFO_PM5_ENABLE;
        vlv_punit_write(dev_priv, PUNIT_REG_DSPSSPM, val);

        vlv_punit_put(dev_priv);
}

#define FW_WM(value, plane) \
        (((value) << DSPFW_ ## plane ## _SHIFT) & DSPFW_ ## plane ## _MASK)

static bool _intel_set_memory_cxsr(struct drm_i915_private *dev_priv, bool enable)
{
        bool was_enabled;
        u32 val;

        if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv)) {
                was_enabled = intel_uncore_read(&dev_priv->uncore, FW_BLC_SELF_VLV) & FW_CSPWRDWNEN;
                intel_uncore_write(&dev_priv->uncore, FW_BLC_SELF_VLV, enable ? FW_CSPWRDWNEN : 0);
                intel_uncore_posting_read(&dev_priv->uncore, FW_BLC_SELF_VLV);
        } else if (IS_G4X(dev_priv) || IS_I965GM(dev_priv)) {
                was_enabled = intel_uncore_read(&dev_priv->uncore, FW_BLC_SELF) & FW_BLC_SELF_EN;
                intel_uncore_write(&dev_priv->uncore, FW_BLC_SELF, enable ? FW_BLC_SELF_EN : 0);
                intel_uncore_posting_read(&dev_priv->uncore, FW_BLC_SELF);
        } else if (IS_PINEVIEW(dev_priv)) {
                val = intel_uncore_read(&dev_priv->uncore, DSPFW3);
                was_enabled = val & PINEVIEW_SELF_REFRESH_EN;
                if (enable)
                        val |= PINEVIEW_SELF_REFRESH_EN;
                else
                        val &= ~PINEVIEW_SELF_REFRESH_EN;
                intel_uncore_write(&dev_priv->uncore, DSPFW3, val);
                intel_uncore_posting_read(&dev_priv->uncore, DSPFW3);
        } else if (IS_I945G(dev_priv) || IS_I945GM(dev_priv)) {
                was_enabled = intel_uncore_read(&dev_priv->uncore, FW_BLC_SELF) & FW_BLC_SELF_EN;
                val = enable ? _MASKED_BIT_ENABLE(FW_BLC_SELF_EN) :
                               _MASKED_BIT_DISABLE(FW_BLC_SELF_EN);
                intel_uncore_write(&dev_priv->uncore, FW_BLC_SELF, val);
                intel_uncore_posting_read(&dev_priv->uncore, FW_BLC_SELF);
        } else if (IS_I915GM(dev_priv)) {
                /*
                 * FIXME can't find a bit like this for 915G, and
                 * and yet it does have the related watermark in
                 * FW_BLC_SELF. What's going on?
                 */
                was_enabled = intel_uncore_read(&dev_priv->uncore, INSTPM) & INSTPM_SELF_EN;
                val = enable ? _MASKED_BIT_ENABLE(INSTPM_SELF_EN) :
                               _MASKED_BIT_DISABLE(INSTPM_SELF_EN);
                intel_uncore_write(&dev_priv->uncore, INSTPM, val);
                intel_uncore_posting_read(&dev_priv->uncore, INSTPM);
        } else {
                return false;
        }

        trace_intel_memory_cxsr(dev_priv, was_enabled, enable);

        drm_dbg_kms(&dev_priv->drm, "memory self-refresh is %s (was %s)\n",
                    enableddisabled(enable),
                    enableddisabled(was_enabled));

        return was_enabled;
}

/**
 * intel_set_memory_cxsr - Configure CxSR state
 * @dev_priv: i915 device
 * @enable: Allow vs. disallow CxSR
 *
 * Allow or disallow the system to enter a special CxSR
 * (C-state self refresh) state. What typically happens in CxSR mode
 * is that several display FIFOs may get combined into a single larger
 * FIFO for a particular plane (so called max FIFO mode) to allow the
 * system to defer memory fetches longer, and the memory will enter
 * self refresh.
 *
 * Note that enabling CxSR does not guarantee that the system enter
 * this special mode, nor does it guarantee that the system stays
 * in that mode once entered. So this just allows/disallows the system
 * to autonomously utilize the CxSR mode. Other factors such as core
 * C-states will affect when/if the system actually enters/exits the
 * CxSR mode.
 *
 * Note that on VLV/CHV this actually only controls the max FIFO mode,
 * and the system is free to enter/exit memory self refresh at any time
 * even when the use of CxSR has been disallowed.
 *
 * While the system is actually in the CxSR/max FIFO mode, some plane
 * control registers will not get latched on vblank. Thus in order to
 * guarantee the system will respond to changes in the plane registers
 * we must always disallow CxSR prior to making changes to those registers.
 * Unfortunately the system will re-evaluate the CxSR conditions at
 * frame start which happens after vblank start (which is when the plane
 * registers would get latched), so we can't proceed with the plane update
 * during the same frame where we disallowed CxSR.
 *
 * Certain platforms also have a deeper HPLL SR mode. Fortunately the
 * HPLL SR mode depends on CxSR itself, so we don't have to hand hold
 * the hardware w.r.t. HPLL SR when writing to plane registers.
 * Disallowing just CxSR is sufficient.
 */
bool intel_set_memory_cxsr(struct drm_i915_private *dev_priv, bool enable)
{
        bool ret;

        mutex_lock(&dev_priv->wm.wm_mutex);
        ret = _intel_set_memory_cxsr(dev_priv, enable);
        if (IS_VALLEYVIEW(dev_priv) || IS_CHERRYVIEW(dev_priv))
                dev_priv->wm.vlv.cxsr = enable;
        else if (IS_G4X(dev_priv))
                dev_priv->wm.g4x.cxsr = enable;
        mutex_unlock(&dev_priv->wm.wm_mutex);

        return ret;
}

/*
 * Latency for FIFO fetches is dependent on several factors:
 *   - memory configuration (speed, channels)
 *   - chipset
 *   - current MCH state
 * It can be fairly high in some situations, so here we assume a fairly
 * pessimal value.  It's a tradeoff between extra memory fetches (if we
 * set this value too high, the FIFO will fetch frequently to stay full)
 * and power consumption (set it too low to save power and we might see
 * FIFO underruns and display "flicker").
 *
 * A value of 5us seems to be a good balance; safe for very low end
 * platforms but not overly aggressive on lower latency configs.
 */
static const int pessimal_latency_ns = 5000;

#define VLV_FIFO_START(dsparb, dsparb2, lo_shift, hi_shift) \
        ((((dsparb) >> (lo_shift)) & 0xff) | ((((dsparb2) >> (hi_shift)) & 0x1) << 8))

static void vlv_get_fifo_size(struct intel_crtc_state *crtc_state)
{
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        struct vlv_fifo_state *fifo_state = &crtc_state->wm.vlv.fifo_state;
        enum pipe pipe = crtc->pipe;
        int sprite0_start, sprite1_start;
        u32 dsparb, dsparb2, dsparb3;

        switch (pipe) {
        case PIPE_A:
                dsparb = intel_uncore_read(&dev_priv->uncore, DSPARB);
                dsparb2 = intel_uncore_read(&dev_priv->uncore, DSPARB2);
                sprite0_start = VLV_FIFO_START(dsparb, dsparb2, 0, 0);
                sprite1_start = VLV_FIFO_START(dsparb, dsparb2, 8, 4);
                break;
        case PIPE_B:
                dsparb = intel_uncore_read(&dev_priv->uncore, DSPARB);
                dsparb2 = intel_uncore_read(&dev_priv->uncore, DSPARB2);
                sprite0_start = VLV_FIFO_START(dsparb, dsparb2, 16, 8);
                sprite1_start = VLV_FIFO_START(dsparb, dsparb2, 24, 12);
                break;
        case PIPE_C:
                dsparb2 = intel_uncore_read(&dev_priv->uncore, DSPARB2);
                dsparb3 = intel_uncore_read(&dev_priv->uncore, DSPARB3);
                sprite0_start = VLV_FIFO_START(dsparb3, dsparb2, 0, 16);
                sprite1_start = VLV_FIFO_START(dsparb3, dsparb2, 8, 20);
                break;
        default:
                MISSING_CASE(pipe);
                return;
        }

        fifo_state->plane[PLANE_PRIMARY] = sprite0_start;
        fifo_state->plane[PLANE_SPRITE0] = sprite1_start - sprite0_start;
        fifo_state->plane[PLANE_SPRITE1] = 511 - sprite1_start;
        fifo_state->plane[PLANE_CURSOR] = 63;
}

static int i9xx_get_fifo_size(struct drm_i915_private *dev_priv,
                              enum i9xx_plane_id i9xx_plane)
{
        u32 dsparb = intel_uncore_read(&dev_priv->uncore, DSPARB);
        int size;

        size = dsparb & 0x7f;
        if (i9xx_plane == PLANE_B)
                size = ((dsparb >> DSPARB_CSTART_SHIFT) & 0x7f) - size;

        drm_dbg_kms(&dev_priv->drm, "FIFO size - (0x%08x) %c: %d\n",
                    dsparb, plane_name(i9xx_plane), size);

        return size;
}

static int i830_get_fifo_size(struct drm_i915_private *dev_priv,
                              enum i9xx_plane_id i9xx_plane)
{
        u32 dsparb = intel_uncore_read(&dev_priv->uncore, DSPARB);
        int size;

        size = dsparb & 0x1ff;
        if (i9xx_plane == PLANE_B)
                size = ((dsparb >> DSPARB_BEND_SHIFT) & 0x1ff) - size;
        size >>= 1; /* Convert to cachelines */

        drm_dbg_kms(&dev_priv->drm, "FIFO size - (0x%08x) %c: %d\n",
                    dsparb, plane_name(i9xx_plane), size);

        return size;
}

static int i845_get_fifo_size(struct drm_i915_private *dev_priv,
                              enum i9xx_plane_id i9xx_plane)
{
        u32 dsparb = intel_uncore_read(&dev_priv->uncore, DSPARB);
        int size;

        size = dsparb & 0x7f;
        size >>= 2; /* Convert to cachelines */

        drm_dbg_kms(&dev_priv->drm, "FIFO size - (0x%08x) %c: %d\n",
                    dsparb, plane_name(i9xx_plane), size);

        return size;
}

/* Pineview has different values for various configs */
static const struct intel_watermark_params pnv_display_wm = {
        .fifo_size = PINEVIEW_DISPLAY_FIFO,
        .max_wm = PINEVIEW_MAX_WM,
        .default_wm = PINEVIEW_DFT_WM,
        .guard_size = PINEVIEW_GUARD_WM,
        .cacheline_size = PINEVIEW_FIFO_LINE_SIZE,
};

static const struct intel_watermark_params pnv_display_hplloff_wm = {
        .fifo_size = PINEVIEW_DISPLAY_FIFO,
        .max_wm = PINEVIEW_MAX_WM,
        .default_wm = PINEVIEW_DFT_HPLLOFF_WM,
        .guard_size = PINEVIEW_GUARD_WM,
        .cacheline_size = PINEVIEW_FIFO_LINE_SIZE,
};

static const struct intel_watermark_params pnv_cursor_wm = {
        .fifo_size = PINEVIEW_CURSOR_FIFO,
        .max_wm = PINEVIEW_CURSOR_MAX_WM,
        .default_wm = PINEVIEW_CURSOR_DFT_WM,
        .guard_size = PINEVIEW_CURSOR_GUARD_WM,
        .cacheline_size = PINEVIEW_FIFO_LINE_SIZE,
};

static const struct intel_watermark_params pnv_cursor_hplloff_wm = {
        .fifo_size = PINEVIEW_CURSOR_FIFO,
        .max_wm = PINEVIEW_CURSOR_MAX_WM,
        .default_wm = PINEVIEW_CURSOR_DFT_WM,
        .guard_size = PINEVIEW_CURSOR_GUARD_WM,
        .cacheline_size = PINEVIEW_FIFO_LINE_SIZE,
};

static const struct intel_watermark_params i965_cursor_wm_info = {
        .fifo_size = I965_CURSOR_FIFO,
        .max_wm = I965_CURSOR_MAX_WM,
        .default_wm = I965_CURSOR_DFT_WM,
        .guard_size = 2,
        .cacheline_size = I915_FIFO_LINE_SIZE,
};

static const struct intel_watermark_params i945_wm_info = {
        .fifo_size = I945_FIFO_SIZE,
        .max_wm = I915_MAX_WM,
        .default_wm = 1,
        .guard_size = 2,
        .cacheline_size = I915_FIFO_LINE_SIZE,
};

static const struct intel_watermark_params i915_wm_info = {
        .fifo_size = I915_FIFO_SIZE,
        .max_wm = I915_MAX_WM,
        .default_wm = 1,
        .guard_size = 2,
        .cacheline_size = I915_FIFO_LINE_SIZE,
};

static const struct intel_watermark_params i830_a_wm_info = {
        .fifo_size = I855GM_FIFO_SIZE,
        .max_wm = I915_MAX_WM,
        .default_wm = 1,
        .guard_size = 2,
        .cacheline_size = I830_FIFO_LINE_SIZE,
};

static const struct intel_watermark_params i830_bc_wm_info = {
        .fifo_size = I855GM_FIFO_SIZE,
        .max_wm = I915_MAX_WM/2,
        .default_wm = 1,
        .guard_size = 2,
        .cacheline_size = I830_FIFO_LINE_SIZE,
};

static const struct intel_watermark_params i845_wm_info = {
        .fifo_size = I830_FIFO_SIZE,
        .max_wm = I915_MAX_WM,
        .default_wm = 1,
        .guard_size = 2,
        .cacheline_size = I830_FIFO_LINE_SIZE,
};

