drm/i915: enable DisplayPort support on IGDNG

[mirror_ubuntu-bionic-kernel.git] / drivers / gpu / drm / i915 / intel_dp.c

/*
 * Copyright © 2008 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:
 *    Keith Packard <keithp@keithp.com>
 *
 */

#include <linux/i2c.h>
#include "drmP.h"
#include "drm.h"
#include "drm_crtc.h"
#include "drm_crtc_helper.h"
#include "intel_drv.h"
#include "i915_drm.h"
#include "i915_drv.h"
#include "intel_dp.h"

#define DP_LINK_STATUS_SIZE     6
#define DP_LINK_CHECK_TIMEOUT   (10 * 1000)

#define DP_LINK_CONFIGURATION_SIZE      9

struct intel_dp_priv {
        uint32_t output_reg;
        uint32_t DP;
        uint8_t  link_configuration[DP_LINK_CONFIGURATION_SIZE];
        uint32_t save_DP;
        uint8_t  save_link_configuration[DP_LINK_CONFIGURATION_SIZE];
        bool has_audio;
        int dpms_mode;
        uint8_t link_bw;
        uint8_t lane_count;
        uint8_t dpcd[4];
        struct intel_output *intel_output;
        struct i2c_adapter adapter;
        struct i2c_algo_dp_aux_data algo;
};

static void
intel_dp_link_train(struct intel_output *intel_output, uint32_t DP,
                    uint8_t link_configuration[DP_LINK_CONFIGURATION_SIZE]);

static void
intel_dp_link_down(struct intel_output *intel_output, uint32_t DP);

static int
intel_dp_max_lane_count(struct intel_output *intel_output)
{
        struct intel_dp_priv   *dp_priv = intel_output->dev_priv;
        int max_lane_count = 4;

        if (dp_priv->dpcd[0] >= 0x11) {
                max_lane_count = dp_priv->dpcd[2] & 0x1f;
                switch (max_lane_count) {
                case 1: case 2: case 4:
                        break;
                default:
                        max_lane_count = 4;
                }
        }
        return max_lane_count;
}

static int
intel_dp_max_link_bw(struct intel_output *intel_output)
{
        struct intel_dp_priv   *dp_priv = intel_output->dev_priv;
        int max_link_bw = dp_priv->dpcd[1];

        switch (max_link_bw) {
        case DP_LINK_BW_1_62:
        case DP_LINK_BW_2_7:
                break;
        default:
                max_link_bw = DP_LINK_BW_1_62;
                break;
        }
        return max_link_bw;
}

static int
intel_dp_link_clock(uint8_t link_bw)
{
        if (link_bw == DP_LINK_BW_2_7)
                return 270000;
        else
                return 162000;
}

/* I think this is a fiction */
static int
intel_dp_link_required(int pixel_clock)
{
        return pixel_clock * 3;
}

static int
intel_dp_mode_valid(struct drm_connector *connector,
                    struct drm_display_mode *mode)
{
        struct intel_output *intel_output = to_intel_output(connector);
        int max_link_clock = intel_dp_link_clock(intel_dp_max_link_bw(intel_output));
        int max_lanes = intel_dp_max_lane_count(intel_output);

        if (intel_dp_link_required(mode->clock) > max_link_clock * max_lanes)
                return MODE_CLOCK_HIGH;

        if (mode->clock < 10000)
                return MODE_CLOCK_LOW;

        return MODE_OK;
}

static uint32_t
pack_aux(uint8_t *src, int src_bytes)
{
        int     i;
        uint32_t v = 0;

        if (src_bytes > 4)
                src_bytes = 4;
        for (i = 0; i < src_bytes; i++)
                v |= ((uint32_t) src[i]) << ((3-i) * 8);
        return v;
}

static void
unpack_aux(uint32_t src, uint8_t *dst, int dst_bytes)
{
        int i;
        if (dst_bytes > 4)
                dst_bytes = 4;
        for (i = 0; i < dst_bytes; i++)
                dst[i] = src >> ((3-i) * 8);
}

/* hrawclock is 1/4 the FSB frequency */
static int
intel_hrawclk(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t clkcfg;

        clkcfg = I915_READ(CLKCFG);
        switch (clkcfg & CLKCFG_FSB_MASK) {
        case CLKCFG_FSB_400:
                return 100;
        case CLKCFG_FSB_533:
                return 133;
        case CLKCFG_FSB_667:
                return 166;
        case CLKCFG_FSB_800:
                return 200;
        case CLKCFG_FSB_1067:
                return 266;
        case CLKCFG_FSB_1333:
                return 333;
        /* these two are just a guess; one of them might be right */
        case CLKCFG_FSB_1600:
        case CLKCFG_FSB_1600_ALT:
                return 400;
        default:
                return 133;
        }
}

static int
intel_dp_aux_ch(struct intel_output *intel_output,
                uint8_t *send, int send_bytes,
                uint8_t *recv, int recv_size)
{
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;
        uint32_t output_reg = dp_priv->output_reg;
        struct drm_device *dev = intel_output->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t ch_ctl = output_reg + 0x10;
        uint32_t ch_data = ch_ctl + 4;
        int i;
        int recv_bytes;
        uint32_t ctl;
        uint32_t status;
        uint32_t aux_clock_divider;
        int try;

