From 575caf45004fb9be983db33f86425c95d4619213 Mon Sep 17 00:00:00 2001 From: Pratyush Yadav Date: Sat, 26 Jun 2021 00:47:24 +0530 Subject: mtd: spi-nor-core: Perform a Soft Reset on shutdown On probe, the SPI NOR core will put a flash in 8D-8D-8D mode if it supports it. But Linux as of now expects to get the flash in 1S-1S-1S mode. Handing the flash to Linux in Octal DTR mode means the kernel will fail to detect the flash. So, we need to reset to Power-on-Reset (POR) state before handing off the flash. A Software Reset command can be used to do this. One limitation of the soft reset is that it will restore state from non-volatile registers in some flashes. This means that if the flash was set to 8D mode in a non-volatile configuration, a soft reset won't help. This commit assumes that we don't set any non-volatile bits anywhere, and the flash doesn't have any non-volatile Octal DTR mode configuration. Since spi-nor-tiny doesn't (and likely shouldn't) have spi_nor_soft_reset(), add a dummy spi_nor_remove() for it that does nothing. Signed-off-by: Pratyush Yadav Reviewed-by: Jagan Teki --- include/linux/mtd/spi-nor.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'include/linux') diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h index b2159f63195..29ce1751567 100644 --- a/include/linux/mtd/spi-nor.h +++ b/include/linux/mtd/spi-nor.h @@ -67,6 +67,8 @@ #define SPINOR_OP_CLFSR 0x50 /* Clear flag status register */ #define SPINOR_OP_RDEAR 0xc8 /* Read Extended Address Register */ #define SPINOR_OP_WREAR 0xc5 /* Write Extended Address Register */ +#define SPINOR_OP_SRSTEN 0x66 /* Software Reset Enable */ +#define SPINOR_OP_SRST 0x99 /* Software Reset */ /* 4-byte address opcodes - used on Spansion and some Macronix flashes. */ #define SPINOR_OP_READ_4B 0x13 /* Read data bytes (low frequency) */ @@ -562,4 +564,19 @@ device_node *spi_nor_get_flash_node(struct spi_nor *nor) */ int spi_nor_scan(struct spi_nor *nor); +#if CONFIG_IS_ENABLED(SPI_FLASH_TINY) +static inline int spi_nor_remove(struct spi_nor *nor) +{ + return 0; +} +#else +/** + * spi_nor_remove() - perform cleanup before booting to the next stage + * @nor: the spi_nor structure + * + * Return: 0 for success, -errno for failure. + */ +int spi_nor_remove(struct spi_nor *nor); +#endif + #endif -- cgit v1.2.3