/**
 * intel_wm_method1 - Method 1 / "small buffer" watermark formula
 * @pixel_rate: Pipe pixel rate in kHz
 * @cpp: Plane bytes per pixel
 * @latency: Memory wakeup latency in 0.1us units
 *
 * Compute the watermark using the method 1 or "small buffer"
 * formula. The caller may additonally add extra cachelines
 * to account for TLB misses and clock crossings.
 *
 * This method is concerned with the short term drain rate
 * of the FIFO, ie. it does not account for blanking periods
 * which would effectively reduce the average drain rate across
 * a longer period. The name "small" refers to the fact the
 * FIFO is relatively small compared to the amount of data
 * fetched.
 *
 * The FIFO level vs. time graph might look something like:
 *
 *   |\   |\
 *   | \  | \
 * __---__---__ (- plane active, _ blanking)
 * -> time
 *
 * or perhaps like this:
 *
 *   |\|\  |\|\
 * __----__----__ (- plane active, _ blanking)
 * -> time
 *
 * Returns:
 * The watermark in bytes
 */
static unsigned int intel_wm_method1(unsigned int pixel_rate,
                                     unsigned int cpp,
                                     unsigned int latency)
{
        u64 ret;

        ret = mul_u32_u32(pixel_rate, cpp * latency);
        ret = DIV_ROUND_UP_ULL(ret, 10000);

        return ret;
}

/**
 * intel_wm_method2 - Method 2 / "large buffer" watermark formula
 * @pixel_rate: Pipe pixel rate in kHz
 * @htotal: Pipe horizontal total
 * @width: Plane width in pixels
 * @cpp: Plane bytes per pixel
 * @latency: Memory wakeup latency in 0.1us units
 *
 * Compute the watermark using the method 2 or "large buffer"
 * formula. The caller may additonally add extra cachelines
 * to account for TLB misses and clock crossings.
 *
 * This method is concerned with the long term drain rate
 * of the FIFO, ie. it does account for blanking periods
 * which effectively reduce the average drain rate across
 * a longer period. The name "large" refers to the fact the
 * FIFO is relatively large compared to the amount of data
 * fetched.
 *
 * The FIFO level vs. time graph might look something like:
 *
 *    |\___       |\___
 *    |    \___   |    \___
 *    |        \  |        \
 * __ --__--__--__--__--__--__ (- plane active, _ blanking)
 * -> time
 *
 * Returns:
 * The watermark in bytes
 */
static unsigned int intel_wm_method2(unsigned int pixel_rate,
                                     unsigned int htotal,
                                     unsigned int width,
                                     unsigned int cpp,
                                     unsigned int latency)
{
        unsigned int ret;

        /*
         * FIXME remove once all users are computing
         * watermarks in the correct place.
         */
        if (WARN_ON_ONCE(htotal == 0))
                htotal = 1;

        ret = (latency * pixel_rate) / (htotal * 10000);
        ret = (ret + 1) * width * cpp;

        return ret;
}

/**
 * intel_calculate_wm - calculate watermark level
 * @pixel_rate: pixel clock
 * @wm: chip FIFO params
 * @fifo_size: size of the FIFO buffer
 * @cpp: bytes per pixel
 * @latency_ns: memory latency for the platform
 *
 * Calculate the watermark level (the level at which the display plane will
 * start fetching from memory again).  Each chip has a different display
 * FIFO size and allocation, so the caller needs to figure that out and pass
 * in the correct intel_watermark_params structure.
 *
 * As the pixel clock runs, the FIFO will be drained at a rate that depends
 * on the pixel size.  When it reaches the watermark level, it'll start
 * fetching FIFO line sized based chunks from memory until the FIFO fills
 * past the watermark point.  If the FIFO drains completely, a FIFO underrun
 * will occur, and a display engine hang could result.
 */
static unsigned int intel_calculate_wm(int pixel_rate,
                                       const struct intel_watermark_params *wm,
                                       int fifo_size, int cpp,
                                       unsigned int latency_ns)
{
        int entries, wm_size;

        /*
         * Note: we need to make sure we don't overflow for various clock &
         * latency values.
         * clocks go from a few thousand to several hundred thousand.
         * latency is usually a few thousand
         */
        entries = intel_wm_method1(pixel_rate, cpp,
                                   latency_ns / 100);
        entries = DIV_ROUND_UP(entries, wm->cacheline_size) +
                wm->guard_size;
        DRM_DEBUG_KMS("FIFO entries required for mode: %d\n", entries);

        wm_size = fifo_size - entries;
        DRM_DEBUG_KMS("FIFO watermark level: %d\n", wm_size);

        /* Don't promote wm_size to unsigned... */
        if (wm_size > wm->max_wm)
                wm_size = wm->max_wm;
        if (wm_size <= 0)
                wm_size = wm->default_wm;

        /*
         * Bspec seems to indicate that the value shouldn't be lower than
         * 'burst size + 1'. Certainly 830 is quite unhappy with low values.
         * Lets go for 8 which is the burst size since certain platforms
         * already use a hardcoded 8 (which is what the spec says should be
         * done).
         */
        if (wm_size <= 8)
                wm_size = 8;

        return wm_size;
}

static bool is_disabling(int old, int new, int threshold)
{
        return old >= threshold && new < threshold;
}

static bool is_enabling(int old, int new, int threshold)
{
        return old < threshold && new >= threshold;
}

static int intel_wm_num_levels(struct drm_i915_private *dev_priv)
{
        return dev_priv->wm.max_level + 1;
}

static bool intel_wm_plane_visible(const struct intel_crtc_state *crtc_state,
                                   const struct intel_plane_state *plane_state)
{
        struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);

        /* FIXME check the 'enable' instead */
        if (!crtc_state->hw.active)
                return false;

        /*
         * Treat cursor with fb as always visible since cursor updates
         * can happen faster than the vrefresh rate, and the current
         * watermark code doesn't handle that correctly. Cursor updates
         * which set/clear the fb or change the cursor size are going
         * to get throttled by intel_legacy_cursor_update() to work
         * around this problem with the watermark code.
         */
        if (plane->id == PLANE_CURSOR)
                return plane_state->hw.fb != NULL;
        else
                return plane_state->uapi.visible;
}

static bool intel_crtc_active(struct intel_crtc *crtc)
{
        /* Be paranoid as we can arrive here with only partial
         * state retrieved from the hardware during setup.
         *
         * We can ditch the adjusted_mode.crtc_clock check as soon
         * as Haswell has gained clock readout/fastboot support.
         *
         * We can ditch the crtc->primary->state->fb check as soon as we can
         * properly reconstruct framebuffers.
         *
         * FIXME: The intel_crtc->active here should be switched to
         * crtc->state->active once we have proper CRTC states wired up
         * for atomic.
         */
        return crtc->active && crtc->base.primary->state->fb &&
                crtc->config->hw.adjusted_mode.crtc_clock;
}

static struct intel_crtc *single_enabled_crtc(struct drm_i915_private *dev_priv)
{
        struct intel_crtc *crtc, *enabled = NULL;

        for_each_intel_crtc(&dev_priv->drm, crtc) {
                if (intel_crtc_active(crtc)) {
                        if (enabled)
                                return NULL;
                        enabled = crtc;
                }
        }

        return enabled;
}

static void pnv_update_wm(struct drm_i915_private *dev_priv)
{
        struct intel_crtc *crtc;
        const struct cxsr_latency *latency;
        u32 reg;
        unsigned int wm;

        latency = intel_get_cxsr_latency(!IS_MOBILE(dev_priv),
                                         dev_priv->is_ddr3,
                                         dev_priv->fsb_freq,
                                         dev_priv->mem_freq);
        if (!latency) {
                drm_dbg_kms(&dev_priv->drm,
                            "Unknown FSB/MEM found, disable CxSR\n");
                intel_set_memory_cxsr(dev_priv, false);
                return;
        }

        crtc = single_enabled_crtc(dev_priv);
        if (crtc) {
                const struct drm_display_mode *pipe_mode =
                        &crtc->config->hw.pipe_mode;
                const struct drm_framebuffer *fb =
                        crtc->base.primary->state->fb;
                int cpp = fb->format->cpp[0];
                int clock = pipe_mode->crtc_clock;

                /* Display SR */
                wm = intel_calculate_wm(clock, &pnv_display_wm,
                                        pnv_display_wm.fifo_size,
                                        cpp, latency->display_sr);
                reg = intel_uncore_read(&dev_priv->uncore, DSPFW1);
                reg &= ~DSPFW_SR_MASK;
                reg |= FW_WM(wm, SR);
                intel_uncore_write(&dev_priv->uncore, DSPFW1, reg);
                drm_dbg_kms(&dev_priv->drm, "DSPFW1 register is %x\n", reg);

                /* cursor SR */
                wm = intel_calculate_wm(clock, &pnv_cursor_wm,
                                        pnv_display_wm.fifo_size,
                                        4, latency->cursor_sr);
                reg = intel_uncore_read(&dev_priv->uncore, DSPFW3);
                reg &= ~DSPFW_CURSOR_SR_MASK;
                reg |= FW_WM(wm, CURSOR_SR);
                intel_uncore_write(&dev_priv->uncore, DSPFW3, reg);

                /* Display HPLL off SR */
                wm = intel_calculate_wm(clock, &pnv_display_hplloff_wm,
                                        pnv_display_hplloff_wm.fifo_size,
                                        cpp, latency->display_hpll_disable);
                reg = intel_uncore_read(&dev_priv->uncore, DSPFW3);
                reg &= ~DSPFW_HPLL_SR_MASK;
                reg |= FW_WM(wm, HPLL_SR);
                intel_uncore_write(&dev_priv->uncore, DSPFW3, reg);

                /* cursor HPLL off SR */
                wm = intel_calculate_wm(clock, &pnv_cursor_hplloff_wm,
                                        pnv_display_hplloff_wm.fifo_size,
                                        4, latency->cursor_hpll_disable);
                reg = intel_uncore_read(&dev_priv->uncore, DSPFW3);
                reg &= ~DSPFW_HPLL_CURSOR_MASK;
                reg |= FW_WM(wm, HPLL_CURSOR);
                intel_uncore_write(&dev_priv->uncore, DSPFW3, reg);
                drm_dbg_kms(&dev_priv->drm, "DSPFW3 register is %x\n", reg);

                intel_set_memory_cxsr(dev_priv, true);
        } else {
                intel_set_memory_cxsr(dev_priv, false);
        }
}

/*
 * Documentation says:
 * "If the line size is small, the TLB fetches can get in the way of the
 *  data fetches, causing some lag in the pixel data return which is not
 *  accounted for in the above formulas. The following adjustment only
 *  needs to be applied if eight whole lines fit in the buffer at once.
 *  The WM is adjusted upwards by the difference between the FIFO size
 *  and the size of 8 whole lines. This adjustment is always performed
 *  in the actual pixel depth regardless of whether FBC is enabled or not."
 */
static unsigned int g4x_tlb_miss_wa(int fifo_size, int width, int cpp)
{
        int tlb_miss = fifo_size * 64 - width * cpp * 8;

        return max(0, tlb_miss);
}

static void g4x_write_wm_values(struct drm_i915_private *dev_priv,
                                const struct g4x_wm_values *wm)
{
        enum pipe pipe;

        for_each_pipe(dev_priv, pipe)
                trace_g4x_wm(intel_crtc_for_pipe(dev_priv, pipe), wm);

        intel_uncore_write(&dev_priv->uncore, DSPFW1,
                   FW_WM(wm->sr.plane, SR) |
                   FW_WM(wm->pipe[PIPE_B].plane[PLANE_CURSOR], CURSORB) |
                   FW_WM(wm->pipe[PIPE_B].plane[PLANE_PRIMARY], PLANEB) |
                   FW_WM(wm->pipe[PIPE_A].plane[PLANE_PRIMARY], PLANEA));
        intel_uncore_write(&dev_priv->uncore, DSPFW2,
                   (wm->fbc_en ? DSPFW_FBC_SR_EN : 0) |