        /* The clock divider is based off the hrawclk,
         * and would like to run at 2MHz. So, take the
         * hrawclk value and divide by 2 and use that
         */
        /* IGDNG: input clock fixed at 125Mhz, so aux_bit_clk always 62 */
        if (IS_IGDNG(dev))
                aux_clock_divider = 62;
        else
                aux_clock_divider = intel_hrawclk(dev) / 2;

        /* Must try at least 3 times according to DP spec */
        for (try = 0; try < 5; try++) {
                /* Load the send data into the aux channel data registers */
                for (i = 0; i < send_bytes; i += 4) {
                        uint32_t    d = pack_aux(send + i, send_bytes - i);;
        
                        I915_WRITE(ch_data + i, d);
                }
        
                ctl = (DP_AUX_CH_CTL_SEND_BUSY |
                       DP_AUX_CH_CTL_TIME_OUT_400us |
                       (send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
                       (5 << DP_AUX_CH_CTL_PRECHARGE_2US_SHIFT) |
                       (aux_clock_divider << DP_AUX_CH_CTL_BIT_CLOCK_2X_SHIFT) |
                       DP_AUX_CH_CTL_DONE |
                       DP_AUX_CH_CTL_TIME_OUT_ERROR |
                       DP_AUX_CH_CTL_RECEIVE_ERROR);
        
                /* Send the command and wait for it to complete */
                I915_WRITE(ch_ctl, ctl);
                (void) I915_READ(ch_ctl);
                for (;;) {
                        udelay(100);
                        status = I915_READ(ch_ctl);
                        if ((status & DP_AUX_CH_CTL_SEND_BUSY) == 0)
                                break;
                }
        
                /* Clear done status and any errors */
                I915_WRITE(ch_ctl, (status |
                                DP_AUX_CH_CTL_DONE |
                                DP_AUX_CH_CTL_TIME_OUT_ERROR |
                                DP_AUX_CH_CTL_RECEIVE_ERROR));
                (void) I915_READ(ch_ctl);
                if ((status & DP_AUX_CH_CTL_TIME_OUT_ERROR) == 0)
                        break;
        }

        if ((status & DP_AUX_CH_CTL_DONE) == 0) {
                DRM_ERROR("dp_aux_ch not done status 0x%08x\n", status);
                return -EBUSY;
        }

        /* Check for timeout or receive error.
         * Timeouts occur when the sink is not connected
         */
        if (status & DP_AUX_CH_CTL_RECEIVE_ERROR) {
                DRM_ERROR("dp_aux_ch receive error status 0x%08x\n", status);
                return -EIO;
        }

        /* Timeouts occur when the device isn't connected, so they're
         * "normal" -- don't fill the kernel log with these */
        if (status & DP_AUX_CH_CTL_TIME_OUT_ERROR) {
                DRM_DEBUG("dp_aux_ch timeout status 0x%08x\n", status);
                return -ETIMEDOUT;
        }

        /* Unload any bytes sent back from the other side */
        recv_bytes = ((status & DP_AUX_CH_CTL_MESSAGE_SIZE_MASK) >>
                      DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT);

        if (recv_bytes > recv_size)
                recv_bytes = recv_size;
        
        for (i = 0; i < recv_bytes; i += 4) {
                uint32_t    d = I915_READ(ch_data + i);

                unpack_aux(d, recv + i, recv_bytes - i);
        }

        return recv_bytes;
}

/* Write data to the aux channel in native mode */
static int
intel_dp_aux_native_write(struct intel_output *intel_output,
                          uint16_t address, uint8_t *send, int send_bytes)
{
        int ret;
        uint8_t msg[20];
        int msg_bytes;
        uint8_t ack;

        if (send_bytes > 16)
                return -1;
        msg[0] = AUX_NATIVE_WRITE << 4;
        msg[1] = address >> 8;
        msg[2] = address & 0xff;
        msg[3] = send_bytes - 1;
        memcpy(&msg[4], send, send_bytes);
        msg_bytes = send_bytes + 4;
        for (;;) {
                ret = intel_dp_aux_ch(intel_output, msg, msg_bytes, &ack, 1);
                if (ret < 0)
                        return ret;
                if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK)
                        break;
                else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)
                        udelay(100);
                else
                        return -EIO;
        }
        return send_bytes;
}

/* Write a single byte to the aux channel in native mode */
static int
intel_dp_aux_native_write_1(struct intel_output *intel_output,
                            uint16_t address, uint8_t byte)
{
        return intel_dp_aux_native_write(intel_output, address, &byte, 1);
}

