drivers: introduce UBI block abstraction

UBI block is an virtual device, that runs on top
of the MTD layer. The blocks are UBI volumes.
Intended to be used in combination with other MTD
drivers.

Despite the fact that it, like mtdblock abstraction,
it used with UCLASS_MTD, they can be used together
on the system without conflicting. For example,
using bcb command:

  # Trying to load bcb via mtdblock:
  $ bcb load mtd 0 mtd_partition_name

  # Trying to load bcb via UBI block:
  $ bcb load ubi 1 ubi_volume_name

User always must attach UBI layer (for example, using
ubi_part()) before using UBI block device.

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

drivers/block/blk-uclass.c

@@ -37,6 +37,7 @@ static struct {
 	{ UCLASS_BLKMAP, "blkmap" },
 	{ UCLASS_RKMTD, "rkmtd" },
 	{ UCLASS_MTD, "mtd" },
+	{ UCLASS_MTD, "ubi" },
 };
 
 static enum uclass_id uclass_name_to_iftype(const char *uclass_idname)

drivers/mtd/ubi/Kconfig

@@ -114,5 +114,12 @@ config MTD_UBI_FM_DEBUG
 	help
 	  Enable UBI fastmap debug
 
+config UBI_BLOCK
+	bool "Enable UBI block device support"
+	depends on BLK
+	default n
+	help
+	  Enable UBI block device support using blk_ops abstraction.
+
 endif # MTD_UBI
 endmenu # "Enable UBI - Unsorted block images"

drivers/mtd/ubi/Makefile

@@ -7,3 +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

drivers/mtd/ubi/block.c

@@ -0,0 +1,130 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * (C) Copyright 2024 SaluteDevices, Inc.
+ *
+ * Author: Alexey Romanov <avromanov@salutedevices.com>
+ */
+
+#include <blk.h>
+#include <part.h>
+#include <ubi_uboot.h>
+#include <dm/device.h>
+#include <dm/device-internal.h>
+
+int ubi_bind(struct udevice *dev)
+{
+	struct blk_desc *bdesc;
+	struct udevice *bdev;
+	int ret;
+
+	ret = blk_create_devicef(dev, "ubi_blk", "blk", UCLASS_MTD,
+				 -1, 512, 0, &bdev);
+	if (ret) {
+		pr_err("Cannot create block device");
+		return ret;
+	}
+
+	bdesc = dev_get_uclass_plat(bdev);
+
+	bdesc->bdev = bdev;
+	bdesc->part_type = PART_TYPE_UBI;
+
+	return 0;
+}
+
+static struct ubi_device *get_ubi_device(void)
+{
+	return ubi_devices[0];
+}
+
+static char *get_volume_name(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->name;
+	}
+
+	return NULL;
+}
+
+static ulong ubi_bread(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,
+		       void *dst)
+{
+	struct blk_desc *block_dev = dev_get_uclass_plat(dev);
+	char *volume_name = get_volume_name(block_dev->hwpart);
+	unsigned int size = blkcnt * block_dev->blksz;
+	loff_t offset = start * block_dev->blksz;
+	int ret;
+
+	if (!volume_name) {
+		pr_err("%s: failed to find volume name for blk=" LBAF "\n", __func__, start);
+		return -EINVAL;
+	}
+
+	ret = ubi_volume_read(volume_name, dst, offset, size);
+	if (ret) {
+		pr_err("%s: failed to read from %s UBI volume\n", __func__, volume_name);
+		return ret;
+	}
+
+	return blkcnt;
+}
+
+static ulong ubi_bwrite(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,
+			const void *src)
+{
+	struct blk_desc *block_dev = dev_get_uclass_plat(dev);
+	char *volume_name = get_volume_name(block_dev->hwpart);
+	unsigned int size = blkcnt * block_dev->blksz;
+	loff_t offset = start * block_dev->blksz;
+	int ret;
+
+	if (!volume_name) {
+		pr_err("%s: failed to find volume for blk=" LBAF "\n", __func__, start);
+		return -EINVAL;
+	}
+
+	ret = ubi_volume_write(volume_name, (void *)src, offset, size);
+	if (ret) {
+		pr_err("%s: failed to write from %s UBI volume\n", __func__, volume_name);
+		return ret;
+	}
+
+	return blkcnt;
+}
+
+static int ubi_blk_probe(struct udevice *dev)
+{
+	int ret;
+
+	ret = device_probe(dev);
+	if (ret) {
+		pr_err("Probing %s failed (err=%d)\n", dev->name, ret);
+		return ret;
+	}
+
+	return 0;
+}
+
+static const struct blk_ops ubi_blk_ops = {
+	.read = ubi_bread,
+	.write = ubi_bwrite,
+};
+
+U_BOOT_DRIVER(ubi_blk) = {
+	.name = "ubi_blk",
+	.id = UCLASS_BLK,
+	.ops = &ubi_blk_ops,
+	.probe = ubi_blk_probe,
+};

include/ubi_uboot.h

@@ -55,4 +55,13 @@ extern struct ubi_device *ubi_devices[];
 int cmd_ubifs_mount(char *vol_name);
 int cmd_ubifs_umount(void);
 
+#if IS_ENABLED(CONFIG_UBI_BLOCK)
+int ubi_bind(struct udevice *dev);
+#else
+static inline int ubi_bind(struct udevice *dev)
+{
+	return -EOPNOTSUPP;
+}
+#endif
+
 #endif