/*
 * Copyright © 2006 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:
 *    Eric Anholt <eric@anholt.net>
 *
 */
#include <linux/dmi.h>
#include <drm/drm_dp_helper.h>
#include <drm/drmP.h>
#include <drm/i915_drm.h>
#include "i915_drv.h"
#include "intel_bios.h"

#define SLAVE_ADDR1     0x70
#define SLAVE_ADDR2     0x72

static int panel_type;

static void *
find_section(struct bdb_header *bdb, int section_id)
{
        u8 *base = (u8 *)bdb;
        int index = 0;
        u16 total, current_size;
        u8 current_id;

        /* skip to first section */
        index += bdb->header_size;
        total = bdb->bdb_size;

        /* walk the sections looking for section_id */
        while (index + 3 < total) {
                current_id = *(base + index);
                index++;

                current_size = *((u16 *)(base + index));
                index += 2;

                if (index + current_size > total)
                        return NULL;

                if (current_id == section_id)
                        return base + index;

                index += current_size;
        }

        return NULL;
}

static u16
get_blocksize(void *p)
{
        u16 *block_ptr, block_size;

        block_ptr = (u16 *)((char *)p - 2);
        block_size = *block_ptr;
        return block_size;
}

static void
fill_detail_timing_data(struct drm_display_mode *panel_fixed_mode,
                        const struct lvds_dvo_timing *dvo_timing)
{
        panel_fixed_mode->hdisplay = (dvo_timing->hactive_hi << 8) |
                dvo_timing->hactive_lo;
        panel_fixed_mode->hsync_start = panel_fixed_mode->hdisplay +
                ((dvo_timing->hsync_off_hi << 8) | dvo_timing->hsync_off_lo);
        panel_fixed_mode->hsync_end = panel_fixed_mode->hsync_start +
                dvo_timing->hsync_pulse_width;
        panel_fixed_mode->htotal = panel_fixed_mode->hdisplay +
                ((dvo_timing->hblank_hi << 8) | dvo_timing->hblank_lo);

        panel_fixed_mode->vdisplay = (dvo_timing->vactive_hi << 8) |
                dvo_timing->vactive_lo;
        panel_fixed_mode->vsync_start = panel_fixed_mode->vdisplay +
                dvo_timing->vsync_off;
        panel_fixed_mode->vsync_end = panel_fixed_mode->vsync_start +
                dvo_timing->vsync_pulse_width;
        panel_fixed_mode->vtotal = panel_fixed_mode->vdisplay +
                ((dvo_timing->vblank_hi << 8) | dvo_timing->vblank_lo);
        panel_fixed_mode->clock = dvo_timing->clock * 10;
        panel_fixed_mode->type = DRM_MODE_TYPE_PREFERRED;

        if (dvo_timing->hsync_positive)
                panel_fixed_mode->flags |= DRM_MODE_FLAG_PHSYNC;
        else
                panel_fixed_mode->flags |= DRM_MODE_FLAG_NHSYNC;

        if (dvo_timing->vsync_positive)
                panel_fixed_mode->flags |= DRM_MODE_FLAG_PVSYNC;
        else
                panel_fixed_mode->flags |= DRM_MODE_FLAG_NVSYNC;

        /* Some VBTs have bogus h/vtotal values */
        if (panel_fixed_mode->hsync_end > panel_fixed_mode->htotal)
                panel_fixed_mode->htotal = panel_fixed_mode->hsync_end + 1;
        if (panel_fixed_mode->vsync_end > panel_fixed_mode->vtotal)
                panel_fixed_mode->vtotal = panel_fixed_mode->vsync_end + 1;

        drm_mode_set_name(panel_fixed_mode);
}

static bool
lvds_dvo_timing_equal_size(const struct lvds_dvo_timing *a,
                           const struct lvds_dvo_timing *b)
{
        if (a->hactive_hi != b->hactive_hi ||
            a->hactive_lo != b->hactive_lo)
                return false;

        if (a->hsync_off_hi != b->hsync_off_hi ||
            a->hsync_off_lo != b->hsync_off_lo)
                return false;

        if (a->hsync_pulse_width != b->hsync_pulse_width)
                return false;

        if (a->hblank_hi != b->hblank_hi ||
            a->hblank_lo != b->hblank_lo)
                return false;

        if (a->vactive_hi != b->vactive_hi ||
            a->vactive_lo != b->vactive_lo)
                return false;

        if (a->vsync_off != b->vsync_off)
                return false;

        if (a->vsync_pulse_width != b->vsync_pulse_width)
                return false;

        if (a->vblank_hi != b->vblank_hi ||
            a->vblank_lo != b->vblank_lo)
                return false;

        return true;
}

static const struct lvds_dvo_timing *
get_lvds_dvo_timing(const struct bdb_lvds_lfp_data *lvds_lfp_data,
                    const struct bdb_lvds_lfp_data_ptrs *lvds_lfp_data_ptrs,
                    int index)
{
        /*
         * the size of fp_timing varies on the different platform.
         * So calculate the DVO timing relative offset in LVDS data
         * entry to get the DVO timing entry
         */

        int lfp_data_size =
                lvds_lfp_data_ptrs->ptr[1].dvo_timing_offset -
                lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset;
        int dvo_timing_offset =
                lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset -
                lvds_lfp_data_ptrs->ptr[0].fp_timing_offset;
        char *entry = (char *)lvds_lfp_data->data + lfp_data_size * index;

        return (struct lvds_dvo_timing *)(entry + dvo_timing_offset);
}

/* get lvds_fp_timing entry
 * this function may return NULL if the corresponding entry is invalid
 */
static const struct lvds_fp_timing *
get_lvds_fp_timing(const struct bdb_header *bdb,
                   const struct bdb_lvds_lfp_data *data,
                   const struct bdb_lvds_lfp_data_ptrs *ptrs,
                   int index)
{
        size_t data_ofs = (const u8 *)data - (const u8 *)bdb;
        u16 data_size = ((const u16 *)data)[-1]; /* stored in header */
        size_t ofs;

        if (index >= ARRAY_SIZE(ptrs->ptr))
                return NULL;
        ofs = ptrs->ptr[index].fp_timing_offset;
        if (ofs < data_ofs ||
            ofs + sizeof(struct lvds_fp_timing) > data_ofs + data_size)
                return NULL;
        return (const struct lvds_fp_timing *)((const u8 *)bdb + ofs);
}

