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Date: Mon, 17 Jun 2019 21:10:02 +0530
From: Sagar Kadam <sagar.kadam@...ive.com>
To: Vignesh Raghavendra <vigneshr@...com>
Cc: marek.vasut@...il.com, tudor.ambarus@...rochip.com,
dwmw2@...radead.org, computersforpeace@...il.com,
miquel.raynal@...tlin.com, richard@....at,
linux-mtd@...ts.infradead.org, linux-kernel@...r.kernel.org,
linux-riscv@...ts.infradead.org,
Palmer Dabbelt <palmer@...ive.com>, aou@...s.berkeley.edu,
Paul Walmsley <paul.walmsley@...ive.com>,
Wesley Terpstra <wesley@...ive.com>
Subject: Re: [PATCH v5 2/3] mtd: spi-nor: add support to unlock flash device
Hello Vignesh,
On Sun, Jun 16, 2019 at 6:35 PM Vignesh Raghavendra <vigneshr@...com> wrote:
>
>
>
> On 12-Jun-19 4:17 PM, Sagar Shrikant Kadam wrote:
> > Nor device (is25wp256 mounted on HiFive unleashed Rev A00 board) from ISSI
> > have memory blocks guarded by block protection bits BP[0,1,2,3].
> >
> > Clearing block protection bits,unlocks the flash memory regions
> > The unlock scheme is registered during nor scans.
> >
> > Based on code developed by Wesley Terpstra <wesley@...ive.com>
> > and/or Palmer Dabbelt <palmer@...ive.com>.
> > https://github.com/riscv/riscv-linux/commit/c94e267766d62bc9a669611c3d0c8ed5ea26569b
> >
> > Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@...ive.com>
> > ---
> > drivers/mtd/spi-nor/spi-nor.c | 51 ++++++++++++++++++++++++++++++++++++++++++-
> > include/linux/mtd/spi-nor.h | 1 +
> > 2 files changed, 51 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
> > index 2d5a925..b7c6261 100644
> > --- a/drivers/mtd/spi-nor/spi-nor.c
> > +++ b/drivers/mtd/spi-nor/spi-nor.c
> > @@ -1461,6 +1461,49 @@ static int macronix_quad_enable(struct spi_nor *nor)
> > }
> >
> > /**
> > + * issi_unlock() - clear BP[0123] write-protection.
> > + * @nor: pointer to a 'struct spi_nor'.
> > + * @ofs: offset from which to unlock memory.
> > + * @len: number of bytes to unlock.
> > + *
> > + * Bits [2345] of the Status Register are BP[0123].
> > + * ISSI chips use a different block protection scheme than other chips.
> > + * Just disable the write-protect unilaterally.
> > + *
> > + * Return: 0 on success, -errno otherwise.
> > + */
> > +static int issi_unlock(struct spi_nor *nor, loff_t ofs, uint64_t len)
> > +{
> > + int ret, val;
> > + u8 mask = SR_BP0 | SR_BP1 | SR_BP2 | SR_BP3;
> > +
> > + val = read_sr(nor);
> > + if (val < 0)
> > + return val;
> > + if (!(val & mask))
> > + return 0;
> > +
> > + write_enable(nor);
> > +
> > + write_sr(nor, val & ~mask);
> > +
> > + ret = spi_nor_wait_till_ready(nor);
> > + if (ret)
> > + return ret;
> > +
> > + ret = read_sr(nor);
> > + if (ret > 0 && !(ret & mask)) {
> > + dev_info(nor->dev,
> > + "ISSI Block Protection Bits cleared SR=0x%x", ret);
> > + ret = 0;
> > + } else {
> > + dev_err(nor->dev, "ISSI Block Protection Bits not cleared\n");
> > + ret = -EINVAL;
> > + }
> > + return ret;
> > +}
> > +
> > +/**
> > * spansion_quad_enable() - set QE bit in Configuraiton Register.
> > * @nor: pointer to a 'struct spi_nor'
> > *
> > @@ -1836,7 +1879,7 @@ static int sr2_bit7_quad_enable(struct spi_nor *nor)
> > SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ) },
> > { "is25wp256", INFO(0x9d7019, 0, 64 * 1024, 1024,
> > SECT_4K | SPI_NOR_DUAL_READ | SPI_NOR_QUAD_READ |
> > - SPI_NOR_4B_OPCODES)
> > + SPI_NOR_4B_OPCODES | SPI_NOR_HAS_LOCK)
> > },
> >
> > /* Macronix */
> > @@ -4080,6 +4123,12 @@ int spi_nor_scan(struct spi_nor *nor, const char *name,
> > nor->flash_is_locked = stm_is_locked;
> > }
> >
> > + /* NOR protection support for ISSI chips */
> > + if (JEDEC_MFR(info) == SNOR_MFR_ISSI ||
> > + info->flags & SPI_NOR_HAS_LOCK) {
>
> This should be:
>
> if (JEDEC_MFR(info) == SNOR_MFR_ISSI &&
> info->flags & SPI_NOR_HAS_LOCK) {
>
> Otherwise you would end up overriding nor->flash_unlock function for
> other vendors too, right?
>
Yes, right. I will submit a v6 for this.
> > + nor->flash_unlock = issi_unlock;
> > +
>
> No need for blank line here.
> Please run ./scripts/checkpatch.pl --strict on all patches and address
> all the issues reported by it.
>
>
Ok. The plain checkpatch.pl run didn't catch this.
I will fix this and provide a v6 for this.
>
> > + }
> > if (nor->flash_lock && nor->flash_unlock && nor->flash_is_locked) {
> > mtd->_lock = spi_nor_lock;
> > mtd->_unlock = spi_nor_unlock;
> > diff --git a/include/linux/mtd/spi-nor.h b/include/linux/mtd/spi-nor.h
> > index ff13297..9a7d719 100644
> > --- a/include/linux/mtd/spi-nor.h
> > +++ b/include/linux/mtd/spi-nor.h
> > @@ -127,6 +127,7 @@
> > #define SR_BP0 BIT(2) /* Block protect 0 */
> > #define SR_BP1 BIT(3) /* Block protect 1 */
> > #define SR_BP2 BIT(4) /* Block protect 2 */
> > +#define SR_BP3 BIT(5) /* Block protect 3 for ISSI device*/
>
> No need to mention ISSI here. I am sure there are devices from other
> vendors with BP3
>
Ok, I will drop this in V6 and submit.
> > #define SR_TB BIT(5) /* Top/Bottom protect */
> > #define SR_SRWD BIT(7) /* SR write protect */
> > /* Spansion/Cypress specific status bits */
> >
>
> Regards
> Vignesh
Thanks & BR,
Sagar Kadam
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