/*
 * Copyright © 2013 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:
 *      Shobhit Kumar <shobhit.kumar@intel.com>
 *      Yogesh Mohan Marimuthu <yogesh.mohan.marimuthu@intel.com>
 */

#include <linux/kernel.h>
#include "intel_drv.h"
#include "i915_drv.h"
#include "intel_dsi.h"

static const u16 lfsr_converts[] = {
        426, 469, 234, 373, 442, 221, 110, 311, 411,            /* 62 - 70 */
        461, 486, 243, 377, 188, 350, 175, 343, 427, 213,       /* 71 - 80 */
        106, 53, 282, 397, 454, 227, 113, 56, 284, 142,         /* 81 - 90 */
        71, 35, 273, 136, 324, 418, 465, 488, 500, 506          /* 91 - 100 */
};

/* Get DSI clock from pixel clock */
static u32 dsi_clk_from_pclk(u32 pclk, enum mipi_dsi_pixel_format fmt,
                             int lane_count)
{
        u32 dsi_clk_khz;
        u32 bpp = mipi_dsi_pixel_format_to_bpp(fmt);

        /* DSI data rate = pixel clock * bits per pixel / lane count
           pixel clock is converted from KHz to Hz */
        dsi_clk_khz = DIV_ROUND_CLOSEST(pclk * bpp, lane_count);

        return dsi_clk_khz;
}

static int dsi_calc_mnp(struct drm_i915_private *dev_priv,
                        struct intel_crtc_state *config,
                        int target_dsi_clk)
{
        unsigned int m_min, m_max, p_min = 2, p_max = 6;
        unsigned int m, n, p;
        unsigned int calc_m, calc_p;
        int delta, ref_clk;

        /* target_dsi_clk is expected in kHz */
        if (target_dsi_clk < 300000 || target_dsi_clk > 1150000) {
                DRM_ERROR("DSI CLK Out of Range\n");
                return -ECHRNG;
        }

        if (IS_CHERRYVIEW(dev_priv)) {
                ref_clk = 100000;
                n = 4;
                m_min = 70;
                m_max = 96;
        } else {
                ref_clk = 25000;
                n = 1;
                m_min = 62;
                m_max = 92;
        }

        calc_p = p_min;
        calc_m = m_min;
        delta = abs(target_dsi_clk - (m_min * ref_clk) / (p_min * n));

        for (m = m_min; m <= m_max && delta; m++) {
                for (p = p_min; p <= p_max && delta; p++) {
                        /*
                         * Find the optimal m and p divisors with minimal delta
                         * +/- the required clock
                         */
                        int calc_dsi_clk = (m * ref_clk) / (p * n);
                        int d = abs(target_dsi_clk - calc_dsi_clk);
                        if (d < delta) {
                                delta = d;
                                calc_m = m;
                                calc_p = p;
                        }
                }
        }

        /* register has log2(N1), this works fine for powers of two */
        config->dsi_pll.ctrl = 1 << (DSI_PLL_P1_POST_DIV_SHIFT + calc_p - 2);
        config->dsi_pll.div =
                (ffs(n) - 1) << DSI_PLL_N1_DIV_SHIFT |
                (u32)lfsr_converts[calc_m - 62] << DSI_PLL_M1_DIV_SHIFT;

        return 0;
}

/*
 * XXX: The muxing and gating is hard coded for now. Need to add support for
 * sharing PLLs with two DSI outputs.
 */
static int vlv_compute_dsi_pll(struct intel_encoder *encoder,
                               struct intel_crtc_state *config)
{
        struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        int ret;
        u32 dsi_clk;

        dsi_clk = dsi_clk_from_pclk(intel_dsi->pclk, intel_dsi->pixel_format,
                                    intel_dsi->lane_count);

        ret = dsi_calc_mnp(dev_priv, config, dsi_clk);
        if (ret) {
                DRM_DEBUG_KMS("dsi_calc_mnp failed\n");
                return ret;
        }

        if (intel_dsi->ports & (1 << PORT_A))
                config->dsi_pll.ctrl |= DSI_PLL_CLK_GATE_DSI0_DSIPLL;

        if (intel_dsi->ports & (1 << PORT_C))
                config->dsi_pll.ctrl |= DSI_PLL_CLK_GATE_DSI1_DSIPLL;

        config->dsi_pll.ctrl |= DSI_PLL_VCO_EN;