                   FW_WM(wm->sr.fbc, FBC_SR) |
                   FW_WM(wm->hpll.fbc, FBC_HPLL_SR) |
                   FW_WM(wm->pipe[PIPE_B].plane[PLANE_SPRITE0], SPRITEB) |
                   FW_WM(wm->pipe[PIPE_A].plane[PLANE_CURSOR], CURSORA) |
                   FW_WM(wm->pipe[PIPE_A].plane[PLANE_SPRITE0], SPRITEA));
        intel_uncore_write(&dev_priv->uncore, DSPFW3,
                   (wm->hpll_en ? DSPFW_HPLL_SR_EN : 0) |
                   FW_WM(wm->sr.cursor, CURSOR_SR) |
                   FW_WM(wm->hpll.cursor, HPLL_CURSOR) |
                   FW_WM(wm->hpll.plane, HPLL_SR));

        intel_uncore_posting_read(&dev_priv->uncore, DSPFW1);
}

#define FW_WM_VLV(value, plane) \
        (((value) << DSPFW_ ## plane ## _SHIFT) & DSPFW_ ## plane ## _MASK_VLV)

static void vlv_write_wm_values(struct drm_i915_private *dev_priv,
                                const struct vlv_wm_values *wm)
{
        enum pipe pipe;

        for_each_pipe(dev_priv, pipe) {
                trace_vlv_wm(intel_crtc_for_pipe(dev_priv, pipe), wm);

                intel_uncore_write(&dev_priv->uncore, VLV_DDL(pipe),
                           (wm->ddl[pipe].plane[PLANE_CURSOR] << DDL_CURSOR_SHIFT) |
                           (wm->ddl[pipe].plane[PLANE_SPRITE1] << DDL_SPRITE_SHIFT(1)) |
                           (wm->ddl[pipe].plane[PLANE_SPRITE0] << DDL_SPRITE_SHIFT(0)) |
                           (wm->ddl[pipe].plane[PLANE_PRIMARY] << DDL_PLANE_SHIFT));
        }

        /*
         * Zero the (unused) WM1 watermarks, and also clear all the
         * high order bits so that there are no out of bounds values
         * present in the registers during the reprogramming.
         */
        intel_uncore_write(&dev_priv->uncore, DSPHOWM, 0);
        intel_uncore_write(&dev_priv->uncore, DSPHOWM1, 0);
        intel_uncore_write(&dev_priv->uncore, DSPFW4, 0);
        intel_uncore_write(&dev_priv->uncore, DSPFW5, 0);
        intel_uncore_write(&dev_priv->uncore, DSPFW6, 0);

        intel_uncore_write(&dev_priv->uncore, DSPFW1,
                   FW_WM(wm->sr.plane, SR) |
                   FW_WM(wm->pipe[PIPE_B].plane[PLANE_CURSOR], CURSORB) |
                   FW_WM_VLV(wm->pipe[PIPE_B].plane[PLANE_PRIMARY], PLANEB) |
                   FW_WM_VLV(wm->pipe[PIPE_A].plane[PLANE_PRIMARY], PLANEA));
        intel_uncore_write(&dev_priv->uncore, DSPFW2,
                   FW_WM_VLV(wm->pipe[PIPE_A].plane[PLANE_SPRITE1], SPRITEB) |
                   FW_WM(wm->pipe[PIPE_A].plane[PLANE_CURSOR], CURSORA) |
                   FW_WM_VLV(wm->pipe[PIPE_A].plane[PLANE_SPRITE0], SPRITEA));
        intel_uncore_write(&dev_priv->uncore, DSPFW3,
                   FW_WM(wm->sr.cursor, CURSOR_SR));

        if (IS_CHERRYVIEW(dev_priv)) {
                intel_uncore_write(&dev_priv->uncore, DSPFW7_CHV,
                           FW_WM_VLV(wm->pipe[PIPE_B].plane[PLANE_SPRITE1], SPRITED) |
                           FW_WM_VLV(wm->pipe[PIPE_B].plane[PLANE_SPRITE0], SPRITEC));
                intel_uncore_write(&dev_priv->uncore, DSPFW8_CHV,
                           FW_WM_VLV(wm->pipe[PIPE_C].plane[PLANE_SPRITE1], SPRITEF) |
                           FW_WM_VLV(wm->pipe[PIPE_C].plane[PLANE_SPRITE0], SPRITEE));
                intel_uncore_write(&dev_priv->uncore, DSPFW9_CHV,
                           FW_WM_VLV(wm->pipe[PIPE_C].plane[PLANE_PRIMARY], PLANEC) |
                           FW_WM(wm->pipe[PIPE_C].plane[PLANE_CURSOR], CURSORC));
                intel_uncore_write(&dev_priv->uncore, DSPHOWM,
                           FW_WM(wm->sr.plane >> 9, SR_HI) |
                           FW_WM(wm->pipe[PIPE_C].plane[PLANE_SPRITE1] >> 8, SPRITEF_HI) |
                           FW_WM(wm->pipe[PIPE_C].plane[PLANE_SPRITE0] >> 8, SPRITEE_HI) |
                           FW_WM(wm->pipe[PIPE_C].plane[PLANE_PRIMARY] >> 8, PLANEC_HI) |
                           FW_WM(wm->pipe[PIPE_B].plane[PLANE_SPRITE1] >> 8, SPRITED_HI) |
                           FW_WM(wm->pipe[PIPE_B].plane[PLANE_SPRITE0] >> 8, SPRITEC_HI) |
                           FW_WM(wm->pipe[PIPE_B].plane[PLANE_PRIMARY] >> 8, PLANEB_HI) |
                           FW_WM(wm->pipe[PIPE_A].plane[PLANE_SPRITE1] >> 8, SPRITEB_HI) |
                           FW_WM(wm->pipe[PIPE_A].plane[PLANE_SPRITE0] >> 8, SPRITEA_HI) |
                           FW_WM(wm->pipe[PIPE_A].plane[PLANE_PRIMARY] >> 8, PLANEA_HI));
        } else {
                intel_uncore_write(&dev_priv->uncore, DSPFW7,
                           FW_WM_VLV(wm->pipe[PIPE_B].plane[PLANE_SPRITE1], SPRITED) |
                           FW_WM_VLV(wm->pipe[PIPE_B].plane[PLANE_SPRITE0], SPRITEC));
                intel_uncore_write(&dev_priv->uncore, DSPHOWM,
                           FW_WM(wm->sr.plane >> 9, SR_HI) |
                           FW_WM(wm->pipe[PIPE_B].plane[PLANE_SPRITE1] >> 8, SPRITED_HI) |
                           FW_WM(wm->pipe[PIPE_B].plane[PLANE_SPRITE0] >> 8, SPRITEC_HI) |
                           FW_WM(wm->pipe[PIPE_B].plane[PLANE_PRIMARY] >> 8, PLANEB_HI) |
                           FW_WM(wm->pipe[PIPE_A].plane[PLANE_SPRITE1] >> 8, SPRITEB_HI) |
                           FW_WM(wm->pipe[PIPE_A].plane[PLANE_SPRITE0] >> 8, SPRITEA_HI) |
                           FW_WM(wm->pipe[PIPE_A].plane[PLANE_PRIMARY] >> 8, PLANEA_HI));
        }

        intel_uncore_posting_read(&dev_priv->uncore, DSPFW1);
}

#undef FW_WM_VLV

static void g4x_setup_wm_latency(struct drm_i915_private *dev_priv)
{
        /* all latencies in usec */
        dev_priv->wm.pri_latency[G4X_WM_LEVEL_NORMAL] = 5;
        dev_priv->wm.pri_latency[G4X_WM_LEVEL_SR] = 12;
        dev_priv->wm.pri_latency[G4X_WM_LEVEL_HPLL] = 35;

        dev_priv->wm.max_level = G4X_WM_LEVEL_HPLL;
}

static int g4x_plane_fifo_size(enum plane_id plane_id, int level)
{
        /*
         * DSPCNTR[13] supposedly controls whether the
         * primary plane can use the FIFO space otherwise
         * reserved for the sprite plane. It's not 100% clear
         * what the actual FIFO size is, but it looks like we
         * can happily set both primary and sprite watermarks
         * up to 127 cachelines. So that would seem to mean
         * that either DSPCNTR[13] doesn't do anything, or that
         * the total FIFO is >= 256 cachelines in size. Either
         * way, we don't seem to have to worry about this
         * repartitioning as the maximum watermark value the
         * register can hold for each plane is lower than the
         * minimum FIFO size.
         */
        switch (plane_id) {
        case PLANE_CURSOR:
                return 63;
        case PLANE_PRIMARY:
                return level == G4X_WM_LEVEL_NORMAL ? 127 : 511;
        case PLANE_SPRITE0:
                return level == G4X_WM_LEVEL_NORMAL ? 127 : 0;
        default:
                MISSING_CASE(plane_id);
                return 0;
        }
}

static int g4x_fbc_fifo_size(int level)
{
        switch (level) {
        case G4X_WM_LEVEL_SR:
                return 7;
        case G4X_WM_LEVEL_HPLL:
                return 15;
        default:
                MISSING_CASE(level);
                return 0;
        }
}

static u16 g4x_compute_wm(const struct intel_crtc_state *crtc_state,
                          const struct intel_plane_state *plane_state,
                          int level)
{
        struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
        struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
        const struct drm_display_mode *pipe_mode =
                &crtc_state->hw.pipe_mode;
        unsigned int latency = dev_priv->wm.pri_latency[level] * 10;
        unsigned int clock, htotal, cpp, width, wm;

        if (latency == 0)
                return USHRT_MAX;

        if (!intel_wm_plane_visible(crtc_state, plane_state))
                return 0;

        cpp = plane_state->hw.fb->format->cpp[0];

        /*
         * WaUse32BppForSRWM:ctg,elk
         *
         * The spec fails to list this restriction for the
         * HPLL watermark, which seems a little strange.
         * Let's use 32bpp for the HPLL watermark as well.
         */
        if (plane->id == PLANE_PRIMARY &&
            level != G4X_WM_LEVEL_NORMAL)
                cpp = max(cpp, 4u);

        clock = pipe_mode->crtc_clock;
        htotal = pipe_mode->crtc_htotal;

        width = drm_rect_width(&plane_state->uapi.dst);

        if (plane->id == PLANE_CURSOR) {
                wm = intel_wm_method2(clock, htotal, width, cpp, latency);
        } else if (plane->id == PLANE_PRIMARY &&
                   level == G4X_WM_LEVEL_NORMAL) {
                wm = intel_wm_method1(clock, cpp, latency);
        } else {
                unsigned int small, large;

                small = intel_wm_method1(clock, cpp, latency);
                large = intel_wm_method2(clock, htotal, width, cpp, latency);

                wm = min(small, large);
        }

        wm += g4x_tlb_miss_wa(g4x_plane_fifo_size(plane->id, level),
                              width, cpp);

        wm = DIV_ROUND_UP(wm, 64) + 2;

        return min_t(unsigned int, wm, USHRT_MAX);
}

static bool g4x_raw_plane_wm_set(struct intel_crtc_state *crtc_state,
                                 int level, enum plane_id plane_id, u16 value)
{
        struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
        bool dirty = false;

        for (; level < intel_wm_num_levels(dev_priv); level++) {
                struct g4x_pipe_wm *raw = &crtc_state->wm.g4x.raw[level];

                dirty |= raw->plane[plane_id] != value;
                raw->plane[plane_id] = value;
        }

        return dirty;
}

static bool g4x_raw_fbc_wm_set(struct intel_crtc_state *crtc_state,
                               int level, u16 value)
{
        struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
        bool dirty = false;

        /* NORMAL level doesn't have an FBC watermark */
        level = max(level, G4X_WM_LEVEL_SR);

        for (; level < intel_wm_num_levels(dev_priv); level++) {
                struct g4x_pipe_wm *raw = &crtc_state->wm.g4x.raw[level];

                dirty |= raw->fbc != value;
                raw->fbc = value;
        }

        return dirty;
}

static u32 ilk_compute_fbc_wm(const struct intel_crtc_state *crtc_state,
                              const struct intel_plane_state *plane_state,
                              u32 pri_val);

static bool g4x_raw_plane_wm_compute(struct intel_crtc_state *crtc_state,
                                     const struct intel_plane_state *plane_state)
{
        struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
        struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
        int num_levels = intel_wm_num_levels(to_i915(plane->base.dev));
        enum plane_id plane_id = plane->id;
        bool dirty = false;
        int level;

        if (!intel_wm_plane_visible(crtc_state, plane_state)) {
                dirty |= g4x_raw_plane_wm_set(crtc_state, 0, plane_id, 0);
                if (plane_id == PLANE_PRIMARY)
                        dirty |= g4x_raw_fbc_wm_set(crtc_state, 0, 0);
                goto out;
        }

        for (level = 0; level < num_levels; level++) {
                struct g4x_pipe_wm *raw = &crtc_state->wm.g4x.raw[level];
                int wm, max_wm;

                wm = g4x_compute_wm(crtc_state, plane_state, level);
                max_wm = g4x_plane_fifo_size(plane_id, level);

                if (wm > max_wm)
                        break;

                dirty |= raw->plane[plane_id] != wm;
                raw->plane[plane_id] = wm;

                if (plane_id != PLANE_PRIMARY ||
                    level == G4X_WM_LEVEL_NORMAL)
                        continue;

                wm = ilk_compute_fbc_wm(crtc_state, plane_state,
                                        raw->plane[plane_id]);
                max_wm = g4x_fbc_fifo_size(level);

