/*
 * 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.
 *
 * Author: Jani Nikula <jani.nikula@intel.com>
 */

#include <drm/drmP.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_crtc.h>
#include <drm/drm_edid.h>
#include <drm/i915_drm.h>
#include <drm/drm_panel.h>
#include <drm/drm_mipi_dsi.h>
#include <linux/slab.h>
#include "i915_drv.h"
#include "intel_drv.h"
#include "intel_dsi.h"

static const struct {
        u16 panel_id;
        struct drm_panel * (*init)(struct intel_dsi *intel_dsi, u16 panel_id);
} intel_dsi_drivers[] = {
        {
                .panel_id = MIPI_DSI_GENERIC_PANEL_ID,
                .init = vbt_panel_init,
        },
};

static void wait_for_dsi_fifo_empty(struct intel_dsi *intel_dsi, enum port port)
{
        struct drm_encoder *encoder = &intel_dsi->base.base;
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 mask;

        mask = LP_CTRL_FIFO_EMPTY | HS_CTRL_FIFO_EMPTY |
                LP_DATA_FIFO_EMPTY | HS_DATA_FIFO_EMPTY;

        if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(port)) & mask) == mask, 100))
                DRM_ERROR("DPI FIFOs are not empty\n");
}

static void write_data(struct drm_i915_private *dev_priv, u32 reg,
                       const u8 *data, u32 len)
{
        u32 i, j;

        for (i = 0; i < len; i += 4) {
                u32 val = 0;

                for (j = 0; j < min_t(u32, len - i, 4); j++)
                        val |= *data++ << 8 * j;

                I915_WRITE(reg, val);
        }
}

static void read_data(struct drm_i915_private *dev_priv, u32 reg,
                      u8 *data, u32 len)
{
        u32 i, j;

        for (i = 0; i < len; i += 4) {
                u32 val = I915_READ(reg);

                for (j = 0; j < min_t(u32, len - i, 4); j++)
                        *data++ = val >> 8 * j;
        }
}

static ssize_t intel_dsi_host_transfer(struct mipi_dsi_host *host,
                                       const struct mipi_dsi_msg *msg)
{
        struct intel_dsi_host *intel_dsi_host = to_intel_dsi_host(host);
        struct drm_device *dev = intel_dsi_host->intel_dsi->base.base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        enum port port = intel_dsi_host->port;
        struct mipi_dsi_packet packet;
        ssize_t ret;
        const u8 *header, *data;
        u32 data_reg, data_mask, ctrl_reg, ctrl_mask;

        ret = mipi_dsi_create_packet(&packet, msg);
        if (ret < 0)
                return ret;

        header = packet.header;
        data = packet.payload;

        if (msg->flags & MIPI_DSI_MSG_USE_LPM) {
                data_reg = MIPI_LP_GEN_DATA(port);
                data_mask = LP_DATA_FIFO_FULL;
                ctrl_reg = MIPI_LP_GEN_CTRL(port);
                ctrl_mask = LP_CTRL_FIFO_FULL;
        } else {
                data_reg = MIPI_HS_GEN_DATA(port);
                data_mask = HS_DATA_FIFO_FULL;
                ctrl_reg = MIPI_HS_GEN_CTRL(port);
                ctrl_mask = HS_CTRL_FIFO_FULL;
        }

        /* note: this is never true for reads */
        if (packet.payload_length) {

                if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(port)) & data_mask) == 0, 50))
                        DRM_ERROR("Timeout waiting for HS/LP DATA FIFO !full\n");

                write_data(dev_priv, data_reg, packet.payload,
                           packet.payload_length);
        }

        if (msg->rx_len) {
                I915_WRITE(MIPI_INTR_STAT(port), GEN_READ_DATA_AVAIL);
        }

        if (wait_for((I915_READ(MIPI_GEN_FIFO_STAT(port)) & ctrl_mask) == 0, 50)) {
                DRM_ERROR("Timeout waiting for HS/LP CTRL FIFO !full\n");
        }

        I915_WRITE(ctrl_reg, header[2] << 16 | header[1] << 8 | header[0]);

        /* ->rx_len is set only for reads */
        if (msg->rx_len) {
                data_mask = GEN_READ_DATA_AVAIL;
                if (wait_for((I915_READ(MIPI_INTR_STAT(port)) & data_mask) == data_mask, 50))
                        DRM_ERROR("Timeout waiting for read data.\n");

                read_data(dev_priv, data_reg, msg->rx_buf, msg->rx_len);
        }

        /* XXX: fix for reads and writes */
        return 4 + packet.payload_length;
}

static int intel_dsi_host_attach(struct mipi_dsi_host *host,
                                 struct mipi_dsi_device *dsi)
{
        return 0;
}

static int intel_dsi_host_detach(struct mipi_dsi_host *host,
                                 struct mipi_dsi_device *dsi)
{
        return 0;
}

static const struct mipi_dsi_host_ops intel_dsi_host_ops = {
        .attach = intel_dsi_host_attach,
        .detach = intel_dsi_host_detach,
        .transfer = intel_dsi_host_transfer,
};

static struct intel_dsi_host *intel_dsi_host_init(struct intel_dsi *intel_dsi,
                                                  enum port port)
{
        struct intel_dsi_host *host;
        struct mipi_dsi_device *device;

        host = kzalloc(sizeof(*host), GFP_KERNEL);
        if (!host)
                return NULL;

        host->base.ops = &intel_dsi_host_ops;
        host->intel_dsi = intel_dsi;
        host->port = port;

