linux-kernel - Re: [PATCH V8 1/1] i2c: i2c-qcom-geni: Add shutdown callback for i2c

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Message-ID: <9ec10130df230a0ff078d9eec47e94b2@codeaurora.org>
Date:   Thu, 18 Feb 2021 19:45:17 +0530
From:   rojay@...eaurora.org
To:     Stephen Boyd <swboyd@...omium.org>
Cc:     wsa@...nel.org, dianders@...omium.org,
        saiprakash.ranjan@...eaurora.org, gregkh@...uxfoundation.org,
        mka@...omium.org, akashast@...eaurora.org,
        msavaliy@....qualcomm.com, skakit@...eaurora.org,
        rnayak@...eaurora.org, agross@...nel.org,
        bjorn.andersson@...aro.org, linux-arm-msm@...r.kernel.org,
        linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
        sumit.semwal@...aro.org, linux-media@...r.kernel.org
Subject: Re: [PATCH V8 1/1] i2c: i2c-qcom-geni: Add shutdown callback for i2c

Hi Stephen,

On 2021-01-13 12:24, Stephen Boyd wrote:
> Quoting Roja Rani Yarubandi (2021-01-08 07:05:45)
>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c 
>> b/drivers/i2c/busses/i2c-qcom-geni.c
>> index 214b4c913a13..c3f584795911 100644
>> --- a/drivers/i2c/busses/i2c-qcom-geni.c
>> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
>> @@ -375,6 +375,32 @@ static void geni_i2c_tx_msg_cleanup(struct 
>> geni_i2c_dev *gi2c,
>>         }
>>  }
>> 
>> +static void geni_i2c_stop_xfer(struct geni_i2c_dev *gi2c)
>> +{
>> +       int ret;
>> +       u32 geni_status;
>> +       struct i2c_msg *cur;
>> +
>> +       /* Resume device, as runtime suspend can happen anytime during 
>> transfer */
>> +       ret = pm_runtime_get_sync(gi2c->se.dev);
>> +       if (ret < 0) {
>> +               dev_err(gi2c->se.dev, "Failed to resume device: %d\n", 
>> ret);
>> +               return;
>> +       }
>> +
>> +       geni_status = readl_relaxed(gi2c->se.base + SE_GENI_STATUS);
>> +       if (geni_status & M_GENI_CMD_ACTIVE) {
>> +               cur = gi2c->cur;
> 
> Why don't we need to hold the spinlock gi2c::lock here?
> 

I am not seeing any race here. May I know which race are you suspecting 
here?

>> +               geni_i2c_abort_xfer(gi2c);
>> +               if (cur->flags & I2C_M_RD)
>> +                       geni_i2c_rx_msg_cleanup(gi2c, cur);
>> +               else
>> +                       geni_i2c_tx_msg_cleanup(gi2c, cur);
>> +       }
>> +
>> +       pm_runtime_put_sync_suspend(gi2c->se.dev);
>> +}
>> +
>>  static int geni_i2c_rx_one_msg(struct geni_i2c_dev *gi2c, struct 
>> i2c_msg *msg,
>>                                 u32 m_param)
>>  {