linux-kernel - Re: [PATCH v2 1/4] spi: cadence-quadspi: Reset CMD

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Date:   Tue, 7 Feb 2023 18:36:07 +0530
From:   "Gole, Dhruva" <d-gole@...com>
To:     Pratyush Yadav <ptyadav@...zon.de>
CC:     Mark Brown <broonie@...nel.org>, <linux-spi@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>,
        Vignesh Raghavendra <vigneshr@...com>,
        Vaishnav Achath <vaishnav.a@...com>,
        <linux-mtd@...ts.infradead.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <Takahiro.Kuwano@...ineon.com>
Subject: Re: [PATCH v2 1/4] spi: cadence-quadspi: Reset CMD_CTRL Reg on cmd
 r/w completion

Thanks for taking a look Pratyush!

On 1/27/2023 8:46 PM, Pratyush Yadav wrote:
> Hi,
>
> On Wed, Jan 25 2023, Dhruva Gole wrote:
>
>> If one leaves the CQSPI_REG_CMDCTRL in an unclean state this may cause
>> issues in future command reads. This issue came to light when some flash
>> reads in STIG mode were coming back dirty.
> Can you explain in more detail what you mean by "reads coming back
> dirty"? Because I don't see any clear reason why not resetting the
> register would break anything. We re-create the register value from the
> scratch on the next read anyway, and as soon as you writel() that, the
> old fields get thrown away anyway.
There's a hardware bug due to which clearing of this register is necessary.
> [...]

-- 
Regards,
Dhruva Gole <d-gole@...com>