kernel: generic: improve FIT partition parser

 * only map filesystems configured in 'loadables'
 * allow mapping more than one filesystem (e.g. customization/branding
   or localization in addition to rootfs)
 * small cleaning here and there

Signed-off-by: Daniel Golle <daniel@makrotopia.org>

target/linux/generic/files/block/partitions/fit.c

@@ -89,12 +89,10 @@ int parse_fit_partitions(struct parsed_partitions *state, u64 fit_start_sector,
 	size_t label_min;
 	struct device_node *np = NULL;
 	const char *bootconf;
-
-	np = of_find_node_by_path("/chosen");
-	if (np)
-		bootconf = of_get_property(np, "bootconf", NULL);
-	else
-		bootconf = NULL;
+	char *loadable;
+	char *select_rootfs = NULL;
+	bool found;
+	int loadables_rem_len, loadable_len;
 
 	if (fit_start_sector % (1<<(PAGE_SHIFT - SECTOR_SHIFT)))
 		return -ERANGE;
@@ -123,7 +121,6 @@ int parse_fit_partitions(struct parsed_partitions *state, u64 fit_start_sector,
 		dsectors = (dsectors>sectors)?sectors:dsectors;
 
 	dsize = dsectors << SECTOR_SHIFT;
-
 	size = fdt_totalsize(init_fit);
 
 	/* silently skip non-external-data legacy FIT images */
@@ -143,6 +140,12 @@ int parse_fit_partitions(struct parsed_partitions *state, u64 fit_start_sector,
 	if (!fit)
 		return -ENOMEM;
 
+	np = of_find_node_by_path("/chosen");
+	if (np)
+		bootconf = of_get_property(np, "bootconf", NULL);
+	else
+		bootconf = NULL;
+
 	config = fdt_path_offset(fit, FIT_CONFS_PATH);
 	if (config < 0) {
 		printk(KERN_ERR "FIT: Cannot find %s node: %d\n", FIT_CONFS_PATH, images);
@@ -172,6 +175,12 @@ int parse_fit_partitions(struct parsed_partitions *state, u64 fit_start_sector,
 		bootconf?"Selected":"Default", bootconf?:config_default,
 		config_description?" (":"", config_description?:"", config_description?")":"");
 
+	if (!config_loadables || !config_loadables_len) {
+		printk(KERN_ERR "FIT: No loadables configured in \"%s\"\n", bootconf?:config_default);
+		ret = -ENOENT;
+		goto ret_out;
+	}
+
 	images = fdt_path_offset(fit, FIT_IMAGES_PATH);
 	if (images < 0) {
 		printk(KERN_ERR "FIT: Cannot find %s node: %d\n", FIT_IMAGES_PATH, images);
@@ -208,6 +217,22 @@ int parse_fit_partitions(struct parsed_partitions *state, u64 fit_start_sector,
 		if (strcmp(image_type, FIT_FILESYSTEM_PROP))
 			continue;
 
+		/* check if sub-image is part of configured loadables */
+		found = false;
+		loadable = config_loadables;
+		loadables_rem_len = config_loadables_len;
+		while (loadables_rem_len > 1) {
+			loadable_len = strnlen(loadable, loadables_rem_len - 1) + 1;
+			loadables_rem_len -= loadable_len;
+			if (!strncmp(image_name, loadable, loadable_len)) {
+				found = true;
+				break;
+			}
+			loadable += loadable_len;
+		}
+		if (!found)
+			continue;
+
 		if (image_pos & ((1 << PAGE_SHIFT)-1)) {
 			printk(KERN_ERR "FIT: image %s start not aligned to page boundaries, skipping\n", image_name);
 			continue;
@@ -228,7 +253,8 @@ int parse_fit_partitions(struct parsed_partitions *state, u64 fit_start_sector,
 		}
 
 		put_partition(state, ++(*slot), fit_start_sector + start_sect, nr_sects);
-		state->parts[*slot].flags = 0;
+		state->parts[*slot].flags = ADDPART_FLAG_READONLY;
+		state->parts[*slot].has_info = true;
 		info = &state->parts[*slot].info;
 
 		label_min = min_t(int, sizeof(info->volname) - 1, image_name_len);
@@ -238,14 +264,16 @@ int parse_fit_partitions(struct parsed_partitions *state, u64 fit_start_sector,
 		snprintf(tmp, sizeof(tmp), "(%s)", info->volname);
 		strlcat(state->pp_buf, tmp, PAGE_SIZE);
 
-		state->parts[*slot].has_info = true;
-		state->parts[*slot].flags |= ADDPART_FLAG_READONLY;
-		if (config_loadables && !strcmp(image_name, config_loadables)) {
-			printk(KERN_DEBUG "FIT: selecting configured loadable \"%s\" to be root filesystem\n", image_name);
+		/* Mark first loadable listed to be mounted as rootfs */
+		if (!strcmp(image_name, config_loadables)) {
+			select_rootfs = image_name;
 			state->parts[*slot].flags |= ADDPART_FLAG_ROOTDEV;
 		}
 	}
 
+	if (select_rootfs)
+		printk(KERN_DEBUG "FIT: selecting configured loadable \"%s\" to be root filesystem\n", select_rootfs);
+
 	if (add_remain && (imgmaxsect + MIN_FREE_SECT) < dsectors) {
 		put_partition(state, ++(*slot), fit_start_sector + imgmaxsect, dsectors - imgmaxsect);
 		state->parts[*slot].flags = 0;

target/linux/generic/hack-5.10/410-block-fit-partition-parser.patch

@@ -156,7 +156,7 @@
  	.name		= "mtdblock",
  	.major		= MTD_BLOCK_MAJOR,
 +#ifdef CONFIG_FIT_PARTITION
-+	.part_bits	= 1,
++	.part_bits	= 2,
 +#else
  	.part_bits	= 0,
 +#endif