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Date: Fri, 23 Oct 2015 11:44:18 +0800
From: Shawn Lin <shawn.lin@...k-chips.com>
To: Ulf Hansson <ulf.hansson@...aro.org>
Cc: shawn.lin@...k-chips.com, Michal Simek <michal.simek@...inx.com>,
Soren Brinkmann <soren.brinkmann@...inx.com>,
linux-mmc <linux-mmc@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [RESEND PATCH v4 3/3] mmc: sdhci-of-arasan: add runtime pm
support
On 2015/10/22 20:08, Ulf Hansson wrote:
> On 22 October 2015 at 11:06, Shawn Lin <shawn.lin@...k-chips.com> wrote:
>> This patch add runtime_suspend and runtime_resume for
>> sdhci-of-arasan. Currently we also power-off phy at
>> runtime_suspend for power-saving.
>>
>> Signed-off-by: Shawn Lin <shawn.lin@...k-chips.com>
>>
>> Serise-changes: 4
>> - remove ifdef for PM callback statement
>> - fix missing pm_runtime_set_active
>> - remove pm_runtime_dont_use_autosuspend from remove hook
>> - add pm_runtime_force_suspend|resume for PM callback to
>> deal with suspend invoked from rpm
>> - remove wrappers of phy ops
>>
>> ---
>>
>> Changes in v2: None
>>
>> drivers/mmc/host/sdhci-of-arasan.c | 85 ++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 82 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci-of-arasan.c b/drivers/mmc/host/sdhci-of-arasan.c
>> index 4f30716..fb1915c 100644
>> --- a/drivers/mmc/host/sdhci-of-arasan.c
>> +++ b/drivers/mmc/host/sdhci-of-arasan.c
>> @@ -30,6 +30,8 @@
>> #define CLK_CTRL_TIMEOUT_MASK (0xf << CLK_CTRL_TIMEOUT_SHIFT)
>> #define CLK_CTRL_TIMEOUT_MIN_EXP 13
>>
>> +#define ARASAN_RPM_DELAY_MS 50
>> +
>> /**
>> * struct sdhci_arasan_data
>> * @clk_ahb: Pointer to the AHB clock
>> @@ -71,6 +73,46 @@ static struct sdhci_pltfm_data sdhci_arasan_pdata = {
>> SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN,
>> };
>>
>> +#ifdef CONFIG_PM
>> +static int sdhci_arasan_runtime_suspend(struct device *dev)
>> +{
>> + struct sdhci_host *host = dev_get_drvdata(dev);
>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>> + struct sdhci_arasan_data *sdhci_arasan = pltfm_host->priv;
>> + int ret;
>> +
>> + ret = sdhci_runtime_suspend_host(host);
>> + if (ret)
>> + return ret;
>> +
>> + if (!IS_ERR(sdhci_arasan->phy))
>> + phy_power_off(sdhci_arasan->phy);
>> +
>> + clk_disable(sdhci_arasan->clk_ahb);
>> + clk_disable(pltfm_host->clk);
>
> The above calls can be changed to clk_disable_unprepare(). Vice verse
> in sdhci_arasan_runtime_resume() below.
>
>> +
>> + return 0;
>> +}
>> +
>> +static int sdhci_arasan_runtime_resume(struct device *dev)
>> +{
>> + struct sdhci_host *host = dev_get_drvdata(dev);
>> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
>> + struct sdhci_arasan_data *sdhci_arasan = pltfm_host->priv;
>> +
>> + clk_enable(pltfm_host->clk);
>> + clk_enable(sdhci_arasan->clk_ahb);
>> +
>> + if (!IS_ERR(sdhci_arasan->phy))
>> + phy_power_on(sdhci_arasan->phy);
>> +
>> + return sdhci_runtime_resume_host(host);
>> +}
>> +#else
>> +#define sdhci_arasan_runtime_suspend NULL
>> +#define sdhci_arasan_runtime_resume NULL
>> +#endif
>> +
>> #ifdef CONFIG_PM_SLEEP
>> /**
>> * sdhci_arasan_suspend - Suspend method for the driver
>> @@ -87,6 +129,12 @@ static int sdhci_arasan_suspend(struct device *dev)
>> struct sdhci_arasan_data *sdhci_arasan = pltfm_host->priv;
>> int ret;
>>
>> + ret = pm_runtime_force_suspend(dev);
>> + if (ret) {
>> + dev_err(dev, "problem force suspending\n");
>> + return ret;
>> + }
>> +
>
> I think your are in right track, but unfortunate you still have some
> work to do. :-)
>
> You can't call sdhci_suspend_host() with a runtime suspended host. You
> will for example access sdhci internal registers, even-though the
> clock to the SDHCI controller is gated, which is not a good idea.
