linux-kernel - Re: [PATCH v2 0/3] mtd: Make sure UBIFS does not do multi-pass page programming on flashes that don't support it

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Message-ID: <20201124134619.2pbg7zejbvwc3e2w@ti.com>
Date:   Tue, 24 Nov 2020 19:16:19 +0530
From:   Pratyush Yadav <p.yadav@...com>
To:     Tudor Ambarus <tudor.ambarus@...rochip.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        Vignesh Raghavendra <vigneshr@...com>,
        <linux-mtd@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v2 0/3] mtd: Make sure UBIFS does not do multi-pass page
 programming on flashes that don't support it

Hi,

On 18/11/20 11:54PM, Pratyush Yadav wrote:
> Hi,
> 
> The Cypress Semper S28 flash family uses 2-bit ECC by default. Under
> this ECC scheme, multi-pass page programs result in a program error.
> This means that unlike many other SPI NOR flashes, bit-walking cannot be
> done. In other words, once a page is programmed, its bits cannot then be
> flipped to 0 without an erase in between.
> 
> This causes problems with UBIFS because it uses bit-walking to clear EC
> and VID magic numbers from a PEB before issuing an erase to preserve the
> file system correctness in case of power cuts.
> 
> This series fixes that by setting mtd->writesize to the ECC block size
> (16) and making sure UBIFS does not try to do a multi-pass write on
> flashes with writesize > 1.
> 
> It is based on the xSPI/8D series that adds support for Cypress S28
> flash [0] (it is in next now). The patches themselves are independent of
> that series in the sense that they don't rely on 8D support. But since
> S28 flash is not supported without that series, these patches don't make
> much sense without it.
> 
> Tested on Cypress S28HS512T and MT35XU512ABA on J7200 and J721E
> respectively.
> 
> [0] https://lore.kernel.org/linux-mtd/20201005153138.6437-1-p.yadav@ti.com/

Any comments on the series? If not, can it be picked up?
 
> Pratyush Yadav (3):
>   UBI: Do not zero out EC and VID on ECC-ed NOR flashes
>   mtd: spi-nor: core: Allow flashes to specify MTD writesize
>   mtd: spi-nor: spansion: Set ECC block size
> 
>  drivers/mtd/spi-nor/core.c     | 4 +++-
>  drivers/mtd/spi-nor/core.h     | 3 +++
>  drivers/mtd/spi-nor/spansion.c | 1 +
>  drivers/mtd/ubi/build.c        | 4 +---
>  drivers/mtd/ubi/io.c           | 9 ++++++++-
>  5 files changed, 16 insertions(+), 5 deletions(-)
> 
> --
> 2.28.0
> 

-- 
Regards,
Pratyush Yadav
Texas Instruments India