        DRM_DEBUG_KMS("dsi pll div %08x, ctrl %08x\n",
                      config->dsi_pll.div, config->dsi_pll.ctrl);

        return 0;
}

static void vlv_enable_dsi_pll(struct intel_encoder *encoder,
                               const struct intel_crtc_state *config)
{
        struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);

        DRM_DEBUG_KMS("\n");

        mutex_lock(&dev_priv->sb_lock);

        vlv_cck_write(dev_priv, CCK_REG_DSI_PLL_CONTROL, 0);
        vlv_cck_write(dev_priv, CCK_REG_DSI_PLL_DIVIDER, config->dsi_pll.div);
        vlv_cck_write(dev_priv, CCK_REG_DSI_PLL_CONTROL,
                      config->dsi_pll.ctrl & ~DSI_PLL_VCO_EN);

        /* wait at least 0.5 us after ungating before enabling VCO */
        usleep_range(1, 10);

        vlv_cck_write(dev_priv, CCK_REG_DSI_PLL_CONTROL, config->dsi_pll.ctrl);

        if (wait_for(vlv_cck_read(dev_priv, CCK_REG_DSI_PLL_CONTROL) &
                                                DSI_PLL_LOCK, 20)) {

                mutex_unlock(&dev_priv->sb_lock);
                DRM_ERROR("DSI PLL lock failed\n");
                return;
        }
        mutex_unlock(&dev_priv->sb_lock);

        DRM_DEBUG_KMS("DSI PLL locked\n");
}

static void vlv_disable_dsi_pll(struct intel_encoder *encoder)
{
        struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
        u32 tmp;

        DRM_DEBUG_KMS("\n");

        mutex_lock(&dev_priv->sb_lock);

        tmp = vlv_cck_read(dev_priv, CCK_REG_DSI_PLL_CONTROL);
        tmp &= ~DSI_PLL_VCO_EN;
        tmp |= DSI_PLL_LDO_GATE;
        vlv_cck_write(dev_priv, CCK_REG_DSI_PLL_CONTROL, tmp);

        mutex_unlock(&dev_priv->sb_lock);
}

static bool bxt_dsi_pll_is_enabled(struct drm_i915_private *dev_priv)
{
        bool enabled;
        u32 val;
        u32 mask;

        mask = BXT_DSI_PLL_DO_ENABLE | BXT_DSI_PLL_LOCKED;
        val = I915_READ(BXT_DSI_PLL_ENABLE);
        enabled = (val & mask) == mask;

        if (!enabled)
                return false;

        /*
         * Both dividers must be programmed with valid values even if only one
         * of the PLL is used, see BSpec/Broxton Clocks. Check this here for
         * paranoia, since BIOS is known to misconfigure PLLs in this way at
         * times, and since accessing DSI registers with invalid dividers
         * causes a system hang.
         */
        val = I915_READ(BXT_DSI_PLL_CTL);
        if (!(val & BXT_DSIA_16X_MASK) || !(val & BXT_DSIC_16X_MASK)) {
                DRM_DEBUG_DRIVER("PLL is enabled with invalid divider settings (%08x)\n",
                                 val);
                enabled = false;
        }

        return enabled;
}

static void bxt_disable_dsi_pll(struct intel_encoder *encoder)
{
        struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
        u32 val;

        DRM_DEBUG_KMS("\n");

        val = I915_READ(BXT_DSI_PLL_ENABLE);
        val &= ~BXT_DSI_PLL_DO_ENABLE;
        I915_WRITE(BXT_DSI_PLL_ENABLE, val);

        /*
         * PLL lock should deassert within 200us.
         * Wait up to 1ms before timing out.
         */
        if (intel_wait_for_register(dev_priv,
                                    BXT_DSI_PLL_ENABLE,
                                    BXT_DSI_PLL_LOCKED,
                                    0,
                                    1))
                DRM_ERROR("Timeout waiting for PLL lock deassertion\n");
}

static void assert_bpp_mismatch(enum mipi_dsi_pixel_format fmt, int pipe_bpp)
{
        int bpp = mipi_dsi_pixel_format_to_bpp(fmt);