/* Try to find integrated panel data */
static void
parse_lfp_panel_data(struct drm_i915_private *dev_priv,
                            struct bdb_header *bdb)
{
        const struct bdb_lvds_options *lvds_options;
        const struct bdb_lvds_lfp_data *lvds_lfp_data;
        const struct bdb_lvds_lfp_data_ptrs *lvds_lfp_data_ptrs;
        const struct lvds_dvo_timing *panel_dvo_timing;
        const struct lvds_fp_timing *fp_timing;
        struct drm_display_mode *panel_fixed_mode;
        int i, downclock, drrs_mode;

        lvds_options = find_section(bdb, BDB_LVDS_OPTIONS);
        if (!lvds_options)
                return;

        dev_priv->vbt.lvds_dither = lvds_options->pixel_dither;
        if (lvds_options->panel_type == 0xff)
                return;

        panel_type = lvds_options->panel_type;

        drrs_mode = (lvds_options->dps_panel_type_bits
                                >> (panel_type * 2)) & MODE_MASK;
        /*
         * VBT has static DRRS = 0 and seamless DRRS = 2.
         * The below piece of code is required to adjust vbt.drrs_type
         * to match the enum drrs_support_type.
         */
        switch (drrs_mode) {
        case 0:
                dev_priv->vbt.drrs_type = STATIC_DRRS_SUPPORT;
                DRM_DEBUG_KMS("DRRS supported mode is static\n");
                break;
        case 2:
                dev_priv->vbt.drrs_type = SEAMLESS_DRRS_SUPPORT;
                DRM_DEBUG_KMS("DRRS supported mode is seamless\n");
                break;
        default:
                dev_priv->vbt.drrs_type = DRRS_NOT_SUPPORTED;
                DRM_DEBUG_KMS("DRRS not supported (VBT input)\n");
                break;
        }

        lvds_lfp_data = find_section(bdb, BDB_LVDS_LFP_DATA);
        if (!lvds_lfp_data)
                return;

        lvds_lfp_data_ptrs = find_section(bdb, BDB_LVDS_LFP_DATA_PTRS);
        if (!lvds_lfp_data_ptrs)
                return;

        dev_priv->vbt.lvds_vbt = 1;

        panel_dvo_timing = get_lvds_dvo_timing(lvds_lfp_data,
                                               lvds_lfp_data_ptrs,
                                               lvds_options->panel_type);

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

        fill_detail_timing_data(panel_fixed_mode, panel_dvo_timing);

        dev_priv->vbt.lfp_lvds_vbt_mode = panel_fixed_mode;

        DRM_DEBUG_KMS("Found panel mode in BIOS VBT tables:\n");
        drm_mode_debug_printmodeline(panel_fixed_mode);

        /*
         * Iterate over the LVDS panel timing info to find the lowest clock
         * for the native resolution.
         */
        downclock = panel_dvo_timing->clock;
        for (i = 0; i < 16; i++) {
                const struct lvds_dvo_timing *dvo_timing;

                dvo_timing = get_lvds_dvo_timing(lvds_lfp_data,
                                                 lvds_lfp_data_ptrs,
                                                 i);
                if (lvds_dvo_timing_equal_size(dvo_timing, panel_dvo_timing) &&
                    dvo_timing->clock < downclock)
                        downclock = dvo_timing->clock;
        }

        if (downclock < panel_dvo_timing->clock && i915.lvds_downclock) {
                dev_priv->lvds_downclock_avail = 1;
                dev_priv->lvds_downclock = downclock * 10;
                DRM_DEBUG_KMS("LVDS downclock is found in VBT. "
                              "Normal Clock %dKHz, downclock %dKHz\n",
                              panel_fixed_mode->clock, 10*downclock);
        }

        fp_timing = get_lvds_fp_timing(bdb, lvds_lfp_data,
                                       lvds_lfp_data_ptrs,
                                       lvds_options->panel_type);
        if (fp_timing) {
                /* check the resolution, just to be sure */
                if (fp_timing->x_res == panel_fixed_mode->hdisplay &&
                    fp_timing->y_res == panel_fixed_mode->vdisplay) {
                        dev_priv->vbt.bios_lvds_val = fp_timing->lvds_reg_val;
                        DRM_DEBUG_KMS("VBT initial LVDS value %x\n",
                                      dev_priv->vbt.bios_lvds_val);
                }
        }
}

static void
parse_lfp_backlight(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
{
        const struct bdb_lfp_backlight_data *backlight_data;
        const struct bdb_lfp_backlight_data_entry *entry;

        backlight_data = find_section(bdb, BDB_LVDS_BACKLIGHT);
        if (!backlight_data)
                return;

        if (backlight_data->entry_size != sizeof(backlight_data->data[0])) {
                DRM_DEBUG_KMS("Unsupported backlight data entry size %u\n",
                              backlight_data->entry_size);
                return;
        }

        entry = &backlight_data->data[panel_type];

        dev_priv->vbt.backlight.present = entry->type == BDB_BACKLIGHT_TYPE_PWM;
        if (!dev_priv->vbt.backlight.present) {
                DRM_DEBUG_KMS("PWM backlight not present in VBT (type %u)\n",
                              entry->type);
                return;
        }

        dev_priv->vbt.backlight.pwm_freq_hz = entry->pwm_freq_hz;
        dev_priv->vbt.backlight.active_low_pwm = entry->active_low_pwm;
        dev_priv->vbt.backlight.min_brightness = entry->min_brightness;
        DRM_DEBUG_KMS("VBT backlight PWM modulation frequency %u Hz, "
                      "active %s, min brightness %u, level %u\n",
                      dev_priv->vbt.backlight.pwm_freq_hz,
                      dev_priv->vbt.backlight.active_low_pwm ? "low" : "high",
                      dev_priv->vbt.backlight.min_brightness,
                      backlight_data->level[panel_type]);
}

