答复: [PATCH v2 3/5] mmc: mediatek: Add PM support for MMC driver
Chaotian Jing (井朝天)
Chaotian.Jing at mediatek.com
Fri Apr 3 01:27:45 PDT 2015
Dear Ulf,
Thanks for your review,
Please help to check my comments:
> -----邮件原件-----
> 发件人: Ulf Hansson [mailto:ulf.hansson at linaro.org]
> 发送时间: 2015年3月31日 22:47
> 收件人: Chaotian Jing (井朝天)
> 抄送: Rob Herring; Matthias Brugger; Chris Ball; Mark Rutland; JamesJJ Liao
> (廖建智); srv_heupstream; Arnd Bergmann; devicetree at vger.kernel.org;
> HONGZHOU Yang; Catalin Marinas; linux-mmc; Will Deacon;
> linux-kernel at vger.kernel.org; linux-gpio at vger.kernel.org; Sascha Hauer;
> Yingjoe Chen (陳英洲); Eddie Huang (黃智傑); Bin Zhang (章斌);
> linux-arm-kernel at lists.infradead.org; linux-mediatek at lists.infradead.org
> 主题: Re: [PATCH v2 3/5] mmc: mediatek: Add PM support for MMC driver
>
> On 17 March 2015 at 04:13, Chaotian Jing <chaotian.jing at mediatek.com>
> wrote:
> > Add PM support for Mediatek MMC driver
> >
> > Signed-off-by: Chaotian Jing <chaotian.jing at mediatek.com>
> > ---
> > drivers/mmc/host/mtk-sd.c | 94
> > ++++++++++++++++++++++++++++++++++++++++++++++-
> > 1 file changed, 93 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> > index 86c999b..e02f6a6 100644
> > --- a/drivers/mmc/host/mtk-sd.c
> > +++ b/drivers/mmc/host/mtk-sd.c
> > @@ -21,6 +21,7 @@
> > #include <linux/of_irq.h>
> > #include <linux/of_gpio.h>
> > #include <linux/platform_device.h>
> > +#include <linux/pm_runtime.h>
> > #include <linux/regulator/consumer.h> #include <linux/spinlock.h>
> >
> > @@ -223,6 +224,7 @@
> > #define MSDC_OCR_AVAIL (MMC_VDD_28_29 | MMC_VDD_29_30
> \
> > | MMC_VDD_30_31 | MMC_VDD_31_32 |
> MMC_VDD_32_33)
> >
> > +#define MTK_MMC_AUTOSUSPEND_DELAY 500
> > #define CMD_TIMEOUT (HZ/10 * 5) /* 100ms x5 */
> > #define DAT_TIMEOUT (HZ * 5) /* 1000ms x5 */
> >
> > @@ -535,6 +537,38 @@ static void msdc_set_mclk(struct msdc_host *host,
> int ddr, u32 hz)
> > dev_dbg(host->dev, "sclk: %d, ddr: %d\n", host->sclk, ddr); }
> >
> > +#ifdef CONFIG_PM
>
> I suggest you move this complete code snippets within the ifdefs for where the
> runtime PM callbacks is implemented.
>
I will remove the CONFIG_PM, because that if the kernel config do not enable CONFIG_PM, it still need do gate/ungate clock.
> > +static int msdc_gate_clock(struct msdc_host *host) {
> > + int ret = 0;
> > + unsigned long flags;
> > +
> > + spin_lock_irqsave(&host->lock, flags);
> > + /* disable SD/MMC/SDIO bus clock */
> > + sdr_set_field(host->base + MSDC_CFG, MSDC_CFG_MODE,
> MSDC_MS);
>
> This seems like it also belongs in the ->set_ios() function, when the rate
> requested by the core is zero!? Maybe that's already dealt with?
Yes, but it is not the same, the set_ios() set the bus clock to 0, only need set the MODE to MSDC_MS.
But the gate clock will gate the source clock of MSDC host, when the host is idle, runtime pm will gate it, but the ios->clock is not 0.
>
> > + /* turn off SDHC functional clock */
> > + clk_disable(host->src_clk);
>
> Change to clk_disable_unprepare() and move it outside the spin_lock.
>
OK, will fix it at next revision.
> > + spin_unlock_irqrestore(&host->lock, flags);
> > + return ret;
> > +}
> > +
> > +static void msdc_ungate_clock(struct msdc_host *host) {
> > + unsigned long flags;
> > +
> > + spin_lock_irqsave(&host->lock, flags);
> > + clk_enable(host->src_clk);
>
> Change to clk_prepare_enable() and move it outside the spin_lock.