                /*
                 * FBC wm is not mandatory as we
                 * can always just disable its use.
                 */
                if (wm > max_wm)
                        wm = USHRT_MAX;

                dirty |= raw->fbc != wm;
                raw->fbc = wm;
        }

        /* mark watermarks as invalid */
        dirty |= g4x_raw_plane_wm_set(crtc_state, level, plane_id, USHRT_MAX);

        if (plane_id == PLANE_PRIMARY)
                dirty |= g4x_raw_fbc_wm_set(crtc_state, level, USHRT_MAX);

 out:
        if (dirty) {
                drm_dbg_kms(&dev_priv->drm,
                            "%s watermarks: normal=%d, SR=%d, HPLL=%d\n",
                            plane->base.name,
                            crtc_state->wm.g4x.raw[G4X_WM_LEVEL_NORMAL].plane[plane_id],
                            crtc_state->wm.g4x.raw[G4X_WM_LEVEL_SR].plane[plane_id],
                            crtc_state->wm.g4x.raw[G4X_WM_LEVEL_HPLL].plane[plane_id]);

                if (plane_id == PLANE_PRIMARY)
                        drm_dbg_kms(&dev_priv->drm,
                                    "FBC watermarks: SR=%d, HPLL=%d\n",
                                    crtc_state->wm.g4x.raw[G4X_WM_LEVEL_SR].fbc,
                                    crtc_state->wm.g4x.raw[G4X_WM_LEVEL_HPLL].fbc);
        }

        return dirty;
}

static bool g4x_raw_plane_wm_is_valid(const struct intel_crtc_state *crtc_state,
                                      enum plane_id plane_id, int level)
{
        const struct g4x_pipe_wm *raw = &crtc_state->wm.g4x.raw[level];

        return raw->plane[plane_id] <= g4x_plane_fifo_size(plane_id, level);
}

static bool g4x_raw_crtc_wm_is_valid(const struct intel_crtc_state *crtc_state,
                                     int level)
{
        struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);

        if (level > dev_priv->wm.max_level)
                return false;

        return g4x_raw_plane_wm_is_valid(crtc_state, PLANE_PRIMARY, level) &&
                g4x_raw_plane_wm_is_valid(crtc_state, PLANE_SPRITE0, level) &&
                g4x_raw_plane_wm_is_valid(crtc_state, PLANE_CURSOR, level);
}

/* mark all levels starting from 'level' as invalid */
static void g4x_invalidate_wms(struct intel_crtc *crtc,
                               struct g4x_wm_state *wm_state, int level)
{
        if (level <= G4X_WM_LEVEL_NORMAL) {
                enum plane_id plane_id;

                for_each_plane_id_on_crtc(crtc, plane_id)
                        wm_state->wm.plane[plane_id] = USHRT_MAX;
        }

        if (level <= G4X_WM_LEVEL_SR) {
                wm_state->cxsr = false;
                wm_state->sr.cursor = USHRT_MAX;
                wm_state->sr.plane = USHRT_MAX;
                wm_state->sr.fbc = USHRT_MAX;
        }

        if (level <= G4X_WM_LEVEL_HPLL) {
                wm_state->hpll_en = false;
                wm_state->hpll.cursor = USHRT_MAX;
                wm_state->hpll.plane = USHRT_MAX;
                wm_state->hpll.fbc = USHRT_MAX;
        }
}

static bool g4x_compute_fbc_en(const struct g4x_wm_state *wm_state,
                               int level)
{
        if (level < G4X_WM_LEVEL_SR)
                return false;

        if (level >= G4X_WM_LEVEL_SR &&
            wm_state->sr.fbc > g4x_fbc_fifo_size(G4X_WM_LEVEL_SR))
                return false;

        if (level >= G4X_WM_LEVEL_HPLL &&
            wm_state->hpll.fbc > g4x_fbc_fifo_size(G4X_WM_LEVEL_HPLL))
                return false;

        return true;
}

static int g4x_compute_pipe_wm(struct intel_atomic_state *state,
                               struct intel_crtc *crtc)
{
        struct intel_crtc_state *crtc_state =
                intel_atomic_get_new_crtc_state(state, crtc);
        struct g4x_wm_state *wm_state = &crtc_state->wm.g4x.optimal;
        u8 active_planes = crtc_state->active_planes & ~BIT(PLANE_CURSOR);
        const struct g4x_pipe_wm *raw;
        const struct intel_plane_state *old_plane_state;
        const struct intel_plane_state *new_plane_state;
        struct intel_plane *plane;
        enum plane_id plane_id;
        int i, level;
        unsigned int dirty = 0;

        for_each_oldnew_intel_plane_in_state(state, plane,
                                             old_plane_state,
                                             new_plane_state, i) {
                if (new_plane_state->hw.crtc != &crtc->base &&
                    old_plane_state->hw.crtc != &crtc->base)
                        continue;

                if (g4x_raw_plane_wm_compute(crtc_state, new_plane_state))
                        dirty |= BIT(plane->id);
        }

        if (!dirty)
                return 0;

        level = G4X_WM_LEVEL_NORMAL;
        if (!g4x_raw_crtc_wm_is_valid(crtc_state, level))
                goto out;

        raw = &crtc_state->wm.g4x.raw[level];
        for_each_plane_id_on_crtc(crtc, plane_id)
                wm_state->wm.plane[plane_id] = raw->plane[plane_id];

        level = G4X_WM_LEVEL_SR;
        if (!g4x_raw_crtc_wm_is_valid(crtc_state, level))
                goto out;

        raw = &crtc_state->wm.g4x.raw[level];
        wm_state->sr.plane = raw->plane[PLANE_PRIMARY];
        wm_state->sr.cursor = raw->plane[PLANE_CURSOR];
        wm_state->sr.fbc = raw->fbc;

        wm_state->cxsr = active_planes == BIT(PLANE_PRIMARY);

        level = G4X_WM_LEVEL_HPLL;
        if (!g4x_raw_crtc_wm_is_valid(crtc_state, level))
                goto out;

        raw = &crtc_state->wm.g4x.raw[level];
        wm_state->hpll.plane = raw->plane[PLANE_PRIMARY];
        wm_state->hpll.cursor = raw->plane[PLANE_CURSOR];
        wm_state->hpll.fbc = raw->fbc;

        wm_state->hpll_en = wm_state->cxsr;

        level++;

 out:
        if (level == G4X_WM_LEVEL_NORMAL)
                return -EINVAL;

        /* invalidate the higher levels */
        g4x_invalidate_wms(crtc, wm_state, level);

        /*
         * Determine if the FBC watermark(s) can be used. IF
         * this isn't the case we prefer to disable the FBC
         * watermark(s) rather than disable the SR/HPLL
         * level(s) entirely. 'level-1' is the highest valid
         * level here.
         */
        wm_state->fbc_en = g4x_compute_fbc_en(wm_state, level - 1);

        return 0;
}

static int g4x_compute_intermediate_wm(struct intel_atomic_state *state,
                                       struct intel_crtc *crtc)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        struct intel_crtc_state *new_crtc_state =
                intel_atomic_get_new_crtc_state(state, crtc);
        const struct intel_crtc_state *old_crtc_state =
                intel_atomic_get_old_crtc_state(state, crtc);
        struct g4x_wm_state *intermediate = &new_crtc_state->wm.g4x.intermediate;
        const struct g4x_wm_state *optimal = &new_crtc_state->wm.g4x.optimal;
        const struct g4x_wm_state *active = &old_crtc_state->wm.g4x.optimal;
        enum plane_id plane_id;

        if (!new_crtc_state->hw.active ||
            drm_atomic_crtc_needs_modeset(&new_crtc_state->uapi)) {
                *intermediate = *optimal;

                intermediate->cxsr = false;
                intermediate->hpll_en = false;
                goto out;
        }

        intermediate->cxsr = optimal->cxsr && active->cxsr &&
                !new_crtc_state->disable_cxsr;
        intermediate->hpll_en = optimal->hpll_en && active->hpll_en &&
                !new_crtc_state->disable_cxsr;
        intermediate->fbc_en = optimal->fbc_en && active->fbc_en;

        for_each_plane_id_on_crtc(crtc, plane_id) {
                intermediate->wm.plane[plane_id] =
                        max(optimal->wm.plane[plane_id],
                            active->wm.plane[plane_id]);

                drm_WARN_ON(&dev_priv->drm, intermediate->wm.plane[plane_id] >
                            g4x_plane_fifo_size(plane_id, G4X_WM_LEVEL_NORMAL));
        }

        intermediate->sr.plane = max(optimal->sr.plane,
                                     active->sr.plane);
        intermediate->sr.cursor = max(optimal->sr.cursor,
                                      active->sr.cursor);
        intermediate->sr.fbc = max(optimal->sr.fbc,
                                   active->sr.fbc);

        intermediate->hpll.plane = max(optimal->hpll.plane,
                                       active->hpll.plane);
        intermediate->hpll.cursor = max(optimal->hpll.cursor,
                                        active->hpll.cursor);
        intermediate->hpll.fbc = max(optimal->hpll.fbc,
                                     active->hpll.fbc);

        drm_WARN_ON(&dev_priv->drm,
                    (intermediate->sr.plane >
                     g4x_plane_fifo_size(PLANE_PRIMARY, G4X_WM_LEVEL_SR) ||
                     intermediate->sr.cursor >
                     g4x_plane_fifo_size(PLANE_CURSOR, G4X_WM_LEVEL_SR)) &&
                    intermediate->cxsr);
        drm_WARN_ON(&dev_priv->drm,
                    (intermediate->sr.plane >
                     g4x_plane_fifo_size(PLANE_PRIMARY, G4X_WM_LEVEL_HPLL) ||
                     intermediate->sr.cursor >
                     g4x_plane_fifo_size(PLANE_CURSOR, G4X_WM_LEVEL_HPLL)) &&
                    intermediate->hpll_en);

        drm_WARN_ON(&dev_priv->drm,
                    intermediate->sr.fbc > g4x_fbc_fifo_size(1) &&
                    intermediate->fbc_en && intermediate->cxsr);
        drm_WARN_ON(&dev_priv->drm,
                    intermediate->hpll.fbc > g4x_fbc_fifo_size(2) &&
                    intermediate->fbc_en && intermediate->hpll_en);

out:
        /*
         * If our intermediate WM are identical to the final WM, then we can
         * omit the post-vblank programming; only update if it's different.
         */
        if (memcmp(intermediate, optimal, sizeof(*intermediate)) != 0)
                new_crtc_state->wm.need_postvbl_update = true;

        return 0;
}

static void g4x_merge_wm(struct drm_i915_private *dev_priv,
                         struct g4x_wm_values *wm)
{
        struct intel_crtc *crtc;
        int num_active_pipes = 0;

        wm->cxsr = true;
        wm->hpll_en = true;
        wm->fbc_en = true;

        for_each_intel_crtc(&dev_priv->drm, crtc) {
                const struct g4x_wm_state *wm_state = &crtc->wm.active.g4x;

                if (!crtc->active)
                        continue;

                if (!wm_state->cxsr)
                        wm->cxsr = false;
                if (!wm_state->hpll_en)
                        wm->hpll_en = false;
                if (!wm_state->fbc_en)
                        wm->fbc_en = false;

                num_active_pipes++;
        }

        if (num_active_pipes != 1) {
                wm->cxsr = false;
                wm->hpll_en = false;
                wm->fbc_en = false;
        }

        for_each_intel_crtc(&dev_priv->drm, crtc) {
                const struct g4x_wm_state *wm_state = &crtc->wm.active.g4x;
                enum pipe pipe = crtc->pipe;

                wm->pipe[pipe] = wm_state->wm;
                if (crtc->active && wm->cxsr)
                        wm->sr = wm_state->sr;
                if (crtc->active && wm->hpll_en)
                        wm->hpll = wm_state->hpll;
        }
}

static void g4x_program_watermarks(struct drm_i915_private *dev_priv)
{
        struct g4x_wm_values *old_wm = &dev_priv->wm.g4x;
        struct g4x_wm_values new_wm = {};

        g4x_merge_wm(dev_priv, &new_wm);

        if (memcmp(old_wm, &new_wm, sizeof(new_wm)) == 0)
                return;

        if (is_disabling(old_wm->cxsr, new_wm.cxsr, true))
                _intel_set_memory_cxsr(dev_priv, false);

        g4x_write_wm_values(dev_priv, &new_wm);

        if (is_enabling(old_wm->cxsr, new_wm.cxsr, true))
                _intel_set_memory_cxsr(dev_priv, true);

        *old_wm = new_wm;
}

static void g4x_initial_watermarks(struct intel_atomic_state *state,
                                   struct intel_crtc *crtc)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        const struct intel_crtc_state *crtc_state =
                intel_atomic_get_new_crtc_state(state, crtc);

        mutex_lock(&dev_priv->wm.wm_mutex);
        crtc->wm.active.g4x = crtc_state->wm.g4x.intermediate;
        g4x_program_watermarks(dev_priv);
        mutex_unlock(&dev_priv->wm.wm_mutex);
}

static void g4x_optimize_watermarks(struct intel_atomic_state *state,
                                    struct intel_crtc *crtc)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        const struct intel_crtc_state *crtc_state =
                intel_atomic_get_new_crtc_state(state, crtc);

        if (!crtc_state->wm.need_postvbl_update)
                return;

        mutex_lock(&dev_priv->wm.wm_mutex);
        crtc->wm.active.g4x = crtc_state->wm.g4x.optimal;
        g4x_program_watermarks(dev_priv);
        mutex_unlock(&dev_priv->wm.wm_mutex);
}