/* Try to find sdvo panel data */
static void
parse_sdvo_panel_data(struct drm_i915_private *dev_priv,
                      struct bdb_header *bdb)
{
        struct lvds_dvo_timing *dvo_timing;
        struct drm_display_mode *panel_fixed_mode;
        int index;

        index = i915.vbt_sdvo_panel_type;
        if (index == -2) {
                DRM_DEBUG_KMS("Ignore SDVO panel mode from BIOS VBT tables.\n");
                return;
        }

        if (index == -1) {
                struct bdb_sdvo_lvds_options *sdvo_lvds_options;

                sdvo_lvds_options = find_section(bdb, BDB_SDVO_LVDS_OPTIONS);
                if (!sdvo_lvds_options)
                        return;

                index = sdvo_lvds_options->panel_type;
        }

        dvo_timing = find_section(bdb, BDB_SDVO_PANEL_DTDS);
        if (!dvo_timing)
                return;

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

        fill_detail_timing_data(panel_fixed_mode, dvo_timing + index);

        dev_priv->vbt.sdvo_lvds_vbt_mode = panel_fixed_mode;

        DRM_DEBUG_KMS("Found SDVO panel mode in BIOS VBT tables:\n");
        drm_mode_debug_printmodeline(panel_fixed_mode);
}

static int intel_bios_ssc_frequency(struct drm_device *dev,
                                    bool alternate)
{
        switch (INTEL_INFO(dev)->gen) {
        case 2:
                return alternate ? 66667 : 48000;
        case 3:
        case 4:
                return alternate ? 100000 : 96000;
        default:
                return alternate ? 100000 : 120000;
        }
}

static void
parse_general_features(struct drm_i915_private *dev_priv,
                       struct bdb_header *bdb)
{
        struct drm_device *dev = dev_priv->dev;
        struct bdb_general_features *general;

        general = find_section(bdb, BDB_GENERAL_FEATURES);
        if (general) {
                dev_priv->vbt.int_tv_support = general->int_tv_support;
                dev_priv->vbt.int_crt_support = general->int_crt_support;
                dev_priv->vbt.lvds_use_ssc = general->enable_ssc;
                dev_priv->vbt.lvds_ssc_freq =
                        intel_bios_ssc_frequency(dev, general->ssc_freq);
                dev_priv->vbt.display_clock_mode = general->display_clock_mode;
                dev_priv->vbt.fdi_rx_polarity_inverted = general->fdi_rx_polarity_inverted;
                DRM_DEBUG_KMS("BDB_GENERAL_FEATURES int_tv_support %d int_crt_support %d lvds_use_ssc %d lvds_ssc_freq %d display_clock_mode %d fdi_rx_polarity_inverted %d\n",
                              dev_priv->vbt.int_tv_support,
                              dev_priv->vbt.int_crt_support,
                              dev_priv->vbt.lvds_use_ssc,
                              dev_priv->vbt.lvds_ssc_freq,
                              dev_priv->vbt.display_clock_mode,
                              dev_priv->vbt.fdi_rx_polarity_inverted);
        }
}

static void
parse_general_definitions(struct drm_i915_private *dev_priv,
                          struct bdb_header *bdb)
{
        struct bdb_general_definitions *general;

        general = find_section(bdb, BDB_GENERAL_DEFINITIONS);
        if (general) {
                u16 block_size = get_blocksize(general);
                if (block_size >= sizeof(*general)) {
                        int bus_pin = general->crt_ddc_gmbus_pin;
                        DRM_DEBUG_KMS("crt_ddc_bus_pin: %d\n", bus_pin);
                        if (intel_gmbus_is_port_valid(bus_pin))
                                dev_priv->vbt.crt_ddc_pin = bus_pin;
                } else {
                        DRM_DEBUG_KMS("BDB_GD too small (%d). Invalid.\n",
                                      block_size);
                }
        }
}

static void
parse_sdvo_device_mapping(struct drm_i915_private *dev_priv,
                          struct bdb_header *bdb)
{
        struct sdvo_device_mapping *p_mapping;
        struct bdb_general_definitions *p_defs;
        union child_device_config *p_child;
        int i, child_device_num, count;
        u16     block_size;

