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[2nd,RESEND,v2,2/6] mtd: spi-nor: Allow flashes to specify MTD writesize

Message ID b2468777053f178bd1542e4b83ba4c6c8935468a.1727399650.git.Takahiro.Kuwano@infineon.com
State New
Delegated to: Jagannadha Sutradharudu Teki
Headers show
Series mtd: Make sure UBIFS does not do multi-pass page programming on flashes that don't support it | expand

Commit Message

Takahiro Kuwano Sept. 27, 2024, 1:18 a.m. UTC 
From: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>

Some flashes like the Infineon SEMPER NOR flash family use ECC. Under
this ECC scheme, multi-pass writes to an ECC block is not allowed.
In other words, once data is programmed to an ECC block, it can't be
programmed again without erasing it first.

Upper layers like file systems need to be given this information so they
do not cause error conditions on the flash by attempting multi-pass
programming. This can be done by setting 'writesize' in 'struct
mtd_info'.

Set the default to 1 but allow flashes to modify it in fixup hooks. If
more flashes show up with this constraint in the future it might be
worth it to add it to 'struct flash_info', but for now increasing its
size is not worth it.

This patch replicates the following upstream linux commit:
afd473e85827 ("mtd: spi-nor: core: Allow flashes to specify MTD writesize")

Acked-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
---
 drivers/mtd/spi/spi-nor-core.c | 3 ++-
 include/linux/mtd/spi-nor.h    | 1 +
 2 files changed, 3 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index e126fa37c16..4dfc110b02a 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -2839,6 +2839,7 @@  static int spi_nor_init_params(struct spi_nor *nor,
 	memset(params, 0, sizeof(*params));
 
 	/* Set SPI NOR sizes. */
+	params->writesize = 1;
 	params->size = info->sector_size * info->n_sectors;
 	params->page_size = info->page_size;
 
@@ -4142,7 +4143,7 @@  int spi_nor_scan(struct spi_nor *nor)
 	mtd->dev = nor->dev;
 	mtd->priv = nor;
 	mtd->type = MTD_NORFLASH;
-	mtd->writesize = 1;
+	mtd->writesize = params.writesize;
 	mtd->flags = MTD_CAP_NORFLASH;
 	mtd->size = params.size;
 	mtd->_erase = spi_nor_erase;
diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
index d1dbf3eadbf..0d37a806c49 100644
--- a/include/linux/mtd/spi-nor.h
+++ b/include/linux/mtd/spi-nor.h
@@ -436,6 +436,7 @@  enum spi_nor_pp_command_index {
 
 struct spi_nor_flash_parameter {
 	u64				size;
+	u32				writesize;
 	u32				page_size;
 	u8				rdsr_dummy;
 	u8				rdsr_addr_nbytes;