/* read bytes from a native aux channel */
static int
intel_dp_aux_native_read(struct intel_output *intel_output,
                         uint16_t address, uint8_t *recv, int recv_bytes)
{
        uint8_t msg[4];
        int msg_bytes;
        uint8_t reply[20];
        int reply_bytes;
        uint8_t ack;
        int ret;

        msg[0] = AUX_NATIVE_READ << 4;
        msg[1] = address >> 8;
        msg[2] = address & 0xff;
        msg[3] = recv_bytes - 1;

        msg_bytes = 4;
        reply_bytes = recv_bytes + 1;

        for (;;) {
                ret = intel_dp_aux_ch(intel_output, msg, msg_bytes,
                                      reply, reply_bytes);
                if (ret == 0)
                        return -EPROTO;
                if (ret < 0)
                        return ret;
                ack = reply[0];
                if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK) {
                        memcpy(recv, reply + 1, ret - 1);
                        return ret - 1;
                }
                else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)
                        udelay(100);
                else
                        return -EIO;
        }
}

static int
intel_dp_i2c_aux_ch(struct i2c_adapter *adapter,
                    uint8_t *send, int send_bytes,
                    uint8_t *recv, int recv_bytes)
{
        struct intel_dp_priv *dp_priv = container_of(adapter,
                                                     struct intel_dp_priv,
                                                     adapter);
        struct intel_output *intel_output = dp_priv->intel_output;

        return intel_dp_aux_ch(intel_output,
                               send, send_bytes, recv, recv_bytes);
}

static int
intel_dp_i2c_init(struct intel_output *intel_output, const char *name)
{
        struct intel_dp_priv   *dp_priv = intel_output->dev_priv;

        DRM_ERROR("i2c_init %s\n", name);
        dp_priv->algo.running = false;
        dp_priv->algo.address = 0;
        dp_priv->algo.aux_ch = intel_dp_i2c_aux_ch;

        memset(&dp_priv->adapter, '\0', sizeof (dp_priv->adapter));
        dp_priv->adapter.owner = THIS_MODULE;
        dp_priv->adapter.class = I2C_CLASS_DDC;
        strncpy (dp_priv->adapter.name, name, sizeof(dp_priv->adapter.name) - 1);
        dp_priv->adapter.name[sizeof(dp_priv->adapter.name) - 1] = '\0';
        dp_priv->adapter.algo_data = &dp_priv->algo;
        dp_priv->adapter.dev.parent = &intel_output->base.kdev;
        
        return i2c_dp_aux_add_bus(&dp_priv->adapter);
}

static bool
intel_dp_mode_fixup(struct drm_encoder *encoder, struct drm_display_mode *mode,
                    struct drm_display_mode *adjusted_mode)
{
        struct intel_output *intel_output = enc_to_intel_output(encoder);
        struct intel_dp_priv   *dp_priv = intel_output->dev_priv;
        int lane_count, clock;
        int max_lane_count = intel_dp_max_lane_count(intel_output);
        int max_clock = intel_dp_max_link_bw(intel_output) == DP_LINK_BW_2_7 ? 1 : 0;
        static int bws[2] = { DP_LINK_BW_1_62, DP_LINK_BW_2_7 };

        for (lane_count = 1; lane_count <= max_lane_count; lane_count <<= 1) {
                for (clock = 0; clock <= max_clock; clock++) {
                        int link_avail = intel_dp_link_clock(bws[clock]) * lane_count;

                        if (intel_dp_link_required(mode->clock) <= link_avail) {
                                dp_priv->link_bw = bws[clock];
                                dp_priv->lane_count = lane_count;
                                adjusted_mode->clock = intel_dp_link_clock(dp_priv->link_bw);
                                DRM_DEBUG("Display port link bw %02x lane count %d clock %d\n",
                                       dp_priv->link_bw, dp_priv->lane_count,
                                       adjusted_mode->clock);
                                return true;
                        }
                }
        }
        return false;
}

struct intel_dp_m_n {
        uint32_t        tu;
        uint32_t        gmch_m;
        uint32_t        gmch_n;
        uint32_t        link_m;
        uint32_t        link_n;
};

static void
intel_reduce_ratio(uint32_t *num, uint32_t *den)
{
        while (*num > 0xffffff || *den > 0xffffff) {
                *num >>= 1;
                *den >>= 1;
        }
}

static void
intel_dp_compute_m_n(int bytes_per_pixel,
                     int nlanes,
                     int pixel_clock,
                     int link_clock,
                     struct intel_dp_m_n *m_n)
{
        m_n->tu = 64;
        m_n->gmch_m = pixel_clock * bytes_per_pixel;
        m_n->gmch_n = link_clock * nlanes;
        intel_reduce_ratio(&m_n->gmch_m, &m_n->gmch_n);
        m_n->link_m = pixel_clock;
        m_n->link_n = link_clock;
        intel_reduce_ratio(&m_n->link_m, &m_n->link_n);
}

void
intel_dp_set_m_n(struct drm_crtc *crtc, struct drm_display_mode *mode,
                 struct drm_display_mode *adjusted_mode)
{
        struct drm_device *dev = crtc->dev;
        struct drm_mode_config *mode_config = &dev->mode_config;
        struct drm_connector *connector;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
        int lane_count = 4;
        struct intel_dp_m_n m_n;

        /*
         * Find the lane count in the intel_output private
         */
        list_for_each_entry(connector, &mode_config->connector_list, head) {
                struct intel_output *intel_output = to_intel_output(connector);
                struct intel_dp_priv *dp_priv = intel_output->dev_priv;

                if (!connector->encoder || connector->encoder->crtc != crtc)
                        continue;

                if (intel_output->type == INTEL_OUTPUT_DISPLAYPORT) {
                        lane_count = dp_priv->lane_count;
                        break;
                }
        }