        p_defs = find_section(bdb, BDB_GENERAL_DEFINITIONS);
        if (!p_defs) {
                DRM_DEBUG_KMS("No general definition block is found, unable to construct sdvo mapping.\n");
                return;
        }
        /* judge whether the size of child device meets the requirements.
         * If the child device size obtained from general definition block
         * is different with sizeof(struct child_device_config), skip the
         * parsing of sdvo device info
         */
        if (p_defs->child_dev_size != sizeof(*p_child)) {
                /* different child dev size . Ignore it */
                DRM_DEBUG_KMS("different child size is found. Invalid.\n");
                return;
        }
        /* get the block size of general definitions */
        block_size = get_blocksize(p_defs);
        /* get the number of child device */
        child_device_num = (block_size - sizeof(*p_defs)) /
                                sizeof(*p_child);
        count = 0;
        for (i = 0; i < child_device_num; i++) {
                p_child = &(p_defs->devices[i]);
                if (!p_child->old.device_type) {
                        /* skip the device block if device type is invalid */
                        continue;
                }
                if (p_child->old.slave_addr != SLAVE_ADDR1 &&
                        p_child->old.slave_addr != SLAVE_ADDR2) {
                        /*
                         * If the slave address is neither 0x70 nor 0x72,
                         * it is not a SDVO device. Skip it.
                         */
                        continue;
                }
                if (p_child->old.dvo_port != DEVICE_PORT_DVOB &&
                        p_child->old.dvo_port != DEVICE_PORT_DVOC) {
                        /* skip the incorrect SDVO port */
                        DRM_DEBUG_KMS("Incorrect SDVO port. Skip it\n");
                        continue;
                }
                DRM_DEBUG_KMS("the SDVO device with slave addr %2x is found on"
                                " %s port\n",
                                p_child->old.slave_addr,
                                (p_child->old.dvo_port == DEVICE_PORT_DVOB) ?
                                        "SDVOB" : "SDVOC");
                p_mapping = &(dev_priv->sdvo_mappings[p_child->old.dvo_port - 1]);
                if (!p_mapping->initialized) {
                        p_mapping->dvo_port = p_child->old.dvo_port;
                        p_mapping->slave_addr = p_child->old.slave_addr;
                        p_mapping->dvo_wiring = p_child->old.dvo_wiring;
                        p_mapping->ddc_pin = p_child->old.ddc_pin;
                        p_mapping->i2c_pin = p_child->old.i2c_pin;
                        p_mapping->initialized = 1;
                        DRM_DEBUG_KMS("SDVO device: dvo=%x, addr=%x, wiring=%d, ddc_pin=%d, i2c_pin=%d\n",
                                      p_mapping->dvo_port,
                                      p_mapping->slave_addr,
                                      p_mapping->dvo_wiring,
                                      p_mapping->ddc_pin,
                                      p_mapping->i2c_pin);
                } else {
                        DRM_DEBUG_KMS("Maybe one SDVO port is shared by "
                                         "two SDVO device.\n");
                }
                if (p_child->old.slave2_addr) {
                        /* Maybe this is a SDVO device with multiple inputs */
                        /* And the mapping info is not added */
                        DRM_DEBUG_KMS("there exists the slave2_addr. Maybe this"
                                " is a SDVO device with multiple inputs.\n");
                }
                count++;
        }

        if (!count) {
                /* No SDVO device info is found */
                DRM_DEBUG_KMS("No SDVO device info is found in VBT\n");
        }
        return;
}

static void
parse_driver_features(struct drm_i915_private *dev_priv,
                       struct bdb_header *bdb)
{
        struct bdb_driver_features *driver;

        driver = find_section(bdb, BDB_DRIVER_FEATURES);
        if (!driver)
                return;

        if (driver->lvds_config == BDB_DRIVER_FEATURE_EDP)
                dev_priv->vbt.edp_support = 1;

        if (driver->dual_frequency)
                dev_priv->render_reclock_avail = true;

        DRM_DEBUG_KMS("DRRS State Enabled:%d\n", driver->drrs_enabled);
        /*
         * If DRRS is not supported, drrs_type has to be set to 0.
         * This is because, VBT is configured in such a way that
         * static DRRS is 0 and DRRS not supported is represented by
         * driver->drrs_enabled=false
         */
        if (!driver->drrs_enabled)
                dev_priv->vbt.drrs_type = DRRS_NOT_SUPPORTED;
}

static void
parse_edp(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
{
        struct bdb_edp *edp;
        struct edp_power_seq *edp_pps;
        struct edp_link_params *edp_link_params;

        edp = find_section(bdb, BDB_EDP);
        if (!edp) {
                if (dev_priv->vbt.edp_support)
                        DRM_DEBUG_KMS("No eDP BDB found but eDP panel supported.\n");
                return;
        }

        switch ((edp->color_depth >> (panel_type * 2)) & 3) {
        case EDP_18BPP:
                dev_priv->vbt.edp_bpp = 18;
                break;
        case EDP_24BPP:
                dev_priv->vbt.edp_bpp = 24;
                break;
        case EDP_30BPP:
                dev_priv->vbt.edp_bpp = 30;
                break;
        }

        /* Get the eDP sequencing and link info */
        edp_pps = &edp->power_seqs[panel_type];
        edp_link_params = &edp->link_params[panel_type];

        dev_priv->vbt.edp_pps = *edp_pps;

        switch (edp_link_params->rate) {
        case EDP_RATE_1_62:
                dev_priv->vbt.edp_rate = DP_LINK_BW_1_62;
                break;
        case EDP_RATE_2_7:
                dev_priv->vbt.edp_rate = DP_LINK_BW_2_7;
                break;
        default:
                DRM_DEBUG_KMS("VBT has unknown eDP link rate value %u\n",
                              edp_link_params->rate);
                break;
        }

        switch (edp_link_params->lanes) {
        case EDP_LANE_1:
                dev_priv->vbt.edp_lanes = 1;
                break;
        case EDP_LANE_2:
                dev_priv->vbt.edp_lanes = 2;
                break;
        case EDP_LANE_4:
                dev_priv->vbt.edp_lanes = 4;
                break;
        default:
                DRM_DEBUG_KMS("VBT has unknown eDP lane count value %u\n",
                              edp_link_params->lanes);
                break;
        }

        switch (edp_link_params->preemphasis) {
        case EDP_PREEMPHASIS_NONE:
                dev_priv->vbt.edp_preemphasis = DP_TRAIN_PRE_EMPH_LEVEL_0;
                break;
        case EDP_PREEMPHASIS_3_5dB:
                dev_priv->vbt.edp_preemphasis = DP_TRAIN_PRE_EMPH_LEVEL_1;
                break;
        case EDP_PREEMPHASIS_6dB:
                dev_priv->vbt.edp_preemphasis = DP_TRAIN_PRE_EMPH_LEVEL_2;
                break;
        case EDP_PREEMPHASIS_9_5dB:
                dev_priv->vbt.edp_preemphasis = DP_TRAIN_PRE_EMPH_LEVEL_3;
                break;
        default:
                DRM_DEBUG_KMS("VBT has unknown eDP pre-emphasis value %u\n",
                              edp_link_params->preemphasis);
                break;
        }

