linux-kernel - Re: [PATCH v2 4/4] i2c: i2c-qcom-geni: Enable i2c controller sharing between two subsystems

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <6fbfe1b0-e99f-43cd-a099-389f65ab5b06@quicinc.com>
Date: Tue, 10 Sep 2024 19:12:34 +0530
From: Mukesh Kumar Savaliya <quic_msavaliy@...cinc.com>
To: Andi Shyti <andi.shyti@...nel.org>
CC: <konrad.dybcio@...aro.org>, <andersson@...nel.org>,
        <linux-arm-msm@...r.kernel.org>, <dmaengine@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-i2c@...r.kernel.org>,
        <conor+dt@...nel.org>, <agross@...nel.org>,
        <devicetree@...r.kernel.org>, <vkoul@...nel.org>, <linux@...blig.org>,
        <dan.carpenter@...aro.org>, <Frank.Li@....com>,
        <konradybcio@...nel.org>, <quic_vdadhani@...cinc.com>
Subject: Re: [PATCH v2 4/4] i2c: i2c-qcom-geni: Enable i2c controller sharing
 between two subsystems

Hi Andi, Sorry for late reply on this.

On 9/7/2024 1:26 PM, Andi Shyti wrote:
> Hi Mukesh,
> 
> On Sat, Sep 07, 2024 at 12:44:38AM GMT, Mukesh Kumar Savaliya wrote:
>> Add support to share I2C SE by two Subsystems in a mutually exclusive way.
>> Use  "qcom,shared-se" flag in a particular i2c instance node if the
>> usecase requires i2c controller to be shared.
>>
>> I2C driver just need to mark first_msg and last_msg flag to help indicate
>> GPI driver to  take lock and unlock TRE there by protecting from concurrent
>> access from other EE or Subsystem.
>>
>> gpi_create_i2c_tre() function at gpi.c will take care of adding Lock and
>> Unlock TRE for the respective transfer operations.
>>
>> Since the GPIOs are also shared for the i2c bus between two SS, do not
>> touch GPIO configuration during runtime suspend and only turn off the
>> clocks. This will allow other SS to continue to transfer the data
>> without any disturbance over the IO lines.
> 
> if I remember correctly, someone already commented on your
> patches to explain and expand the achronyms you are using. Please
> improve the commit log so that people who don't know this device
> can understand.
> 
Sure, Andi. Noted and addressed over comment. Will add full form for the 
acronyms.
> ...
> 
>> @@ -631,8 +636,11 @@ static int geni_i2c_gpi_xfer(struct geni_i2c_dev *gi2c, struct i2c_msg msgs[], i
>>   		dma_async_issue_pending(gi2c->tx_c);
>>   
>>   		time_left = wait_for_completion_timeout(&gi2c->done, XFER_TIMEOUT);
>> -		if (!time_left)
>> +		if (!time_left) {
>> +			dev_err(gi2c->se.dev, "I2C timeout gpi flags:%d addr:0x%x\n",
>> +						gi2c->cur->flags, gi2c->cur->addr);
> 
> Please, don't print out here. The user doesn't really need to
> know, let the upper levels decide what to do.
Sure, can remove this completely and user can handle , print it.

> 
>>   			gi2c->err = -ETIMEDOUT;
>> +		}
>>   
>>   		if (gi2c->err) {
>>   			ret = gi2c->err;
>> @@ -800,6 +808,11 @@ static int geni_i2c_probe(struct platform_device *pdev)
>>   		gi2c->clk_freq_out = KHZ(100);
>>   	}
>>   
>> +	if (of_property_read_bool(pdev->dev.of_node, "qcom,shared-se")) {
>> +		gi2c->is_shared = true;
>> +		dev_dbg(&pdev->dev, "Shared SE Usecase\n");
> 
> Please, improve this debug message.
> 
"I2C is shared between subsystems" ?
> The rest looks good to me.
> 
> Thanks,
> Andi