drm/edid: use struct drm_edid for override/firmware EDID

There's a lot going on here, but the main thing is switching the
firmware EDID loader to use struct drm_edid. Unfortunately, it's
difficult to reasonably split to smaller pieces.

Convert the EDID loader to struct drm_edid. There's a functional change
in validation; it no longer tries to fix errors or filter invalid
blocks. It's stricter in this sense. Hopefully this will not be an
issue.

As a by-product, this change also allows HF-EEODB extended EDIDs to be
passed via override/firmware EDID.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/e64267c28eca483e83c802bc06ddd149bdcdfc66.1666614699.git.jani.nikula@intel.com

drivers/gpu/drm/drm_edid.c

@@ -2202,25 +2202,20 @@ static void connector_bad_edid(struct drm_connector *connector,
 }
 
 /* Get override or firmware EDID */
-static struct edid *drm_get_override_edid(struct drm_connector *connector,
-					  size_t *alloc_size)
+static const struct drm_edid *drm_edid_override_get(struct drm_connector *connector)
 {
-	struct edid *override = NULL;
+	const struct drm_edid *override = NULL;
 
 	mutex_lock(&connector->edid_override_mutex);
 
 	if (connector->edid_override)
-		override = drm_edid_duplicate(connector->edid_override->edid);
+		override = drm_edid_dup(connector->edid_override);
 
 	mutex_unlock(&connector->edid_override_mutex);
 
 	if (!override)
 		override = drm_edid_load_firmware(connector);
 
-	/* FIXME: Get alloc size from deeper down the stack */
-	if (!IS_ERR_OR_NULL(override) && alloc_size)
-		*alloc_size = edid_size(override);
-
 	return IS_ERR(override) ? NULL : override;
 }
 
@@ -2296,14 +2291,14 @@ int drm_edid_override_reset(struct drm_connector *connector)
  */
 int drm_edid_override_connector_update(struct drm_connector *connector)
 {
-	struct edid *override;
+	const struct drm_edid *override;
 	int num_modes = 0;
 
-	override = drm_get_override_edid(connector, NULL);
+	override = drm_edid_override_get(connector);
 	if (override) {
-		drm_connector_update_edid_property(connector, override);
-		num_modes = drm_add_edid_modes(connector, override);
-		kfree(override);
+		num_modes = drm_edid_connector_update(connector, override);
+
+		drm_edid_free(override);
 
 		DRM_DEBUG_KMS("[CONNECTOR:%d:%s] adding %d modes via fallback override/firmware EDID\n",
 			      connector->base.id, connector->name, num_modes);
@@ -2354,12 +2349,19 @@ static struct edid *_drm_do_get_edid(struct drm_connector *connector,
 {
 	enum edid_block_status status;
 	int i, num_blocks, invalid_blocks = 0;
+	const struct drm_edid *override;
 	struct edid *edid, *new;
 	size_t alloc_size = EDID_LENGTH;
 
-	edid = drm_get_override_edid(connector, &alloc_size);
-	if (edid)
+	override = drm_edid_override_get(connector);
+	if (override) {
+		alloc_size = override->size;
+		edid = kmemdup(override->edid, alloc_size, GFP_KERNEL);
+		drm_edid_free(override);
+		if (!edid)
+			return NULL;
 		goto ok;
+	}
 
 	edid = kmalloc(alloc_size, GFP_KERNEL);
 	if (!edid)

drivers/gpu/drm/drm_edid_load.c

@@ -159,22 +159,12 @@ static const u8 generic_edid[GENERIC_EDIDS][128] = {
 	},
 };
 
-static int edid_size(const u8 *edid, int data_size)
-{
-	if (data_size < EDID_LENGTH)
-		return 0;
-
-	return (edid[0x7e] + 1) * EDID_LENGTH;
-}
-
-static void *edid_load(struct drm_connector *connector, const char *name)
+static const struct drm_edid *edid_load(struct drm_connector *connector, const char *name)
 {
 	const struct firmware *fw = NULL;
 	const u8 *fwdata;
-	u8 *edid;
+	const struct drm_edid *drm_edid;
 	int fwsize, builtin;
-	int i, valid_extensions = 0;
-	bool print_bad_edid = !connector->bad_edid_counter || drm_debug_enabled(DRM_UT_KMS);
 
 	builtin = match_string(generic_edid_name, GENERIC_EDIDS, name);
 	if (builtin >= 0) {
@@ -203,69 +193,26 @@ static void *edid_load(struct drm_connector *connector, const char *name)
 		fwsize = fw->size;
 	}
 