        /*
         * Compute the GMCH and Link ratios. The '3' here is
         * the number of bytes_per_pixel post-LUT, which we always
         * set up for 8-bits of R/G/B, or 3 bytes total.
         */
        intel_dp_compute_m_n(3, lane_count,
                             mode->clock, adjusted_mode->clock, &m_n);

        if (IS_IGDNG(dev)) {
                if (intel_crtc->pipe == 0) {
                        I915_WRITE(TRANSA_DATA_M1,
                                   ((m_n.tu - 1) << PIPE_GMCH_DATA_M_TU_SIZE_SHIFT) |
                                   m_n.gmch_m);
                        I915_WRITE(TRANSA_DATA_N1, m_n.gmch_n);
                        I915_WRITE(TRANSA_DP_LINK_M1, m_n.link_m);
                        I915_WRITE(TRANSA_DP_LINK_N1, m_n.link_n);
                } else {
                        I915_WRITE(TRANSB_DATA_M1,
                                   ((m_n.tu - 1) << PIPE_GMCH_DATA_M_TU_SIZE_SHIFT) |
                                   m_n.gmch_m);
                        I915_WRITE(TRANSB_DATA_N1, m_n.gmch_n);
                        I915_WRITE(TRANSB_DP_LINK_M1, m_n.link_m);
                        I915_WRITE(TRANSB_DP_LINK_N1, m_n.link_n);
                }
        } else {
                if (intel_crtc->pipe == 0) {
                        I915_WRITE(PIPEA_GMCH_DATA_M,
                                   ((m_n.tu - 1) << PIPE_GMCH_DATA_M_TU_SIZE_SHIFT) |
                                   m_n.gmch_m);
                        I915_WRITE(PIPEA_GMCH_DATA_N,
                                   m_n.gmch_n);
                        I915_WRITE(PIPEA_DP_LINK_M, m_n.link_m);
                        I915_WRITE(PIPEA_DP_LINK_N, m_n.link_n);
                } else {
                        I915_WRITE(PIPEB_GMCH_DATA_M,
                                   ((m_n.tu - 1) << PIPE_GMCH_DATA_M_TU_SIZE_SHIFT) |
                                   m_n.gmch_m);
                        I915_WRITE(PIPEB_GMCH_DATA_N,
                                        m_n.gmch_n);
                        I915_WRITE(PIPEB_DP_LINK_M, m_n.link_m);
                        I915_WRITE(PIPEB_DP_LINK_N, m_n.link_n);
                }
        }
}

static void
intel_dp_mode_set(struct drm_encoder *encoder, struct drm_display_mode *mode,
                  struct drm_display_mode *adjusted_mode)
{
        struct intel_output *intel_output = enc_to_intel_output(encoder);
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;
        struct drm_crtc *crtc = intel_output->enc.crtc;
        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);

        dp_priv->DP = (DP_LINK_TRAIN_OFF |
                        DP_VOLTAGE_0_4 |
                        DP_PRE_EMPHASIS_0 |
                        DP_SYNC_VS_HIGH |
                        DP_SYNC_HS_HIGH);

        switch (dp_priv->lane_count) {
        case 1:
                dp_priv->DP |= DP_PORT_WIDTH_1;
                break;
        case 2:
                dp_priv->DP |= DP_PORT_WIDTH_2;
                break;
        case 4:
                dp_priv->DP |= DP_PORT_WIDTH_4;
                break;
        }
        if (dp_priv->has_audio)
                dp_priv->DP |= DP_AUDIO_OUTPUT_ENABLE;

        memset(dp_priv->link_configuration, 0, DP_LINK_CONFIGURATION_SIZE);
        dp_priv->link_configuration[0] = dp_priv->link_bw;
        dp_priv->link_configuration[1] = dp_priv->lane_count;

        /*
         * Check for DPCD version > 1.1,
         * enable enahanced frame stuff in that case
         */
        if (dp_priv->dpcd[0] >= 0x11) {
                dp_priv->link_configuration[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
                dp_priv->DP |= DP_ENHANCED_FRAMING;
        }

        if (intel_crtc->pipe == 1)
                dp_priv->DP |= DP_PIPEB_SELECT;
}


static void
intel_dp_dpms(struct drm_encoder *encoder, int mode)
{
        struct intel_output *intel_output = enc_to_intel_output(encoder);
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;
        struct drm_device *dev = intel_output->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        uint32_t dp_reg = I915_READ(dp_priv->output_reg);

        if (mode != DRM_MODE_DPMS_ON) {
                if (dp_reg & DP_PORT_EN)
                        intel_dp_link_down(intel_output, dp_priv->DP);
        } else {
                if (!(dp_reg & DP_PORT_EN))
                        intel_dp_link_train(intel_output, dp_priv->DP, dp_priv->link_configuration);
        }
        dp_priv->dpms_mode = mode;
}