        WARN(bpp != pipe_bpp,
             "bpp match assertion failure (expected %d, current %d)\n",
             bpp, pipe_bpp);
}

static u32 vlv_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
                            struct intel_crtc_state *config)
{
        struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        u32 dsi_clock, pclk;
        u32 pll_ctl, pll_div;
        u32 m = 0, p = 0, n;
        int refclk = IS_CHERRYVIEW(dev_priv) ? 100000 : 25000;
        int i;

        DRM_DEBUG_KMS("\n");

        mutex_lock(&dev_priv->sb_lock);
        pll_ctl = vlv_cck_read(dev_priv, CCK_REG_DSI_PLL_CONTROL);
        pll_div = vlv_cck_read(dev_priv, CCK_REG_DSI_PLL_DIVIDER);
        mutex_unlock(&dev_priv->sb_lock);

        config->dsi_pll.ctrl = pll_ctl & ~DSI_PLL_LOCK;
        config->dsi_pll.div = pll_div;

        /* mask out other bits and extract the P1 divisor */
        pll_ctl &= DSI_PLL_P1_POST_DIV_MASK;
        pll_ctl = pll_ctl >> (DSI_PLL_P1_POST_DIV_SHIFT - 2);

        /* N1 divisor */
        n = (pll_div & DSI_PLL_N1_DIV_MASK) >> DSI_PLL_N1_DIV_SHIFT;
        n = 1 << n; /* register has log2(N1) */

        /* mask out the other bits and extract the M1 divisor */
        pll_div &= DSI_PLL_M1_DIV_MASK;
        pll_div = pll_div >> DSI_PLL_M1_DIV_SHIFT;

        while (pll_ctl) {
                pll_ctl = pll_ctl >> 1;
                p++;
        }
        p--;

        if (!p) {
                DRM_ERROR("wrong P1 divisor\n");
                return 0;
        }

        for (i = 0; i < ARRAY_SIZE(lfsr_converts); i++) {
                if (lfsr_converts[i] == pll_div)
                        break;
        }

        if (i == ARRAY_SIZE(lfsr_converts)) {
                DRM_ERROR("wrong m_seed programmed\n");
                return 0;
        }

        m = i + 62;

        dsi_clock = (m * refclk) / (p * n);

        /* pixel_format and pipe_bpp should agree */
        assert_bpp_mismatch(intel_dsi->pixel_format, pipe_bpp);

        pclk = DIV_ROUND_CLOSEST(dsi_clock * intel_dsi->lane_count, pipe_bpp);

        return pclk;
}

static u32 bxt_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
                            struct intel_crtc_state *config)
{
        u32 pclk;
        u32 dsi_clk;
        u32 dsi_ratio;
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);

        /* Divide by zero */
        if (!pipe_bpp) {
                DRM_ERROR("Invalid BPP(0)\n");
                return 0;
        }

        config->dsi_pll.ctrl = I915_READ(BXT_DSI_PLL_CTL);

        dsi_ratio = config->dsi_pll.ctrl & BXT_DSI_PLL_RATIO_MASK;

        dsi_clk = (dsi_ratio * BXT_REF_CLOCK_KHZ) / 2;

        /* pixel_format and pipe_bpp should agree */
        assert_bpp_mismatch(intel_dsi->pixel_format, pipe_bpp);

        pclk = DIV_ROUND_CLOSEST(dsi_clk * intel_dsi->lane_count, pipe_bpp);

        DRM_DEBUG_DRIVER("Calculated pclk=%u\n", pclk);
        return pclk;
}

u32 intel_dsi_get_pclk(struct intel_encoder *encoder, int pipe_bpp,
                       struct intel_crtc_state *config)
{
        if (IS_BROXTON(encoder->base.dev))
                return bxt_dsi_get_pclk(encoder, pipe_bpp, config);
        else
                return vlv_dsi_get_pclk(encoder, pipe_bpp, config);
}

static void vlv_dsi_reset_clocks(struct intel_encoder *encoder, enum port port)
{
        u32 temp;
        struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);

        temp = I915_READ(MIPI_CTRL(port));
        temp &= ~ESCAPE_CLOCK_DIVIDER_MASK;
        I915_WRITE(MIPI_CTRL(port), temp |
                        intel_dsi->escape_clk_div <<
                        ESCAPE_CLOCK_DIVIDER_SHIFT);
}