/* latency must be in 0.1us units. */
static unsigned int vlv_wm_method2(unsigned int pixel_rate,
                                   unsigned int htotal,
                                   unsigned int width,
                                   unsigned int cpp,
                                   unsigned int latency)
{
        unsigned int ret;

        ret = intel_wm_method2(pixel_rate, htotal,
                               width, cpp, latency);
        ret = DIV_ROUND_UP(ret, 64);

        return ret;
}

static void vlv_setup_wm_latency(struct drm_i915_private *dev_priv)
{
        /* all latencies in usec */
        dev_priv->wm.pri_latency[VLV_WM_LEVEL_PM2] = 3;

        dev_priv->wm.max_level = VLV_WM_LEVEL_PM2;

        if (IS_CHERRYVIEW(dev_priv)) {
                dev_priv->wm.pri_latency[VLV_WM_LEVEL_PM5] = 12;
                dev_priv->wm.pri_latency[VLV_WM_LEVEL_DDR_DVFS] = 33;

                dev_priv->wm.max_level = VLV_WM_LEVEL_DDR_DVFS;
        }
}

static u16 vlv_compute_wm_level(const struct intel_crtc_state *crtc_state,
                                const struct intel_plane_state *plane_state,
                                int level)
{
        struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
        struct drm_i915_private *dev_priv = to_i915(plane->base.dev);
        const struct drm_display_mode *pipe_mode =
                &crtc_state->hw.pipe_mode;
        unsigned int clock, htotal, cpp, width, wm;

        if (dev_priv->wm.pri_latency[level] == 0)
                return USHRT_MAX;

        if (!intel_wm_plane_visible(crtc_state, plane_state))
                return 0;

        cpp = plane_state->hw.fb->format->cpp[0];
        clock = pipe_mode->crtc_clock;
        htotal = pipe_mode->crtc_htotal;
        width = crtc_state->pipe_src_w;

        if (plane->id == PLANE_CURSOR) {
                /*
                 * FIXME the formula gives values that are
                 * too big for the cursor FIFO, and hence we
                 * would never be able to use cursors. For
                 * now just hardcode the watermark.
                 */
                wm = 63;
        } else {
                wm = vlv_wm_method2(clock, htotal, width, cpp,
                                    dev_priv->wm.pri_latency[level] * 10);
        }

        return min_t(unsigned int, wm, USHRT_MAX);
}

static bool vlv_need_sprite0_fifo_workaround(unsigned int active_planes)
{
        return (active_planes & (BIT(PLANE_SPRITE0) |
                                 BIT(PLANE_SPRITE1))) == BIT(PLANE_SPRITE1);
}

static int vlv_compute_fifo(struct intel_crtc_state *crtc_state)
{
        struct intel_crtc *crtc = to_intel_crtc(crtc_state->uapi.crtc);
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        const struct g4x_pipe_wm *raw =
                &crtc_state->wm.vlv.raw[VLV_WM_LEVEL_PM2];
        struct vlv_fifo_state *fifo_state = &crtc_state->wm.vlv.fifo_state;
        u8 active_planes = crtc_state->active_planes & ~BIT(PLANE_CURSOR);
        int num_active_planes = hweight8(active_planes);
        const int fifo_size = 511;
        int fifo_extra, fifo_left = fifo_size;
        int sprite0_fifo_extra = 0;
        unsigned int total_rate;
        enum plane_id plane_id;

        /*
         * When enabling sprite0 after sprite1 has already been enabled
         * we tend to get an underrun unless sprite0 already has some
         * FIFO space allcoated. Hence we always allocate at least one
         * cacheline for sprite0 whenever sprite1 is enabled.
         *
         * All other plane enable sequences appear immune to this problem.
         */
        if (vlv_need_sprite0_fifo_workaround(active_planes))
                sprite0_fifo_extra = 1;

        total_rate = raw->plane[PLANE_PRIMARY] +
                raw->plane[PLANE_SPRITE0] +
                raw->plane[PLANE_SPRITE1] +
                sprite0_fifo_extra;

        if (total_rate > fifo_size)
                return -EINVAL;

        if (total_rate == 0)
                total_rate = 1;

        for_each_plane_id_on_crtc(crtc, plane_id) {
                unsigned int rate;

                if ((active_planes & BIT(plane_id)) == 0) {
                        fifo_state->plane[plane_id] = 0;
                        continue;
                }

                rate = raw->plane[plane_id];
                fifo_state->plane[plane_id] = fifo_size * rate / total_rate;
                fifo_left -= fifo_state->plane[plane_id];
        }

        fifo_state->plane[PLANE_SPRITE0] += sprite0_fifo_extra;
        fifo_left -= sprite0_fifo_extra;

        fifo_state->plane[PLANE_CURSOR] = 63;

        fifo_extra = DIV_ROUND_UP(fifo_left, num_active_planes ?: 1);

        /* spread the remainder evenly */
        for_each_plane_id_on_crtc(crtc, plane_id) {
                int plane_extra;

                if (fifo_left == 0)
                        break;

                if ((active_planes & BIT(plane_id)) == 0)
                        continue;

                plane_extra = min(fifo_extra, fifo_left);
                fifo_state->plane[plane_id] += plane_extra;
                fifo_left -= plane_extra;
        }

        drm_WARN_ON(&dev_priv->drm, active_planes != 0 && fifo_left != 0);

        /* give it all to the first plane if none are active */
        if (active_planes == 0) {
                drm_WARN_ON(&dev_priv->drm, fifo_left != fifo_size);
                fifo_state->plane[PLANE_PRIMARY] = fifo_left;
        }

        return 0;
}

/* mark all levels starting from 'level' as invalid */
static void vlv_invalidate_wms(struct intel_crtc *crtc,
                               struct vlv_wm_state *wm_state, int level)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);

        for (; level < intel_wm_num_levels(dev_priv); level++) {
                enum plane_id plane_id;

                for_each_plane_id_on_crtc(crtc, plane_id)
                        wm_state->wm[level].plane[plane_id] = USHRT_MAX;

                wm_state->sr[level].cursor = USHRT_MAX;
                wm_state->sr[level].plane = USHRT_MAX;
        }
}

static u16 vlv_invert_wm_value(u16 wm, u16 fifo_size)
{
        if (wm > fifo_size)
                return USHRT_MAX;
        else
                return fifo_size - wm;
}

/*
 * Starting from 'level' set all higher
 * levels to 'value' in the "raw" watermarks.
 */
static bool vlv_raw_plane_wm_set(struct intel_crtc_state *crtc_state,
                                 int level, enum plane_id plane_id, u16 value)
{
        struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
        int num_levels = intel_wm_num_levels(dev_priv);
        bool dirty = false;

        for (; level < num_levels; level++) {
                struct g4x_pipe_wm *raw = &crtc_state->wm.vlv.raw[level];

                dirty |= raw->plane[plane_id] != value;
                raw->plane[plane_id] = value;
        }

        return dirty;
}

static bool vlv_raw_plane_wm_compute(struct intel_crtc_state *crtc_state,
                                     const struct intel_plane_state *plane_state)
{
        struct intel_plane *plane = to_intel_plane(plane_state->uapi.plane);
        struct drm_i915_private *dev_priv = to_i915(crtc_state->uapi.crtc->dev);
        enum plane_id plane_id = plane->id;
        int num_levels = intel_wm_num_levels(to_i915(plane->base.dev));
        int level;
        bool dirty = false;

        if (!intel_wm_plane_visible(crtc_state, plane_state)) {
                dirty |= vlv_raw_plane_wm_set(crtc_state, 0, plane_id, 0);
                goto out;
        }

        for (level = 0; level < num_levels; level++) {
                struct g4x_pipe_wm *raw = &crtc_state->wm.vlv.raw[level];
                int wm = vlv_compute_wm_level(crtc_state, plane_state, level);
                int max_wm = plane_id == PLANE_CURSOR ? 63 : 511;

                if (wm > max_wm)
                        break;

                dirty |= raw->plane[plane_id] != wm;
                raw->plane[plane_id] = wm;
        }

        /* mark all higher levels as invalid */
        dirty |= vlv_raw_plane_wm_set(crtc_state, level, plane_id, USHRT_MAX);

out:
        if (dirty)
                drm_dbg_kms(&dev_priv->drm,
                            "%s watermarks: PM2=%d, PM5=%d, DDR DVFS=%d\n",
                            plane->base.name,
                            crtc_state->wm.vlv.raw[VLV_WM_LEVEL_PM2].plane[plane_id],
                            crtc_state->wm.vlv.raw[VLV_WM_LEVEL_PM5].plane[plane_id],
                            crtc_state->wm.vlv.raw[VLV_WM_LEVEL_DDR_DVFS].plane[plane_id]);

        return dirty;
}

static bool vlv_raw_plane_wm_is_valid(const struct intel_crtc_state *crtc_state,
                                      enum plane_id plane_id, int level)
{
        const struct g4x_pipe_wm *raw =
                &crtc_state->wm.vlv.raw[level];
        const struct vlv_fifo_state *fifo_state =
                &crtc_state->wm.vlv.fifo_state;

        return raw->plane[plane_id] <= fifo_state->plane[plane_id];
}

static bool vlv_raw_crtc_wm_is_valid(const struct intel_crtc_state *crtc_state, int level)
{
        return vlv_raw_plane_wm_is_valid(crtc_state, PLANE_PRIMARY, level) &&
                vlv_raw_plane_wm_is_valid(crtc_state, PLANE_SPRITE0, level) &&
                vlv_raw_plane_wm_is_valid(crtc_state, PLANE_SPRITE1, level) &&
                vlv_raw_plane_wm_is_valid(crtc_state, PLANE_CURSOR, level);
}

static int vlv_compute_pipe_wm(struct intel_atomic_state *state,
                               struct intel_crtc *crtc)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        struct intel_crtc_state *crtc_state =
                intel_atomic_get_new_crtc_state(state, crtc);
        struct vlv_wm_state *wm_state = &crtc_state->wm.vlv.optimal;
        const struct vlv_fifo_state *fifo_state =
                &crtc_state->wm.vlv.fifo_state;
        u8 active_planes = crtc_state->active_planes & ~BIT(PLANE_CURSOR);
        int num_active_planes = hweight8(active_planes);
        bool needs_modeset = drm_atomic_crtc_needs_modeset(&crtc_state->uapi);
        const struct intel_plane_state *old_plane_state;
        const struct intel_plane_state *new_plane_state;
        struct intel_plane *plane;
        enum plane_id plane_id;
        int level, ret, i;
        unsigned int dirty = 0;

        for_each_oldnew_intel_plane_in_state(state, plane,
                                             old_plane_state,
                                             new_plane_state, i) {
                if (new_plane_state->hw.crtc != &crtc->base &&
                    old_plane_state->hw.crtc != &crtc->base)
                        continue;

                if (vlv_raw_plane_wm_compute(crtc_state, new_plane_state))
                        dirty |= BIT(plane->id);
        }

        /*
         * DSPARB registers may have been reset due to the
         * power well being turned off. Make sure we restore
         * them to a consistent state even if no primary/sprite
         * planes are initially active.
         */
        if (needs_modeset)
                crtc_state->fifo_changed = true;

        if (!dirty)
                return 0;

        /* cursor changes don't warrant a FIFO recompute */
        if (dirty & ~BIT(PLANE_CURSOR)) {
                const struct intel_crtc_state *old_crtc_state =
                        intel_atomic_get_old_crtc_state(state, crtc);
                const struct vlv_fifo_state *old_fifo_state =
                        &old_crtc_state->wm.vlv.fifo_state;

                ret = vlv_compute_fifo(crtc_state);
                if (ret)
                        return ret;

                if (needs_modeset ||
                    memcmp(old_fifo_state, fifo_state,
                           sizeof(*fifo_state)) != 0)
                        crtc_state->fifo_changed = true;
        }