        switch (edp_link_params->vswing) {
        case EDP_VSWING_0_4V:
                dev_priv->vbt.edp_vswing = DP_TRAIN_VOLTAGE_SWING_LEVEL_0;
                break;
        case EDP_VSWING_0_6V:
                dev_priv->vbt.edp_vswing = DP_TRAIN_VOLTAGE_SWING_LEVEL_1;
                break;
        case EDP_VSWING_0_8V:
                dev_priv->vbt.edp_vswing = DP_TRAIN_VOLTAGE_SWING_LEVEL_2;
                break;
        case EDP_VSWING_1_2V:
                dev_priv->vbt.edp_vswing = DP_TRAIN_VOLTAGE_SWING_LEVEL_3;
                break;
        default:
                DRM_DEBUG_KMS("VBT has unknown eDP voltage swing value %u\n",
                              edp_link_params->vswing);
                break;
        }

        if (bdb->version >= 173) {
                uint8_t vswing;

                vswing = (edp->edp_vswing_preemph >> (panel_type * 4)) & 0xF;
                dev_priv->vbt.edp_low_vswing = vswing == 0;
        }
}

static void
parse_psr(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
{
        struct bdb_psr *psr;
        struct psr_table *psr_table;

        psr = find_section(bdb, BDB_PSR);
        if (!psr) {
                DRM_DEBUG_KMS("No PSR BDB found.\n");
                return;
        }

        psr_table = &psr->psr_table[panel_type];

        dev_priv->vbt.psr.full_link = psr_table->full_link;
        dev_priv->vbt.psr.require_aux_wakeup = psr_table->require_aux_to_wakeup;

        /* Allowed VBT values goes from 0 to 15 */
        dev_priv->vbt.psr.idle_frames = psr_table->idle_frames < 0 ? 0 :
                psr_table->idle_frames > 15 ? 15 : psr_table->idle_frames;

        switch (psr_table->lines_to_wait) {
        case 0:
                dev_priv->vbt.psr.lines_to_wait = PSR_0_LINES_TO_WAIT;
                break;
        case 1:
                dev_priv->vbt.psr.lines_to_wait = PSR_1_LINE_TO_WAIT;
                break;
        case 2:
                dev_priv->vbt.psr.lines_to_wait = PSR_4_LINES_TO_WAIT;
                break;
        case 3:
                dev_priv->vbt.psr.lines_to_wait = PSR_8_LINES_TO_WAIT;
                break;
        default:
                DRM_DEBUG_KMS("VBT has unknown PSR lines to wait %u\n",
                              psr_table->lines_to_wait);
                break;
        }

        dev_priv->vbt.psr.tp1_wakeup_time = psr_table->tp1_wakeup_time;
        dev_priv->vbt.psr.tp2_tp3_wakeup_time = psr_table->tp2_tp3_wakeup_time;
}

static u8 *goto_next_sequence(u8 *data, int *size)
{
        u16 len;
        int tmp = *size;

        if (--tmp < 0)
                return NULL;

        /* goto first element */
        data++;
        while (1) {
                switch (*data) {
                case MIPI_SEQ_ELEM_SEND_PKT:
                        /*
                         * skip by this element payload size
                         * skip elem id, command flag and data type
                         */
                        tmp -= 5;
                        if (tmp < 0)
                                return NULL;

                        data += 3;
                        len = *((u16 *)data);

                        tmp -= len;
                        if (tmp < 0)
                                return NULL;

                        /* skip by len */
                        data = data + 2 + len;
                        break;
                case MIPI_SEQ_ELEM_DELAY:
                        /* skip by elem id, and delay is 4 bytes */
                        tmp -= 5;
                        if (tmp < 0)
                                return NULL;

                        data += 5;
                        break;
                case MIPI_SEQ_ELEM_GPIO:
                        tmp -= 3;
                        if (tmp < 0)
                                return NULL;

                        data += 3;
                        break;
                default:
                        DRM_ERROR("Unknown element\n");
                        return NULL;
                }

                /* end of sequence ? */
                if (*data == 0)
                        break;
        }

        /* goto next sequence or end of block byte */
        if (--tmp < 0)
                return NULL;

        data++;

        /* update amount of data left for the sequence block to be parsed */
        *size = tmp;
        return data;
}

static void
parse_mipi(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
{
        struct bdb_mipi_config *start;
        struct bdb_mipi_sequence *sequence;
        struct mipi_config *config;
        struct mipi_pps_data *pps;
        u8 *data, *seq_data;
        int i, panel_id, seq_size;
        u16 block_size;

        /* parse MIPI blocks only if LFP type is MIPI */
        if (!dev_priv->vbt.has_mipi)
                return;

        /* Initialize this to undefined indicating no generic MIPI support */
        dev_priv->vbt.dsi.panel_id = MIPI_DSI_UNDEFINED_PANEL_ID;

        /* Block #40 is already parsed and panel_fixed_mode is
         * stored in dev_priv->lfp_lvds_vbt_mode
         * resuse this when needed
         */

        /* Parse #52 for panel index used from panel_type already
         * parsed
         */
        start = find_section(bdb, BDB_MIPI_CONFIG);
        if (!start) {
                DRM_DEBUG_KMS("No MIPI config BDB found");
                return;
        }

        DRM_DEBUG_DRIVER("Found MIPI Config block, panel index = %d\n",
                                                                panel_type);

        /*
         * get hold of the correct configuration block and pps data as per
         * the panel_type as index
         */
        config = &start->config[panel_type];
        pps = &start->pps[panel_type];

        /* store as of now full data. Trim when we realise all is not needed */
        dev_priv->vbt.dsi.config = kmemdup(config, sizeof(struct mipi_config), GFP_KERNEL);
        if (!dev_priv->vbt.dsi.config)
                return;

        dev_priv->vbt.dsi.pps = kmemdup(pps, sizeof(struct mipi_pps_data), GFP_KERNEL);
        if (!dev_priv->vbt.dsi.pps) {
                kfree(dev_priv->vbt.dsi.config);
                return;
        }