/* Program BXT Mipi clocks and dividers */
static void bxt_dsi_program_clocks(struct drm_device *dev, enum port port,
                                   const struct intel_crtc_state *config)
{
        struct drm_i915_private *dev_priv = to_i915(dev);
        u32 tmp;
        u32 dsi_rate = 0;
        u32 pll_ratio = 0;
        u32 rx_div;
        u32 tx_div;
        u32 rx_div_upper;
        u32 rx_div_lower;
        u32 mipi_8by3_divider;

        /* Clear old configurations */
        tmp = I915_READ(BXT_MIPI_CLOCK_CTL);
        tmp &= ~(BXT_MIPI_TX_ESCLK_FIXDIV_MASK(port));
        tmp &= ~(BXT_MIPI_RX_ESCLK_UPPER_FIXDIV_MASK(port));
        tmp &= ~(BXT_MIPI_8X_BY3_DIVIDER_MASK(port));
        tmp &= ~(BXT_MIPI_RX_ESCLK_LOWER_FIXDIV_MASK(port));

        /* Get the current DSI rate(actual) */
        pll_ratio = config->dsi_pll.ctrl & BXT_DSI_PLL_RATIO_MASK;
        dsi_rate = (BXT_REF_CLOCK_KHZ * pll_ratio) / 2;

        /*
         * tx clock should be <= 20MHz and the div value must be
         * subtracted by 1 as per bspec
         */
        tx_div = DIV_ROUND_UP(dsi_rate, 20000) - 1;
        /*
         * rx clock should be <= 150MHz and the div value must be
         * subtracted by 1 as per bspec
         */
        rx_div = DIV_ROUND_UP(dsi_rate, 150000) - 1;

        /*
         * rx divider value needs to be updated in the
         * two differnt bit fields in the register hence splitting the
         * rx divider value accordingly
         */
        rx_div_lower = rx_div & RX_DIVIDER_BIT_1_2;
        rx_div_upper = (rx_div & RX_DIVIDER_BIT_3_4) >> 2;

        /* As per bpsec program the 8/3X clock divider to the below value */
        if (dev_priv->vbt.dsi.config->is_cmd_mode)
                mipi_8by3_divider = 0x2;
        else
                mipi_8by3_divider = 0x3;

        tmp |= BXT_MIPI_8X_BY3_DIVIDER(port, mipi_8by3_divider);
        tmp |= BXT_MIPI_TX_ESCLK_DIVIDER(port, tx_div);
        tmp |= BXT_MIPI_RX_ESCLK_LOWER_DIVIDER(port, rx_div_lower);
        tmp |= BXT_MIPI_RX_ESCLK_UPPER_DIVIDER(port, rx_div_upper);

        I915_WRITE(BXT_MIPI_CLOCK_CTL, tmp);
}

static int bxt_compute_dsi_pll(struct intel_encoder *encoder,
                               struct intel_crtc_state *config)
{
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        u8 dsi_ratio;
        u32 dsi_clk;

        dsi_clk = dsi_clk_from_pclk(intel_dsi->pclk, intel_dsi->pixel_format,
                                    intel_dsi->lane_count);

        /*
         * From clock diagram, to get PLL ratio divider, divide double of DSI
         * link rate (i.e., 2*8x=16x frequency value) by ref clock. Make sure to
         * round 'up' the result
         */
        dsi_ratio = DIV_ROUND_UP(dsi_clk * 2, BXT_REF_CLOCK_KHZ);
        if (dsi_ratio < BXT_DSI_PLL_RATIO_MIN ||
            dsi_ratio > BXT_DSI_PLL_RATIO_MAX) {
                DRM_ERROR("Cant get a suitable ratio from DSI PLL ratios\n");
                return -ECHRNG;
        }

        /*
         * Program DSI ratio and Select MIPIC and MIPIA PLL output as 8x
         * Spec says both have to be programmed, even if one is not getting
         * used. Configure MIPI_CLOCK_CTL dividers in modeset
         */
        config->dsi_pll.ctrl = dsi_ratio | BXT_DSIA_16X_BY2 | BXT_DSIC_16X_BY2;

