linux-kernel - Re: [PATCH 2/2] mtd: spi-nor: intel-spi: fix forced writable option

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Date:   Tue, 2 Jun 2020 16:36:31 +0000
From:   "Daniel Walker (danielwa)" <danielwa@...co.com>
To:     "Jinhua Wu (jinhwu)" <jinhwu@...co.com>
CC:     Vignesh Raghavendra <vigneshr@...com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "xe-linux-external(mailer list)" <xe-linux-external@...co.com>,
        Tudor Ambarus <tudor.ambarus@...rochip.com>,
        Miquel Raynal <miquel.raynal@...tlin.com>,
        Richard Weinberger <richard@....at>,
        "linux-mtd@...ts.infradead.org" <linux-mtd@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Mika Westerberg <mika.westerberg@...ux.intel.com>
Subject: Re: [PATCH 2/2] mtd: spi-nor: intel-spi: fix forced writable option

On Thu, May 28, 2020 at 03:55:21PM +0000, Jinhua Wu (jinhwu) wrote:
> On 2020/5/28, 11:48 PM, "Jinhua Wu" <jinhwu@...co.com> wrote:
> Hi Vignesh,
> BIOS just locked down parts of flash (such as, code region), others are still 
> writeable. Once the SPI locked down,it can't be override unless platfrom reset 
> and set WPD (write protect disable) will fail, so ispi->writeable will always
> be 0, then the driver will always make the whole flash read only, even if we
> have set the parameter writable = 1. 
> Now the flash is totally not writeable, just part of it is read only. Why not  making
> 'writeable' working when explicitly enabled?
> 
> >On 2020/5/28, 7:02 PM, "Vignesh Raghavendra" <vigneshr@...com> wrote:
> >    On 18/05/20 11:29 pm, Daniel Walker wrote:
> >    > This option currently doesn't work as expected. If the BIOS has this
> >    > flash as read-only there is no way to change this thru the driver.
> >    > There is a parameter which allows the flash to become writable with the
> >    > "writable" option to the module, but it does nothing if the BIOS has it
> >    > set to read-only.
> >    > 
> >    > I would expect this option would make the flash writable regardless of
> >    > the BIOS settings. This patch changes this option so the BIOS setting
> >    > doesn't stop the writable option from enabling read write on the flash.
> >    > 
> >
> >    I am confused you say "If the BIOS has this flash as read-only there is
> >    no way to change this thru the driver", so is it possible to override
> >    BIOS setting? If yes, where is the code in the driver?
> >
> >    What happens if BIOS is set to allow writes but writeable is set to 0?
> >
> >    Also please send patch series as thread (2/2 in reply to 1/2). You can
> >    use tool like git send-email
> >



Vignesh, do you still have concerns about this change ?


Daniel