mtd: core: Constify buf in mtd_write_user_prot_reg()

The write buffer comes from user and should be const.
Constify write buffer in mtd core and across all _write_user_prot_reg()
users. cfi_cmdset_{0001, 0002} and onenand_base will pay the cost of an
explicit cast to discard the const qualifier since the beginning, since
they are using an otp_op_t function prototype that is used for both reads
and writes. mtd_dataflash and SPI NOR will benefit of the const buffer
because they are using different paths for writes and reads.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20210403060931.7119-1-tudor.ambarus@microchip.com

1 files changed, 4 insertions, 2 deletions

diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h
index e9b6b2e76cdb..28a2e0be97a3 100644
--- a/drivers/mtd/spi-nor/core.h
+++ b/drivers/mtd/spi-nor/core.h
@@ -211,7 +211,8 @@ struct spi_nor_otp_organization {
  */
 struct spi_nor_otp_ops {
 	int (*read)(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf);
-	int (*write)(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf);
+	int (*write)(struct spi_nor *nor, loff_t addr, size_t len,
+		     const u8 *buf);
 	int (*lock)(struct spi_nor *nor, unsigned int region);
 	int (*is_locked)(struct spi_nor *nor, unsigned int region);
 };
@@ -504,7 +505,8 @@ ssize_t spi_nor_write_data(struct spi_nor *nor, loff_t to, size_t len,
 			   const u8 *buf);
 
 int spi_nor_otp_read_secr(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf);
-int spi_nor_otp_write_secr(struct spi_nor *nor, loff_t addr, size_t len, u8 *buf);
+int spi_nor_otp_write_secr(struct spi_nor *nor, loff_t addr, size_t len,
+			   const u8 *buf);
 int spi_nor_otp_lock_sr2(struct spi_nor *nor, unsigned int region);
 int spi_nor_otp_is_locked_sr2(struct spi_nor *nor, unsigned int region);