From: Pratyush Yadav <p.yadav@ti.com>
To: Tudor Ambarus <tudor.ambarus@microchip.com>,
Michael Walle <michael@walle.cc>,
Miquel Raynal <miquel.raynal@bootlin.com>,
Richard Weinberger <richard@nod.at>,
Vignesh Raghavendra <vigneshr@ti.com>,
Mark Brown <broonie@kernel.org>, <linux-mtd@lists.infradead.org>,
<linux-kernel@vger.kernel.org>, <linux-spi@vger.kernel.org>
Cc: Pratyush Yadav <p.yadav@ti.com>
Subject: [PATCH 0/6] Avoid odd length/address read/writes in 8D-8D-8D mode.
Date: Fri, 7 May 2021 00:48:23 +0530 [thread overview]
Message-ID: <20210506191829.8271-1-p.yadav@ti.com> (raw)
Hi,
On Octal DTR flashes like Micron Xcella or Cypress S28 family, reads or
writes cannot start at an odd address in 8D-8D-8D mode. Neither can they
be odd bytes long. Upper layers like filesystems don't know what mode
the flash is in, and hence don't know the read/write address or length
limitations. They might issue reads or writes that leave the flash in an
error state. In fact, using UBIFS on top of the flash was how I first
noticed this problem.
This series fixes that problem by padding the read/write with extra
bytes to make sure the final operation has an even address and length.
More info in patches 5 and 6.
Patches 1-3 fix some existing odd-byte long reads. Patch 4 adds checks
to disallow odd length command/address/dummy/data phases in 8D-8D-8D
mode. Note that this does not restrict the _value_ of the address from
being odd since this is a restriction on the flash, not the protocol
itself.
Patch 4 should go through the SPI tree but I have included it in this
series because if it goes in before patches 1-3, Micron MT35XU and
Cypress S28HS flashes will stop working correctly.
Tested on TI J721E for Micron MT35 and on TI J7200 for Cypress S28.
Pratyush Yadav (6):
mtd: spi-nor: core: use 2 data bytes for template ops
mtd: spi-nor: spansion: write 2 bytes when disabling Octal DTR mode
mtd: spi-nor: micron-st: write 2 bytes when disabling Octal DTR mode
spi: spi-mem: reject partial cycle transfers in 8D-8D-8D mode
mtd: spi-nor: core; avoid odd length/address reads on 8D-8D-8D mode
mtd: spi-nor: core; avoid odd length/address writes in 8D-8D-8D mode
drivers/mtd/spi-nor/core.c | 157 +++++++++++++++++++++++++++++++-
drivers/mtd/spi-nor/micron-st.c | 22 ++++-
drivers/mtd/spi-nor/spansion.c | 18 +++-
drivers/spi/spi-mem.c | 12 ++-
4 files changed, 194 insertions(+), 15 deletions(-)
--
2.30.0
next reply other threads:[~2021-05-06 19:18 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-06 19:18 Pratyush Yadav [this message]
2021-05-06 19:18 ` [PATCH 1/6] mtd: spi-nor: core: use 2 data bytes for template ops Pratyush Yadav
2021-05-06 19:18 ` [PATCH 2/6] mtd: spi-nor: spansion: write 2 bytes when disabling Octal DTR mode Pratyush Yadav
2021-05-06 19:18 ` [PATCH 3/6] mtd: spi-nor: micron-st: " Pratyush Yadav
2021-05-06 19:18 ` [PATCH 4/6] spi: spi-mem: reject partial cycle transfers in 8D-8D-8D mode Pratyush Yadav
2021-05-07 12:55 ` Mark Brown
2021-05-07 13:56 ` Pratyush Yadav
2021-05-07 15:31 ` Mark Brown
2021-05-07 15:48 ` Mark Brown
2021-05-07 16:49 ` Pratyush Yadav
2021-05-06 19:18 ` [PATCH 5/6] mtd: spi-nor: core; avoid odd length/address reads on " Pratyush Yadav
2021-05-07 15:51 ` Michael Walle
2021-05-07 18:04 ` Pratyush Yadav
2021-05-07 18:14 ` Michael Walle
2021-05-07 18:23 ` Pratyush Yadav
2021-05-06 19:18 ` [PATCH 6/6] mtd: spi-nor: core; avoid odd length/address writes in " Pratyush Yadav
2021-05-07 15:56 ` Michael Walle
2021-05-07 17:02 ` Pratyush Yadav
2021-05-07 15:50 ` [PATCH 0/6] Avoid odd length/address read/writes " Mark Brown
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