/*
 * Fetch AUX CH registers 0x202 - 0x207 which contain
 * link status information
 */
static bool
intel_dp_get_link_status(struct intel_output *intel_output,
                         uint8_t link_status[DP_LINK_STATUS_SIZE])
{
        int ret;

        ret = intel_dp_aux_native_read(intel_output,
                                       DP_LANE0_1_STATUS,
                                       link_status, DP_LINK_STATUS_SIZE);
        if (ret != DP_LINK_STATUS_SIZE)
                return false;
        return true;
}

static uint8_t
intel_dp_link_status(uint8_t link_status[DP_LINK_STATUS_SIZE],
                     int r)
{
        return link_status[r - DP_LANE0_1_STATUS];
}

static void
intel_dp_save(struct drm_connector *connector)
{
        struct intel_output *intel_output = to_intel_output(connector);
        struct drm_device *dev = intel_output->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;

        dp_priv->save_DP = I915_READ(dp_priv->output_reg);
        intel_dp_aux_native_read(intel_output, DP_LINK_BW_SET,
                                 dp_priv->save_link_configuration,
                                 sizeof (dp_priv->save_link_configuration));
}

static uint8_t
intel_get_adjust_request_voltage(uint8_t link_status[DP_LINK_STATUS_SIZE],
                                 int lane)
{
        int         i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
        int         s = ((lane & 1) ?
                         DP_ADJUST_VOLTAGE_SWING_LANE1_SHIFT :
                         DP_ADJUST_VOLTAGE_SWING_LANE0_SHIFT);
        uint8_t l = intel_dp_link_status(link_status, i);

        return ((l >> s) & 3) << DP_TRAIN_VOLTAGE_SWING_SHIFT;
}

static uint8_t
intel_get_adjust_request_pre_emphasis(uint8_t link_status[DP_LINK_STATUS_SIZE],
                                      int lane)
{
        int         i = DP_ADJUST_REQUEST_LANE0_1 + (lane >> 1);
        int         s = ((lane & 1) ?
                         DP_ADJUST_PRE_EMPHASIS_LANE1_SHIFT :
                         DP_ADJUST_PRE_EMPHASIS_LANE0_SHIFT);
        uint8_t l = intel_dp_link_status(link_status, i);

        return ((l >> s) & 3) << DP_TRAIN_PRE_EMPHASIS_SHIFT;
}


#if 0
static char     *voltage_names[] = {
        "0.4V", "0.6V", "0.8V", "1.2V"
};
static char     *pre_emph_names[] = {
        "0dB", "3.5dB", "6dB", "9.5dB"
};
static char     *link_train_names[] = {
        "pattern 1", "pattern 2", "idle", "off"
};
#endif

/*
 * These are source-specific values; current Intel hardware supports
 * a maximum voltage of 800mV and a maximum pre-emphasis of 6dB
 */
#define I830_DP_VOLTAGE_MAX         DP_TRAIN_VOLTAGE_SWING_800

static uint8_t
intel_dp_pre_emphasis_max(uint8_t voltage_swing)
{
        switch (voltage_swing & DP_TRAIN_VOLTAGE_SWING_MASK) {
        case DP_TRAIN_VOLTAGE_SWING_400:
                return DP_TRAIN_PRE_EMPHASIS_6;
        case DP_TRAIN_VOLTAGE_SWING_600:
                return DP_TRAIN_PRE_EMPHASIS_6;
        case DP_TRAIN_VOLTAGE_SWING_800:
                return DP_TRAIN_PRE_EMPHASIS_3_5;
        case DP_TRAIN_VOLTAGE_SWING_1200:
        default:
                return DP_TRAIN_PRE_EMPHASIS_0;
        }
}

static void
intel_get_adjust_train(struct intel_output *intel_output,
                       uint8_t link_status[DP_LINK_STATUS_SIZE],
                       int lane_count,
                       uint8_t train_set[4])
{
        uint8_t v = 0;
        uint8_t p = 0;
        int lane;

        for (lane = 0; lane < lane_count; lane++) {
                uint8_t this_v = intel_get_adjust_request_voltage(link_status, lane);
                uint8_t this_p = intel_get_adjust_request_pre_emphasis(link_status, lane);

                if (this_v > v)
                        v = this_v;
                if (this_p > p)
                        p = this_p;
        }

        if (v >= I830_DP_VOLTAGE_MAX)
                v = I830_DP_VOLTAGE_MAX | DP_TRAIN_MAX_SWING_REACHED;

        if (p >= intel_dp_pre_emphasis_max(v))
                p = intel_dp_pre_emphasis_max(v) | DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;

        for (lane = 0; lane < 4; lane++)
                train_set[lane] = v | p;
}

static uint32_t
intel_dp_signal_levels(uint8_t train_set, int lane_count)
{
        uint32_t        signal_levels = 0;