        /* We have mandatory mipi config blocks. Initialize as generic panel */
        dev_priv->vbt.dsi.panel_id = MIPI_DSI_GENERIC_PANEL_ID;

        /* Check if we have sequence block as well */
        sequence = find_section(bdb, BDB_MIPI_SEQUENCE);
        if (!sequence) {
                DRM_DEBUG_KMS("No MIPI Sequence found, parsing complete\n");
                return;
        }

        DRM_DEBUG_DRIVER("Found MIPI sequence block\n");

        block_size = get_blocksize(sequence);

        /*
         * parse the sequence block for individual sequences
         */
        dev_priv->vbt.dsi.seq_version = sequence->version;

        seq_data = &sequence->data[0];

        /*
         * sequence block is variable length and hence we need to parse and
         * get the sequence data for specific panel id
         */
        for (i = 0; i < MAX_MIPI_CONFIGURATIONS; i++) {
                panel_id = *seq_data;
                seq_size = *((u16 *) (seq_data + 1));
                if (panel_id == panel_type)
                        break;

                /* skip the sequence including seq header of 3 bytes */
                seq_data = seq_data + 3 + seq_size;
                if ((seq_data - &sequence->data[0]) > block_size) {
                        DRM_ERROR("Sequence start is beyond sequence block size, corrupted sequence block\n");
                        return;
                }
        }

        if (i == MAX_MIPI_CONFIGURATIONS) {
                DRM_ERROR("Sequence block detected but no valid configuration\n");
                return;
        }

        /* check if found sequence is completely within the sequence block
         * just being paranoid */
        if (seq_size > block_size) {
                DRM_ERROR("Corrupted sequence/size, bailing out\n");
                return;
        }

        /* skip the panel id(1 byte) and seq size(2 bytes) */
        dev_priv->vbt.dsi.data = kmemdup(seq_data + 3, seq_size, GFP_KERNEL);
        if (!dev_priv->vbt.dsi.data)
                return;

        /*
         * loop into the sequence data and split into multiple sequneces
         * There are only 5 types of sequences as of now
         */
        data = dev_priv->vbt.dsi.data;
        dev_priv->vbt.dsi.size = seq_size;

        /* two consecutive 0x00 indicate end of all sequences */
        while (1) {
                int seq_id = *data;
                if (MIPI_SEQ_MAX > seq_id && seq_id > MIPI_SEQ_UNDEFINED) {
                        dev_priv->vbt.dsi.sequence[seq_id] = data;
                        DRM_DEBUG_DRIVER("Found mipi sequence - %d\n", seq_id);
                } else {
                        DRM_ERROR("undefined sequence\n");
                        goto err;
                }

                /* partial parsing to skip elements */
                data = goto_next_sequence(data, &seq_size);

                if (data == NULL) {
                        DRM_ERROR("Sequence elements going beyond block itself. Sequence block parsing failed\n");
                        goto err;
                }

                if (*data == 0)
                        break; /* end of sequence reached */
        }

        DRM_DEBUG_DRIVER("MIPI related vbt parsing complete\n");
        return;
err:
        kfree(dev_priv->vbt.dsi.data);
        dev_priv->vbt.dsi.data = NULL;

        /* error during parsing so set all pointers to null
         * because of partial parsing */
        memset(dev_priv->vbt.dsi.sequence, 0, sizeof(dev_priv->vbt.dsi.sequence));
}

static void parse_ddi_port(struct drm_i915_private *dev_priv, enum port port,
                           struct bdb_header *bdb)
{
        union child_device_config *it, *child = NULL;
        struct ddi_vbt_port_info *info = &dev_priv->vbt.ddi_port_info[port];
        uint8_t hdmi_level_shift;
        int i, j;
        bool is_dvi, is_hdmi, is_dp, is_edp, is_crt;
        uint8_t aux_channel;
        /* Each DDI port can have more than one value on the "DVO Port" field,
         * so look for all the possible values for each port and abort if more
         * than one is found. */
        int dvo_ports[][2] = {
                {DVO_PORT_HDMIA, DVO_PORT_DPA},
                {DVO_PORT_HDMIB, DVO_PORT_DPB},
                {DVO_PORT_HDMIC, DVO_PORT_DPC},
                {DVO_PORT_HDMID, DVO_PORT_DPD},
                {DVO_PORT_CRT, -1 /* Port E can only be DVO_PORT_CRT */ },
        };

        /* Find the child device to use, abort if more than one found. */
        for (i = 0; i < dev_priv->vbt.child_dev_num; i++) {
                it = dev_priv->vbt.child_dev + i;

                for (j = 0; j < 2; j++) {
                        if (dvo_ports[port][j] == -1)
                                break;

                        if (it->common.dvo_port == dvo_ports[port][j]) {
                                if (child) {
                                        DRM_DEBUG_KMS("More than one child device for port %c in VBT.\n",
                                                      port_name(port));
                                        return;
                                }
                                child = it;
                        }
                }
        }
        if (!child)
                return;

        aux_channel = child->raw[25];

        is_dvi = child->common.device_type & DEVICE_TYPE_TMDS_DVI_SIGNALING;
        is_dp = child->common.device_type & DEVICE_TYPE_DISPLAYPORT_OUTPUT;
        is_crt = child->common.device_type & DEVICE_TYPE_ANALOG_OUTPUT;
        is_hdmi = is_dvi && (child->common.device_type & DEVICE_TYPE_NOT_HDMI_OUTPUT) == 0;
        is_edp = is_dp && (child->common.device_type & DEVICE_TYPE_INTERNAL_CONNECTOR);

        info->supports_dvi = is_dvi;
        info->supports_hdmi = is_hdmi;
        info->supports_dp = is_dp;

