[Intel-gfx] [PATCH 4/9] drm/i915/bios: parse compression parameters block

[Jani Nikula]

Check for child devices that specify compression, and store the device
specific compression parameters in the display device data struct for
later use. Warn if compression is requested but not available.

Use fairly rigid checks for compression data for starters. These can be
made more dynamic later.

Log about DSC presence in DDI port parse, though this is not universal
across platforms.

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/i915/display/intel_bios.c     | 61 ++++++++++++++++++-
 drivers/gpu/drm/i915/display/intel_vbt_defs.h |  2 +-
 2 files changed, 60 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_bios.c b/drivers/gpu/drm/i915/display/intel_bios.c
index 12d2fb0156b4..51068a0a1c42 100644
--- a/drivers/gpu/drm/i915/display/intel_bios.c
+++ b/drivers/gpu/drm/i915/display/intel_bios.c
@@ -61,6 +61,7 @@
 /* Wrapper for VBT child device config */
 struct display_device_data {
 	struct child_device_config child;
+	struct dsc_compression_parameters_entry *dsc;
 	struct list_head node;
 };
 
@@ -1237,6 +1238,57 @@ parse_mipi_sequence(struct drm_i915_private *dev_priv,
 	memset(dev_priv->vbt.dsi.sequence, 0, sizeof(dev_priv->vbt.dsi.sequence));
 }
 
+static void
+parse_compression_parameters(struct drm_i915_private *i915,
+			     const struct bdb_header *bdb)
+{
+	const struct bdb_compression_parameters *params;
+	struct display_device_data *devdata;
+	const struct child_device_config *child;
+	u16 block_size;
+	int index;
+
+	if (bdb->version < 198)
+		return;
+
+	params = find_section(bdb, BDB_COMPRESSION_PARAMETERS);
+	if (params) {
+		/* Sanity checks */
+		if (params->entry_size != sizeof(params->data[0])) {
+			DRM_DEBUG_KMS("unsupported compression param entry size\n");
+			return;
+		}
+
+		block_size = get_blocksize(params);
+		if (block_size < sizeof(*params)) {
+			DRM_DEBUG_KMS("expecting 16 compression param entries\n");
+			return;
+		}
+	}
+
+	list_for_each_entry(devdata, &i915->vbt.display_devices, node) {
+		child = &devdata->child;
+
+		if (!child->compression_enable)
+			continue;
+
+		if (!params) {
+			DRM_DEBUG_KMS("child wants compression, unavailable\n");
+			continue;
+		}
+
+		if (child->compression_method_cps) {
+			DRM_DEBUG_KMS("CPS compression not supported\n");
+			continue;
+		}
+
+		index = child->compression_structure_index;
+
+		devdata->dsc = kmemdup(&params->data[index],
+				       sizeof(*devdata->dsc), GFP_KERNEL);
+	}
+}
+
 static u8 translate_iboost(u8 val)
 {
 	static const u8 mapping[] = { 1, 3, 7 }; /* See VBT spec */
@@ -1469,10 +1521,11 @@ static void parse_ddi_port(struct drm_i915_private *dev_priv,
 	if (bdb_version >= 209)
 		info->supports_tbt = child->tbt;
 
-	DRM_DEBUG_KMS("Port %c VBT info: CRT:%d DVI:%d HDMI:%d DP:%d eDP:%d LSPCON:%d USB-Type-C:%d TBT:%d\n",
+	DRM_DEBUG_KMS("Port %c VBT info: CRT:%d DVI:%d HDMI:%d DP:%d eDP:%d LSPCON:%d USB-Type-C:%d TBT:%d DSC:%d\n",
 		      port_name(port), is_crt, is_dvi, is_hdmi, is_dp, is_edp,
 		      HAS_LSPCON(dev_priv) && child->lspcon,
-		      info->supports_typec_usb, info->supports_tbt);
+		      info->supports_typec_usb, info->supports_tbt,
+		      devdata->dsc != NULL);
 
 	if (is_edp && is_dvi)
 		DRM_DEBUG_KMS("Internal DP port %c is TMDS compatible\n",
@@ -1871,6 +1924,9 @@ void intel_bios_init(struct drm_i915_private *dev_priv)
 	parse_mipi_config(dev_priv, bdb);
 	parse_mipi_sequence(dev_priv, bdb);
 
+	/* Depends on child device list */
+	parse_compression_parameters(dev_priv, bdb);
+
 	/* Further processing on pre-parsed data */
 	parse_sdvo_device_mapping(dev_priv, bdb->version);
 	parse_ddi_ports(dev_priv, bdb->version);
@@ -1895,6 +1951,7 @@ void intel_bios_driver_remove(struct drm_i915_private *dev_priv)
 
 	list_for_each_entry_safe(devdata, n, &dev_priv->vbt.display_devices, node) {
 		list_del(&devdata->node);
+		kfree(devdata->dsc);
 		kfree(devdata);
 	}
 
diff --git a/drivers/gpu/drm/i915/display/intel_vbt_defs.h b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
index 69a7cb1fa121..372d8b62ba1a 100644
--- a/drivers/gpu/drm/i915/display/intel_vbt_defs.h
+++ b/drivers/gpu/drm/i915/display/intel_vbt_defs.h
@@ -368,7 +368,7 @@ struct child_device_config {
 			u16 dtd_buf_ptr;			/* 161 */
 			u8 edidless_efp:1;			/* 161 */
 			u8 compression_enable:1;		/* 198 */
-			u8 compression_method:1;		/* 198 */
+			u8 compression_method_cps:1;		/* 198 */
 			u8 ganged_edp:1;			/* 202 */
 			u8 reserved0:4;
 			u8 compression_structure_index:4;	/* 198 */
-- 
2.20.1