        /*
         * We should call mipi_dsi_host_register(&host->base) here, but we don't
         * have a host->dev, and we don't have OF stuff either. So just use the
         * dsi framework as a library and hope for the best. Create the dsi
         * devices by ourselves here too. Need to be careful though, because we
         * don't initialize any of the driver model devices here.
         */
        device = kzalloc(sizeof(*device), GFP_KERNEL);
        if (!device) {
                kfree(host);
                return NULL;
        }

        device->host = &host->base;
        host->device = device;

        return host;
}

/*
 * send a video mode command
 *
 * XXX: commands with data in MIPI_DPI_DATA?
 */
static int dpi_send_cmd(struct intel_dsi *intel_dsi, u32 cmd, bool hs,
                        enum port port)
{
        struct drm_encoder *encoder = &intel_dsi->base.base;
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        u32 mask;

        /* XXX: pipe, hs */
        if (hs)
                cmd &= ~DPI_LP_MODE;
        else
                cmd |= DPI_LP_MODE;

        /* clear bit */
        I915_WRITE(MIPI_INTR_STAT(port), SPL_PKT_SENT_INTERRUPT);

        /* XXX: old code skips write if control unchanged */
        if (cmd == I915_READ(MIPI_DPI_CONTROL(port)))
                DRM_ERROR("Same special packet %02x twice in a row.\n", cmd);

        I915_WRITE(MIPI_DPI_CONTROL(port), cmd);

        mask = SPL_PKT_SENT_INTERRUPT;
        if (wait_for((I915_READ(MIPI_INTR_STAT(port)) & mask) == mask, 100))
                DRM_ERROR("Video mode command 0x%08x send failed.\n", cmd);

        return 0;
}

static void band_gap_reset(struct drm_i915_private *dev_priv)
{
        mutex_lock(&dev_priv->sb_lock);

        vlv_flisdsi_write(dev_priv, 0x08, 0x0001);
        vlv_flisdsi_write(dev_priv, 0x0F, 0x0005);
        vlv_flisdsi_write(dev_priv, 0x0F, 0x0025);
        udelay(150);
        vlv_flisdsi_write(dev_priv, 0x0F, 0x0000);
        vlv_flisdsi_write(dev_priv, 0x08, 0x0000);

        mutex_unlock(&dev_priv->sb_lock);
}

static inline bool is_vid_mode(struct intel_dsi *intel_dsi)
{
        return intel_dsi->operation_mode == INTEL_DSI_VIDEO_MODE;
}

static inline bool is_cmd_mode(struct intel_dsi *intel_dsi)
{
        return intel_dsi->operation_mode == INTEL_DSI_COMMAND_MODE;
}

static void intel_dsi_hot_plug(struct intel_encoder *encoder)
{
        DRM_DEBUG_KMS("\n");
}

static bool intel_dsi_compute_config(struct intel_encoder *encoder,
                                     struct intel_crtc_state *config)
{
        struct intel_dsi *intel_dsi = container_of(encoder, struct intel_dsi,
                                                   base);
        struct intel_connector *intel_connector = intel_dsi->attached_connector;
        struct drm_display_mode *fixed_mode = intel_connector->panel.fixed_mode;
        struct drm_display_mode *adjusted_mode = &config->base.adjusted_mode;

        DRM_DEBUG_KMS("\n");

        if (fixed_mode)
                intel_fixed_panel_mode(fixed_mode, adjusted_mode);

        /* DSI uses short packets for sync events, so clear mode flags for DSI */
        adjusted_mode->flags = 0;

        return true;
}

static void intel_dsi_port_enable(struct intel_encoder *encoder)
{
        struct drm_device *dev = encoder->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        enum port port;
        u32 temp;

        if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK) {
                temp = I915_READ(VLV_CHICKEN_3);
                temp &= ~PIXEL_OVERLAP_CNT_MASK |
                                        intel_dsi->pixel_overlap <<
                                        PIXEL_OVERLAP_CNT_SHIFT;
                I915_WRITE(VLV_CHICKEN_3, temp);
        }

        for_each_dsi_port(port, intel_dsi->ports) {
                temp = I915_READ(MIPI_PORT_CTRL(port));
                temp &= ~LANE_CONFIGURATION_MASK;
                temp &= ~DUAL_LINK_MODE_MASK;

                if (intel_dsi->ports == ((1 << PORT_A) | (1 << PORT_C))) {
                        temp |= (intel_dsi->dual_link - 1)
                                                << DUAL_LINK_MODE_SHIFT;
                        temp |= intel_crtc->pipe ?
                                        LANE_CONFIGURATION_DUAL_LINK_B :
                                        LANE_CONFIGURATION_DUAL_LINK_A;
                }
                /* assert ip_tg_enable signal */
                I915_WRITE(MIPI_PORT_CTRL(port), temp | DPI_ENABLE);
                POSTING_READ(MIPI_PORT_CTRL(port));
        }
}

