On Thursday, May 05, 2011, Guennadi Liakhovetski wrote:
> Adding support for runtime power-management to the MMCIF driver allows
> it to save power as long as no card is present. To also allow to turn
> off the power domain at that time, we release DMA channels during that
> time, since on some sh-mobile systems the DMA controller(s) and the
> MMCIF block belong to the same power domain. System-wide power
> management has been tested with experimental PM patches on AP4-based
> systems.
>
> Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
> ---
>
> This patch supersedes:
>
> [PATCH 2/3 v3] MMC: add runtime and system power-management support to the MMCIF driver
>
> and has been tested to work with Rafael's suspend git-tree, power-domains
> branch.
>
> drivers/mmc/host/sh_mmcif.c | 78 ++++++++++++++++++++++++++++++++++++++-----
> 1 files changed, 69 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/mmc/host/sh_mmcif.c b/drivers/mmc/host/sh_mmcif.c
> index d3871b6..14f8edb 100644
> --- a/drivers/mmc/host/sh_mmcif.c
> +++ b/drivers/mmc/host/sh_mmcif.c
> @@ -29,6 +29,7 @@
> #include <linux/mmc/sh_mmcif.h>
> #include <linux/pagemap.h>
> #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
> #include <linux/spinlock.h>
>
> #define DRIVER_NAME "sh_mmcif"
> @@ -173,6 +174,7 @@ struct sh_mmcif_host {
> struct completion intr_wait;
> enum mmcif_state state;
> spinlock_t lock;
> + bool power;
>
> /* DMA support */
> struct dma_chan *chan_rx;
> @@ -877,11 +879,24 @@ static void sh_mmcif_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> if (ios->power_mode == MMC_POWER_UP) {
> if (p->set_pwr)
> p->set_pwr(host->pd, ios->power_mode);
> + if (!host->power) {
> + /* See if we also get DMA */
> + sh_mmcif_request_dma(host, host->pd->dev.platform_data);
> + pm_runtime_get_sync(&host->pd->dev);
> + host->power = true;
> + }
> } else if (ios->power_mode == MMC_POWER_OFF || !ios->clock) {
> /* clock stop */
> sh_mmcif_clock_control(host, 0);
> - if (ios->power_mode == MMC_POWER_OFF && p->down_pwr)
> - p->down_pwr(host->pd);
> + if (ios->power_mode == MMC_POWER_OFF) {
> + if (host->power) {
> + pm_runtime_put(&host->pd->dev);
> + sh_mmcif_release_dma(host);
> + host->power = false;
> + }
> + if (p->down_pwr)
> + p->down_pwr(host->pd);
> + }
> host->state = STATE_IDLE;
> return;
> }
> @@ -957,7 +972,7 @@ static irqreturn_t sh_mmcif_intr(int irq, void *dev_id)
> sh_mmcif_bitclr(host, MMCIF_CE_INT_MASK, state);
> err = 1;
> } else {
> - dev_dbg(&host->pd->dev, "Not support int\n");
> + dev_dbg(&host->pd->dev, "Unsupported interrupt: 0x%x\n", state);
> sh_mmcif_writel(host->addr, MMCIF_CE_INT, ~state);
> sh_mmcif_bitclr(host, MMCIF_CE_INT_MASK, state);
> err = 1;
> @@ -1053,8 +1068,12 @@ static int __devinit sh_mmcif_probe(struct platform_device *pdev)
> sh_mmcif_sync_reset(host);
> platform_set_drvdata(pdev, host);
>
> - /* See if we also get DMA */
> - sh_mmcif_request_dma(host, pd);
> + pm_runtime_enable(&pdev->dev);
> + host->power = false;
> +
> + ret = pm_runtime_resume(&pdev->dev);
> + if (ret < 0)
> + goto clean_up2;
>
> mmc_add_host(mmc);
>
