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SubjectRe: [PATCH V1] mmc: sdhci-msm: Add system suspend/resume callbacks
On 2020-01-22 22:27, Stephen Boyd wrote:
> Quoting Shaik Sajida Bhanu (2020-01-21 06:30:22)
>> Add system suspend/resume callbacks to sdhci-msm platform driver.
>
> Yes, but why? There are already suspend/resume callbacks so this is
> replacing them too.
>

Sure. Will update the commit text.

The present suspend/resume callbacks are only disabling the clocks.

Since eMMC/SDcard would be powered off during system suspend, we can do
little more like

resetting controller, disabling interrupts. So updating the existing
callbacks.

>>
>> Signed-off-by: Shaik Sajida Bhanu <sbhanu@codeaurora.org>
>> ---
>> drivers/mmc/host/sdhci-msm.c | 47
>> ++++++++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 45 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci-msm.c
>> b/drivers/mmc/host/sdhci-msm.c
>> index 71f29ba..4984857 100644
>> --- a/drivers/mmc/host/sdhci-msm.c
>> +++ b/drivers/mmc/host/sdhci-msm.c
>> @@ -2028,9 +2028,52 @@ static __maybe_unused int
>> sdhci_msm_runtime_resume(struct device *dev)
>> return 0;
>> }
>>
>> +static int sdhci_msm_suspend(struct device *dev)
>> +{
>> + struct sdhci_host *host = dev_get_drvdata(dev);
>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>> + struct sdhci_msm_host *msm_host =
>> sdhci_pltfm_priv(pltfm_host);
>> + int ret = 0;
>> +
>> + if (host->mmc->caps2 & MMC_CAP2_CQE) {
>
> It would be nice if this if check was rolled into cqhci_suspend so that
> all the callers wouldn't have to check it.
>
>> + ret = cqhci_suspend(host->mmc);
>> + if (ret)
>> + return ret;
>> + }
>> +
>> + disable_irq(msm_host->pwr_irq);
>
> Why is the irq disabled? Please add a comment.
>

Will add a comment.

During system suspend all SDHC interrupts can be disabled since device
would be

in power down state.

>> + ret = sdhci_suspend_host(host);
>> + if (ret)
>> + return ret;
>> +
>> + return sdhci_msm_runtime_suspend(dev);
>
> pm_runtime_force_suspend() does different things than just call the
> runtime suspend function for the driver. For example, it disables
> runtime PM on the device. Can you explain in the commit text how this
> is
> a correct conversion?
>

Will invoke pm_runtime_force_suspend() here instead of
sdhci_msm_runtime_suspend()

>> +}
>> +
>> +static int sdhci_msm_resume(struct device *dev)
>> +{
>> + struct sdhci_host *host = dev_get_drvdata(dev);
>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>> + struct sdhci_msm_host *msm_host =
>> sdhci_pltfm_priv(pltfm_host);
>> + int ret = 0;
>> +
>> + ret = sdhci_msm_runtime_resume(dev);
>> + if (ret)
>> + return ret;
>> +
>> + ret = sdhci_resume_host(host);
>> + if (ret < 0)
>> + return ret;
>> + enable_irq(msm_host->pwr_irq);
>
> Same question here about irq. Deserves a comment.
>
>> +
>> + if (host->mmc->caps2 & MMC_CAP2_CQE)
>> + ret = cqhci_resume(host->mmc);
>> +
>> + return ret;
>> +}
>> +
>> static const struct dev_pm_ops sdhci_msm_pm_ops = {
>> - SET_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend,
>> - pm_runtime_force_resume)
>> + SET_SYSTEM_SLEEP_PM_OPS(sdhci_msm_suspend,
>> + sdhci_msm_resume)
>> SET_RUNTIME_PM_OPS(sdhci_msm_runtime_suspend,
>> sdhci_msm_runtime_resume,
>> NULL)

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