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

        for_each_dsi_port(port, intel_dsi->ports) {
                /* de-assert ip_tg_enable signal */
                temp = I915_READ(MIPI_PORT_CTRL(port));
                I915_WRITE(MIPI_PORT_CTRL(port), temp & ~DPI_ENABLE);
                POSTING_READ(MIPI_PORT_CTRL(port));
        }
}

static void intel_dsi_device_ready(struct intel_encoder *encoder)
{
        struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        enum port port;
        u32 val;

        DRM_DEBUG_KMS("\n");

        mutex_lock(&dev_priv->sb_lock);
        /* program rcomp for compliance, reduce from 50 ohms to 45 ohms
         * needed everytime after power gate */
        vlv_flisdsi_write(dev_priv, 0x04, 0x0004);
        mutex_unlock(&dev_priv->sb_lock);

        /* bandgap reset is needed after everytime we do power gate */
        band_gap_reset(dev_priv);

        for_each_dsi_port(port, intel_dsi->ports) {

                I915_WRITE(MIPI_DEVICE_READY(port), ULPS_STATE_ENTER);
                usleep_range(2500, 3000);

                /* Enable MIPI PHY transparent latch
                 * Common bit for both MIPI Port A & MIPI Port C
                 * No similar bit in MIPI Port C reg
                 */
                val = I915_READ(MIPI_PORT_CTRL(PORT_A));
                I915_WRITE(MIPI_PORT_CTRL(PORT_A), val | LP_OUTPUT_HOLD);
                usleep_range(1000, 1500);

                I915_WRITE(MIPI_DEVICE_READY(port), ULPS_STATE_EXIT);
                usleep_range(2500, 3000);

                I915_WRITE(MIPI_DEVICE_READY(port), DEVICE_READY);
                usleep_range(2500, 3000);
        }
}

static void intel_dsi_enable(struct intel_encoder *encoder)
{
        struct drm_device *dev = encoder->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        enum port port;

        DRM_DEBUG_KMS("\n");

        if (is_cmd_mode(intel_dsi)) {
                for_each_dsi_port(port, intel_dsi->ports)
                        I915_WRITE(MIPI_MAX_RETURN_PKT_SIZE(port), 8 * 4);
        } else {
                msleep(20); /* XXX */
                for_each_dsi_port(port, intel_dsi->ports)
                        dpi_send_cmd(intel_dsi, TURN_ON, false, port);
                msleep(100);

                drm_panel_enable(intel_dsi->panel);

                for_each_dsi_port(port, intel_dsi->ports)
                        wait_for_dsi_fifo_empty(intel_dsi, port);

                intel_dsi_port_enable(encoder);
        }
}

static void intel_dsi_pre_enable(struct intel_encoder *encoder)
{
        struct drm_device *dev = encoder->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        struct intel_crtc *intel_crtc = to_intel_crtc(encoder->base.crtc);
        enum pipe pipe = intel_crtc->pipe;
        enum port port;
        u32 tmp;

        DRM_DEBUG_KMS("\n");

        /* Disable DPOunit clock gating, can stall pipe
         * and we need DPLL REFA always enabled */
        tmp = I915_READ(DPLL(pipe));
        tmp |= DPLL_REFA_CLK_ENABLE_VLV;
        I915_WRITE(DPLL(pipe), tmp);

        /* update the hw state for DPLL */
        intel_crtc->config->dpll_hw_state.dpll = DPLL_INTEGRATED_CLOCK_VLV |
                DPLL_REFA_CLK_ENABLE_VLV;

        tmp = I915_READ(DSPCLK_GATE_D);
        tmp |= DPOUNIT_CLOCK_GATE_DISABLE;
        I915_WRITE(DSPCLK_GATE_D, tmp);

        /* put device in ready state */
        intel_dsi_device_ready(encoder);

        msleep(intel_dsi->panel_on_delay);

        drm_panel_prepare(intel_dsi->panel);

        for_each_dsi_port(port, intel_dsi->ports)
                wait_for_dsi_fifo_empty(intel_dsi, port);

        /* Enable port in pre-enable phase itself because as per hw team
         * recommendation, port should be enabled befor plane & pipe */
        intel_dsi_enable(encoder);
}

static void intel_dsi_enable_nop(struct intel_encoder *encoder)
{
        DRM_DEBUG_KMS("\n");

        /* for DSI port enable has to be done before pipe
         * and plane enable, so port enable is done in
         * pre_enable phase itself unlike other encoders
         */
}

static void intel_dsi_pre_disable(struct intel_encoder *encoder)
{
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        enum port port;

