[PATCH v3 2/3] drivers: introduce mtdblock abstraction
Alexey Romanov
avromanov at salutedevices.com
Thu Apr 4 12:58:12 CEST 2024
MTD block - abstraction over MTD subsystem, allowing
to read and write in blocks using BLK UCLASS.
Signed-off-by: Alexey Romanov <avromanov at salutedevices.com>
---
drivers/block/blk-uclass.c | 1 +
drivers/mtd/Makefile | 1 +
drivers/mtd/mtdblock.c | 227 +++++++++++++++++++++++++++++++++++++
include/linux/mtd/mtd.h | 12 ++
4 files changed, 241 insertions(+)
create mode 100644 drivers/mtd/mtdblock.c
diff --git a/drivers/block/blk-uclass.c b/drivers/block/blk-uclass.c
index 77066da352..ab0a9105c9 100644
--- a/drivers/block/blk-uclass.c
+++ b/drivers/block/blk-uclass.c
@@ -37,6 +37,7 @@ static struct {
{ UCLASS_PVBLOCK, "pvblock" },
{ UCLASS_BLKMAP, "blkmap" },
{ UCLASS_RKMTD, "rkmtd" },
+ { UCLASS_MTD, "mtd" },
};
static enum uclass_id uclass_name_to_iftype(const char *uclass_idname)
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index c638980ea2..993b122ac4 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -26,6 +26,7 @@ obj-y += onenand/
obj-y += spi/
obj-$(CONFIG_MTD_UBI) += ubi/
obj-$(CONFIG_NVMXIP) += nvmxip/
+obj-$(CONFIG_BLK) += mtdblock.o
#SPL/TPL build
else
diff --git a/drivers/mtd/mtdblock.c b/drivers/mtd/mtdblock.c
new file mode 100644
index 0000000000..e56fa49064
--- /dev/null
+++ b/drivers/mtd/mtdblock.c
@@ -0,0 +1,227 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * MTD block - abstraction over MTD subsystem, allowing
+ * to read and write in blocks using BLK UCLASS.
+ *
+ * - Read algorithm:
+ *
+ * 1. Convert start block number to start address.
+ * 2. Read block_dev->blksz bytes using mtd_read() and
+ * add to start address pointer block_dev->blksz bytes,
+ * until the requested number of blocks have been read.
+ *
+ * - Write algorithm:
+ *
+ * 1. Convert start block number to start address.
+ * 2. Round this address down by mtd->erasesize.
+ *
+ * Erase addr Start addr
+ * | |
+ * v v
+ * +----------------+----------------+----------------+
+ * | blksz | blksz | blksz |
+ * +----------------+----------------+----------------+
+ *
+ * 3. Calculate offset between this two addresses.
+ * 4. Read mtd->erasesize bytes using mtd_read() into
+ * temporary buffer from erase address.
+ *
+ * Erase addr Start addr
+ * | |
+ * v v
+ * +----------------+----------------+----------------+
+ * | blksz | blksz | blksz |
+ * +----------------+----------------+----------------+
+ * ^
+ * |
+ * |
+ * mtd_read()
+ * from here
+ *
+ * 5. Copy data from user buffer to temporary buffer with offset,
+ * calculated at step 3.
+ * 6. Erase and write mtd->erasesize bytes at erase address
+ * pointer using mtd_erase/mtd_write().
+ * 7. Add to erase address pointer mtd->erasesize bytes.
+ * 8. goto 1 until the requested number of blocks have
+ * been written.
+ *
+ * (C) Copyright 2024 SaluteDevices, Inc.
+ *
+ * Author: Alexey Romanov <avromanov at salutedevices.com>
+ */
+
+#include <blk.h>
+#include <part.h>
+#include <dm/device.h>
+#include <dm/device-internal.h>
+#include <linux/mtd/mtd.h>
+
+int mtd_bind(struct udevice *dev, struct mtd_info **mtd)
+{
+ struct blk_desc *bdesc;
+ struct udevice *bdev;
+ int ret;
+
+ ret = blk_create_devicef(dev, "mtd_blk", "blk", UCLASS_MTD,
+ dev_seq(dev), 512, 0, &bdev);
+ if (ret) {
+ pr_err("Cannot create block device\n");
+ return ret;
+ }
+
+ bdesc = dev_get_uclass_plat(bdev);
+ dev_set_priv(bdev, mtd);
+ bdesc->bdev = bdev;
+ bdesc->part_type = PART_TYPE_MTD;
+
+ return 0;
+}
+
+static ulong mtd_blk_read(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,
+ void *dst)
+{
+ struct blk_desc *block_dev = dev_get_uclass_plat(dev);
+ struct mtd_info *mtd = blk_desc_to_mtd(block_dev);
+ unsigned int sect_size = block_dev->blksz;
