mtd: add support for parsing partitions defined in OF

Add support for parsing partitions defined in device-trees via the
`partitions` node with `fixed-partitions` compatible.

The `mtdparts`/`mtdids` mechanism takes precedence. If some partitions
are defined for a MTD device via this mechanism, the code won't register
partitions for that MTD device from OF, even if they are defined.

Signed-off-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Miquel Raynal <miquel.raynal@bootlin.com>
Tested-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>
Cc: Simon Glass <sjg@chromium.org>
Cc: Heiko Schocher <hs@denx.de>
Cc: Patrick Delaunay <patrick.delaunay@st.com>

drivers/mtd/mtd_uboot.c

@@ -198,53 +198,11 @@ static void mtd_del_all_parts(void)
 	} while (ret > 0);
 }
 
-int mtd_probe_devices(void)
+static int parse_mtdparts(const char *mtdparts, const char *mtdids)
 {
-	static char *old_mtdparts;
+	const char *mtdparts_next;
-	static char *old_mtdids;
-	const char *mtdparts = get_mtdparts();
-	const char *mtdids = get_mtdids();
-	const char *mtdparts_next = mtdparts;
 	struct mtd_info *mtd;
 
-	mtd_probe_uclass_mtd_devs();
-
-	/*
-	 * Check if mtdparts/mtdids changed, if the MTD dev list was updated
-	 * or if our previous attempt to delete existing partititions failed.
-	 * In any of these cases we want to update the partitions, otherwise,
-	 * everything is up-to-date and we can return 0 directly.
-	 */
-	if ((!mtdparts && !old_mtdparts && !mtdids && !old_mtdids) ||
-	    (mtdparts && old_mtdparts && mtdids && old_mtdids &&
-	     !mtd_dev_list_updated() && !mtd_del_all_parts_failed &&
-	     !strcmp(mtdparts, old_mtdparts) &&
-	     !strcmp(mtdids, old_mtdids)))
-		return 0;
-
-	/* Update the local copy of mtdparts */
-	free(old_mtdparts);
-	free(old_mtdids);
-	old_mtdparts = strdup(mtdparts);
-	old_mtdids = strdup(mtdids);
-
-	/*
-	 * Remove all old parts. Note that partition removal can fail in case
-	 * one of the partition is still being used by an MTD user, so this
-	 * does not guarantee that all old partitions are gone.
-	 */
-	mtd_del_all_parts();
-
-	/*
-	 * Call mtd_dev_list_updated() to clear updates generated by our own
-	 * parts removal loop.
-	 */
-	mtd_dev_list_updated();
-
-	/* If either mtdparts or mtdids is empty, then exit */
-	if (!mtdparts || !mtdids)
-		return 0;
-
 	/* Start the parsing by ignoring the extra 'mtdparts=' prefix, if any */
 	if (!strncmp(mtdparts, "mtdparts=", sizeof("mtdparts=") - 1))
 		mtdparts += 9;
@@ -343,6 +301,66 @@ int mtd_probe_devices(void)
 		put_mtd_device(mtd);
 	}
 
+	return 0;
+}
+
+int mtd_probe_devices(void)
+{
+	static char *old_mtdparts;
+	static char *old_mtdids;
+	const char *mtdparts = get_mtdparts();
+	const char *mtdids = get_mtdids();
+	struct mtd_info *mtd;
+
+	mtd_probe_uclass_mtd_devs();
+
+	/*
+	 * Check if mtdparts/mtdids changed, if the MTD dev list was updated
+	 * or if our previous attempt to delete existing partititions failed.
+	 * In any of these cases we want to update the partitions, otherwise,
+	 * everything is up-to-date and we can return 0 directly.
+	 */
+	if ((!mtdparts && !old_mtdparts && !mtdids && !old_mtdids) ||
+	    (mtdparts && old_mtdparts && mtdids && old_mtdids &&
+	     !mtd_dev_list_updated() && !mtd_del_all_parts_failed &&
+	     !strcmp(mtdparts, old_mtdparts) &&
+	     !strcmp(mtdids, old_mtdids)))
+		return 0;
+
+	/* Update the local copy of mtdparts */
+	free(old_mtdparts);
+	free(old_mtdids);
+	old_mtdparts = strdup(mtdparts);
+	old_mtdids = strdup(mtdids);
+
+	/*
+	 * Remove all old parts. Note that partition removal can fail in case
+	 * one of the partition is still being used by an MTD user, so this
+	 * does not guarantee that all old partitions are gone.
+	 */
+	mtd_del_all_parts();
+
+	/*
+	 * Call mtd_dev_list_updated() to clear updates generated by our own
+	 * parts removal loop.
+	 */
+	mtd_dev_list_updated();
+
+	/* If both mtdparts and mtdids are non-empty, parse */
+	if (mtdparts && mtdids) {
+		if (parse_mtdparts(mtdparts, mtdids) < 0)
+			printf("Failed parsing MTD partitions from mtdparts!\n");
+	}
+
+	/* Fallback to OF partitions */
+	mtd_for_each_device(mtd) {
+		if (list_empty(&mtd->partitions)) {
+			if (add_mtd_partitions_of(mtd) < 0)
+				printf("Failed parsing MTD %s OF partitions!\n",
+					mtd->name);
+		}
+	}
+
 	/*
 	 * Call mtd_dev_list_updated() to clear updates generated by our own
 	 * parts registration loop.