        DRM_DEBUG_KMS("\n");

        if (is_vid_mode(intel_dsi)) {
                /* Send Shutdown command to the panel in LP mode */
                for_each_dsi_port(port, intel_dsi->ports)
                        dpi_send_cmd(intel_dsi, SHUTDOWN, false, port);
                msleep(10);
        }
}

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

        DRM_DEBUG_KMS("\n");

        if (is_vid_mode(intel_dsi)) {
                for_each_dsi_port(port, intel_dsi->ports)
                        wait_for_dsi_fifo_empty(intel_dsi, port);

                intel_dsi_port_disable(encoder);
                msleep(2);
        }

        for_each_dsi_port(port, intel_dsi->ports) {
                /* Panel commands can be sent when clock is in LP11 */
                I915_WRITE(MIPI_DEVICE_READY(port), 0x0);

                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);

                I915_WRITE(MIPI_EOT_DISABLE(port), CLOCKSTOP);

                temp = I915_READ(MIPI_DSI_FUNC_PRG(port));
                temp &= ~VID_MODE_FORMAT_MASK;
                I915_WRITE(MIPI_DSI_FUNC_PRG(port), temp);

                I915_WRITE(MIPI_DEVICE_READY(port), 0x1);
        }
        /* if disable packets are sent before sending shutdown packet then in
         * some next enable sequence send turn on packet error is observed */
        drm_panel_disable(intel_dsi->panel);

        for_each_dsi_port(port, intel_dsi->ports)
                wait_for_dsi_fifo_empty(intel_dsi, port);
}

static void intel_dsi_clear_device_ready(struct intel_encoder *encoder)
{
        struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        enum port port;
        u32 val;

        DRM_DEBUG_KMS("\n");
        for_each_dsi_port(port, intel_dsi->ports) {

                I915_WRITE(MIPI_DEVICE_READY(port), DEVICE_READY |
                                                        ULPS_STATE_ENTER);
                usleep_range(2000, 2500);

                I915_WRITE(MIPI_DEVICE_READY(port), DEVICE_READY |
                                                        ULPS_STATE_EXIT);
                usleep_range(2000, 2500);

                I915_WRITE(MIPI_DEVICE_READY(port), DEVICE_READY |
                                                        ULPS_STATE_ENTER);
                usleep_range(2000, 2500);

                /* Wait till Clock lanes are in LP-00 state for MIPI Port A
                 * only. MIPI Port C has no similar bit for checking
                 */
                if (wait_for(((I915_READ(MIPI_PORT_CTRL(PORT_A)) & AFE_LATCHOUT)
                                                        == 0x00000), 30))
                        DRM_ERROR("DSI LP not going Low\n");

                /* Disable MIPI PHY transparent latch
                 * Common bit for both MIPI Port A & MIPI Port C
                 */
                val = I915_READ(MIPI_PORT_CTRL(PORT_A));
                I915_WRITE(MIPI_PORT_CTRL(PORT_A), val & ~LP_OUTPUT_HOLD);
                usleep_range(1000, 1500);

                I915_WRITE(MIPI_DEVICE_READY(port), 0x00);
                usleep_range(2000, 2500);
        }

        vlv_disable_dsi_pll(encoder);
}

static void intel_dsi_post_disable(struct intel_encoder *encoder)
{
        struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        u32 val;

        DRM_DEBUG_KMS("\n");

        intel_dsi_disable(encoder);

        intel_dsi_clear_device_ready(encoder);

        val = I915_READ(DSPCLK_GATE_D);
        val &= ~DPOUNIT_CLOCK_GATE_DISABLE;
        I915_WRITE(DSPCLK_GATE_D, val);

        drm_panel_unprepare(intel_dsi->panel);

        msleep(intel_dsi->panel_off_delay);
        msleep(intel_dsi->panel_pwr_cycle_delay);
}

static bool intel_dsi_get_hw_state(struct intel_encoder *encoder,
                                   enum pipe *pipe)
{
        struct drm_i915_private *dev_priv = encoder->base.dev->dev_private;
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
        struct drm_device *dev = encoder->base.dev;
        enum intel_display_power_domain power_domain;
        u32 dpi_enabled, func;
        enum port port;

        DRM_DEBUG_KMS("\n");

        power_domain = intel_display_port_power_domain(encoder);
        if (!intel_display_power_is_enabled(dev_priv, power_domain))
                return false;

        /* XXX: this only works for one DSI output */
        for_each_dsi_port(port, intel_dsi->ports) {
                func = I915_READ(MIPI_DSI_FUNC_PRG(port));
                dpi_enabled = I915_READ(MIPI_PORT_CTRL(port)) &
                                                        DPI_ENABLE;