+ lbaint_t cur = start;
+ ulong read_cnt = 0;
+
+ while (read_cnt < blkcnt) {
+ int ret;
+ loff_t sect_start = cur * sect_size;
+ size_t retlen;
+
+ ret = mtd_read(mtd, sect_start, sect_size, &retlen, dst);
+ if (ret)
+ return ret;
+
+ if (retlen != sect_size) {
+ pr_err("mtdblock: failed to read block 0x%lx\n", cur);
+ return -EIO;
+ }
+
+ cur++;
+ dst += sect_size;
+ read_cnt++;
+ }
+
+ return read_cnt;
+}
+
+static int mtd_erase_write(struct mtd_info *mtd, uint64_t start, const void *src)
+{
+ int ret;
+ size_t retlen;
+ struct erase_info erase = { 0 };
+
+ erase.mtd = mtd;
+ erase.addr = start;
+ erase.len = mtd->erasesize;
+
+ ret = mtd_erase(mtd, &erase);
+ if (ret)
+ return ret;
+
+ ret = mtd_write(mtd, start, mtd->erasesize, &retlen, src);
+ if (ret)
+ return ret;
+
+ if (retlen != mtd->erasesize) {
+ pr_err("mtdblock: failed to read block at 0x%llx\n", start);
+ return -EIO;
+ }
+
+ return 0;
+}
+
+static ulong mtd_blk_write(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,
+ const void *src)
+{
+ struct blk_desc *block_dev = dev_get_uclass_plat(dev);
+ struct mtd_info *mtd = blk_desc_to_mtd(block_dev);
+ unsigned int sect_size = block_dev->blksz;
+ lbaint_t cur = start, blocks_todo = blkcnt;
+ ulong write_cnt = 0;
+ u8 *buf;
+ int ret = 0;
+
+ buf = malloc(mtd->erasesize);
+ if (!buf)
+ return -ENOMEM;
+
+ while (blocks_todo > 0) {
+ loff_t sect_start = cur * sect_size;
+ loff_t erase_start = ALIGN_DOWN(sect_start, mtd->erasesize);
+ u32 offset = sect_start - erase_start;
+ size_t cur_size = min_t(size_t, mtd->erasesize - offset,
+ blocks_todo * sect_size);
+ size_t retlen;
+ lbaint_t written;
+
+ ret = mtd_read(mtd, erase_start, mtd->erasesize, &retlen, buf);
+ if (ret)
+ goto out;
+
+ if (retlen != mtd->erasesize) {
+ pr_err("mtdblock: failed to read block 0x%lx\n", cur);
+ ret = -EIO;
+ goto out;
+ }
+
+ memcpy(buf + offset, src, cur_size);
+
+ ret = mtd_erase_write(mtd, erase_start, buf);
+ if (ret)
+ goto out;
+
+ written = cur_size / sect_size;
+
+ blocks_todo -= written;
+ cur += written;
+ src += cur_size;
+ write_cnt += written;
+ }
+
+out:
+ free(buf);
+
+ if (ret)
+ return ret;
+
+ return write_cnt;
+}
+
+static int mtd_blk_probe(struct udevice *dev)
+{
+ struct blk_desc *bdesc;
+ struct mtd_info *mtd;
+ int ret;
+
+ ret = device_probe(dev);
+ if (ret) {
+ pr_err("Probing %s failed (err=%d)\n", dev->name, ret);
+ return ret;
+ }
+
+ bdesc = dev_get_uclass_plat(dev);
+ mtd = blk_desc_to_mtd(bdesc);
+
+ if (mtd_type_is_nand(mtd))
+ pr_warn("MTD device '%s' is NAND, please use UBI devices instead\n",
+ mtd->name);
+
+ return 0;
+}
+
+static const struct blk_ops mtd_blk_ops = {
+ .read = mtd_blk_read,
+ .write = mtd_blk_write,
+};
+
+U_BOOT_DRIVER(mtd_blk) = {
+ .name = "mtd_blk",
+ .id = UCLASS_BLK,
+ .ops = &mtd_blk_ops,
+ .probe = mtd_blk_probe,
+};
diff --git a/include/linux/mtd/mtd.h b/include/linux/mtd/mtd.h
index 09f5269887..9b997fadd1 100644
--- a/include/linux/mtd/mtd.h
+++ b/include/linux/mtd/mtd.h
@@ -26,6 +26,9 @@
#include <dm/device.h>
#endif
#include <dm/ofnode.h>
+#if IS_ENABLED(CONFIG_BLK)
+#include <blk.h>
+#endif
#define MAX_MTD_DEVICES 32
#endif
@@ -412,6 +415,15 @@ int mtd_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
int mtd_panic_write(struct mtd_info *mtd, loff_t to, size_t len, size_t *retlen,
const u_char *buf);
+#if IS_ENABLED(CONFIG_BLK)
+static inline struct mtd_info *blk_desc_to_mtd(struct blk_desc *bdesc)
+{
+ return *((struct mtd_info **)dev_get_priv(bdesc->bdev));
+}
+
+int mtd_bind(struct udevice *dev, struct mtd_info **mtd);
+#endif
+
int mtd_read_oob(struct mtd_info *mtd, loff_t from, struct mtd_oob_ops *ops);
int mtd_write_oob(struct mtd_info *mtd, loff_t to, struct mtd_oob_ops *ops);
--
2.34.1
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