>
> Now, this leads me to the following questions/ideas, which I am really
> glad we can bring up within this context.
>
> So, sdhci_suspend_host() and sdhci_runtime_suspend_host() performs
> very similar actions, but not completely the same.
>
> I have a feeling that we might be able to merge the above functions
> into one function. The only thing that may differ between system PM
> and runtime PM, is probably the wakeup settings and since that is
> possible to control before the sdhci variant host driver decide to
> call these functions, merging them might work.
>
>>>From a wakeup point of view, does your case have different settings
> between system PM and runtime PM?
>
> What do you think?
My case doesn't have diff settings between system PM and runtime PM.
If my understanding is proper, I guess you want to remove
sdhci_suspend|resume_host and assign pm_runtime_force_suspend|resume to
SET_SYSTEM_SLEEP_PM_OPS directly by sdhci variant HCs?
If that is the case, I guess we should look more precisely into other
sdhci variant HCs to check whether they need to do diff things for
system PM and RPM or not.
>
>> ret = sdhci_suspend_host(host);
>> if (ret)
>> return ret;
>> @@ -140,18 +188,39 @@ static int sdhci_arasan_resume(struct device *dev)
>> }
>> }
>>
>> - return sdhci_resume_host(host);
>> + ret = sdhci_resume_host(host);
>> + if (ret)
>> + goto err_resume_host;
>> +
>> + ret = pm_runtime_force_resume(dev);
>> + if (ret) {
>> + dev_err(dev, "problem force resuming\n");
>> + goto err_force_resume;
>> + }
>> +
>> + return 0;
>>
>> +err_force_resume:
>> + sdhci_suspend_host(host);
>> +err_resume_host:
>> + if (!IS_ERR(sdhci_arasan->phy))
>> + phy_power_off(sdhci_arasan->phy);
>> err_phy_power:
>> clk_disable(pltfm_host->clk);
>> err_clk_en:
>> clk_disable(sdhci_arasan->clk_ahb);
>> return ret;
>> }
>> +#else
>> +#define sdhci_arasan_suspend NULL
>> +#define sdhci_arasan_resume NULL
>> #endif /* ! CONFIG_PM_SLEEP */
>>
>> -static SIMPLE_DEV_PM_OPS(sdhci_arasan_dev_pm_ops, sdhci_arasan_suspend,
>> - sdhci_arasan_resume);
>> +static const struct dev_pm_ops sdhci_arasan_dev_pm_ops = {
>> + SET_SYSTEM_SLEEP_PM_OPS(sdhci_arasan_suspend, sdhci_arasan_resume)
>> + SET_RUNTIME_PM_OPS(sdhci_arasan_runtime_suspend,
>> + sdhci_arasan_runtime_resume, NULL)
>> +};
>>
>> static int sdhci_arasan_probe(struct platform_device *pdev)
>> {
>> @@ -237,6 +306,12 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>> }
>> }
>>
>> + pm_runtime_set_active(&pdev->dev);
>> + pm_runtime_set_autosuspend_delay(&pdev->dev, ARASAN_RPM_DELAY_MS);
>> + pm_runtime_use_autosuspend(&pdev->dev);
>> + pm_runtime_enable(&pdev->dev);
>> + pm_suspend_ignore_children(&pdev->dev, 1);
>> +
>> ret = sdhci_add_host(host);
>> if (ret)
>> goto err_pltfm_free;
>> @@ -244,6 +319,7 @@ static int sdhci_arasan_probe(struct platform_device *pdev)
>> return 0;
>>
>> err_pltfm_free:
>> + pm_runtime_disable(&pdev->dev);
>> sdhci_pltfm_free(pdev);
>> err_phy_power:
>> if (!IS_ERR(sdhci_arasan->phy))
>> @@ -265,6 +341,9 @@ static int sdhci_arasan_remove(struct platform_device *pdev)
>> if (!IS_ERR(sdhci_arasan->phy))
>> phy_exit(sdhci_arasan->phy);
>>
>> + pm_runtime_get_sync(&pdev->dev);
>> + pm_runtime_disable(&pdev->dev);
>> +
>
> I think a pm_runtime_put_noidle() would be good as well, since it
> restores the usage counter.
>
>> clk_disable_unprepare(sdhci_arasan->clk_ahb);
>>
>> return sdhci_pltfm_unregister(pdev);
>> --
>> 2.3.7
>>
>>
>
> Kind regards
> Uffe
> --
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>
>
--
Best Regards
Shawn Lin
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