drivers/mtd/mtdpart.c

@@ -892,6 +892,69 @@ int add_mtd_partitions(struct mtd_info *master,
 	return 0;
 }
 
+#if CONFIG_IS_ENABLED(DM) && CONFIG_IS_ENABLED(OF_CONTROL)
+int add_mtd_partitions_of(struct mtd_info *master)
+{
+	ofnode parts, child;
+	int i = 0;
+
+	if (!master->dev)
+		return 0;
+
+	parts = ofnode_find_subnode(mtd_get_ofnode(master), "partitions");
+	if (!ofnode_valid(parts) || !ofnode_is_available(parts) ||
+	    !ofnode_device_is_compatible(parts, "fixed-partitions"))
+		return 0;
+
+	ofnode_for_each_subnode(child, parts) {
+		struct mtd_partition part = { 0 };
+		struct mtd_info *slave;
+		fdt_addr_t offset, size;
+
+		if (!ofnode_is_available(child))
+			continue;
+
+		offset = ofnode_get_addr_size_index_notrans(child, 0, &size);
+		if (offset == FDT_ADDR_T_NONE || !size) {
+			debug("Missing partition offset/size on \"%s\" partition\n",
+			      master->name);
+			continue;
+		}
+
+		part.name = ofnode_read_string(child, "label");
+		if (!part.name)
+			part.name = ofnode_read_string(child, "name");
+
+		/*
+		 * .mask_flags is used to remove flags in allocate_partition(),
+		 * so when "read-only" is present, we add MTD_WRITABLE to the
+		 * mask, and so MTD_WRITABLE will be removed on partition
+		 * allocation
+		 */
+		if (ofnode_read_bool(child, "read-only"))
+			part.mask_flags |= MTD_WRITEABLE;
+		if (ofnode_read_bool(child, "lock"))
+			part.mask_flags |= MTD_POWERUP_LOCK;
+
+		part.offset = offset;
+		part.size = size;
+		part.ecclayout = master->ecclayout;
+
+		slave = allocate_partition(master, &part, i++, 0);
+		if (IS_ERR(slave))
+			return PTR_ERR(slave);
+
+		mutex_lock(&mtd_partitions_mutex);
+		list_add_tail(&slave->node, &master->partitions);
+		mutex_unlock(&mtd_partitions_mutex);
+
+		add_mtd_device(slave);
+	}
+
+	return 0;
+}
+#endif /* CONFIG_IS_ENABLED(DM) && CONFIG_IS_ENABLED(OF_CONTROL) */
+
 #ifndef __UBOOT__
 static DEFINE_SPINLOCK(part_parser_lock);
 static LIST_HEAD(part_parsers);

include/linux/mtd/mtd.h

@@ -581,6 +581,16 @@ static inline int del_mtd_partitions(struct mtd_info *mtd)
 }
 #endif
 
+#if defined(CONFIG_MTD_PARTITIONS) && CONFIG_IS_ENABLED(DM) && \
+    CONFIG_IS_ENABLED(OF_CONTROL)
+int add_mtd_partitions_of(struct mtd_info *master);
+#else
+static inline int add_mtd_partitions_of(struct mtd_info *master)
+{
+	return 0;
+}
+#endif
+
 struct mtd_info *__mtd_next_device(int i);
 #define mtd_for_each_device(mtd)			\
 	for ((mtd) = __mtd_next_device(0);		\