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Date:   Wed, 1 Nov 2023 09:51:58 -0700
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Subject: Re: [PATCH v2] i2c: designware: Fix corrupted memory seen in the ISR
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To:     Serge Semin <fancer.lancer@gmail.com>
Cc:     Jarkko Nikula <jarkko.nikula@linux.intel.com>,
        Yann Sionneau <yann@sionneau.net>,
        Wolfram Sang <wsa@kernel.org>,
        Yann Sionneau <ysionneau@kalrayinc.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Mika Westerberg <mika.westerberg@linux.intel.com>,
        Jan Dabros <jsd@semihalf.com>,
        Andi Shyti <andi.shyti@kernel.org>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org,
        Julian Vetter <jvetter@kalrayinc.com>,
        Jonathan Borne <jborne@kalray.eu>
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From:   Jan Bottorff <janb@os.amperecomputing.com>
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On 10/31/2023 6:06 AM, Serge Semin wrote:
> On Tue, Oct 31, 2023 at 02:10:13PM +0200, Jarkko Nikula wrote:
>> On 10/31/23 10:44, Yann Sionneau wrote:
>>>
>>> Le 31/10/2023 à 01:12, Jan Bottorff a écrit :
>>>> On 10/26/2023 4:18 AM, Wolfram Sang wrote:
>>>>> So, someone wants to come up with a patch to move to non-relaxed io
>>>>> accessors?
>>>>>
...
>>>> I could make the patch if we have consensus (or maintainers
>>>> decision) on which way to go: 1) only writes to DW_IC_INTR_MASK are
>>>> non-relaxed, 2) make all read/write accessors use the non-relaxed
>>>> version.
>>>
>>> Fine with me, let's go for #2 :)
>>>
>> Also simplicity votes for #2.
> 
> +1 for the option #2. Let's do it and be finally over with this
> patch.)
> 
> -Serge(y)

I think we have agreement to make the dw i2c driver regmap accessors use 
the non-relaxed low-level functions, like writel instead of 
writel_relaxed. These low level functions have memory barriers on 
platforms that require them.

I'll work on a patch for this.

- Jan