Re: [PATCH v2 2/3] drivers: introduce mtdblock abstraction

On 07.03.24 14:07, Alexey Romanov wrote:

MTD block - abstraction over MTD subsystem, allowing to read and write in blocks using BLK UCLASS.

Signed-off-by: Alexey Romanov avromanov@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..b409674173 --- /dev/null +++ b/drivers/mtd/mtdblock.c @@ -0,0 +1,227 @@ +// SPDX-License-Identifier: GPL-2.0+

nits:

GPL-2.0-or-later see https://spdx.org/licenses/GPL-2.0-or-later.html

+/*

• • 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@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_bread(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,

nits:

Reading bread I thought of nutrition. How about mtd_blk_read()?

•        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_bwrite(struct udevice *dev, lbaint_t start, lbaint_t blkcnt,

mtd_blk_write()?

Best regards

Heinrich

• 	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_bread,
• .write = mtd_bwrite,

+};

+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);