        /* initially allow all levels */
        wm_state->num_levels = intel_wm_num_levels(dev_priv);
        /*
         * Note that enabling cxsr with no primary/sprite planes
         * enabled can wedge the pipe. Hence we only allow cxsr
         * with exactly one enabled primary/sprite plane.
         */
        wm_state->cxsr = crtc->pipe != PIPE_C && num_active_planes == 1;

        for (level = 0; level < wm_state->num_levels; level++) {
                const struct g4x_pipe_wm *raw = &crtc_state->wm.vlv.raw[level];
                const int sr_fifo_size = INTEL_NUM_PIPES(dev_priv) * 512 - 1;

                if (!vlv_raw_crtc_wm_is_valid(crtc_state, level))
                        break;

                for_each_plane_id_on_crtc(crtc, plane_id) {
                        wm_state->wm[level].plane[plane_id] =
                                vlv_invert_wm_value(raw->plane[plane_id],
                                                    fifo_state->plane[plane_id]);
                }

                wm_state->sr[level].plane =
                        vlv_invert_wm_value(max3(raw->plane[PLANE_PRIMARY],
                                                 raw->plane[PLANE_SPRITE0],
                                                 raw->plane[PLANE_SPRITE1]),
                                            sr_fifo_size);

                wm_state->sr[level].cursor =
                        vlv_invert_wm_value(raw->plane[PLANE_CURSOR],
                                            63);
        }

        if (level == 0)
                return -EINVAL;

        /* limit to only levels we can actually handle */
        wm_state->num_levels = level;

        /* invalidate the higher levels */

        vlv_invalidate_wms(crtc, wm_state, level);

        return 0;
}

#define VLV_FIFO(plane, value) \
        (((value) << DSPARB_ ## plane ## _SHIFT_VLV) & DSPARB_ ## plane ## _MASK_VLV)

static void vlv_atomic_update_fifo(struct intel_atomic_state *state,
                                   struct intel_crtc *crtc)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        struct intel_uncore *uncore = &dev_priv->uncore;
        const struct intel_crtc_state *crtc_state =
                intel_atomic_get_new_crtc_state(state, crtc);
        const struct vlv_fifo_state *fifo_state =
                &crtc_state->wm.vlv.fifo_state;
        int sprite0_start, sprite1_start, fifo_size;
        u32 dsparb, dsparb2, dsparb3;

        if (!crtc_state->fifo_changed)
                return;

        sprite0_start = fifo_state->plane[PLANE_PRIMARY];
        sprite1_start = fifo_state->plane[PLANE_SPRITE0] + sprite0_start;
        fifo_size = fifo_state->plane[PLANE_SPRITE1] + sprite1_start;

        drm_WARN_ON(&dev_priv->drm, fifo_state->plane[PLANE_CURSOR] != 63);
        drm_WARN_ON(&dev_priv->drm, fifo_size != 511);

        trace_vlv_fifo_size(crtc, sprite0_start, sprite1_start, fifo_size);

        /*
         * uncore.lock serves a double purpose here. It allows us to
         * use the less expensive I915_{READ,WRITE}_FW() functions, and
         * it protects the DSPARB registers from getting clobbered by
         * parallel updates from multiple pipes.
         *
         * intel_pipe_update_start() has already disabled interrupts
         * for us, so a plain spin_lock() is sufficient here.
         */
        spin_lock(&uncore->lock);

        switch (crtc->pipe) {
        case PIPE_A:
                dsparb = intel_uncore_read_fw(uncore, DSPARB);
                dsparb2 = intel_uncore_read_fw(uncore, DSPARB2);

                dsparb &= ~(VLV_FIFO(SPRITEA, 0xff) |
                            VLV_FIFO(SPRITEB, 0xff));
                dsparb |= (VLV_FIFO(SPRITEA, sprite0_start) |
                           VLV_FIFO(SPRITEB, sprite1_start));

                dsparb2 &= ~(VLV_FIFO(SPRITEA_HI, 0x1) |
                             VLV_FIFO(SPRITEB_HI, 0x1));
                dsparb2 |= (VLV_FIFO(SPRITEA_HI, sprite0_start >> 8) |
                           VLV_FIFO(SPRITEB_HI, sprite1_start >> 8));

                intel_uncore_write_fw(uncore, DSPARB, dsparb);
                intel_uncore_write_fw(uncore, DSPARB2, dsparb2);
                break;
        case PIPE_B:
                dsparb = intel_uncore_read_fw(uncore, DSPARB);
                dsparb2 = intel_uncore_read_fw(uncore, DSPARB2);

                dsparb &= ~(VLV_FIFO(SPRITEC, 0xff) |
                            VLV_FIFO(SPRITED, 0xff));
                dsparb |= (VLV_FIFO(SPRITEC, sprite0_start) |
                           VLV_FIFO(SPRITED, sprite1_start));

                dsparb2 &= ~(VLV_FIFO(SPRITEC_HI, 0xff) |
                             VLV_FIFO(SPRITED_HI, 0xff));
                dsparb2 |= (VLV_FIFO(SPRITEC_HI, sprite0_start >> 8) |
                           VLV_FIFO(SPRITED_HI, sprite1_start >> 8));

                intel_uncore_write_fw(uncore, DSPARB, dsparb);
                intel_uncore_write_fw(uncore, DSPARB2, dsparb2);
                break;
        case PIPE_C:
                dsparb3 = intel_uncore_read_fw(uncore, DSPARB3);
                dsparb2 = intel_uncore_read_fw(uncore, DSPARB2);

                dsparb3 &= ~(VLV_FIFO(SPRITEE, 0xff) |
                             VLV_FIFO(SPRITEF, 0xff));
                dsparb3 |= (VLV_FIFO(SPRITEE, sprite0_start) |
                            VLV_FIFO(SPRITEF, sprite1_start));

                dsparb2 &= ~(VLV_FIFO(SPRITEE_HI, 0xff) |
                             VLV_FIFO(SPRITEF_HI, 0xff));
                dsparb2 |= (VLV_FIFO(SPRITEE_HI, sprite0_start >> 8) |
                           VLV_FIFO(SPRITEF_HI, sprite1_start >> 8));

                intel_uncore_write_fw(uncore, DSPARB3, dsparb3);
                intel_uncore_write_fw(uncore, DSPARB2, dsparb2);
                break;
        default:
                break;
        }

        intel_uncore_posting_read_fw(uncore, DSPARB);

        spin_unlock(&uncore->lock);
}

#undef VLV_FIFO

static int vlv_compute_intermediate_wm(struct intel_atomic_state *state,
                                       struct intel_crtc *crtc)
{
        struct intel_crtc_state *new_crtc_state =
                intel_atomic_get_new_crtc_state(state, crtc);
        const struct intel_crtc_state *old_crtc_state =
                intel_atomic_get_old_crtc_state(state, crtc);
        struct vlv_wm_state *intermediate = &new_crtc_state->wm.vlv.intermediate;
        const struct vlv_wm_state *optimal = &new_crtc_state->wm.vlv.optimal;
        const struct vlv_wm_state *active = &old_crtc_state->wm.vlv.optimal;
        int level;

        if (!new_crtc_state->hw.active ||
            drm_atomic_crtc_needs_modeset(&new_crtc_state->uapi)) {
                *intermediate = *optimal;

                intermediate->cxsr = false;
                goto out;
        }

        intermediate->num_levels = min(optimal->num_levels, active->num_levels);
        intermediate->cxsr = optimal->cxsr && active->cxsr &&
                !new_crtc_state->disable_cxsr;

        for (level = 0; level < intermediate->num_levels; level++) {
                enum plane_id plane_id;

                for_each_plane_id_on_crtc(crtc, plane_id) {
                        intermediate->wm[level].plane[plane_id] =
                                min(optimal->wm[level].plane[plane_id],
                                    active->wm[level].plane[plane_id]);
                }

                intermediate->sr[level].plane = min(optimal->sr[level].plane,
                                                    active->sr[level].plane);
                intermediate->sr[level].cursor = min(optimal->sr[level].cursor,
                                                     active->sr[level].cursor);
        }

        vlv_invalidate_wms(crtc, intermediate, level);

out:
        /*
         * If our intermediate WM are identical to the final WM, then we can
         * omit the post-vblank programming; only update if it's different.
         */
        if (memcmp(intermediate, optimal, sizeof(*intermediate)) != 0)
                new_crtc_state->wm.need_postvbl_update = true;

        return 0;
}

static void vlv_merge_wm(struct drm_i915_private *dev_priv,
                         struct vlv_wm_values *wm)
{
        struct intel_crtc *crtc;
        int num_active_pipes = 0;

        wm->level = dev_priv->wm.max_level;
        wm->cxsr = true;

        for_each_intel_crtc(&dev_priv->drm, crtc) {
                const struct vlv_wm_state *wm_state = &crtc->wm.active.vlv;

                if (!crtc->active)
                        continue;

                if (!wm_state->cxsr)
                        wm->cxsr = false;

                num_active_pipes++;
                wm->level = min_t(int, wm->level, wm_state->num_levels - 1);
        }

        if (num_active_pipes != 1)
                wm->cxsr = false;

        if (num_active_pipes > 1)
                wm->level = VLV_WM_LEVEL_PM2;

        for_each_intel_crtc(&dev_priv->drm, crtc) {
                const struct vlv_wm_state *wm_state = &crtc->wm.active.vlv;
                enum pipe pipe = crtc->pipe;

                wm->pipe[pipe] = wm_state->wm[wm->level];
                if (crtc->active && wm->cxsr)
                        wm->sr = wm_state->sr[wm->level];

                wm->ddl[pipe].plane[PLANE_PRIMARY] = DDL_PRECISION_HIGH | 2;
                wm->ddl[pipe].plane[PLANE_SPRITE0] = DDL_PRECISION_HIGH | 2;
                wm->ddl[pipe].plane[PLANE_SPRITE1] = DDL_PRECISION_HIGH | 2;
                wm->ddl[pipe].plane[PLANE_CURSOR] = DDL_PRECISION_HIGH | 2;
        }
}

static void vlv_program_watermarks(struct drm_i915_private *dev_priv)
{
        struct vlv_wm_values *old_wm = &dev_priv->wm.vlv;
        struct vlv_wm_values new_wm = {};

        vlv_merge_wm(dev_priv, &new_wm);

        if (memcmp(old_wm, &new_wm, sizeof(new_wm)) == 0)
                return;

        if (is_disabling(old_wm->level, new_wm.level, VLV_WM_LEVEL_DDR_DVFS))
                chv_set_memory_dvfs(dev_priv, false);

        if (is_disabling(old_wm->level, new_wm.level, VLV_WM_LEVEL_PM5))
                chv_set_memory_pm5(dev_priv, false);

        if (is_disabling(old_wm->cxsr, new_wm.cxsr, true))
                _intel_set_memory_cxsr(dev_priv, false);

        vlv_write_wm_values(dev_priv, &new_wm);

        if (is_enabling(old_wm->cxsr, new_wm.cxsr, true))
                _intel_set_memory_cxsr(dev_priv, true);

        if (is_enabling(old_wm->level, new_wm.level, VLV_WM_LEVEL_PM5))
                chv_set_memory_pm5(dev_priv, true);

        if (is_enabling(old_wm->level, new_wm.level, VLV_WM_LEVEL_DDR_DVFS))
                chv_set_memory_dvfs(dev_priv, true);

        *old_wm = new_wm;
}

static void vlv_initial_watermarks(struct intel_atomic_state *state,
                                   struct intel_crtc *crtc)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        const struct intel_crtc_state *crtc_state =
                intel_atomic_get_new_crtc_state(state, crtc);

        mutex_lock(&dev_priv->wm.wm_mutex);
        crtc->wm.active.vlv = crtc_state->wm.vlv.intermediate;
        vlv_program_watermarks(dev_priv);
        mutex_unlock(&dev_priv->wm.wm_mutex);
}

static void vlv_optimize_watermarks(struct intel_atomic_state *state,
                                    struct intel_crtc *crtc)
{
        struct drm_i915_private *dev_priv = to_i915(crtc->base.dev);
        const struct intel_crtc_state *crtc_state =
                intel_atomic_get_new_crtc_state(state, crtc);

        if (!crtc_state->wm.need_postvbl_update)
                return;

        mutex_lock(&dev_priv->wm.wm_mutex);
        crtc->wm.active.vlv = crtc_state->wm.vlv.optimal;
        vlv_program_watermarks(dev_priv);
        mutex_unlock(&dev_priv->wm.wm_mutex);
}

static void i965_update_wm(struct drm_i915_private *dev_priv)
{
        struct intel_crtc *crtc;
        int srwm = 1;
        int cursor_sr = 16;
        bool cxsr_enabled;

        /* Calc sr entries for one plane configs */
        crtc = single_enabled_crtc(dev_priv);
        if (crtc) {
                /* self-refresh has much higher latency */
                static const int sr_latency_ns = 12000;
                const struct drm_display_mode *pipe_mode =
                        &crtc->config->hw.pipe_mode;
                const struct drm_framebuffer *fb =
                        crtc->base.primary->state->fb;
                int clock = pipe_mode->crtc_clock;
                int htotal = pipe_mode->crtc_htotal;
                int hdisplay = crtc->config->pipe_src_w;
                int cpp = fb->format->cpp[0];
                int entries;

                entries = intel_wm_method2(clock, htotal,
                                           hdisplay, cpp, sr_latency_ns / 100);
                entries = DIV_ROUND_UP(entries, I915_FIFO_LINE_SIZE);
                srwm = I965_FIFO_SIZE - entries;
                if (srwm < 0)
                        srwm = 1;
                srwm &= 0x1ff;
                drm_dbg_kms(&dev_priv->drm,
                            "self-refresh entries: %d, wm: %d\n",
                            entries, srwm);

                entries = intel_wm_method2(clock, htotal,
                                           crtc->base.cursor->state->crtc_w, 4,
                                           sr_latency_ns / 100);
                entries = DIV_ROUND_UP(entries,
                                       i965_cursor_wm_info.cacheline_size) +
                        i965_cursor_wm_info.guard_size;

                cursor_sr = i965_cursor_wm_info.fifo_size - entries;
                if (cursor_sr > i965_cursor_wm_info.max_wm)
                        cursor_sr = i965_cursor_wm_info.max_wm;

                drm_dbg_kms(&dev_priv->drm,
                            "self-refresh watermark: display plane %d "
                            "cursor %d\n", srwm, cursor_sr);

                cxsr_enabled = true;
        } else {
                cxsr_enabled = false;
                /* Turn off self refresh if both pipes are enabled */
                intel_set_memory_cxsr(dev_priv, false);
        }

        drm_dbg_kms(&dev_priv->drm,
                    "Setting FIFO watermarks - A: 8, B: 8, C: 8, SR %d\n",
                    srwm);