                /* Due to some hardware limitations on BYT, MIPI Port C DPI
                 * Enable bit does not get set. To check whether DSI Port C
                 * was enabled in BIOS, check the Pipe B enable bit
                 */
                if (IS_VALLEYVIEW(dev) && !IS_CHERRYVIEW(dev) &&
                    (port == PORT_C))
                        dpi_enabled = I915_READ(PIPECONF(PIPE_B)) &
                                                        PIPECONF_ENABLE;

                if (dpi_enabled || (func & CMD_MODE_DATA_WIDTH_MASK)) {
                        if (I915_READ(MIPI_DEVICE_READY(port)) & DEVICE_READY) {
                                *pipe = port == PORT_A ? PIPE_A : PIPE_B;
                                return true;
                        }
                }
        }

        return false;
}

static void intel_dsi_get_config(struct intel_encoder *encoder,
                                 struct intel_crtc_state *pipe_config)
{
        u32 pclk;
        DRM_DEBUG_KMS("\n");

        /*
         * DPLL_MD is not used in case of DSI, reading will get some default value
         * set dpll_md = 0
         */
        pipe_config->dpll_hw_state.dpll_md = 0;

        pclk = vlv_get_dsi_pclk(encoder, pipe_config->pipe_bpp);
        if (!pclk)
                return;

        pipe_config->base.adjusted_mode.crtc_clock = pclk;
        pipe_config->port_clock = pclk;
}

static enum drm_mode_status
intel_dsi_mode_valid(struct drm_connector *connector,
                     struct drm_display_mode *mode)
{
        struct intel_connector *intel_connector = to_intel_connector(connector);
        struct drm_display_mode *fixed_mode = intel_connector->panel.fixed_mode;

        DRM_DEBUG_KMS("\n");

        if (mode->flags & DRM_MODE_FLAG_DBLSCAN) {
                DRM_DEBUG_KMS("MODE_NO_DBLESCAN\n");
                return MODE_NO_DBLESCAN;
        }

        if (fixed_mode) {
                if (mode->hdisplay > fixed_mode->hdisplay)
                        return MODE_PANEL;
                if (mode->vdisplay > fixed_mode->vdisplay)
                        return MODE_PANEL;
        }

        return MODE_OK;
}

/* return txclkesc cycles in terms of divider and duration in us */
static u16 txclkesc(u32 divider, unsigned int us)
{
        switch (divider) {
        case ESCAPE_CLOCK_DIVIDER_1:
        default:
                return 20 * us;
        case ESCAPE_CLOCK_DIVIDER_2:
                return 10 * us;
        case ESCAPE_CLOCK_DIVIDER_4:
                return 5 * us;
        }
}

/* return pixels in terms of txbyteclkhs */
static u16 txbyteclkhs(u16 pixels, int bpp, int lane_count,
                       u16 burst_mode_ratio)
{
        return DIV_ROUND_UP(DIV_ROUND_UP(pixels * bpp * burst_mode_ratio,
                                         8 * 100), lane_count);
}

static void set_dsi_timings(struct drm_encoder *encoder,
                            const struct drm_display_mode *mode)
{
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(encoder);
        enum port port;
        unsigned int bpp = intel_crtc->config->pipe_bpp;
        unsigned int lane_count = intel_dsi->lane_count;

        u16 hactive, hfp, hsync, hbp, vfp, vsync, vbp;

        hactive = mode->hdisplay;
        hfp = mode->hsync_start - mode->hdisplay;
        hsync = mode->hsync_end - mode->hsync_start;
        hbp = mode->htotal - mode->hsync_end;

        if (intel_dsi->dual_link) {
                hactive /= 2;
                if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK)
                        hactive += intel_dsi->pixel_overlap;
                hfp /= 2;
                hsync /= 2;
                hbp /= 2;
        }

        vfp = mode->vsync_start - mode->vdisplay;
        vsync = mode->vsync_end - mode->vsync_start;
        vbp = mode->vtotal - mode->vsync_end;

        /* horizontal values are in terms of high speed byte clock */
        hactive = txbyteclkhs(hactive, bpp, lane_count,
                              intel_dsi->burst_mode_ratio);
        hfp = txbyteclkhs(hfp, bpp, lane_count, intel_dsi->burst_mode_ratio);
        hsync = txbyteclkhs(hsync, bpp, lane_count,
                            intel_dsi->burst_mode_ratio);
        hbp = txbyteclkhs(hbp, bpp, lane_count, intel_dsi->burst_mode_ratio);

        for_each_dsi_port(port, intel_dsi->ports) {
                I915_WRITE(MIPI_HACTIVE_AREA_COUNT(port), hactive);
                I915_WRITE(MIPI_HFP_COUNT(port), hfp);

                /* meaningful for video mode non-burst sync pulse mode only,
                 * can be zero for non-burst sync events and burst modes */
                I915_WRITE(MIPI_HSYNC_PADDING_COUNT(port), hsync);
                I915_WRITE(MIPI_HBP_COUNT(port), hbp);