        DRM_DEBUG_KMS("Port %c VBT info: DP:%d HDMI:%d DVI:%d EDP:%d CRT:%d\n",
                      port_name(port), is_dp, is_hdmi, is_dvi, is_edp, is_crt);

        if (is_edp && is_dvi)
                DRM_DEBUG_KMS("Internal DP port %c is TMDS compatible\n",
                              port_name(port));
        if (is_crt && port != PORT_E)
                DRM_DEBUG_KMS("Port %c is analog\n", port_name(port));
        if (is_crt && (is_dvi || is_dp))
                DRM_DEBUG_KMS("Analog port %c is also DP or TMDS compatible\n",
                              port_name(port));
        if (is_dvi && (port == PORT_A || port == PORT_E))
                DRM_DEBUG_KMS("Port %c is TMDS compatible\n", port_name(port));

        if (!is_dvi && !is_dp && !is_crt)
                DRM_DEBUG_KMS("Port %c is not DP/TMDS/CRT compatible\n",
                              port_name(port));
        if (is_edp && (port == PORT_B || port == PORT_C || port == PORT_E))
                DRM_DEBUG_KMS("Port %c is internal DP\n", port_name(port));

        if (is_dvi) {
                if (child->common.ddc_pin == 0x05 && port != PORT_B)
                        DRM_DEBUG_KMS("Unexpected DDC pin for port B\n");
                if (child->common.ddc_pin == 0x04 && port != PORT_C)
                        DRM_DEBUG_KMS("Unexpected DDC pin for port C\n");
                if (child->common.ddc_pin == 0x06 && port != PORT_D)
                        DRM_DEBUG_KMS("Unexpected DDC pin for port D\n");
        }

        if (is_dp) {
                if (aux_channel == 0x40 && port != PORT_A)
                        DRM_DEBUG_KMS("Unexpected AUX channel for port A\n");
                if (aux_channel == 0x10 && port != PORT_B)
                        DRM_DEBUG_KMS("Unexpected AUX channel for port B\n");
                if (aux_channel == 0x20 && port != PORT_C)
                        DRM_DEBUG_KMS("Unexpected AUX channel for port C\n");
                if (aux_channel == 0x30 && port != PORT_D)
                        DRM_DEBUG_KMS("Unexpected AUX channel for port D\n");
        }

        if (bdb->version >= 158) {
                /* The VBT HDMI level shift values match the table we have. */
                hdmi_level_shift = child->raw[7] & 0xF;
                DRM_DEBUG_KMS("VBT HDMI level shift for port %c: %d\n",
                              port_name(port),
                              hdmi_level_shift);
                info->hdmi_level_shift = hdmi_level_shift;
        }
}

static void parse_ddi_ports(struct drm_i915_private *dev_priv,
                            struct bdb_header *bdb)
{
        struct drm_device *dev = dev_priv->dev;
        enum port port;

        if (!HAS_DDI(dev))
                return;

        if (!dev_priv->vbt.child_dev_num)
                return;

        if (bdb->version < 155)
                return;

        for (port = PORT_A; port < I915_MAX_PORTS; port++)
                parse_ddi_port(dev_priv, port, bdb);
}

static void
parse_device_mapping(struct drm_i915_private *dev_priv,
                       struct bdb_header *bdb)
{
        struct bdb_general_definitions *p_defs;
        union child_device_config *p_child, *child_dev_ptr;
        int i, child_device_num, count;
        u16     block_size;

        p_defs = find_section(bdb, BDB_GENERAL_DEFINITIONS);
        if (!p_defs) {
                DRM_DEBUG_KMS("No general definition block is found, no devices defined.\n");
                return;
        }
        /* judge whether the size of child device meets the requirements.
         * If the child device size obtained from general definition block
         * is different with sizeof(struct child_device_config), skip the
         * parsing of sdvo device info
         */
        if (p_defs->child_dev_size != sizeof(*p_child)) {
                /* different child dev size . Ignore it */
                DRM_DEBUG_KMS("different child size is found. Invalid.\n");
                return;
        }
        /* get the block size of general definitions */
        block_size = get_blocksize(p_defs);
        /* get the number of child device */
        child_device_num = (block_size - sizeof(*p_defs)) /
                                sizeof(*p_child);
        count = 0;
        /* get the number of child device that is present */
        for (i = 0; i < child_device_num; i++) {
                p_child = &(p_defs->devices[i]);
                if (!p_child->common.device_type) {
                        /* skip the device block if device type is invalid */
                        continue;
                }
                count++;
        }
        if (!count) {
                DRM_DEBUG_KMS("no child dev is parsed from VBT\n");
                return;
        }
        dev_priv->vbt.child_dev = kcalloc(count, sizeof(*p_child), GFP_KERNEL);
        if (!dev_priv->vbt.child_dev) {
                DRM_DEBUG_KMS("No memory space for child device\n");
                return;
        }

        dev_priv->vbt.child_dev_num = count;
        count = 0;
        for (i = 0; i < child_device_num; i++) {
                p_child = &(p_defs->devices[i]);
                if (!p_child->common.device_type) {
                        /* skip the device block if device type is invalid */
                        continue;
                }

                if (p_child->common.dvo_port >= DVO_PORT_MIPIA
                    && p_child->common.dvo_port <= DVO_PORT_MIPID
                    &&p_child->common.device_type & DEVICE_TYPE_MIPI_OUTPUT) {
                        DRM_DEBUG_KMS("Found MIPI as LFP\n");
                        dev_priv->vbt.has_mipi = 1;
                        dev_priv->vbt.dsi.port = p_child->common.dvo_port;
                }

                child_dev_ptr = dev_priv->vbt.child_dev + count;
                count++;
                memcpy((void *)child_dev_ptr, (void *)p_child,
                                        sizeof(*p_child));
        }
        return;
}

static void
init_vbt_defaults(struct drm_i915_private *dev_priv)
{
        struct drm_device *dev = dev_priv->dev;
        enum port port;

        dev_priv->vbt.crt_ddc_pin = GMBUS_PORT_VGADDC;

        /* Default to having backlight */
        dev_priv->vbt.backlight.present = true;