-	if (edid_size(fwdata, fwsize) != fwsize) {
-		DRM_ERROR("Size of EDID firmware \"%s\" is invalid "
-			  "(expected %d, got %d\n", name,
-			  edid_size(fwdata, fwsize), (int)fwsize);
-		edid = ERR_PTR(-EINVAL);
-		goto out;
-	}
-
-	edid = kmemdup(fwdata, fwsize, GFP_KERNEL);
-	if (edid == NULL) {
-		edid = ERR_PTR(-ENOMEM);
-		goto out;
-	}
+	drm_dbg_kms(connector->dev, "[CONNECTOR:%d:%s] Loaded %s firmware EDID \"%s\"\n",
+		    connector->base.id, connector->name,
+		    builtin >= 0 ? "built-in" : "external", name);
 
-	if (!drm_edid_block_valid(edid, 0, print_bad_edid,
-				  &connector->edid_corrupt)) {
-		connector->bad_edid_counter++;
-		DRM_ERROR("Base block of EDID firmware \"%s\" is invalid ",
-		    name);
-		kfree(edid);
-		edid = ERR_PTR(-EINVAL);
-		goto out;
+	drm_edid = drm_edid_alloc(fwdata, fwsize);
+	if (!drm_edid_valid(drm_edid)) {
+		drm_err(connector->dev, "Invalid firmware EDID \"%s\"\n", name);
+		drm_edid_free(drm_edid);
+		drm_edid = ERR_PTR(-EINVAL);
 	}
 
-	for (i = 1; i <= edid[0x7e]; i++) {
-		if (i != valid_extensions + 1)
-			memcpy(edid + (valid_extensions + 1) * EDID_LENGTH,
-			    edid + i * EDID_LENGTH, EDID_LENGTH);
-		if (drm_edid_block_valid(edid + i * EDID_LENGTH, i,
-					 print_bad_edid,
-					 NULL))
-			valid_extensions++;
-	}
-
-	if (valid_extensions != edid[0x7e]) {
-		u8 *new_edid;
-
-		edid[EDID_LENGTH-1] += edid[0x7e] - valid_extensions;
-		DRM_INFO("Found %d valid extensions instead of %d in EDID data "
-		    "\"%s\" for connector \"%s\"\n", valid_extensions,
-		    edid[0x7e], name, connector->name);
-		edid[0x7e] = valid_extensions;
-
-		new_edid = krealloc(edid, (valid_extensions + 1) * EDID_LENGTH,
-				    GFP_KERNEL);
-		if (new_edid)
-			edid = new_edid;
-	}
-
-	DRM_INFO("Got %s EDID base block and %d extension%s from "
-	    "\"%s\" for connector \"%s\"\n", (builtin >= 0) ? "built-in" :
-	    "external", valid_extensions, valid_extensions == 1 ? "" : "s",
-	    name, connector->name);
-
-out:
 	release_firmware(fw);
-	return edid;
+
+	return drm_edid;
 }
 
-struct edid *drm_edid_load_firmware(struct drm_connector *connector)
+const struct drm_edid *drm_edid_load_firmware(struct drm_connector *connector)
 {
 	char *edidname, *last, *colon, *fwstr, *edidstr, *fallback = NULL;
-	struct edid *edid;
+	const struct drm_edid *drm_edid;
 
 	if (edid_firmware[0] == '\0')
 		return ERR_PTR(-ENOENT);
@@ -308,8 +255,9 @@ struct edid *drm_edid_load_firmware(struct drm_connector *connector)
 	if (*last == '\n')
 		*last = '\0';
 
-	edid = edid_load(connector, edidname);
+	drm_edid = edid_load(connector, edidname);
+
 	kfree(fwstr);
 
-	return edid;
+	return drm_edid;
 }

include/drm/drm_edid.h

@@ -388,11 +388,11 @@ int drm_av_sync_delay(struct drm_connector *connector,
 		      const struct drm_display_mode *mode);
 
 #ifdef CONFIG_DRM_LOAD_EDID_FIRMWARE
-struct edid *drm_edid_load_firmware(struct drm_connector *connector);
+const struct drm_edid *drm_edid_load_firmware(struct drm_connector *connector);
 int __drm_set_edid_firmware_path(const char *path);
 int __drm_get_edid_firmware_path(char *buf, size_t bufsize);
 #else
-static inline struct edid *
+static inline const struct drm_edid *
 drm_edid_load_firmware(struct drm_connector *connector)
 {
 	return ERR_PTR(-ENOENT);