        /* 965 has limitations... */
        intel_uncore_write(&dev_priv->uncore, DSPFW1, FW_WM(srwm, SR) |
                   FW_WM(8, CURSORB) |
                   FW_WM(8, PLANEB) |
                   FW_WM(8, PLANEA));
        intel_uncore_write(&dev_priv->uncore, DSPFW2, FW_WM(8, CURSORA) |
                   FW_WM(8, PLANEC_OLD));
        /* update cursor SR watermark */
        intel_uncore_write(&dev_priv->uncore, DSPFW3, FW_WM(cursor_sr, CURSOR_SR));

        if (cxsr_enabled)
                intel_set_memory_cxsr(dev_priv, true);
}

#undef FW_WM

static struct intel_crtc *intel_crtc_for_plane(struct drm_i915_private *i915,
                                               enum i9xx_plane_id i9xx_plane)
{
        struct intel_plane *plane;

        for_each_intel_plane(&i915->drm, plane) {
                if (plane->id == PLANE_PRIMARY &&
                    plane->i9xx_plane == i9xx_plane)
                        return intel_crtc_for_pipe(i915, plane->pipe);
        }

        return NULL;
}

static void i9xx_update_wm(struct drm_i915_private *dev_priv)
{
        const struct intel_watermark_params *wm_info;
        u32 fwater_lo;
        u32 fwater_hi;
        int cwm, srwm = 1;
        int fifo_size;
        int planea_wm, planeb_wm;
        struct intel_crtc *crtc, *enabled = NULL;

        if (IS_I945GM(dev_priv))
                wm_info = &i945_wm_info;
        else if (DISPLAY_VER(dev_priv) != 2)
                wm_info = &i915_wm_info;
        else
                wm_info = &i830_a_wm_info;

        if (DISPLAY_VER(dev_priv) == 2)
                fifo_size = i830_get_fifo_size(dev_priv, PLANE_A);
        else
                fifo_size = i9xx_get_fifo_size(dev_priv, PLANE_A);
        crtc = intel_crtc_for_plane(dev_priv, PLANE_A);
        if (intel_crtc_active(crtc)) {
                const struct drm_display_mode *pipe_mode =
                        &crtc->config->hw.pipe_mode;
                const struct drm_framebuffer *fb =
                        crtc->base.primary->state->fb;
                int cpp;

                if (DISPLAY_VER(dev_priv) == 2)
                        cpp = 4;
                else
                        cpp = fb->format->cpp[0];

                planea_wm = intel_calculate_wm(pipe_mode->crtc_clock,
                                               wm_info, fifo_size, cpp,
                                               pessimal_latency_ns);
                enabled = crtc;
        } else {
                planea_wm = fifo_size - wm_info->guard_size;
                if (planea_wm > (long)wm_info->max_wm)
                        planea_wm = wm_info->max_wm;
        }

        if (DISPLAY_VER(dev_priv) == 2)
                wm_info = &i830_bc_wm_info;

        if (DISPLAY_VER(dev_priv) == 2)
                fifo_size = i830_get_fifo_size(dev_priv, PLANE_B);
        else
                fifo_size = i9xx_get_fifo_size(dev_priv, PLANE_B);
        crtc = intel_crtc_for_plane(dev_priv, PLANE_B);
        if (intel_crtc_active(crtc)) {
                const struct drm_display_mode *pipe_mode =
                        &crtc->config->hw.pipe_mode;
                const struct drm_framebuffer *fb =
                        crtc->base.primary->state->fb;
                int cpp;

                if (DISPLAY_VER(dev_priv) == 2)
                        cpp = 4;
                else
                        cpp = fb->format->cpp[0];

                planeb_wm = intel_calculate_wm(pipe_mode->crtc_clock,
                                               wm_info, fifo_size, cpp,
                                               pessimal_latency_ns);
                if (enabled == NULL)
                        enabled = crtc;
                else
                        enabled = NULL;
        } else {
                planeb_wm = fifo_size - wm_info->guard_size;
                if (planeb_wm > (long)wm_info->max_wm)
                        planeb_wm = wm_info->max_wm;
        }

        drm_dbg_kms(&dev_priv->drm,
                    "FIFO watermarks - A: %d, B: %d\n", planea_wm, planeb_wm);

        if (IS_I915GM(dev_priv) && enabled) {
                struct drm_i915_gem_object *obj;

                obj = intel_fb_obj(enabled->base.primary->state->fb);

                /* self-refresh seems busted with untiled */
                if (!i915_gem_object_is_tiled(obj))
                        enabled = NULL;
        }

        /*
         * Overlay gets an aggressive default since video jitter is bad.
         */
        cwm = 2;

        /* Play safe and disable self-refresh before adjusting watermarks. */
        intel_set_memory_cxsr(dev_priv, false);

        /* Calc sr entries for one plane configs */
        if (HAS_FW_BLC(dev_priv) && enabled) {
                /* self-refresh has much higher latency */
                static const int sr_latency_ns = 6000;
                const struct drm_display_mode *pipe_mode =
                        &enabled->config->hw.pipe_mode;
                const struct drm_framebuffer *fb =
                        enabled->base.primary->state->fb;
                int clock = pipe_mode->crtc_clock;
                int htotal = pipe_mode->crtc_htotal;
                int hdisplay = enabled->config->pipe_src_w;
                int cpp;
                int entries;

                if (IS_I915GM(dev_priv) || IS_I945GM(dev_priv))
                        cpp = 4;
                else
                        cpp = fb->format->cpp[0];

                entries = intel_wm_method2(clock, htotal, hdisplay, cpp,
                                           sr_latency_ns / 100);
                entries = DIV_ROUND_UP(entries, wm_info->cacheline_size);
                drm_dbg_kms(&dev_priv->drm,
                            "self-refresh entries: %d\n", entries);
                srwm = wm_info->fifo_size - entries;
                if (srwm < 0)
                        srwm = 1;

                if (IS_I945G(dev_priv) || IS_I945GM(dev_priv))
                        intel_uncore_write(&dev_priv->uncore, FW_BLC_SELF,
                                   FW_BLC_SELF_FIFO_MASK | (srwm & 0xff));
                else
                        intel_uncore_write(&dev_priv->uncore, FW_BLC_SELF, srwm & 0x3f);
        }

        drm_dbg_kms(&dev_priv->drm,
                    "Setting FIFO watermarks - A: %d, B: %d, C: %d, SR %d\n",
                     planea_wm, planeb_wm, cwm, srwm);

        fwater_lo = ((planeb_wm & 0x3f) << 16) | (planea_wm & 0x3f);
        fwater_hi = (cwm & 0x1f);

        /* Set request length to 8 cachelines per fetch */
        fwater_lo = fwater_lo | (1 << 24) | (1 << 8);
        fwater_hi = fwater_hi | (1 << 8);

        intel_uncore_write(&dev_priv->uncore, FW_BLC, fwater_lo);
        intel_uncore_write(&dev_priv->uncore, FW_BLC2, fwater_hi);

        if (enabled)
                intel_set_memory_cxsr(dev_priv, true);
}

static void i845_update_wm(struct drm_i915_private *dev_priv)
{
        struct intel_crtc *crtc;
        const struct drm_display_mode *pipe_mode;
        u32 fwater_lo;
        int planea_wm;

        crtc = single_enabled_crtc(dev_priv);
        if (crtc == NULL)
                return;

        pipe_mode = &crtc->config->hw.pipe_mode;
        planea_wm = intel_calculate_wm(pipe_mode->crtc_clock,
                                       &i845_wm_info,
                                       i845_get_fifo_size(dev_priv, PLANE_A),
                                       4, pessimal_latency_ns);
        fwater_lo = intel_uncore_read(&dev_priv->uncore, FW_BLC) & ~0xfff;
        fwater_lo |= (3<<8) | planea_wm;

        drm_dbg_kms(&dev_priv->drm,
                    "Setting FIFO watermarks - A: %d\n", planea_wm);

        intel_uncore_write(&dev_priv->uncore, FW_BLC, fwater_lo);
}

/* latency must be in 0.1us units. */
static unsigned int ilk_wm_method1(unsigned int pixel_rate,
                                   unsigned int cpp,
                                   unsigned int latency)
{
        unsigned int ret;

        ret = intel_wm_method1(pixel_rate, cpp, latency);
        ret = DIV_ROUND_UP(ret, 64) + 2;

        return ret;
}

/* latency must be in 0.1us units. */
static unsigned int ilk_wm_method2(unsigned int pixel_rate,
                                   unsigned int htotal,
                                   unsigned int width,
                                   unsigned int cpp,
                                   unsigned int latency)
{
        unsigned int ret;

        ret = intel_wm_method2(pixel_rate, htotal,
                               width, cpp, latency);
        ret = DIV_ROUND_UP(ret, 64) + 2;

        return ret;
}

static u32 ilk_wm_fbc(u32 pri_val, u32 horiz_pixels, u8 cpp)
{
        /*
         * Neither of these should be possible since this function shouldn't be
         * called if the CRTC is off or the plane is invisible.  But let's be
         * extra paranoid to avoid a potential divide-by-zero if we screw up
         * elsewhere in the driver.
         */
        if (WARN_ON(!cpp))
                return 0;
        if (WARN_ON(!horiz_pixels))
                return 0;

        return DIV_ROUND_UP(pri_val * 64, horiz_pixels * cpp) + 2;
}

struct ilk_wm_maximums {
        u16 pri;
        u16 spr;
        u16 cur;
        u16 fbc;
};

/*
 * For both WM_PIPE and WM_LP.
 * mem_value must be in 0.1us units.
 */
static u32 ilk_compute_pri_wm(const struct intel_crtc_state *crtc_state,
                              const struct intel_plane_state *plane_state,
                              u32 mem_value, bool is_lp)
{
        u32 method1, method2;
        int cpp;

        if (mem_value == 0)
                return U32_MAX;

        if (!intel_wm_plane_visible(crtc_state, plane_state))
                return 0;

        cpp = plane_state->hw.fb->format->cpp[0];

        method1 = ilk_wm_method1(crtc_state->pixel_rate, cpp, mem_value);

        if (!is_lp)
                return method1;

        method2 = ilk_wm_method2(crtc_state->pixel_rate,
                                 crtc_state->hw.pipe_mode.crtc_htotal,
                                 drm_rect_width(&plane_state->uapi.dst),
                                 cpp, mem_value);

        return min(method1, method2);
}

/*
 * For both WM_PIPE and WM_LP.
 * mem_value must be in 0.1us units.
 */
static u32 ilk_compute_spr_wm(const struct intel_crtc_state *crtc_state,
                              const struct intel_plane_state *plane_state,
                              u32 mem_value)
{
        u32 method1, method2;
        int cpp;

        if (mem_value == 0)
                return U32_MAX;

        if (!intel_wm_plane_visible(crtc_state, plane_state))
                return 0;

        cpp = plane_state->hw.fb->format->cpp[0];

        method1 = ilk_wm_method1(crtc_state->pixel_rate, cpp, mem_value);
        method2 = ilk_wm_method2(crtc_state->pixel_rate,
                                 crtc_state->hw.pipe_mode.crtc_htotal,
                                 drm_rect_width(&plane_state->uapi.dst),
                                 cpp, mem_value);
        return min(method1, method2);
}

/*
 * For both WM_PIPE and WM_LP.
 * mem_value must be in 0.1us units.
 */
static u32 ilk_compute_cur_wm(const struct intel_crtc_state *crtc_state,
                              const struct intel_plane_state *plane_state,
                              u32 mem_value)
{
        int cpp;

        if (mem_value == 0)
                return U32_MAX;

        if (!intel_wm_plane_visible(crtc_state, plane_state))
                return 0;

        cpp = plane_state->hw.fb->format->cpp[0];

        return ilk_wm_method2(crtc_state->pixel_rate,
                              crtc_state->hw.pipe_mode.crtc_htotal,
                              drm_rect_width(&plane_state->uapi.dst),
                              cpp, mem_value);
}

