linux-kernel - Re: [PATCH V4] mmc: sdhci-msm: Reset GCC_SDCC

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Message-ID: <e85dace0-66f5-6ef1-425a-d5cff4278c19@quicinc.com>
Date:   Sun, 24 Apr 2022 15:52:50 +0530
From:   "Sajida Bhanu (Temp)" <quic_c_sbhanu@...cinc.com>
To:     Philipp Zabel <p.zabel@...gutronix.de>, <adrian.hunter@...el.com>,
        <agross@...nel.org>, <bjorn.andersson@...aro.org>,
        <ulf.hansson@...aro.org>, <chris@...ntf.net>,
        <venkatg@...eaurora.org>, <gdjakov@...sol.com>,
        <quic_asutoshd@...cinc.com>
CC:     <linux-mmc@...r.kernel.org>, <linux-arm-msm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <quic_rampraka@...cinc.com>,
        <quic_pragalla@...cinc.com>, <quic_sartgarg@...cinc.com>,
        <quic_nitirawa@...cinc.com>, <quic_sayalil@...cinc.com>
Subject: Re: [PATCH V4] mmc: sdhci-msm: Reset GCC_SDCC_BCR register for SDHC

Hi,

Thanks for the review.

Please find the inline comments.

Thanks,

Sajida

On 4/21/2022 3:26 PM, Philipp Zabel wrote:
> On Do, 2022-04-21 at 10:32 +0530, Sajida Bhanu (Temp) wrote:
>> Hi,
>>
>> Thanks for the review.
>>
>> Please find the inline comments.
>>
>> Thanks,
>>
>> Sajida
>>
>> On 4/19/2022 12:52 PM, Philipp Zabel wrote:
>>> Hi Sajida,
>>>
>>> On Di, 2022-04-19 at 11:46 +0530, Sajida Bhanu (Temp) wrote:
>>> [...]
>>>>>> +static int sdhci_msm_gcc_reset(struct device *dev, struct sdhci_host *host)
>>>>>> +{
>>>>>> +	struct reset_control *reset;
>>>>>> +	int ret = 0;
>>>>> No need to initialize ret.
>>>>>
>>>>>> +
>>>>>> +	reset = reset_control_get_optional_exclusive(dev, NULL);
>>>>>> +	if (IS_ERR(reset))
>>>>>> +		return dev_err_probe(dev, PTR_ERR(reset),
>>>>>> +				"unable to acquire core_reset\n");
>>>>>> +
>>>>>> +	if (!reset)
>>>>>> +		return ret;
>>>> Here we are returning ret directly if reset is NULL , so ret
>>>> initialization is required.
>>> You are right. I would just "return 0;" here, but this is correct as
>>> is.
>> Ok
>>>>>> +
>>>>>> +	ret = reset_control_assert(reset);
>>>>>> +	if (ret)
>>>>>> +		return dev_err_probe(dev, ret, "core_reset assert failed\n");
>>>>> Missing reset_control_put(reset) in the error path.
>>>> Sure will add
>>>>>> +
>>>>>> +	/*
>>>>>> +	 * The hardware requirement for delay between assert/deassert
>>>>>> +	 * is at least 3-4 sleep clock (32.7KHz) cycles, which comes to
>>>>>> +	 * ~125us (4/32768). To be on the safe side add 200us delay.
>>>>>> +	 */
>>>>>> +	usleep_range(200, 210);
>>>>>> +
>>>>>> +	ret = reset_control_deassert(reset);
>>>>>> +	if (ret)
>>>>>> +		return dev_err_probe(dev, ret, "core_reset deassert failed\n");
>>>>> Same as above. Maybe make both ret = dev_err_probe() and goto ...
>>>> In both cases error message is different so I think goto not good idea here.
>>> You could goto after the error message. Either way is fine.
>> Sorry didn't get this ..can  you please help
> I meant you could either use goto after the error messages:
>
> +static int sdhci_msm_gcc_reset(struct device *dev, struct sdhci_host *host)
> +{
> [...]
> +	ret = reset_control_assert(reset);
> +	if (ret) {
> +		dev_err_probe(dev, ret, "core_reset assert failed\n");
> +		goto out_reset_put;
> +	}
> [...]
> +	ret = reset_control_deassert(reset);
> +	if (ret) {
> +		dev_err_probe(dev, ret, "core_reset deassert failed\n");
> +		goto out_reset_put;
> +	}
> +
> +	usleep_range(200, 210);
> +
> +out_reset_put:
> +	reset_control_put(reset);
> +
> +	return ret;
> +}
>
> Or not use goto and copy the reset_control_put() into each error path:
>
> +static int sdhci_msm_gcc_reset(struct device *dev, struct sdhci_host *host)
> +{
> [...]
> +	ret = reset_control_assert(reset);
> +	if (ret) {
> +		reset_control_put(reset);
> +		return dev_err_probe(dev, ret, "core_reset assert failed\n");
> +	}
> [...]
> +	ret = reset_control_deassert(reset);
> +	if (ret) {
> +		reset_control_put(reset);
> +		return dev_err_probe(dev, ret, "core_reset deassert failed\n");
> +	}
> +
> +	usleep_range(200, 210);
> +	reset_control_put(reset);
> +
> +	return 0;
> +}
>
> regards
> Philipp
Sure I will call reset_control_put() in each error path