        switch (train_set & DP_TRAIN_VOLTAGE_SWING_MASK) {
        case DP_TRAIN_VOLTAGE_SWING_400:
        default:
                signal_levels |= DP_VOLTAGE_0_4;
                break;
        case DP_TRAIN_VOLTAGE_SWING_600:
                signal_levels |= DP_VOLTAGE_0_6;
                break;
        case DP_TRAIN_VOLTAGE_SWING_800:
                signal_levels |= DP_VOLTAGE_0_8;
                break;
        case DP_TRAIN_VOLTAGE_SWING_1200:
                signal_levels |= DP_VOLTAGE_1_2;
                break;
        }
        switch (train_set & DP_TRAIN_PRE_EMPHASIS_MASK) {
        case DP_TRAIN_PRE_EMPHASIS_0:
        default:
                signal_levels |= DP_PRE_EMPHASIS_0;
                break;
        case DP_TRAIN_PRE_EMPHASIS_3_5:
                signal_levels |= DP_PRE_EMPHASIS_3_5;
                break;
        case DP_TRAIN_PRE_EMPHASIS_6:
                signal_levels |= DP_PRE_EMPHASIS_6;
                break;
        case DP_TRAIN_PRE_EMPHASIS_9_5:
                signal_levels |= DP_PRE_EMPHASIS_9_5;
                break;
        }
        return signal_levels;
}

static uint8_t
intel_get_lane_status(uint8_t link_status[DP_LINK_STATUS_SIZE],
                      int lane)
{
        int i = DP_LANE0_1_STATUS + (lane >> 1);
        int s = (lane & 1) * 4;
        uint8_t l = intel_dp_link_status(link_status, i);

        return (l >> s) & 0xf;
}

/* Check for clock recovery is done on all channels */
static bool
intel_clock_recovery_ok(uint8_t link_status[DP_LINK_STATUS_SIZE], int lane_count)
{
        int lane;
        uint8_t lane_status;

        for (lane = 0; lane < lane_count; lane++) {
                lane_status = intel_get_lane_status(link_status, lane);
                if ((lane_status & DP_LANE_CR_DONE) == 0)
                        return false;
        }
        return true;
}

/* Check to see if channel eq is done on all channels */
#define CHANNEL_EQ_BITS (DP_LANE_CR_DONE|\
                         DP_LANE_CHANNEL_EQ_DONE|\
                         DP_LANE_SYMBOL_LOCKED)
static bool
intel_channel_eq_ok(uint8_t link_status[DP_LINK_STATUS_SIZE], int lane_count)
{
        uint8_t lane_align;
        uint8_t lane_status;
        int lane;

        lane_align = intel_dp_link_status(link_status,
                                          DP_LANE_ALIGN_STATUS_UPDATED);
        if ((lane_align & DP_INTERLANE_ALIGN_DONE) == 0)
                return false;
        for (lane = 0; lane < lane_count; lane++) {
                lane_status = intel_get_lane_status(link_status, lane);
                if ((lane_status & CHANNEL_EQ_BITS) != CHANNEL_EQ_BITS)
                        return false;
        }
        return true;
}

static bool
intel_dp_set_link_train(struct intel_output *intel_output,
                        uint32_t dp_reg_value,
                        uint8_t dp_train_pat,
                        uint8_t train_set[4],
                        bool first)
{
        struct drm_device *dev = intel_output->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;
        int ret;

        I915_WRITE(dp_priv->output_reg, dp_reg_value);
        POSTING_READ(dp_priv->output_reg);
        if (first)
                intel_wait_for_vblank(dev);

        intel_dp_aux_native_write_1(intel_output,
                                    DP_TRAINING_PATTERN_SET,
                                    dp_train_pat);

        ret = intel_dp_aux_native_write(intel_output,
                                        DP_TRAINING_LANE0_SET, train_set, 4);
        if (ret != 4)
                return false;

        return true;
}

static void
intel_dp_link_train(struct intel_output *intel_output, uint32_t DP,
                    uint8_t link_configuration[DP_LINK_CONFIGURATION_SIZE])
{
        struct drm_device *dev = intel_output->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;
        uint8_t train_set[4];
        uint8_t link_status[DP_LINK_STATUS_SIZE];
        int i;
        uint8_t voltage;
        bool clock_recovery = false;
        bool channel_eq = false;
        bool first = true;
        int tries;

        /* Write the link configuration data */
        intel_dp_aux_native_write(intel_output, 0x100,
                                  link_configuration, DP_LINK_CONFIGURATION_SIZE);

        DP |= DP_PORT_EN;
        DP &= ~DP_LINK_TRAIN_MASK;
        memset(train_set, 0, 4);
        voltage = 0xff;
        tries = 0;
        clock_recovery = false;
        for (;;) {
                /* Use train_set[0] to set the voltage and pre emphasis values */
                uint32_t    signal_levels = intel_dp_signal_levels(train_set[0], dp_priv->lane_count);
                DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;

                if (!intel_dp_set_link_train(intel_output, DP | DP_LINK_TRAIN_PAT_1,
                                             DP_TRAINING_PATTERN_1, train_set, first))
                        break;
                first = false;
                /* Set training pattern 1 */

                udelay(100);
                if (!intel_dp_get_link_status(intel_output, link_status))
                        break;

                if (intel_clock_recovery_ok(link_status, dp_priv->lane_count)) {
                        clock_recovery = true;
                        break;
                }

                /* Check to see if we've tried the max voltage */
                for (i = 0; i < dp_priv->lane_count; i++)
                        if ((train_set[i] & DP_TRAIN_MAX_SWING_REACHED) == 0)
                                break;
                if (i == dp_priv->lane_count)
                        break;