        /* As per recommendation from hardware team,
         * Prog PVD ratio =1 if dsi ratio <= 50
         */
        if (dsi_ratio <= 50)
                config->dsi_pll.ctrl |= BXT_DSI_PLL_PVD_RATIO_1;

        return 0;
}

static void bxt_enable_dsi_pll(struct intel_encoder *encoder,
                               const struct intel_crtc_state *config)
{
        struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        enum port port;
        u32 val;

        DRM_DEBUG_KMS("\n");

        /* Configure PLL vales */
        I915_WRITE(BXT_DSI_PLL_CTL, config->dsi_pll.ctrl);
        POSTING_READ(BXT_DSI_PLL_CTL);

        /* Program TX, RX, Dphy clocks */
        for_each_dsi_port(port, intel_dsi->ports)
                bxt_dsi_program_clocks(encoder->base.dev, port, config);

        /* Enable DSI PLL */
        val = I915_READ(BXT_DSI_PLL_ENABLE);
        val |= BXT_DSI_PLL_DO_ENABLE;
        I915_WRITE(BXT_DSI_PLL_ENABLE, val);

        /* Timeout and fail if PLL not locked */
        if (intel_wait_for_register(dev_priv,
                                    BXT_DSI_PLL_ENABLE,
                                    BXT_DSI_PLL_LOCKED,
                                    BXT_DSI_PLL_LOCKED,
                                    1)) {
                DRM_ERROR("Timed out waiting for DSI PLL to lock\n");
                return;
        }

        DRM_DEBUG_KMS("DSI PLL locked\n");
}

bool intel_dsi_pll_is_enabled(struct drm_i915_private *dev_priv)
{
        if (IS_BROXTON(dev_priv))
                return bxt_dsi_pll_is_enabled(dev_priv);

        MISSING_CASE(INTEL_DEVID(dev_priv));

        return false;
}

int intel_compute_dsi_pll(struct intel_encoder *encoder,
                          struct intel_crtc_state *config)
{
        struct drm_device *dev = encoder->base.dev;

        if (IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev))
                return vlv_compute_dsi_pll(encoder, config);
        else if (IS_BROXTON(dev))
                return bxt_compute_dsi_pll(encoder, config);

        return -ENODEV;
}

void intel_enable_dsi_pll(struct intel_encoder *encoder,
                          const struct intel_crtc_state *config)
{
        struct drm_device *dev = encoder->base.dev;

        if (IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev))
                vlv_enable_dsi_pll(encoder, config);
        else if (IS_BROXTON(dev))
                bxt_enable_dsi_pll(encoder, config);
}

void intel_disable_dsi_pll(struct intel_encoder *encoder)
{
        struct drm_device *dev = encoder->base.dev;

        if (IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev))
                vlv_disable_dsi_pll(encoder);
        else if (IS_BROXTON(dev))
                bxt_disable_dsi_pll(encoder);
}

static void bxt_dsi_reset_clocks(struct intel_encoder *encoder, enum port port)
{
        u32 tmp;
        struct drm_device *dev = encoder->base.dev;
        struct drm_i915_private *dev_priv = to_i915(dev);

        /* Clear old configurations */
        tmp = I915_READ(BXT_MIPI_CLOCK_CTL);
        tmp &= ~(BXT_MIPI_TX_ESCLK_FIXDIV_MASK(port));
        tmp &= ~(BXT_MIPI_RX_ESCLK_UPPER_FIXDIV_MASK(port));
        tmp &= ~(BXT_MIPI_8X_BY3_DIVIDER_MASK(port));
        tmp &= ~(BXT_MIPI_RX_ESCLK_LOWER_FIXDIV_MASK(port));
        I915_WRITE(BXT_MIPI_CLOCK_CTL, tmp);
        I915_WRITE(MIPI_EOT_DISABLE(port), CLOCKSTOP);
}

void intel_dsi_reset_clocks(struct intel_encoder *encoder, enum port port)
{
        struct drm_device *dev = encoder->base.dev;

        if (IS_BROXTON(dev))
                bxt_dsi_reset_clocks(encoder, port);
        else if (IS_VALLEYVIEW(dev) || IS_CHERRYVIEW(dev))
                vlv_dsi_reset_clocks(encoder, port);
}