Messages in this thread | ![/](/images/icornerl.gif) | | Date | Fri, 30 Jun 2023 16:38:32 +0200 | From | Michael Walle <> | Subject | Re: [PATCH v4 2/2] mtd: spi-nor: Avoid setting SRWD bit in SR if WP# signal not connected |
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Am 2023-06-30 16:22, schrieb Amit Kumar Mahapatra: > 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: Amit Kumar Mahapatra <amit.kumar-mahapatra@amd.com> > --- > drivers/mtd/spi-nor/core.c | 3 +++ > drivers/mtd/spi-nor/core.h | 1 + > drivers/mtd/spi-nor/debugfs.c | 1 + > drivers/mtd/spi-nor/swp.c | 9 +++++++-- > 4 files changed, 12 insertions(+), 2 deletions(-) > > diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c > index 0bb0ad14a2fc..520f5ab86d2b 100644 > --- a/drivers/mtd/spi-nor/core.c > +++ b/drivers/mtd/spi-nor/core.c > @@ -2864,6 +2864,9 @@ static void spi_nor_init_flags(struct spi_nor > *nor) > if (flags & NO_CHIP_ERASE) > nor->flags |= SNOR_F_NO_OP_CHIP_ERASE; > > + if (of_property_read_bool(np, "no-wp")) > + nor->flags |= SNOR_F_NO_WP; > +
Not moved below the first of_property_read_bool() in that function (as pointed out before). It's just a minor nit.
But with or without that fixed:
Reviewed-by: Michael Walle <michael@walle.cc>
> if (flags & SPI_NOR_RWW && nor->info->n_banks > 1 && > !nor->controller_ops) > nor->flags |= SNOR_F_RWW; > diff --git a/drivers/mtd/spi-nor/core.h b/drivers/mtd/spi-nor/core.h > index 4fb5ff09c63a..55b5e7abce6e 100644 > --- a/drivers/mtd/spi-nor/core.h > +++ b/drivers/mtd/spi-nor/core.h > @@ -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 { > diff --git a/drivers/mtd/spi-nor/debugfs.c > b/drivers/mtd/spi-nor/debugfs.c > index e11536fffe0f..6e163cb5b478 100644 > --- a/drivers/mtd/spi-nor/debugfs.c > +++ b/drivers/mtd/spi-nor/debugfs.c > @@ -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 > > diff --git a/drivers/mtd/spi-nor/swp.c b/drivers/mtd/spi-nor/swp.c > index 0ba716e84377..5ab9d5324860 100644 > --- a/drivers/mtd/spi-nor/swp.c > +++ b/drivers/mtd/spi-nor/swp.c > @@ -214,8 +214,13 @@ 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 */ > - status_new |= SR_SRWD; > + /* > + * 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) > status_new |= tb_mask;
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