Unverified Commit 18d7d01a authored by Amit Kumar Mahapatra's avatar Amit Kumar Mahapatra Committed by Tudor Ambarus
Browse files

mtd: spi-nor: Avoid setting SRWD bit in SR if WP# signal not connected 



Setting the status register write disable (SRWD) bit in the status
register (SR) with WP# signal of the flash left floating or wrongly tied to
GND (that includes internal pull-downs), will configure the SR permanently
as read-only. If WP# signal is left floating or wrongly tied to GND, avoid
setting SRWD bit while writing the SR during flash protection.

Signed-off-by: default avatarAmit Kumar Mahapatra <amit.kumar-mahapatra@amd.com>
Reviewed-by: default avatarMichael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20230630142233.63585-3-amit.kumar-mahapatra@amd.com


Signed-off-by: default avatarTudor Ambarus <tudor.ambarus@linaro.org>
parent cfc2928c

drivers/mtd/spi-nor/core.c

+3 −0
Original line number Diff line number Diff line
@@ -2844,6 +2844,9 @@ static void spi_nor_init_flags(struct spi_nor *nor) 
	if (of_property_read_bool(np, "broken-flash-reset"))

		nor->flags |= SNOR_F_BROKEN_RESET;



	if (of_property_read_bool(np, "no-wp"))

		nor->flags |= SNOR_F_NO_WP;



	if (flags & SPI_NOR_SWP_IS_VOLATILE)

		nor->flags |= SNOR_F_SWP_IS_VOLATILE;

drivers/mtd/spi-nor/core.h

+1 −0
Original line number Diff line number Diff line
@@ -132,6 +132,7 @@ enum spi_nor_option_flags { 
	SNOR_F_SWP_IS_VOLATILE	= BIT(13),

	SNOR_F_RWW		= BIT(14),

	SNOR_F_ECC		= BIT(15),

	SNOR_F_NO_WP		= BIT(16),

};



struct spi_nor_read_command {

drivers/mtd/spi-nor/debugfs.c

+1 −0
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ static const char *const snor_f_names[] = { 
	SNOR_F_NAME(SWP_IS_VOLATILE),

	SNOR_F_NAME(RWW),

	SNOR_F_NAME(ECC),

	SNOR_F_NAME(NO_WP),

};

#undef SNOR_F_NAME

drivers/mtd/spi-nor/swp.c

+7 −2
Original line number Diff line number Diff line
@@ -214,7 +214,12 @@ static int spi_nor_sr_lock(struct spi_nor *nor, loff_t ofs, uint64_t len) 


	status_new = (status_old & ~mask & ~tb_mask) | val;



	/* Disallow further writes if WP pin is asserted */

	/*

	 * Disallow further writes if WP# pin is neither left floating nor

	 * wrongly tied to GND (that includes internal pull-downs).

	 * WP# pin hard strapped to GND can be a valid use case.

	 */

	if (!(nor->flags & SNOR_F_NO_WP))

		status_new |= SR_SRWD;



	if (!use_top)