                /* vertical values are in terms of lines */
                I915_WRITE(MIPI_VFP_COUNT(port), vfp);
                I915_WRITE(MIPI_VSYNC_PADDING_COUNT(port), vsync);
                I915_WRITE(MIPI_VBP_COUNT(port), vbp);
        }
}

static void intel_dsi_prepare(struct intel_encoder *intel_encoder)
{
        struct drm_encoder *encoder = &intel_encoder->base;
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *intel_crtc = to_intel_crtc(encoder->crtc);
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(encoder);
        struct drm_display_mode *adjusted_mode =
                &intel_crtc->config->base.adjusted_mode;
        enum port port;
        unsigned int bpp = intel_crtc->config->pipe_bpp;
        u32 val, tmp;
        u16 mode_hdisplay;

        DRM_DEBUG_KMS("pipe %c\n", pipe_name(intel_crtc->pipe));

        mode_hdisplay = adjusted_mode->hdisplay;

        if (intel_dsi->dual_link) {
                mode_hdisplay /= 2;
                if (intel_dsi->dual_link == DSI_DUAL_LINK_FRONT_BACK)
                        mode_hdisplay += intel_dsi->pixel_overlap;
        }

        for_each_dsi_port(port, intel_dsi->ports) {
                /* escape clock divider, 20MHz, shared for A and C.
                 * device ready must be off when doing this! txclkesc? */
                tmp = I915_READ(MIPI_CTRL(PORT_A));
                tmp &= ~ESCAPE_CLOCK_DIVIDER_MASK;
                I915_WRITE(MIPI_CTRL(PORT_A), tmp | ESCAPE_CLOCK_DIVIDER_1);

                /* read request priority is per pipe */
                tmp = I915_READ(MIPI_CTRL(port));
                tmp &= ~READ_REQUEST_PRIORITY_MASK;
                I915_WRITE(MIPI_CTRL(port), tmp | READ_REQUEST_PRIORITY_HIGH);

                /* XXX: why here, why like this? handling in irq handler?! */
                I915_WRITE(MIPI_INTR_STAT(port), 0xffffffff);
                I915_WRITE(MIPI_INTR_EN(port), 0xffffffff);

                I915_WRITE(MIPI_DPHY_PARAM(port), intel_dsi->dphy_reg);

                I915_WRITE(MIPI_DPI_RESOLUTION(port),
                        adjusted_mode->vdisplay << VERTICAL_ADDRESS_SHIFT |
                        mode_hdisplay << HORIZONTAL_ADDRESS_SHIFT);
        }

        set_dsi_timings(encoder, adjusted_mode);

        val = intel_dsi->lane_count << DATA_LANES_PRG_REG_SHIFT;
        if (is_cmd_mode(intel_dsi)) {
                val |= intel_dsi->channel << CMD_MODE_CHANNEL_NUMBER_SHIFT;
                val |= CMD_MODE_DATA_WIDTH_8_BIT; /* XXX */
        } else {
                val |= intel_dsi->channel << VID_MODE_CHANNEL_NUMBER_SHIFT;

                /* XXX: cross-check bpp vs. pixel format? */
                val |= intel_dsi->pixel_format;
        }

        tmp = 0;
        if (intel_dsi->eotp_pkt == 0)
                tmp |= EOT_DISABLE;
        if (intel_dsi->clock_stop)
                tmp |= CLOCKSTOP;

        for_each_dsi_port(port, intel_dsi->ports) {
                I915_WRITE(MIPI_DSI_FUNC_PRG(port), val);

                /* timeouts for recovery. one frame IIUC. if counter expires,
                 * EOT and stop state. */

                /*
                 * In burst mode, value greater than one DPI line Time in byte
                 * clock (txbyteclkhs) To timeout this timer 1+ of the above
                 * said value is recommended.
                 *
                 * In non-burst mode, Value greater than one DPI frame time in
                 * byte clock(txbyteclkhs) To timeout this timer 1+ of the above
                 * said value is recommended.
                 *
                 * In DBI only mode, value greater than one DBI frame time in
                 * byte clock(txbyteclkhs) To timeout this timer 1+ of the above
                 * said value is recommended.
                 */

                if (is_vid_mode(intel_dsi) &&
                        intel_dsi->video_mode_format == VIDEO_MODE_BURST) {
                        I915_WRITE(MIPI_HS_TX_TIMEOUT(port),
                                txbyteclkhs(adjusted_mode->htotal, bpp,
                                        intel_dsi->lane_count,
                                        intel_dsi->burst_mode_ratio) + 1);
                } else {
                        I915_WRITE(MIPI_HS_TX_TIMEOUT(port),
                                txbyteclkhs(adjusted_mode->vtotal *
                                        adjusted_mode->htotal,
                                        bpp, intel_dsi->lane_count,
                                        intel_dsi->burst_mode_ratio) + 1);
                }
                I915_WRITE(MIPI_LP_RX_TIMEOUT(port), intel_dsi->lp_rx_timeout);
                I915_WRITE(MIPI_TURN_AROUND_TIMEOUT(port),
                                                intel_dsi->turn_arnd_val);
                I915_WRITE(MIPI_DEVICE_RESET_TIMER(port),
                                                intel_dsi->rst_timer_val);

