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 --- drivers/mtd/spi/Kconfig | 7 +++++ drivers/mtd/spi/sf_probe.c | 6 ++++ drivers/mtd/spi/spi-nor-core.c | 68 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 81 insertions(+) (limited to 'drivers/mtd') diff --git a/drivers/mtd/spi/Kconfig b/drivers/mtd/spi/Kconfig index a701167dcc..185ebbeb02 100644 --- a/drivers/mtd/spi/Kconfig +++ b/drivers/mtd/spi/Kconfig @@ -97,6 +97,13 @@ config SPI_FLASH_SMART_HWCAPS can support a type of operation in a much more refined way compared to using flags like SPI_RX_DUAL, SPI_TX_QUAD, etc. +config SPI_FLASH_SOFT_RESET + bool "Software Reset support for SPI NOR flashes" + default n + help + Enable support for xSPI Software Reset. It will be used to switch from + Octal DTR mode to legacy mode on shutdown and boot (if enabled). + config SPI_FLASH_BAR bool "SPI flash Bank/Extended address register support" help diff --git a/drivers/mtd/spi/sf_probe.c b/drivers/mtd/spi/sf_probe.c index 7edb8759fd..f461082e03 100644 --- a/drivers/mtd/spi/sf_probe.c +++ b/drivers/mtd/spi/sf_probe.c @@ -151,6 +151,11 @@ int spi_flash_std_probe(struct udevice *dev) static int spi_flash_std_remove(struct udevice *dev) { struct spi_flash *flash = dev_get_uclass_priv(dev); + int ret; + + ret = spi_nor_remove(flash); + if (ret) + return ret; if (CONFIG_IS_ENABLED(SPI_FLASH_MTD)) spi_flash_mtd_unregister(flash); @@ -178,6 +183,7 @@ U_BOOT_DRIVER(jedec_spi_nor) = { .remove = spi_flash_std_remove, .priv_auto = sizeof(struct spi_nor), .ops = &spi_flash_std_ops, + .flags = DM_FLAG_OS_PREPARE, }; DM_DRIVER_ALIAS(jedec_spi_nor, spansion_m25p16) diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c index 0d38ffc4f3..642068a4e2 100644 --- a/drivers/mtd/spi/spi-nor-core.c +++ b/drivers/mtd/spi/spi-nor-core.c @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -200,6 +201,8 @@ struct spi_nor_fixups { struct spi_nor_flash_parameter *params); }; +#define SPI_NOR_SRST_SLEEP_LEN 200 + /** * spi_nor_get_cmd_ext() - Get the command opcode extension based on the * extension type. @@ -2971,6 +2974,71 @@ static int spi_nor_init(struct spi_nor *nor) return 0; } +#ifdef CONFIG_SPI_FLASH_SOFT_RESET +/** + * spi_nor_soft_reset() - perform the JEDEC Software Reset sequence + * @nor: the spi_nor structure + * + * This function can be used to switch from Octal DTR mode to legacy mode on a + * flash that supports it. The soft reset is executed in Octal DTR mode. + * + * Return: 0 for success, -errno for failure. + */ +static int spi_nor_soft_reset(struct spi_nor *nor) +{ + struct spi_mem_op op; + int ret; + enum spi_nor_cmd_ext ext; + + ext = nor->cmd_ext_type; + nor->cmd_ext_type = SPI_NOR_EXT_REPEAT; + + 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_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR); + ret = spi_mem_exec_op(nor->spi, &op); + if (ret) { + dev_warn(nor->dev, "Software reset enable failed: %d\n", ret); + goto out; + } + + 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_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR); + ret = spi_mem_exec_op(nor->spi, &op); + if (ret) { + dev_warn(nor->dev, "Software reset failed: %d\n", ret); + goto out; + } + + /* + * 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, wait for 200ms just to be sure. + */ + udelay(SPI_NOR_SRST_SLEEP_LEN); + +out: + nor->cmd_ext_type = ext; + return ret; +} +#endif /* CONFIG_SPI_FLASH_SOFT_RESET */ + +int spi_nor_remove(struct spi_nor *nor) +{ +#ifdef CONFIG_SPI_FLASH_SOFT_RESET + if (nor->info->flags & SPI_NOR_OCTAL_DTR_READ && + nor->flags & SNOR_F_SOFT_RESET) + return spi_nor_soft_reset(nor); +#endif + + return 0; +} + void spi_nor_set_fixups(struct spi_nor *nor) { } -- cgit v1.2.3