[PATCH v2 12/18] DRM/KMS/EDID: Use Extension Block Fixup Code also for 'firmware' EDID (v2)

[Egbert Eich <eich@suse.com>]

in drm_edid.c there's now code to fix extension blockmaps if the number
of extensions has changed. This code also rearranges the EDID blocks.
Replace the exisiting EDID rearrange code with a call to this code.

v2: Make adjustments required by patch reordering, add missing memcpy().

Signed-off-by: Egbert Eich <eich@suse.com>
---
 drivers/gpu/drm/drm_edid.c      |   64 +++++++++++++++++++++++++++++++++++----
 drivers/gpu/drm/drm_edid_load.c |   54 +++++++-------------------------
 include/drm/drm_edid.h          |    1 +
 3 files changed, 71 insertions(+), 48 deletions(-)

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index 8239c42..a47fa7f 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -407,6 +407,18 @@ fixup_blockmaps(u8 **blockp, int eblock_cnt)
 	return eblock_cnt;
 }
 
+static void
+fixup_edid(u8 **blockp, int valid_extensions)
+{
+	if (valid_extensions != (*blockp)[EDID_EXTENSION_FLAG_OFFSET]) {
+		if (valid_extensions)
+			valid_extensions = fixup_blockmaps(blockp, valid_extensions);
+
+		(*blockp)[EDID_CHECKSUM_OFFSET] += (*blockp)[EDID_EXTENSION_FLAG_OFFSET] - valid_extensions;
+		(*blockp)[EDID_EXTENSION_FLAG_OFFSET] = valid_extensions;
+	}
+}
+
 static u8 *
 drm_do_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
 {
@@ -487,12 +499,7 @@ drm_do_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
 	}
 
 done_fix_extension_count:
-	if (valid_extensions != block[EDID_EXTENSION_FLAG_OFFSET]) {
-		if (valid_extensions)
-			valid_extensions = fixup_blockmaps(&block, valid_extensions);
-		block[EDID_CHECKSUM_OFFSET] += block[EDID_EXTENSION_FLAG_OFFSET] - valid_extensions;
-		block[EDID_EXTENSION_FLAG_OFFSET] = valid_extensions;
-	}
+	fixup_edid(&block, valid_extensions);
 
 	return block;
 
@@ -509,6 +516,51 @@ out:
 }
 
 /**
+ * Validate an entire EDID blob.
+ * \param connector: drm_connector struct of the used connector.
+ * \param blockp: pointer to address of an raw EDID data block.
+ * \param len: size if block in bytes.
+ *
+ * validate block and return corrected block in \param block.
+ * \return: number of valid extensions or -errno if unsuccessful.
+ */
+int
+drm_validate_edid_blob(struct drm_connector *connector, u8 **blockp, int len)
+{
+	int n_blocks = len / EDID_LENGTH;
+	int valid_extensions = 0, ret = 0;
+	bool print_bad_edid = !connector->bad_edid_counter || (drm_debug & DRM_UT_KMS);
+
+	if (!blockp || !*blockp)
+		ret = -EINVAL;
+	else if (!n_blocks || !drm_edid_block_valid(*blockp, 0, print_bad_edid)) {
+		kfree(*blockp);
+		*blockp = NULL;
+		ret = -EINVAL;
+	}
+	if (!ret) {
+		int cnt = 0;
+		n_blocks--;
+		if ((*blockp)[EDID_EXTENSION_FLAG_OFFSET] < n_blocks)
+			n_blocks = (*blockp)[EDID_EXTENSION_FLAG_OFFSET];
+
+		while (n_blocks--) {
+			cnt++;
+			if (drm_edid_block_valid(*blockp + cnt * EDID_LENGTH,
+						 valid_extensions + 1, print_bad_edid)) {
+				valid_extensions++;
+				if (cnt != valid_extensions)
+					memcpy(*blockp + valid_extensions * EDID_LENGTH,
+					       *blockp + cnt * EDID_LENGTH, EDID_LENGTH);
+			}
+		}
+		fixup_edid(blockp, valid_extensions);
+	} else
+		connector->bad_edid_counter++;
+	return ret;
+}
+
+/**
  * Probe DDC presence.
  *
  * \param adapter : i2c device adaptor
diff --git a/drivers/gpu/drm/drm_edid_load.c b/drivers/gpu/drm/drm_edid_load.c
index 9c15c4a..8f26790 100644
--- a/drivers/gpu/drm/drm_edid_load.c
+++ b/drivers/gpu/drm/drm_edid_load.c
@@ -119,11 +119,10 @@ static struct edid *edid_load(struct drm_connector *connector, char *name,
 {
 	const struct firmware *fw;
 	struct platform_device *pdev;
-	u8 *fwdata = NULL, *edid, *new_edid;
+	u8 *fwdata = NULL;
+	struct edid *edid;
 	int fwsize, expected;
 	int builtin = 0, err = 0;
-	int i, valid_extensions = 0;
-	bool print_bad_edid = !connector->bad_edid_counter || (drm_debug & DRM_UT_KMS);
 