>
OK, will fix it at next revision,
> > + /* enable SD/MMC/SDIO bus clock:
> > + * it will be automatically gated when the bus is idle
> > + * (set MSDC_CFG_CKPDN bit to have it always on)
> > + */
> > + sdr_set_field(host->base + MSDC_CFG, MSDC_CFG_MODE,
> MSDC_SDMMC);
> > + while (!(readl(host->base + MSDC_CFG) & MSDC_CFG_CKSTB))
> > + cpu_relax();
>
> I guess you already have this piece of code in ->set_ios() in some form!?
>
> What's missing here is a kind of a save/restore mechanism of the clock. You
> need to save the value for the clock in msdc_ungate_clock() and restore the
> clock here. Else you might end up ungating the clock when it actually should
> remain gated.
>
When we ungate the clock or change the frequency of the clock, both need wait the clock stable.
> > + spin_unlock_irqrestore(&host->lock, flags); } #endif
> > +
> > static inline u32 msdc_cmd_find_resp(struct msdc_host *host,
> > struct mmc_request *mrq, struct mmc_command *cmd)
> {
> > @@ -702,6 +736,9 @@ static void msdc_request_done(struct msdc_host
> *host, struct mmc_request *mrq)
> > if (mrq->data)
> > msdc_unprepare_data(host, mrq);
> > mmc_request_done(host->mmc, mrq);
> > +
> > + pm_runtime_mark_last_busy(host->dev);
> > + pm_runtime_put_autosuspend(host->dev);
> > }
> >
> > /* returns true if command is fully handled; returns false otherwise
> > */ @@ -863,6 +900,8 @@ static void msdc_ops_request(struct mmc_host
> *mmc, struct mmc_request *mrq)
> > }
> > spin_unlock_irqrestore(&host->lock, flags);
> >
> > + pm_runtime_get_sync(host->dev);
> > +
> > if (mrq->data)
> > msdc_prepare_data(host, mrq);
> >
> > @@ -1003,6 +1042,8 @@ static int msdc_ops_switch_volt(struct mmc_host
> > *mmc, struct mmc_ios *ios)
> >
> > if (!IS_ERR(mmc->supply.vqmmc)) {
> >
> > + pm_runtime_get_sync(host->dev);
> > +
> > if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330) {
> > min_uv = 3300000;
> > max_uv = 3300000; @@ -1011,6 +1052,9 @@
> static
> > int msdc_ops_switch_volt(struct mmc_host *mmc, struct mmc_ios *ios)
> > max_uv = 1800000;
> > } else {
> > dev_err(host->dev, "Unsupported signal
> > voltage!\n");
> > +
> > + pm_runtime_mark_last_busy(host->dev);
> > + pm_runtime_put_autosuspend(host->dev);
> > return -EINVAL;
>
> I suggest to assign a local "ret" variable which value you can return at the end
> of this function. Thus you won't need to duplicate the
> pm_runtime*() calls.
>
OK, will fix at next revision.
> > }
> >
> > @@ -1022,6 +1066,8 @@ static int msdc_ops_switch_volt(struct mmc_host
> *mmc, struct mmc_ios *ios)
> > }
> > }
> >
> > + pm_runtime_mark_last_busy(host->dev);
> > + pm_runtime_put_autosuspend(host->dev);
> > return ret;
> > }
> >
> > @@ -1186,6 +1232,8 @@ static void msdc_ops_set_ios(struct mmc_host
> *mmc, struct mmc_ios *ios)
> > int ret;
> > u32 ddr = 0;
> >
> > + pm_runtime_get_sync(host->dev);
> > +
> > if (ios->timing == MMC_TIMING_UHS_DDR50)
> > ddr = 1;
> >
> > @@ -1230,6 +1278,9 @@ static void msdc_ops_set_ios(struct mmc_host
> > *mmc, struct mmc_ios *ios)
> >
> > if (host->mclk != ios->clock || host->ddr != ddr)
> > msdc_set_mclk(host, ddr, ios->clock);
> > +
> > + pm_runtime_mark_last_busy(host->dev);
> > + pm_runtime_put_autosuspend(host->dev);
> > }
> >
> > static struct mmc_host_ops mt_msdc_ops = { @@ -1341,6 +1392,11 @@
> > static int msdc_drv_probe(struct platform_device *pdev)
> > platform_set_drvdata(pdev, mmc);
> > clk_prepare(host->src_clk);
> >
> > + pm_runtime_enable(host->dev);
> > + pm_runtime_get_sync(host->dev);
> > + pm_runtime_set_autosuspend_delay(host->dev,
> MTK_MMC_AUTOSUSPEND_DELAY);
> > + pm_runtime_use_autosuspend(host->dev);
>
> This shall be changed to the following:
>
Ok, will fix it.
