drivers/gpu/drm/i915/intel_bios.c

/*
 * 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 "drmP.h"
#include "drm.h"
#include "i915_drm.h"
#include "i915_drv.h"
#include "intel_bios.h"


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 < total) {
		current_id = *(base + index);
		index++;
		current_size = *((u16 *)(base + index));
		index += 2;
		if (current_id == section_id)
			return base + index;
		index += current_size;
	}

	return NULL;
}

/* Try to find panel data */
static void
parse_panel_data(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
{
	struct bdb_lvds_options *lvds_options;
	struct bdb_lvds_lfp_data *lvds_lfp_data;
	struct bdb_lvds_lfp_data_entry *entry;
	struct lvds_dvo_timing *dvo_timing;
	struct drm_display_mode *panel_fixed_mode;

	/* Defaults if we can't find VBT info */
	dev_priv->lvds_dither = 0;
	dev_priv->lvds_vbt = 0;

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

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

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

	dev_priv->lvds_vbt = 1;

	entry = &lvds_lfp_data->data[lvds_options->panel_type];
	dvo_timing = &entry->dvo_timing;

	panel_fixed_mode = drm_calloc(1, sizeof(*panel_fixed_mode),
				      DRM_MEM_DRIVER);

	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;

	/* 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);

	dev_priv->vbt_mode = panel_fixed_mode;

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

	return;
}

static void
parse_general_features(struct drm_i915_private *dev_priv,
		       struct bdb_header *bdb)
{
	struct bdb_general_features *general;

	/* Set sensible defaults in case we can't find the general block */
	dev_priv->int_tv_support = 1;
	dev_priv->int_crt_support = 1;

	general = find_section(bdb, BDB_GENERAL_FEATURES);
	if (general) {
		dev_priv->int_tv_support = general->int_tv_support;
		dev_priv->int_crt_support = general->int_crt_support;
		dev_priv->lvds_use_ssc = general->enable_ssc;

		if (dev_priv->lvds_use_ssc) {
		  if (IS_I855(dev_priv->dev))
		    dev_priv->lvds_ssc_freq = general->ssc_freq ? 66 : 48;
		  else
		    dev_priv->lvds_ssc_freq = general->ssc_freq ? 100 : 96;
		}
	}
}

/**
 * intel_init_bios - initialize VBIOS settings & find VBT
 * @dev: DRM device
 *
 * Loads the Video BIOS and checks that the VBT exists.  Sets scratch registers
 * to appropriate values.
 *
 * VBT existence is a sanity check that is relied on by other i830_bios.c code.
 * Note that it would be better to use a BIOS call to get the VBT, as BIOSes may
 * feed an updated VBT back through that, compared to what we'll fetch using
 * this method of groping around in the BIOS data.
 *
 * Returns 0 on success, nonzero on failure.
 */
bool
intel_init_bios(struct drm_device *dev)
{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct pci_dev *pdev = dev->pdev;
	struct vbt_header *vbt = NULL;
	struct bdb_header *bdb;
	u8 __iomem *bios;
	size_t size;
	int i;

	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)) {
			vbt = (struct vbt_header *)(bios + i);
			break;
		}
	}

	if (!vbt) {
		DRM_ERROR("VBT signature missing\n");
		pci_unmap_rom(pdev, bios);
		return -1;
	}

	bdb = (struct bdb_header *)(bios + i + vbt->bdb_offset);

	/* Grab useful general definitions */
	parse_general_features(dev_priv, bdb);
	parse_panel_data(dev_priv, bdb);

	pci_unmap_rom(pdev, bios);

	return 0;
}