        /* LFP panel data */
        dev_priv->vbt.lvds_dither = 1;
        dev_priv->vbt.lvds_vbt = 0;

        /* SDVO panel data */
        dev_priv->vbt.sdvo_lvds_vbt_mode = NULL;

        /* general features */
        dev_priv->vbt.int_tv_support = 1;
        dev_priv->vbt.int_crt_support = 1;

        /* Default to using SSC */
        dev_priv->vbt.lvds_use_ssc = 1;
        /*
         * Core/SandyBridge/IvyBridge use alternative (120MHz) reference
         * clock for LVDS.
         */
        dev_priv->vbt.lvds_ssc_freq = intel_bios_ssc_frequency(dev,
                        !HAS_PCH_SPLIT(dev));
        DRM_DEBUG_KMS("Set default to SSC at %d kHz\n", dev_priv->vbt.lvds_ssc_freq);

        for (port = PORT_A; port < I915_MAX_PORTS; port++) {
                struct ddi_vbt_port_info *info =
                        &dev_priv->vbt.ddi_port_info[port];

                info->hdmi_level_shift = HDMI_LEVEL_SHIFT_UNKNOWN;

                info->supports_dvi = (port != PORT_A && port != PORT_E);
                info->supports_hdmi = info->supports_dvi;
                info->supports_dp = (port != PORT_E);
        }
}

static int intel_no_opregion_vbt_callback(const struct dmi_system_id *id)
{
        DRM_DEBUG_KMS("Falling back to manually reading VBT from "
                      "VBIOS ROM for %s\n",
                      id->ident);
        return 1;
}

static const struct dmi_system_id intel_no_opregion_vbt[] = {
        {
                .callback = intel_no_opregion_vbt_callback,
                .ident = "ThinkCentre A57",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "97027RG"),
                },
        },
        { }
};

static struct bdb_header *validate_vbt(char *base, size_t size,
                                       struct vbt_header *vbt,
                                       const char *source)
{
        size_t offset;
        struct bdb_header *bdb;

        if (vbt == NULL) {
                DRM_DEBUG_DRIVER("VBT signature missing\n");
                return NULL;
        }

        offset = (char *)vbt - base;
        if (offset + sizeof(struct vbt_header) > size) {
                DRM_DEBUG_DRIVER("VBT header incomplete\n");
                return NULL;
        }

        if (memcmp(vbt->signature, "$VBT", 4)) {
                DRM_DEBUG_DRIVER("VBT invalid signature\n");
                return NULL;
        }

        offset += vbt->bdb_offset;
        if (offset + sizeof(struct bdb_header) > size) {
                DRM_DEBUG_DRIVER("BDB header incomplete\n");
                return NULL;
        }

        bdb = (struct bdb_header *)(base + offset);
        if (offset + bdb->bdb_size > size) {
                DRM_DEBUG_DRIVER("BDB incomplete\n");
                return NULL;
        }

        DRM_DEBUG_KMS("Using VBT from %s: %20s\n",
                      source, vbt->signature);
        return bdb;
}

/**
 * intel_parse_bios - find VBT and initialize settings from the BIOS
 * @dev: DRM device
 *
 * Loads the Video BIOS and checks that the VBT exists.  Sets scratch registers
 * to appropriate values.
 *
 * Returns 0 on success, nonzero on failure.
 */
int
intel_parse_bios(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct pci_dev *pdev = dev->pdev;
        struct bdb_header *bdb = NULL;
        u8 __iomem *bios = NULL;

        if (HAS_PCH_NOP(dev))
                return -ENODEV;

        init_vbt_defaults(dev_priv);

        /* XXX Should this validation be moved to intel_opregion.c? */
        if (!dmi_check_system(intel_no_opregion_vbt) && dev_priv->opregion.vbt)
                bdb = validate_vbt((char *)dev_priv->opregion.header, OPREGION_SIZE,
                                   (struct vbt_header *)dev_priv->opregion.vbt,
                                   "OpRegion");

        if (bdb == NULL) {
                size_t i, size;

                bios = pci_map_rom(pdev, &size);
                if (!bios)
                        return -1;

                /* Scour memory looking for the VBT signature */
                for (i = 0; i + 4 < size; i++) {
                        if (memcmp(bios + i, "$VBT", 4) == 0) {
                                bdb = validate_vbt(bios, size,
                                                   (struct vbt_header *)(bios + i),
                                                   "PCI ROM");
                                break;
                        }
                }

                if (!bdb) {
                        pci_unmap_rom(pdev, bios);
                        return -1;
                }
        }

        /* Grab useful general definitions */
        parse_general_features(dev_priv, bdb);
        parse_general_definitions(dev_priv, bdb);
        parse_lfp_panel_data(dev_priv, bdb);
        parse_lfp_backlight(dev_priv, bdb);
        parse_sdvo_panel_data(dev_priv, bdb);
        parse_sdvo_device_mapping(dev_priv, bdb);
        parse_device_mapping(dev_priv, bdb);
        parse_driver_features(dev_priv, bdb);
        parse_edp(dev_priv, bdb);
        parse_psr(dev_priv, bdb);
        parse_mipi(dev_priv, bdb);
        parse_ddi_ports(dev_priv, bdb);

        if (bios)
                pci_unmap_rom(pdev, bios);

        return 0;
}

/* Ensure that vital registers have been initialised, even if the BIOS
 * is absent or just failing to do its job.
 */
void intel_setup_bios(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

         /* Set the Panel Power On/Off timings if uninitialized. */
        if (!HAS_PCH_SPLIT(dev) &&
            I915_READ(PP_ON_DELAYS) == 0 && I915_READ(PP_OFF_DELAYS) == 0) {
                /* Set T2 to 40ms and T5 to 200ms */
                I915_WRITE(PP_ON_DELAYS, 0x019007d0);

                /* Set T3 to 35ms and Tx to 200ms */
                I915_WRITE(PP_OFF_DELAYS, 0x015e07d0);
        }
}