                /* dphy stuff */

                /* in terms of low power clock */
                I915_WRITE(MIPI_INIT_COUNT(port),
                                txclkesc(intel_dsi->escape_clk_div, 100));


                /* recovery disables */
                I915_WRITE(MIPI_EOT_DISABLE(port), tmp);

                /* in terms of low power clock */
                I915_WRITE(MIPI_INIT_COUNT(port), intel_dsi->init_count);

                /* in terms of txbyteclkhs. actual high to low switch +
                 * MIPI_STOP_STATE_STALL * MIPI_LP_BYTECLK.
                 *
                 * XXX: write MIPI_STOP_STATE_STALL?
                 */
                I915_WRITE(MIPI_HIGH_LOW_SWITCH_COUNT(port),
                                                intel_dsi->hs_to_lp_count);

                /* XXX: low power clock equivalence in terms of byte clock.
                 * the number of byte clocks occupied in one low power clock.
                 * based on txbyteclkhs and txclkesc.
                 * txclkesc time / txbyteclk time * (105 + MIPI_STOP_STATE_STALL
                 * ) / 105.???
                 */
                I915_WRITE(MIPI_LP_BYTECLK(port), intel_dsi->lp_byte_clk);

                /* the bw essential for transmitting 16 long packets containing
                 * 252 bytes meant for dcs write memory command is programmed in
                 * this register in terms of byte clocks. based on dsi transfer
                 * rate and the number of lanes configured the time taken to
                 * transmit 16 long packets in a dsi stream varies. */
                I915_WRITE(MIPI_DBI_BW_CTRL(port), intel_dsi->bw_timer);

                I915_WRITE(MIPI_CLK_LANE_SWITCH_TIME_CNT(port),
                intel_dsi->clk_lp_to_hs_count << LP_HS_SSW_CNT_SHIFT |
                intel_dsi->clk_hs_to_lp_count << HS_LP_PWR_SW_CNT_SHIFT);

                if (is_vid_mode(intel_dsi))
                        /* Some panels might have resolution which is not a
                         * multiple of 64 like 1366 x 768. Enable RANDOM
                         * resolution support for such panels by default */
                        I915_WRITE(MIPI_VIDEO_MODE_FORMAT(port),
                                intel_dsi->video_frmt_cfg_bits |
                                intel_dsi->video_mode_format |
                                IP_TG_CONFIG |
                                RANDOM_DPI_DISPLAY_RESOLUTION);
        }
}

static void intel_dsi_pre_pll_enable(struct intel_encoder *encoder)
{
        DRM_DEBUG_KMS("\n");

        intel_dsi_prepare(encoder);

        vlv_enable_dsi_pll(encoder);
}

static enum drm_connector_status
intel_dsi_detect(struct drm_connector *connector, bool force)
{
        return connector_status_connected;
}

static int intel_dsi_get_modes(struct drm_connector *connector)
{
        struct intel_connector *intel_connector = to_intel_connector(connector);
        struct drm_display_mode *mode;

        DRM_DEBUG_KMS("\n");

        if (!intel_connector->panel.fixed_mode) {
                DRM_DEBUG_KMS("no fixed mode\n");
                return 0;
        }

        mode = drm_mode_duplicate(connector->dev,
                                  intel_connector->panel.fixed_mode);
        if (!mode) {
                DRM_DEBUG_KMS("drm_mode_duplicate failed\n");
                return 0;
        }

        drm_mode_probed_add(connector, mode);
        return 1;
}

static void intel_dsi_connector_destroy(struct drm_connector *connector)
{
        struct intel_connector *intel_connector = to_intel_connector(connector);

        DRM_DEBUG_KMS("\n");
        intel_panel_fini(&intel_connector->panel);
        drm_connector_cleanup(connector);
        kfree(connector);
}

static void intel_dsi_encoder_destroy(struct drm_encoder *encoder)
{
        struct intel_dsi *intel_dsi = enc_to_intel_dsi(encoder);

        if (intel_dsi->panel) {
                drm_panel_detach(intel_dsi->panel);
                /* XXX: Logically this call belongs in the panel driver. */
                drm_panel_remove(intel_dsi->panel);
        }
        intel_encoder_destroy(encoder);
}

static const struct drm_encoder_funcs intel_dsi_funcs = {
        .destroy = intel_dsi_encoder_destroy,
};

static const struct drm_connector_helper_funcs intel_dsi_connector_helper_funcs = {
        .get_modes = intel_dsi_get_modes,
        .mode_valid = intel_dsi_mode_valid,
        .best_encoder = intel_best_encoder,
};

static const struct drm_connector_funcs intel_dsi_connector_funcs = {
        .dpms = intel_connector_dpms,
        .detect = intel_dsi_detect,
        .destroy = intel_dsi_connector_destroy,
        .fill_modes = drm_helper_probe_single_connector_modes,
        .atomic_get_property = intel_connector_atomic_get_property,
        .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
        .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
};

void intel_dsi_init(struct drm_device *dev)
{
        struct intel_dsi *intel_dsi;
        struct intel_encoder *intel_encoder;
        struct drm_encoder *encoder;
        struct intel_connector *intel_connector;
        struct drm_connector *connector;
        struct drm_display_mode *scan, *fixed_mode = NULL;
        struct drm_i915_private *dev_priv = dev->dev_private;
        enum port port;
        unsigned int i;