                /* Check to see if we've tried the same voltage 5 times */
                if ((train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK) == voltage) {
                        ++tries;
                        if (tries == 5)
                                break;
                } else
                        tries = 0;
                voltage = train_set[0] & DP_TRAIN_VOLTAGE_SWING_MASK;

                /* Compute new train_set as requested by target */
                intel_get_adjust_train(intel_output, link_status, dp_priv->lane_count, train_set);
        }

        /* channel equalization */
        tries = 0;
        channel_eq = false;
        for (;;) {
                /* Use train_set[0] to set the voltage and pre emphasis values */
                uint32_t    signal_levels = intel_dp_signal_levels(train_set[0], dp_priv->lane_count);
                DP = (DP & ~(DP_VOLTAGE_MASK|DP_PRE_EMPHASIS_MASK)) | signal_levels;

                /* channel eq pattern */
                if (!intel_dp_set_link_train(intel_output, DP | DP_LINK_TRAIN_PAT_2,
                                             DP_TRAINING_PATTERN_2, train_set,
                                             false))
                        break;

                udelay(400);
                if (!intel_dp_get_link_status(intel_output, link_status))
                        break;

                if (intel_channel_eq_ok(link_status, dp_priv->lane_count)) {
                        channel_eq = true;
                        break;
                }

                /* Try 5 times */
                if (tries > 5)
                        break;

                /* Compute new train_set as requested by target */
                intel_get_adjust_train(intel_output, link_status, dp_priv->lane_count, train_set);
                ++tries;
        }

        I915_WRITE(dp_priv->output_reg, DP | DP_LINK_TRAIN_OFF);
        POSTING_READ(dp_priv->output_reg);
        intel_dp_aux_native_write_1(intel_output,
                                    DP_TRAINING_PATTERN_SET, DP_TRAINING_PATTERN_DISABLE);
}

static void
intel_dp_link_down(struct intel_output *intel_output, uint32_t DP)
{
        struct drm_device *dev = intel_output->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;

        DP &= ~DP_LINK_TRAIN_MASK;
        I915_WRITE(dp_priv->output_reg, DP | DP_LINK_TRAIN_PAT_IDLE);
        POSTING_READ(dp_priv->output_reg);

        udelay(17000);

        I915_WRITE(dp_priv->output_reg, DP & ~DP_PORT_EN);
        POSTING_READ(dp_priv->output_reg);
}

static void
intel_dp_restore(struct drm_connector *connector)
{
        struct intel_output *intel_output = to_intel_output(connector);
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;

        if (dp_priv->save_DP & DP_PORT_EN)
                intel_dp_link_train(intel_output, dp_priv->save_DP, dp_priv->save_link_configuration);
        else
                intel_dp_link_down(intel_output,  dp_priv->save_DP);
}

/*
 * According to DP spec
 * 5.1.2:
 *  1. Read DPCD
 *  2. Configure link according to Receiver Capabilities
 *  3. Use Link Training from 2.5.3.3 and 3.5.1.3
 *  4. Check link status on receipt of hot-plug interrupt
 */

static void
intel_dp_check_link_status(struct intel_output *intel_output)
{
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;
        uint8_t link_status[DP_LINK_STATUS_SIZE];

        if (!intel_output->enc.crtc)
                return;

        if (!intel_dp_get_link_status(intel_output, link_status)) {
                intel_dp_link_down(intel_output, dp_priv->DP);
                return;
        }

        if (!intel_channel_eq_ok(link_status, dp_priv->lane_count))
                intel_dp_link_train(intel_output, dp_priv->DP, dp_priv->link_configuration);
}

static enum drm_connector_status
igdng_dp_detect(struct drm_connector *connector)
{
        struct intel_output *intel_output = to_intel_output(connector);
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;
        enum drm_connector_status status;

        status = connector_status_disconnected;
        if (intel_dp_aux_native_read(intel_output,
                                     0x000, dp_priv->dpcd,
                                     sizeof (dp_priv->dpcd)) == sizeof (dp_priv->dpcd))
        {
                if (dp_priv->dpcd[0] != 0)
                        status = connector_status_connected;
        }
        return status;
}

/**
 * Uses CRT_HOTPLUG_EN and CRT_HOTPLUG_STAT to detect DP connection.
 *
 * \return true if DP port is connected.
 * \return false if DP port is disconnected.
 */
static enum drm_connector_status
intel_dp_detect(struct drm_connector *connector)
{
        struct intel_output *intel_output = to_intel_output(connector);
        struct drm_device *dev = intel_output->base.dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;
        uint32_t temp, bit;
        enum drm_connector_status status;

        dp_priv->has_audio = false;

        if (IS_IGDNG(dev))
                return igdng_dp_detect(connector);

        temp = I915_READ(PORT_HOTPLUG_EN);

        I915_WRITE(PORT_HOTPLUG_EN,
               temp |
               DPB_HOTPLUG_INT_EN |
               DPC_HOTPLUG_INT_EN |
               DPD_HOTPLUG_INT_EN);