 	pdev = platform_device_register_simple(connector_name, -1, NULL, 0);
 	if (IS_ERR(pdev)) {
@@ -137,7 +136,7 @@ static struct edid *edid_load(struct drm_connector *connector, char *name,
 	platform_device_unregister(pdev);
 
 	if (err) {
-		i = 0;
+		int i = 0;
 		while (i < GENERIC_EDIDS && strcmp(name, generic_edid_name[i]))
 			i++;
 		if (i < GENERIC_EDIDS) {
@@ -174,49 +173,20 @@ static struct edid *edid_load(struct drm_connector *connector, char *name,
 	}
 	memcpy(edid, fwdata, fwsize);
 
-	if (!drm_edid_block_valid(edid, 0, print_bad_edid)) {
-		connector->bad_edid_counter++;
-		DRM_ERROR("Base block of EDID firmware \"%s\" is invalid ",
-		    name);
-		kfree(edid);
-		err = -EINVAL;
-		goto relfw_out;
-	}
-
-	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))
-			valid_extensions++;
-	}
-
-	if (valid_extensions != edid[0x7e]) {
-		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 == NULL) {
-			err = -ENOMEM;
-			kfree(edid);
-			goto relfw_out;
-		}
-		edid = new_edid;
-	}
-
-	DRM_INFO("Got %s EDID base block and %d extension%s from "
-	    "\"%s\" for connector \"%s\"\n", builtin ? "built-in" :
-	    "external", valid_extensions, valid_extensions == 1 ? "" : "s",
-	    name, connector_name);
+	err = drm_validate_edid_blob(connector, (u8 **)&edid, fwsize);
+	if (err < 0)
+		DRM_ERROR("EDID firmware \"%s\" is invalid ", name);
+	else
+		DRM_INFO("Got %s EDID base block and %d extension%s from "
+			 "\"%s\" for connector \"%s\"\n", builtin ? "built-in" :
+			 "external", edid->extensions, edid->extensions == 1 ? "" : "s",
+			 name, connector_name);
 
 relfw_out:
 	release_firmware(fw);
 
 out:
-	if (err)
+	if (err < 0)
 		return ERR_PTR(err);
 
 	return edid;
diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h
index c0a77bd..53c619c 100644
--- a/include/drm/drm_edid.h
+++ b/include/drm/drm_edid.h
@@ -255,5 +255,6 @@ struct drm_connector *drm_select_eld(struct drm_encoder *encoder,
 #ifdef CONFIG_DRM_LOAD_EDID_FIRMWARE
 struct edid *drm_load_edid_firmware(struct drm_connector *connector);
 #endif
+int drm_validate_edid_blob(struct drm_connector *connector, u8 **blockp, int len);
 
 #endif /* __DRM_EDID_H__ */
-- 
1.7.7