disk: support UBI partitions

UBI partition is abstraction over UBI volumes.
Can be used by UBI block device.

Signed-off-by: Alexey Romanov <avromanov@salutedevices.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Signed-off-by: Michael Trimarchi <michael@amarulasolutions.com>

drivers/mtd/ubi/Makefile

@@ -7,4 +7,4 @@ obj-y += attach.o build.o vtbl.o vmt.o upd.o kapi.o eba.o io.o wl.o crc32.o
 obj-$(CONFIG_MTD_UBI_FASTMAP) += fastmap.o
 obj-y += misc.o
 obj-y += debug.o
-obj-$(CONFIG_UBI_BLOCK) += block.o
+obj-$(CONFIG_UBI_BLOCK) += block.o part.o

drivers/mtd/ubi/part.c

@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2024 SaluteDevices, Inc.
+ *
+ * Author: Alexey Romanov <avromanov@salutedevices.com>
+ */
+
+#include <memalign.h>
+#include <part.h>
+#include <ubi_uboot.h>
+
+static inline struct ubi_device *get_ubi_device(void)
+{
+	return ubi_devices[0];
+}
+
+static struct ubi_volume *ubi_get_volume_by_index(int vol_id)
+{
+	struct ubi_device *ubi = get_ubi_device();
+	int i;
+
+	for (i = 0; i < (ubi->vtbl_slots + 1); i++) {
+		struct ubi_volume *volume = ubi->volumes[i];
+
+		if (!volume)
+			continue;
+
+		if (volume->vol_id >= UBI_INTERNAL_VOL_START)
+			continue;
+
+		if (volume->vol_id == vol_id)
+			return volume;
+	}
+
+	return NULL;
+}
+
+static int __maybe_unused part_get_info_ubi(struct blk_desc *dev_desc, int part_idx,
+					    struct disk_partition *info)
+{
+	struct ubi_volume *vol;
+
+	/*
+	 * We must use part_idx - 1 instead of part_idx, because
+	 * part_get_info_by_name() start indexing at 1, not 0.
+	 * ubi volumes idexed starting at 0
+	 */
+	vol = ubi_get_volume_by_index(part_idx - 1);
+	if (!vol)
+		return 0;
+
+	snprintf(info->name, PART_NAME_LEN, vol->name);
+
+	info->start = 0;
+	info->size = (unsigned long)vol->used_bytes / dev_desc->blksz;
+	info->blksz = dev_desc->blksz;
+
+	/* Save UBI volume ID in blk device descriptor */
+	dev_desc->hwpart = vol->vol_id;
+
+	return 0;
+}
+
+static void __maybe_unused part_print_ubi(struct blk_desc *dev_desc)
+{
+	struct ubi_device *ubi = get_ubi_device();
+	int i;
+
+	for (i = 0; i < (ubi->vtbl_slots + 1); i++) {
+		struct ubi_volume *volume = ubi->volumes[i];
+
+		if (!volume)
+			continue;
+
+		if (volume->vol_id >= UBI_INTERNAL_VOL_START)
+			continue;
+
+		printf("%d: %s\n", volume->vol_id, volume->name);
+	}
+}
+
+static int part_test_ubi(struct blk_desc *dev_desc)
+{
+	ALLOC_CACHE_ALIGN_BUFFER(unsigned char, buffer, dev_desc->blksz);
+
+	if (blk_dread(dev_desc, 0, 1, (ulong *)buffer) != 1)
+		return -1;
+
+	return 0;
+}
+
+U_BOOT_PART_TYPE(ubi) = {
+	.name	= "ubi",
+	.part_type	= PART_TYPE_UBI,
+	.max_entries	= UBI_ENTRY_NUMBERS,
+	.get_info	= part_get_info_ptr(part_get_info_ubi),
+	.print	= part_print_ptr(part_print_ubi),
+	.test	= part_test_ubi,
+};

include/part.h

@@ -31,6 +31,7 @@ struct block_drvr {
 #define PART_TYPE_AMIGA		0x04
 #define PART_TYPE_EFI		0x05
 #define PART_TYPE_MTD		0x06
+#define PART_TYPE_UBI		0x07
 
 /* maximum number of partition entries supported by search */
 #define DOS_ENTRY_NUMBERS	8
@@ -38,6 +39,7 @@ struct block_drvr {
 #define MAC_ENTRY_NUMBERS	64
 #define AMIGA_ENTRY_NUMBERS	8
 #define MTD_ENTRY_NUMBERS	64
+#define UBI_ENTRY_NUMBERS	UBI_MAX_VOLUMES
 
 /*
  * Type string for U-Boot bootable partitions