        DRM_DEBUG_KMS("\n");

        /* There is no detection method for MIPI so rely on VBT */
        if (!dev_priv->vbt.has_mipi)
                return;

        if (IS_VALLEYVIEW(dev)) {
                dev_priv->mipi_mmio_base = VLV_MIPI_BASE;

        } else {
                DRM_ERROR("Unsupported Mipi device to reg base");
                return;
        }

        intel_dsi = kzalloc(sizeof(*intel_dsi), GFP_KERNEL);
        if (!intel_dsi)
                return;

        intel_connector = intel_connector_alloc();
        if (!intel_connector) {
                kfree(intel_dsi);
                return;
        }

        intel_encoder = &intel_dsi->base;
        encoder = &intel_encoder->base;
        intel_dsi->attached_connector = intel_connector;

        connector = &intel_connector->base;

        drm_encoder_init(dev, encoder, &intel_dsi_funcs, DRM_MODE_ENCODER_DSI);

        /* XXX: very likely not all of these are needed */
        intel_encoder->hot_plug = intel_dsi_hot_plug;
        intel_encoder->compute_config = intel_dsi_compute_config;
        intel_encoder->pre_pll_enable = intel_dsi_pre_pll_enable;
        intel_encoder->pre_enable = intel_dsi_pre_enable;
        intel_encoder->enable = intel_dsi_enable_nop;
        intel_encoder->disable = intel_dsi_pre_disable;
        intel_encoder->post_disable = intel_dsi_post_disable;
        intel_encoder->get_hw_state = intel_dsi_get_hw_state;
        intel_encoder->get_config = intel_dsi_get_config;

        intel_connector->get_hw_state = intel_connector_get_hw_state;
        intel_connector->unregister = intel_connector_unregister;

        /* Pipe A maps to MIPI DSI port A, pipe B maps to MIPI DSI port C */
        if (dev_priv->vbt.dsi.config->dual_link) {
                /* XXX: does dual link work on either pipe? */
                intel_encoder->crtc_mask = (1 << PIPE_A);
                intel_dsi->ports = ((1 << PORT_A) | (1 << PORT_C));
        } else if (dev_priv->vbt.dsi.port == DVO_PORT_MIPIA) {
                intel_encoder->crtc_mask = (1 << PIPE_A);
                intel_dsi->ports = (1 << PORT_A);
        } else if (dev_priv->vbt.dsi.port == DVO_PORT_MIPIC) {
                intel_encoder->crtc_mask = (1 << PIPE_B);
                intel_dsi->ports = (1 << PORT_C);
        }

        /* Create a DSI host (and a device) for each port. */
        for_each_dsi_port(port, intel_dsi->ports) {
                struct intel_dsi_host *host;

                host = intel_dsi_host_init(intel_dsi, port);
                if (!host)
                        goto err;

                intel_dsi->dsi_hosts[port] = host;
        }

        for (i = 0; i < ARRAY_SIZE(intel_dsi_drivers); i++) {
                intel_dsi->panel = intel_dsi_drivers[i].init(intel_dsi,
                                                             intel_dsi_drivers[i].panel_id);
                if (intel_dsi->panel)
                        break;
        }

        if (!intel_dsi->panel) {
                DRM_DEBUG_KMS("no device found\n");
                goto err;
        }

        intel_encoder->type = INTEL_OUTPUT_DSI;
        intel_encoder->cloneable = 0;
        drm_connector_init(dev, connector, &intel_dsi_connector_funcs,
                           DRM_MODE_CONNECTOR_DSI);

        drm_connector_helper_add(connector, &intel_dsi_connector_helper_funcs);

        connector->display_info.subpixel_order = SubPixelHorizontalRGB; /*XXX*/
        connector->interlace_allowed = false;
        connector->doublescan_allowed = false;

        intel_connector_attach_encoder(intel_connector, intel_encoder);

        drm_connector_register(connector);

        drm_panel_attach(intel_dsi->panel, connector);

        mutex_lock(&dev->mode_config.mutex);
        drm_panel_get_modes(intel_dsi->panel);
        list_for_each_entry(scan, &connector->probed_modes, head) {
                if ((scan->type & DRM_MODE_TYPE_PREFERRED)) {
                        fixed_mode = drm_mode_duplicate(dev, scan);
                        break;
                }
        }
        mutex_unlock(&dev->mode_config.mutex);

        if (!fixed_mode) {
                DRM_DEBUG_KMS("no fixed mode\n");
                goto err;
        }

        intel_panel_init(&intel_connector->panel, fixed_mode, NULL);

        return;

err:
        drm_encoder_cleanup(&intel_encoder->base);
        kfree(intel_dsi);
        kfree(intel_connector);
}