/* Only for WM_LP. */
static u32 ilk_compute_fbc_wm(const struct intel_crtc_state *crtc_state,
                              const struct intel_plane_state *plane_state,
                              u32 pri_val)
{
        int cpp;

        if (!intel_wm_plane_visible(crtc_state, plane_state))
                return 0;

        cpp = plane_state->hw.fb->format->cpp[0];

        return ilk_wm_fbc(pri_val, drm_rect_width(&plane_state->uapi.dst),
                          cpp);
}

static unsigned int
ilk_display_fifo_size(const struct drm_i915_private *dev_priv)
{
        if (DISPLAY_VER(dev_priv) >= 8)
                return 3072;
        else if (DISPLAY_VER(dev_priv) >= 7)
                return 768;
        else
                return 512;
}

static unsigned int
ilk_plane_wm_reg_max(const struct drm_i915_private *dev_priv,
                     int level, bool is_sprite)
{
        if (DISPLAY_VER(dev_priv) >= 8)
                /* BDW primary/sprite plane watermarks */
                return level == 0 ? 255 : 2047;
        else if (DISPLAY_VER(dev_priv) >= 7)
                /* IVB/HSW primary/sprite plane watermarks */
                return level == 0 ? 127 : 1023;
        else if (!is_sprite)
                /* ILK/SNB primary plane watermarks */
                return level == 0 ? 127 : 511;
        else
                /* ILK/SNB sprite plane watermarks */
                return level == 0 ? 63 : 255;
}

static unsigned int
ilk_cursor_wm_reg_max(const struct drm_i915_private *dev_priv, int level)
{
        if (DISPLAY_VER(dev_priv) >= 7)
                return level == 0 ? 63 : 255;
        else
                return level == 0 ? 31 : 63;
}

static unsigned int ilk_fbc_wm_reg_max(const struct drm_i915_private *dev_priv)
{
        if (DISPLAY_VER(dev_priv) >= 8)
                return 31;
        else
                return 15;
}

/* Calculate the maximum primary/sprite plane watermark */
static unsigned int ilk_plane_wm_max(const struct drm_i915_private *dev_priv,
                                     int level,
                                     const struct intel_wm_config *config,
                                     enum intel_ddb_partitioning ddb_partitioning,
                                     bool is_sprite)
{
        unsigned int fifo_size = ilk_display_fifo_size(dev_priv);

        /* if sprites aren't enabled, sprites get nothing */
        if (is_sprite && !config->sprites_enabled)
                return 0;

        /* HSW allows LP1+ watermarks even with multiple pipes */
        if (level == 0 || config->num_pipes_active > 1) {
                fifo_size /= INTEL_NUM_PIPES(dev_priv);

                /*
                 * For some reason the non self refresh
                 * FIFO size is only half of the self
                 * refresh FIFO size on ILK/SNB.
                 */
                if (DISPLAY_VER(dev_priv) <= 6)
                        fifo_size /= 2;
        }

        if (config->sprites_enabled) {
                /* level 0 is always calculated with 1:1 split */
                if (level > 0 && ddb_partitioning == INTEL_DDB_PART_5_6) {
                        if (is_sprite)
                                fifo_size *= 5;
                        fifo_size /= 6;
                } else {
                        fifo_size /= 2;
                }
        }

        /* clamp to max that the registers can hold */
        return min(fifo_size, ilk_plane_wm_reg_max(dev_priv, level, is_sprite));
}

/* Calculate the maximum cursor plane watermark */
static unsigned int ilk_cursor_wm_max(const struct drm_i915_private *dev_priv,
                                      int level,
                                      const struct intel_wm_config *config)
{
        /* HSW LP1+ watermarks w/ multiple pipes */
        if (level > 0 && config->num_pipes_active > 1)
                return 64;

        /* otherwise just report max that registers can hold */
        return ilk_cursor_wm_reg_max(dev_priv, level);
}

static void ilk_compute_wm_maximums(const struct drm_i915_private *dev_priv,
                                    int level,
                                    const struct intel_wm_config *config,
                                    enum intel_ddb_partitioning ddb_partitioning,
                                    struct ilk_wm_maximums *max)
{
        max->pri = ilk_plane_wm_max(dev_priv, level, config, ddb_partitioning, false);
        max->spr = ilk_plane_wm_max(dev_priv, level, config, ddb_partitioning, true);
        max->cur = ilk_cursor_wm_max(dev_priv, level, config);
        max->fbc = ilk_fbc_wm_reg_max(dev_priv);
}

static void ilk_compute_wm_reg_maximums(const struct drm_i915_private *dev_priv,
                                        int level,
                                        struct ilk_wm_maximums *max)
{
        max->pri = ilk_plane_wm_reg_max(dev_priv, level, false);
        max->spr = ilk_plane_wm_reg_max(dev_priv, level, true);
        max->cur = ilk_cursor_wm_reg_max(dev_priv, level);
        max->fbc = ilk_fbc_wm_reg_max(dev_priv);
}

static bool ilk_validate_wm_level(int level,
                                  const struct ilk_wm_maximums *max,
                                  struct intel_wm_level *result)
{
        bool ret;

        /* already determined to be invalid? */
        if (!result->enable)
                return false;

        result->enable = result->pri_val <= max->pri &&
                         result->spr_val <= max->spr &&
                         result->cur_val <= max->cur;

        ret = result->enable;

        /*
         * HACK until we can pre-compute everything,
         * and thus fail gracefully if LP0 watermarks
         * are exceeded...
         */
        if (level == 0 && !result->enable) {
                if (result->pri_val > max->pri)
                        DRM_DEBUG_KMS("Primary WM%d too large %u (max %u)\n",
                                      level, result->pri_val, max->pri);
                if (result->spr_val > max->spr)
                        DRM_DEBUG_KMS("Sprite WM%d too large %u (max %u)\n",
                                      level, result->spr_val, max->spr);
                if (result->cur_val > max->cur)
                        DRM_DEBUG_KMS("Cursor WM%d too large %u (max %u)\n",
                                      level, result->cur_val, max->cur);

                result->pri_val = min_t(u32, result->pri_val, max->pri);
                result->spr_val = min_t(u32, result->spr_val, max->spr);
                result->cur_val = min_t(u32, result->cur_val, max->cur);
                result->enable = true;
        }

        return ret;
}

static void ilk_compute_wm_level(const struct drm_i915_private *dev_priv,
                                 const struct intel_crtc *crtc,
                                 int level,
                                 struct intel_crtc_state *crtc_state,
                                 const struct intel_plane_state *pristate,
                                 const struct intel_plane_state *sprstate,
                                 const struct intel_plane_state *curstate,
                                 struct intel_wm_level *result)
{
        u16 pri_latency = dev_priv->wm.pri_latency[level];
        u16 spr_latency = dev_priv->wm.spr_latency[level];
        u16 cur_latency = dev_priv->wm.cur_latency[level];

        /* WM1+ latency values stored in 0.5us units */
        if (level > 0) {
                pri_latency *= 5;
                spr_latency *= 5;
                cur_latency *= 5;
        }

        if (pristate) {
                result->pri_val = ilk_compute_pri_wm(crtc_state, pristate,
                                                     pri_latency, level);
                result->fbc_val = ilk_compute_fbc_wm(crtc_state, pristate, result->pri_val);
        }

        if (sprstate)
                result->spr_val = ilk_compute_spr_wm(crtc_state, sprstate, spr_latency);

        if (curstate)
                result->cur_val = ilk_compute_cur_wm(crtc_state, curstate, cur_latency);

        result->enable = true;
}

static void intel_read_wm_latency(struct drm_i915_private *dev_priv,
                                  u16 wm[8])
{
        struct intel_uncore *uncore = &dev_priv->uncore;

        if (DISPLAY_VER(dev_priv) >= 9) {
                u32 val;
                int ret, i;
                int level, max_level = ilk_wm_max_level(dev_priv);
                int mult = IS_DG2(dev_priv) ? 2 : 1;

                /* read the first set of memory latencies[0:3] */
                val = 0; /* data0 to be programmed to 0 for first set */
                ret = sandybridge_pcode_read(dev_priv,
                                             GEN9_PCODE_READ_MEM_LATENCY,
                                             &val, NULL);

                if (ret) {
                        drm_err(&dev_priv->drm,
                                "SKL Mailbox read error = %d\n", ret);
                        return;
                }

                wm[0] = (val & GEN9_MEM_LATENCY_LEVEL_MASK) * mult;
                wm[1] = ((val >> GEN9_MEM_LATENCY_LEVEL_1_5_SHIFT) &
                                GEN9_MEM_LATENCY_LEVEL_MASK) * mult;
                wm[2] = ((val >> GEN9_MEM_LATENCY_LEVEL_2_6_SHIFT) &
                                GEN9_MEM_LATENCY_LEVEL_MASK) * mult;
                wm[3] = ((val >> GEN9_MEM_LATENCY_LEVEL_3_7_SHIFT) &
                                GEN9_MEM_LATENCY_LEVEL_MASK) * mult;

                /* read the second set of memory latencies[4:7] */
                val = 1; /* data0 to be programmed to 1 for second set */
                ret = sandybridge_pcode_read(dev_priv,
                                             GEN9_PCODE_READ_MEM_LATENCY,
                                             &val, NULL);
                if (ret) {
                        drm_err(&dev_priv->drm,
                                "SKL Mailbox read error = %d\n", ret);
                        return;
                }

                wm[4] = (val & GEN9_MEM_LATENCY_LEVEL_MASK) * mult;
                wm[5] = ((val >> GEN9_MEM_LATENCY_LEVEL_1_5_SHIFT) &
                                GEN9_MEM_LATENCY_LEVEL_MASK) * mult;
                wm[6] = ((val >> GEN9_MEM_LATENCY_LEVEL_2_6_SHIFT) &
                                GEN9_MEM_LATENCY_LEVEL_MASK) * mult;
                wm[7] = ((val >> GEN9_MEM_LATENCY_LEVEL_3_7_SHIFT) &
                                GEN9_MEM_LATENCY_LEVEL_MASK) * mult;

                /*
                 * If a level n (n > 1) has a 0us latency, all levels m (m >= n)
                 * need to be disabled. We make sure to sanitize the values out
                 * of the punit to satisfy this requirement.
                 */
                for (level = 1; level <= max_level; level++) {
                        if (wm[level] == 0) {
                                for (i = level + 1; i <= max_level; i++)
                                        wm[i] = 0;

                                max_level = level - 1;

                                break;
                        }
                }

                /*
                 * WaWmMemoryReadLatency
                 *
                 * punit doesn't take into account the read latency so we need
                 * to add proper adjustement to each valid level we retrieve
                 * from the punit when level 0 response data is 0us.
                 */
                if (wm[0] == 0) {
                        u8 adjust = DISPLAY_VER(dev_priv) >= 12 ? 3 : 2;

                        for (level = 0; level <= max_level; level++)
                                wm[level] += adjust;
                }

                /*
                 * WA Level-0 adjustment for 16GB DIMMs: SKL+
                 * If we could not get dimm info enable this WA to prevent from
                 * any underrun. If not able to get Dimm info assume 16GB dimm
                 * to avoid any underrun.
                 */
                if (dev_priv->dram_info.wm_lv_0_adjust_needed)
                        wm[0] += 1;
        } else if (IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv)) {
                u64 sskpd = intel_uncore_read64(uncore, MCH_SSKPD);

                wm[0] = (sskpd >> 56) & 0xFF;
                if (wm[0] == 0)
                        wm[0] = sskpd & 0xF;
                wm[1] = (sskpd >> 4) & 0xFF;
                wm[2] = (sskpd >> 12) & 0xFF;
                wm[3] = (sskpd >> 20) & 0x1FF;
                wm[4] = (sskpd >> 32) & 0x1FF;
        } else if (DISPLAY_VER(dev_priv) >= 6) {
                u32 sskpd = intel_uncore_read(uncore, MCH_SSKPD);

                wm[0] = (sskpd >> SSKPD_WM0_SHIFT) & SSKPD_WM_MASK;
                wm[1] = (sskpd >> SSKPD_WM1_SHIFT) & SSKPD_WM_MASK;
                wm[2] = (sskpd >> SSKPD_WM2_SHIFT) & SSKPD_WM_MASK;
                wm[3] = (sskpd >> SSKPD_WM3_SHIFT) & SSKPD_WM_MASK;
        } else if (DISPLAY_VER(dev_priv) >= 5) {
                u32 mltr = intel_uncore_read(uncore, MLTR_ILK);

                /* ILK primary LP0 latency is 700 ns */
                wm[0] = 7;
                wm[1] = (mltr >> MLTR_WM1_SHIFT) & ILK_SRLT_MASK;
                wm[2] = (mltr >> MLTR_WM2_SHIFT) & ILK_SRLT_MASK;
        } else {
                MISSING_CASE(INTEL_DEVID(dev_priv));
        }
}

static void intel_fixup_spr_wm_latency(struct drm_i915_private *dev_priv,
                                       u16 wm[5])
{
        /* ILK sprite LP0 latency is 1300 ns */
        if (DISPLAY_VER(dev_priv) == 5)
                wm[0] = 13;