We don't want to enter a stateful mode, where a X-X-X I/O mode is entered by setting a non-volatile bit, because in case of a reset or a crash, once in the non-volatile mode, we may not be able to recover in bootloaders and we may break the SPI NOR boot.
Forbid by default the I/O modes that are set via a non-volatile bit. SPI_NOR_IO_MODE_EN_VOLATILE should be set just for the flashes that don't define the optional SFDP SCCR Map, so that we don't pollute the flash info flags. Signed-off-by: Tudor Ambarus <tudor.amba...@microchip.com> --- drivers/mtd/spi-nor/core.c | 6 ++++++ drivers/mtd/spi-nor/core.h | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c index 34edfcf33172..c149b318e2e8 100644 --- a/drivers/mtd/spi-nor/core.c +++ b/drivers/mtd/spi-nor/core.c @@ -3089,6 +3089,9 @@ static int spi_nor_octal_dtr_enable(struct spi_nor *nor, bool enable) nor->write_proto == SNOR_PROTO_8_8_8_DTR)) return 0; + if (!(nor->flags & SNOR_F_IO_MODE_EN_VOLATILE)) + return 0; + ret = nor->params->octal_dtr_enable(nor, enable); if (ret) return ret; @@ -3474,6 +3477,9 @@ int spi_nor_scan(struct spi_nor *nor, const char *name, if (info->flags & SPI_NOR_4B_OPCODES) nor->flags |= SNOR_F_4B_OPCODES; + if (info->flags & SPI_NOR_IO_MODE_EN_VOLATILE) + nor->flags |= SNOR_F_IO_MODE_EN_VOLATILE; + ret = spi_nor_set_addr_width(nor); if (ret) return ret; diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h index 10dc03506f93..c2755c82f978 100644 --- a/drivers/mtd/spi-nor/core.h +++ b/drivers/mtd/spi-nor/core.h @@ -27,6 +27,7 @@ enum spi_nor_option_flags { SNOR_F_HAS_4BIT_BP = BIT(12), SNOR_F_HAS_SR_BP3_BIT6 = BIT(13), SNOR_F_SOFT_RESET = BIT(14), + SNOR_F_IO_MODE_EN_VOLATILE = BIT(15), }; struct spi_nor_read_command { @@ -323,6 +324,11 @@ struct flash_info { */ #define SPI_NOR_OCTAL_DTR_READ BIT(19) /* Flash supports octal DTR Read. */ #define SPI_NOR_OCTAL_DTR_PP BIT(20) /* Flash supports Octal DTR Page Program */ +#define SPI_NOR_IO_MODE_EN_VOLATILE BIT(21) /* + * Flash enables the best + * available I/O mode via a + * volatile bit. + */ /* Part specific fixup hooks. */ const struct spi_nor_fixups *fixups; -- 2.25.1