[Intel-gfx] [PATCH v2 3/9] drm/i915/bios: Get access to the tail end of the LFP data block

[Ville Syrjala]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

We need to start parsing stuff from the tail end of the LFP data block.
This is made awkward by the fact that the fp_timing table has variable
size. So we must use a bit more finesse to get the tail end, and to
make sure we allocate enough memory for it to make sure our struct
representation fits.

v2: Rebase due to the preallocation of BDB blocks
v3: Rebase due to min_size WARN relocation
v4: Document BDB_LVDS_LFP_DATA vs. BDB_LVDS_LFP_DATA_PTRS order (Jani)

Reviewed-by: Jani Nikula <jani.nikula at intel.com>
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/display/intel_bios.c     | 43 ++++++++++++++++++-
 drivers/gpu/drm/i915/display/intel_vbt_defs.h | 17 ++++++++
 2 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index 7bc3d55b6bb0..ecfce9adfbbb 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -186,10 +186,14 @@ static const struct {
 	  .min_size = sizeof(struct bdb_edp), },
 	{ .section_id = BDB_LVDS_OPTIONS,
 	  .min_size = sizeof(struct bdb_lvds_options), },
+	/*
+	 * BDB_LVDS_LFP_DATA depends on BDB_LVDS_LFP_DATA_PTRS,
+	 * so keep the two ordered.
+	 */
 	{ .section_id = BDB_LVDS_LFP_DATA_PTRS,
 	  .min_size = sizeof(struct bdb_lvds_lfp_data_ptrs), },
 	{ .section_id = BDB_LVDS_LFP_DATA,
-	  .min_size = sizeof(struct bdb_lvds_lfp_data), },
+	  .min_size = 0, /* special case */ },
 	{ .section_id = BDB_LVDS_BACKLIGHT,
 	  .min_size = sizeof(struct bdb_lfp_backlight_data), },
 	{ .section_id = BDB_LFP_POWER,
@@ -204,6 +208,23 @@ static const struct {
 	  .min_size = sizeof(struct bdb_generic_dtd), },
 };
 
+static size_t lfp_data_min_size(struct drm_i915_private *i915)
+{
+	const struct bdb_lvds_lfp_data_ptrs *ptrs;
+	size_t size;
+
+	ptrs = find_section(i915, BDB_LVDS_LFP_DATA_PTRS);
+	if (!ptrs)
+		return 0;
+
+	size = sizeof(struct bdb_lvds_lfp_data);
+	if (ptrs->panel_name.table_size)
+		size = max(size, ptrs->panel_name.offset +
+			   sizeof(struct bdb_lvds_lfp_data_tail));
+
+	return size;
+}
+
 static bool validate_lfp_data_ptrs(const void *bdb,
 				   const struct bdb_lvds_lfp_data_ptrs *ptrs)
 {
@@ -491,6 +512,9 @@ static void init_bdb_blocks(struct drm_i915_private *i915,
 		enum bdb_block_id section_id = bdb_blocks[i].section_id;
 		size_t min_size = bdb_blocks[i].min_size;
 
+		if (section_id == BDB_LVDS_LFP_DATA)
+			min_size = lfp_data_min_size(i915);
+
 		init_bdb_block(i915, bdb, section_id, min_size);
 	}
 }
@@ -561,6 +585,16 @@ get_lvds_fp_timing(const struct bdb_lvds_lfp_data *data,
 	return (const void *)data + ptrs->ptr[index].fp_timing.offset;
 }
 
+static const struct bdb_lvds_lfp_data_tail *
+get_lfp_data_tail(const struct bdb_lvds_lfp_data *data,
+		  const struct bdb_lvds_lfp_data_ptrs *ptrs)
+{
+	if (ptrs->panel_name.table_size)
+		return (const void *)data + ptrs->panel_name.offset;
+	else
+		return NULL;
+}
+
 /* Parse general panel options */
 static void
 parse_panel_options(struct drm_i915_private *i915)
@@ -665,6 +699,7 @@ static void
 parse_lfp_data(struct drm_i915_private *i915)
 {
 	const struct bdb_lvds_lfp_data *data;
+	const struct bdb_lvds_lfp_data_tail *tail;
 	const struct bdb_lvds_lfp_data_ptrs *ptrs;
 
 	ptrs = find_section(i915, BDB_LVDS_LFP_DATA_PTRS);
@@ -677,6 +712,12 @@ parse_lfp_data(struct drm_i915_private *i915)
 
 	if (!i915->vbt.lfp_lvds_vbt_mode)
 		parse_lfp_panel_dtd(i915, data, ptrs);
+
+	tail = get_lfp_data_tail(data, ptrs);
+	if (!tail)
+		return;
+
+	(void)tail;
 }
 
 static void
diff --git a/drivers/gpu/drm/i915/display/intel_vbt_defs.h b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
index e4a11c3e3f3e..2554f4b9b4da 100644
--- a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
+++ b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
@@ -783,6 +783,23 @@ struct lvds_lfp_panel_name {
 	u8 name[13];
 } __packed;
 
+struct lvds_lfp_black_border {
+	u8 top; /* 227 */
+	u8 bottom; /* 227 */
+	u8 left; /* 238 */
+	u8 right; /* 238 */
+} __packed;
+
+struct bdb_lvds_lfp_data_tail {
+	struct lvds_lfp_panel_name panel_name[16]; /* 156-163? */
+	u16 scaling_enable; /* 187 */
+	u8 seamless_drrs_min_refresh_rate[16]; /* 188 */
+	u8 pixel_overlap_count[16]; /* 208 */
+	struct lvds_lfp_black_border black_border[16]; /* 227 */
+	u16 dual_lfp_port_sync_enable; /* 231 */
+	u16 gpu_dithering_for_banding_artifacts; /* 245 */
+} __packed;
+
 /*
  * Block 43 - LFP Backlight Control Data Block
  */
-- 
2.35.1