From d73ee7534cc537b98b61bfd83dbce5bb12aecb80 Mon Sep 17 00:00:00 2001 From: Pratyush Yadav Date: Mon, 5 Oct 2020 21:01:35 +0530 Subject: [PATCH] mtd: spi-nor: core: perform a Soft Reset on shutdown Perform a Soft Reset on shutdown on flashes that support it so that the flash can be reset to its initial state and any configurations made by spi-nor (given that they're only done in volatile registers) will be reset. This will hand back the flash in pristine state for any further operations on it. Signed-off-by: Pratyush Yadav Signed-off-by: Vignesh Raghavendra Reviewed-by: Tudor Ambarus Link: https://lore.kernel.org/r/20201005153138.6437-13-p.yadav@ti.com --- drivers/mtd/spi-nor/core.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ include/linux/mtd/spi-nor.h | 2 ++ 2 files changed, 47 insertions(+) diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c index 7b9ec02734f2..633a1af8a0fe 100644 --- a/drivers/mtd/spi-nor/core.c +++ b/drivers/mtd/spi-nor/core.c @@ -40,6 +40,9 @@ #define SPI_NOR_MAX_ADDR_WIDTH 4 +#define SPI_NOR_SRST_SLEEP_MIN 200 +#define SPI_NOR_SRST_SLEEP_MAX 400 + /** * spi_nor_get_cmd_ext() - Get the command opcode extension based on the * extension type. @@ -3174,6 +3177,45 @@ static int spi_nor_init(struct spi_nor *nor) return 0; } +static void spi_nor_soft_reset(struct spi_nor *nor) +{ + struct spi_mem_op op; + int ret; + + op = (struct spi_mem_op)SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_SRSTEN, 0), + SPI_MEM_OP_NO_DUMMY, + SPI_MEM_OP_NO_ADDR, + SPI_MEM_OP_NO_DATA); + + spi_nor_spimem_setup_op(nor, &op, nor->reg_proto); + + ret = spi_mem_exec_op(nor->spimem, &op); + if (ret) { + dev_warn(nor->dev, "Software reset failed: %d\n", ret); + return; + } + + op = (struct spi_mem_op)SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_SRST, 0), + SPI_MEM_OP_NO_DUMMY, + SPI_MEM_OP_NO_ADDR, + SPI_MEM_OP_NO_DATA); + + spi_nor_spimem_setup_op(nor, &op, nor->reg_proto); + + ret = spi_mem_exec_op(nor->spimem, &op); + if (ret) { + dev_warn(nor->dev, "Software reset failed: %d\n", ret); + return; + } + + /* + * Software Reset is not instant, and the delay varies from flash to + * flash. Looking at a few flashes, most range somewhere below 100 + * microseconds. So, sleep for a range of 200-400 us. + */ + usleep_range(SPI_NOR_SRST_SLEEP_MIN, SPI_NOR_SRST_SLEEP_MAX); +} + /* mtd resume handler */ static void spi_nor_resume(struct mtd_info *mtd) { @@ -3193,6 +3235,9 @@ void spi_nor_restore(struct spi_nor *nor) if (nor->addr_width == 4 && !(nor->flags & SNOR_F_4B_OPCODES) && nor->flags & SNOR_F_BROKEN_RESET) nor->params->set_4byte_addr_mode(nor, false); + + if (nor->flags & SNOR_F_SOFT_RESET) + spi_nor_soft_reset(nor); } EXPORT_SYMBOL_GPL(spi_nor_restore); diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h index cd549042c53d..299685d15dc2 100644 --- a/include/linux/mtd/spi-nor.h +++ b/include/linux/mtd/spi-nor.h @@ -51,6 +51,8 @@ #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) */ -- 2.11.0