> pm_runtime_set_active();
> pm_runtime_set_autosuspend_delay(host->dev,
> MTK_MMC_AUTOSUSPEND_DELAY);
> pm_runtime_use_autosuspend(host->dev);
> pm_runtime_enable(host->dev);
>
> ... and to simplify error handling, move it just prior mmc_add_host().
>
Will fix it at next revision.
> > +
> > ret = devm_request_irq(&pdev->dev, (unsigned int) host->irq,
> msdc_irq,
> > IRQF_TRIGGER_LOW | IRQF_ONESHOT, pdev->name,
> host);
> > if (ret)
> > @@ -1348,10 +1404,15 @@ static int msdc_drv_probe(struct
> > platform_device *pdev)
> >
> > ret = mmc_add_host(mmc);
> > if (ret)
> > - goto release;
> > + goto end;
> >
> > + pm_runtime_mark_last_busy(host->dev);
> > + pm_runtime_put_autosuspend(host->dev);
>
> According to above, remove these pm_runtime_*() calls.
>
Okay.
> > return 0;
> >
> > +end:
> > + pm_runtime_put_sync(host->dev);
>
> According to above, remove the pm_runtime_put_sync().
> Will remove it at next revision,
> > + pm_runtime_disable(host->dev);
> > release:
> > platform_set_drvdata(pdev, NULL);
> > msdc_deinit_hw(host);
> > @@ -1364,6 +1425,7 @@ release_mem:
> > dma_free_coherent(&pdev->dev,
> > MAX_BD_NUM * sizeof(struct
> mt_bdma_desc),
> > host->dma.bd, host->dma.bd_addr);
> > +
> > host_free:
> > mmc_free_host(mmc);
> >
> > @@ -1378,10 +1440,14 @@ static int msdc_drv_remove(struct
> platform_device *pdev)
> > mmc = platform_get_drvdata(pdev);
> > host = mmc_priv(mmc);
> >
> > + pm_runtime_get_sync(host->dev);
> > +
> > platform_set_drvdata(pdev, NULL);
> > mmc_remove_host(host->mmc);
> > msdc_deinit_hw(host);
> >
> > + pm_runtime_put_sync(host->dev);
>
> Change to pm_runtime_put_noidle() and reverse the order of the call to
> pm_runtime_disable().
>
Ok. Will fix it at next revision,
> > + pm_runtime_disable(host->dev);
> > dma_free_coherent(&pdev->dev,
> > MAX_GPD_NUM * sizeof(struct
> mt_gpdma_desc),
> > host->dma.gpd, host->dma.gpd_addr); @@
> -1393,6
> > +1459,31 @@ static int msdc_drv_remove(struct platform_device *pdev)
> > return 0;
> > }
> >
> > +#ifdef CONFIG_PM
> > +static int msdc_runtime_suspend(struct device *dev) {
> > + int ret = 0;
> > + struct mmc_host *mmc = dev_get_drvdata(dev);
> > + struct msdc_host *host = mmc_priv(mmc);
> > +
> > + ret = msdc_gate_clock(host);
> > + return ret;
> > +}
> > +
> > +static int msdc_runtime_resume(struct device *dev) {
> > + struct mmc_host *mmc = dev_get_drvdata(dev);
> > + struct msdc_host *host = mmc_priv(mmc);
> > +
> > + msdc_ungate_clock(host);
> > + return 0;
> > +}
> > +#endif
> > +
> > +static const struct dev_pm_ops msdc_dev_pm_ops = {
> > + SET_RUNTIME_PM_OPS(msdc_runtime_suspend,
> msdc_runtime_resume,
> > +NULL) };
> > +
> > static const struct of_device_id msdc_of_ids[] = {
> > { .compatible = "mediatek,mt8135-mmc", },
> > {}
> > @@ -1404,6 +1495,7 @@ static struct platform_driver mt_msdc_driver = {
> > .driver = {
> > .name = "mtk-msdc",
> > .of_match_table = msdc_of_ids,
> > + .pm = &msdc_dev_pm_ops,
> > },
> > };
> >
> > --
> > 1.8.1.1.dirty
> >
>
> Kind regards
> Uffe
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