> @@ -1063,13 +1082,13 @@ static int __devinit sh_mmcif_probe(struct platform_device *pdev)
> ret = request_irq(irq[0], sh_mmcif_intr, 0, "sh_mmc:error", host);
> if (ret) {
> dev_err(&pdev->dev, "request_irq error (sh_mmc:error)\n");
> - goto clean_up2;
> + goto clean_up3;
> }
> ret = request_irq(irq[1], sh_mmcif_intr, 0, "sh_mmc:int", host);
> if (ret) {
> free_irq(irq[0], host);
> dev_err(&pdev->dev, "request_irq error (sh_mmc:int)\n");
> - goto clean_up2;
> + goto clean_up3;
> }
>
> sh_mmcif_detect(host->mmc);
> @@ -1079,7 +1098,11 @@ static int __devinit sh_mmcif_probe(struct platform_device *pdev)
> sh_mmcif_readl(host->addr, MMCIF_CE_VERSION) & 0x0000ffff);
> return ret;
>
> +clean_up3:
> + mmc_remove_host(mmc);
> + pm_runtime_suspend(&pdev->dev);
> clean_up2:
> + pm_runtime_disable(&pdev->dev);
> clk_disable(host->hclk);
> clean_up1:
> mmc_free_host(mmc);
> @@ -1094,9 +1117,9 @@ static int __devexit sh_mmcif_remove(struct platform_device *pdev)
> struct sh_mmcif_host *host = platform_get_drvdata(pdev);
> int irq[2];
>
> - mmc_remove_host(host->mmc);
> - sh_mmcif_release_dma(host);
> + pm_runtime_get_sync(&pdev->dev);
>
> + mmc_remove_host(host->mmc);
> sh_mmcif_writel(host->addr, MMCIF_CE_INT_MASK, MASK_ALL);
>
> if (host->addr)
> @@ -1112,15 +1135,52 @@ static int __devexit sh_mmcif_remove(struct platform_device *pdev)
>
> clk_disable(host->hclk);
> mmc_free_host(host->mmc);
> + pm_runtime_put_sync(&pdev->dev);
> + pm_runtime_disable(&pdev->dev);
>
> return 0;
> }
>
> +#ifdef CONFIG_PM
> +static int sh_mmcif_suspend(struct device *dev)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct sh_mmcif_host *host = platform_get_drvdata(pdev);
> + int ret = mmc_suspend_host(host->mmc);
> +
> + if (!ret) {
> + sh_mmcif_writel(host->addr, MMCIF_CE_INT_MASK, MASK_ALL);
> + clk_disable(host->hclk);
> + }
> +
> + return ret;
> +}
> +
> +static int sh_mmcif_resume(struct device *dev)
> +{
> + struct platform_device *pdev = to_platform_device(dev);
> + struct sh_mmcif_host *host = platform_get_drvdata(pdev);
> +
> + clk_enable(host->hclk);
> +
> + return mmc_resume_host(host->mmc);
> +}
> +#else
> +#define sh_mmcif_suspend NULL
> +#define sh_mmcif_resume NULL
> +#endif /* CONFIG_PM */
> +
> +static const struct dev_pm_ops sh_mmcif_dev_pm_ops = {
> + .suspend = sh_mmcif_suspend,
> + .resume = sh_mmcif_resume,
> +};
So this means the driver only has system-wide suspend/resume callbacks.
I guess hibernation is not supported by the target platform(s) yet, so
the freeze/thaw etc. callbacks are not necessary at the moment, but in case
they are supposed to be the same as the suspend/resume ones, it wouldn't
hurt to use SET_SYSTEM_SLEEP_PM_OPS (as defined in include/linux/pm.h).
Also, runtime PM callbacks are not present. Is it intentional? I thought
they would be necessary to save/restore the device state over the power
domain power down/power up, wouldn't they?
> +
> static struct platform_driver sh_mmcif_driver = {
> .probe = sh_mmcif_probe,
> .remove = sh_mmcif_remove,
> .driver = {
> .name = DRIVER_NAME,
> + .pm = &sh_mmcif_dev_pm_ops,
> },
> };
Thanks,
Rafael
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