linux-kernel - Re: [V2] i2c: i2c-qcom-geni: Correct I2C TRE sequence

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Date: Thu, 1 Feb 2024 15:51:56 +0530
From: Viken Dadhaniya <quic_vdadhani@...cinc.com>
To: Andi Shyti <andi.shyti@...nel.org>,
        Dmitry Baryshkov
	<dmitry.baryshkov@...aro.org>
CC: <andersson@...nel.org>, <konrad.dybcio@...aro.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-i2c@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <vkoul@...nel.org>,
        <quic_bjorande@...cinc.com>, <manivannan.sadhasivam@...aro.org>,
        <quic_msavaliy@...cinc.com>, <quic_vtanuku@...cinc.com>
Subject: Re: [V2] i2c: i2c-qcom-geni: Correct I2C TRE sequence



On 1/30/2024 3:12 PM, Andi Shyti wrote:
> Hi Dmitry,
> 
> thanks a lot for your review!
> 
> On Tue, Jan 30, 2024 at 01:49:57AM +0200, Dmitry Baryshkov wrote:
>> On Mon, 29 Jan 2024 at 08:10, Viken Dadhaniya <quic_vdadhani@...cinc.com> wrote:
>>>
>>> For i2c read operation, we are getting gsi mode timeout due
>>> to malformed TRE(Transfer Ring Element). Currently we are
>>> configuring incorrect TRE sequence in gpi driver
>>> (drivers/dma/qcom/gpi.c) as below
>>>
>>> - Sets up CONFIG
>>> - Sets up DMA tre
>>> - Sets up GO tre
>>>
>>> As per HPG(Hardware programming guide), We should configure TREs in below
>>> sequence for any i2c transfer
>>>
>>> - Sets up CONFIG tre
>>> - Sets up GO tre
>>> - Sets up DMA tre
>>
>> It is not clear how this is relevant and/or affected by swapping
>> I2C_WRITE and I2C_READ gpi calls.
>>
>>>
>>> For only write operation or write followed by read operation,
>>> existing software sequence is correct.
>>>
>>> for only read operation, TRE sequence need to be corrected.
>>> Hence, we have changed the sequence to submit GO tre before DMA tre.
>>>
>>> Tested covering i2c read/write transfer on QCM6490 RB3 board.
>>
>> Please read Documentation/process/submitting-patches.rst, understand
>> it and write a proper commit message.
>>
>>>
>>> Signed-off-by: Viken Dadhaniya <quic_vdadhani@...cinc.com>
>>> Fixes: commit d8703554f4de ("i2c: qcom-geni: Add support for GPI DMA")
>>
>> As it was pointed out, this line shows ignorance of the mentioned file
>> and of the existing community practices.
> 
> If the issue is only in the commit message Viken can propose a
> proper commit message as reply to this e-mail and I can fix it
> before merging the change.
> 
> Important is that no issue is seen in the code.
> 
> Please, Viken, can you either send a v3 with a proper commit
> message or write it in the reply to this e-mail with the changes
> that Dmitry suggested.
> 

Submitted V3 with proper commit log

>>> ---
>>> v1 -> v2:
>>> - Remove redundant check.
>>> - update commit log.
>>> - add fix tag.
>>> ---
>>> ---
>>>   drivers/i2c/busses/i2c-qcom-geni.c | 14 +++++++-------
>>>   1 file changed, 7 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/drivers/i2c/busses/i2c-qcom-geni.c b/drivers/i2c/busses/i2c-qcom-geni.c
>>> index 0d2e7171e3a6..da94df466e83 100644
>>> --- a/drivers/i2c/busses/i2c-qcom-geni.c
>>> +++ b/drivers/i2c/busses/i2c-qcom-geni.c
>>> @@ -613,20 +613,20 @@ static int geni_i2c_gpi_xfer(struct geni_i2c_dev *gi2c, struct i2c_msg msgs[], i
>>>
>>>                  peripheral.addr = msgs[i].addr;
>>>
>>> +               ret =  geni_i2c_gpi(gi2c, &msgs[i], &config,
>>> +                                   &tx_addr, &tx_buf, I2C_WRITE, gi2c->tx_c);
>>> +               if (ret)
>>> +                       goto err;
>>> +
>>>                  if (msgs[i].flags & I2C_M_RD) {
>>>                          ret =  geni_i2c_gpi(gi2c, &msgs[i], &config,
>>>                                              &rx_addr, &rx_buf, I2C_READ, gi2c->rx_c);
>>>                          if (ret)
>>>                                  goto err;
>>> -               }
>>> -
>>> -               ret =  geni_i2c_gpi(gi2c, &msgs[i], &config,
>>> -                                   &tx_addr, &tx_buf, I2C_WRITE, gi2c->tx_c);
>>> -               if (ret)
>>> -                       goto err;
>>>
>>> -               if (msgs[i].flags & I2C_M_RD)
>>>                          dma_async_issue_pending(gi2c->rx_c);
>>> +               }
>>> +
>>>                  dma_async_issue_pending(gi2c->tx_c);
>>>
>>>                  timeout = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
>>> --
>>> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
>>> of Code Aurora Forum, hosted by The Linux Foundation
> 
> If you are going to submit again, please make also sure that the
> e-mail is formatted properly.
> 
> I'm not sure that this footer will be accepted by git.
> 
> Thanks,
> Andi
> 

Submitted V3 with proper email format.

>>>
>>>
>>
>>
>> -- 
>> With best wishes
>> Dmitry