        POSTING_READ(PORT_HOTPLUG_EN);

        switch (dp_priv->output_reg) {
        case DP_B:
                bit = DPB_HOTPLUG_INT_STATUS;
                break;
        case DP_C:
                bit = DPC_HOTPLUG_INT_STATUS;
                break;
        case DP_D:
                bit = DPD_HOTPLUG_INT_STATUS;
                break;
        default:
                return connector_status_unknown;
        }

        temp = I915_READ(PORT_HOTPLUG_STAT);

        if ((temp & bit) == 0)
                return connector_status_disconnected;

        status = connector_status_disconnected;
        if (intel_dp_aux_native_read(intel_output,
                                     0x000, dp_priv->dpcd,
                                     sizeof (dp_priv->dpcd)) == sizeof (dp_priv->dpcd))
        {
                if (dp_priv->dpcd[0] != 0)
                        status = connector_status_connected;
        }
        return status;
}

static int intel_dp_get_modes(struct drm_connector *connector)
{
        struct intel_output *intel_output = to_intel_output(connector);

        /* We should parse the EDID data and find out if it has an audio sink
         */

        return intel_ddc_get_modes(intel_output);
}

static void
intel_dp_destroy (struct drm_connector *connector)
{
        struct intel_output *intel_output = to_intel_output(connector);

        if (intel_output->i2c_bus)
                intel_i2c_destroy(intel_output->i2c_bus);
        drm_sysfs_connector_remove(connector);
        drm_connector_cleanup(connector);
        kfree(intel_output);
}

static const struct drm_encoder_helper_funcs intel_dp_helper_funcs = {
        .dpms = intel_dp_dpms,
        .mode_fixup = intel_dp_mode_fixup,
        .prepare = intel_encoder_prepare,
        .mode_set = intel_dp_mode_set,
        .commit = intel_encoder_commit,
};

static const struct drm_connector_funcs intel_dp_connector_funcs = {
        .dpms = drm_helper_connector_dpms,
        .save = intel_dp_save,
        .restore = intel_dp_restore,
        .detect = intel_dp_detect,
        .fill_modes = drm_helper_probe_single_connector_modes,
        .destroy = intel_dp_destroy,
};

static const struct drm_connector_helper_funcs intel_dp_connector_helper_funcs = {
        .get_modes = intel_dp_get_modes,
        .mode_valid = intel_dp_mode_valid,
        .best_encoder = intel_best_encoder,
};

static void intel_dp_enc_destroy(struct drm_encoder *encoder)
{
        drm_encoder_cleanup(encoder);
}

static const struct drm_encoder_funcs intel_dp_enc_funcs = {
        .destroy = intel_dp_enc_destroy,
};

void
intel_dp_hot_plug(struct intel_output *intel_output)
{
        struct intel_dp_priv *dp_priv = intel_output->dev_priv;

        if (dp_priv->dpms_mode == DRM_MODE_DPMS_ON)
                intel_dp_check_link_status(intel_output);
}

void
intel_dp_init(struct drm_device *dev, int output_reg)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_connector *connector;
        struct intel_output *intel_output;
        struct intel_dp_priv *dp_priv;
        const char *name = NULL;

        intel_output = kcalloc(sizeof(struct intel_output) + 
                               sizeof(struct intel_dp_priv), 1, GFP_KERNEL);
        if (!intel_output)
                return;

        dp_priv = (struct intel_dp_priv *)(intel_output + 1);

        connector = &intel_output->base;
        drm_connector_init(dev, connector, &intel_dp_connector_funcs,
                           DRM_MODE_CONNECTOR_DisplayPort);
        drm_connector_helper_add(connector, &intel_dp_connector_helper_funcs);

        intel_output->type = INTEL_OUTPUT_DISPLAYPORT;

        connector->interlace_allowed = true;
        connector->doublescan_allowed = 0;

        dp_priv->intel_output = intel_output;
        dp_priv->output_reg = output_reg;
        dp_priv->has_audio = false;
        dp_priv->dpms_mode = DRM_MODE_DPMS_ON;
        intel_output->dev_priv = dp_priv;

        drm_encoder_init(dev, &intel_output->enc, &intel_dp_enc_funcs,
                         DRM_MODE_ENCODER_TMDS);
        drm_encoder_helper_add(&intel_output->enc, &intel_dp_helper_funcs);

        drm_mode_connector_attach_encoder(&intel_output->base,
                                          &intel_output->enc);
        drm_sysfs_connector_add(connector);

        /* Set up the DDC bus. */
        switch (output_reg) {
                case DP_B:
                case PCH_DP_B:
                        name = "DPDDC-B";
                        break;
                case DP_C:
                case PCH_DP_C:
                        name = "DPDDC-C";
                        break;
                case DP_D:
                case PCH_DP_D:
                        name = "DPDDC-D";
                        break;
        }

        intel_dp_i2c_init(intel_output, name);
        intel_output->ddc_bus = &dp_priv->adapter;
        intel_output->hot_plug = intel_dp_hot_plug;

        /* For G4X desktop chip, PEG_BAND_GAP_DATA 3:0 must first be written
         * 0xd.  Failure to do so will result in spurious interrupts being
         * generated on the port when a cable is not attached.
         */
        if (IS_G4X(dev) && !IS_GM45(dev)) {
                u32 temp = I915_READ(PEG_BAND_GAP_DATA);
                I915_WRITE(PEG_BAND_GAP_DATA, (temp & ~0xf) | 0xd);
        }
}