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Message-ID: <d560c9b0-d2cf-18da-3470-a51468413955@linux.intel.com>
Date:   Mon, 5 Jun 2023 10:41:18 +0300
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Subject: Re: [PATCH v1] i2c: designware: Handle invalid SMBus block data
 response length
To:     Tam Chi Nguyen <tamnguyenchi@amperemail.onmicrosoft.com>,
        Tam Nguyen <tamnguyenchi@os.amperecomputing.com>,
        linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org
Cc:     patches@amperecomputing.com, andriy.shevchenko@linux.intel.com,
        mika.westerberg@linux.intel.com, jsd@semihalf.com,
        chuong@os.amperecomputing.com, darren@os.amperecomputing.com,
        stable@vger.kernel.org
References: <20230523082118.10935-1-tamnguyenchi@os.amperecomputing.com>
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From:   Jarkko Nikula <jarkko.nikula@linux.intel.com>
In-Reply-To: <95d838d5-ea27-ef75-4ac6-575ebd75111a@amperemail.onmicrosoft.com>
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Hi

On 6/2/23 07:30, Tam Chi Nguyen wrote:
> Hi Jarkko,
> 
> Before pushing the v2 patch, I have one more question to ask.
> 
> The commit f53f15ba5a85 ("i2c: designware: Get right data length"), you 
> mentioned,
> does not handle bit 11 set (on a HW where it's supported) correctly.
> "tmp" was not marked with DW_IC_DATA_CMD_DAT when passing to 
> i2c_dw_recv_len function.
> 
> So I plan to update it in the v2 patch by adding this
>      regmap_read(dev->map, DW_IC_DATA_CMD, &tmp);
>      tmp &= DW_IC_DATA_CMD_DAT;
> 
> My question is: does it need a separate patch for this change?
> 
I think for now bit 11 gets masked since tmp variable is assigned to u8 
variables when calling i2c_dw_recv_len() and writing to *buf pointer but 
your proposal indeed makes code more robust both your patch point of 
view or any other future change. So separate patch makes sense in my 
opinion.