Re: [PATCH v3 1/2] mmc: sdhci: fix abort due to missing runtime PM

[Dong Aisheng <b29396@freescale.com>]

On Thu, May 21, 2015 at 09:15:03AM +0200, Stefan Agner wrote:
> When using i.MX ESDHC driver, while entering suspend while the device
> is in runtime PM, the sdhci_(suspend|resume)_host function are called
> with disabled clocks. Since this functions access the SDHC host
> registers, this leads to an external abort on Vybrid SoC:
> 
> [   37.772967] Unhandled fault: imprecise external abort (0x1c06) at 0x76f5f000
> [   37.780304] Internal error: : 1c06 [#1] ARM
> [   37.784670] Modules linked in:
> [   37.787908] CPU: 0 PID: 428 Comm: sh Not tainted 3.18.0-rc5-00119-geefd097-dirty #1540
> [   37.796142] task: 8e246c00 ti: 8ca6c000 task.ti: 8ca6c000
> [   37.801785] PC is at esdhc_writel_le+0x40/0xec
> [   37.806431] LR is at sdhci_set_card_detection+0xe0/0xe4
> [   37.811877] pc : [<803f0584>]    lr : [<803eaaa0>]    psr: 400f0013
> [   37.811877] sp : 8ca6dd28  ip : 00000001  fp : 8ca6dd3c
> [   37.823766] r10: 807a233c  r9 : 00000000  r8 : 8e8b7210
> [   37.829194] r7 : 802d8a08  r6 : 8082e928  r5 : 00000000  r4 : 00000002
> [   37.835974] r3 : 8ea34e90  r2 : 00000038  r1 : 00000000  r0 : 8ea32ac0
> ...
> 
> Clocks need to be enabled to access the registers. Fix the issue by
> add runtime PM enabled pltfm implementation of suspend/resume which
> take care of clocks by using the runtime PM API properly.
> 
> Signed-off-by: Stefan Agner <stefan@agner.ch>
> ---
> Changes since v2:
> - Implement a generic pltfm suspend/resume function instead of a local
>   function in sdhci-esdhc-imx.c
> - Convert sdhci-pxav3 to use the runtime PM enabled pltfm suspend/resume
>   function too
> 
>  drivers/mmc/host/sdhci-esdhc-imx.c |  2 +-
>  drivers/mmc/host/sdhci-pltfm.c     | 36 ++++++++++++++++++++++++++++++++++++
>  drivers/mmc/host/sdhci-pltfm.h     |  2 ++
>  3 files changed, 39 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/mmc/host/sdhci-esdhc-imx.c b/drivers/mmc/host/sdhci-esdhc-imx.c
> index 82f512d..7b7b3a3 100644
> --- a/drivers/mmc/host/sdhci-esdhc-imx.c
> +++ b/drivers/mmc/host/sdhci-esdhc-imx.c
> @@ -1132,7 +1132,7 @@ static int sdhci_esdhc_runtime_resume(struct device *dev)
>  #endif
>  
>  static const struct dev_pm_ops sdhci_esdhc_pmops = {
> -	SET_SYSTEM_SLEEP_PM_OPS(sdhci_pltfm_suspend, sdhci_pltfm_resume)
> +	SET_SYSTEM_SLEEP_PM_OPS(sdhci_pltfm_rpm_suspend, sdhci_pltfm_rpm_resume)
>  	SET_RUNTIME_PM_OPS(sdhci_esdhc_runtime_suspend,
>  				sdhci_esdhc_runtime_resume, NULL)
>  };
> diff --git a/drivers/mmc/host/sdhci-pltfm.c b/drivers/mmc/host/sdhci-pltfm.c
> index a207f5a..38c03cd 100644
> --- a/drivers/mmc/host/sdhci-pltfm.c
> +++ b/drivers/mmc/host/sdhci-pltfm.c
> @@ -31,6 +31,7 @@
>  #include <linux/err.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> +#include <linux/pm_runtime.h>
>  #ifdef CONFIG_PPC
>  #include <asm/machdep.h>
>  #endif
> @@ -256,6 +257,41 @@ const struct dev_pm_ops sdhci_pltfm_pmops = {
>  	.resume		= sdhci_pltfm_resume,
>  };
>  EXPORT_SYMBOL_GPL(sdhci_pltfm_pmops);
> +
> +int sdhci_pltfm_rpm_suspend(struct device *dev)

Why invent a new API?
Can't put into sdhci_pltfm_suspend?

Regards
Dong Aisheng

> +{
> +	int ret;
> +	struct sdhci_host *host = dev_get_drvdata(dev);
> +
> +	pm_runtime_get_sync(dev);
> +	ret = sdhci_suspend_host(host);
> +	pm_runtime_mark_last_busy(dev);
> +	pm_runtime_put_autosuspend(dev);
> +	if (ret)
> +		return ret;
> +
> +	return pm_runtime_force_suspend(dev);
> +}
> +EXPORT_SYMBOL_GPL(sdhci_pltfm_rpm_suspend);
> +
> +int sdhci_pltfm_rpm_resume(struct device *dev)
> +{
> +	int ret;
> +	struct sdhci_host *host = dev_get_drvdata(dev);
> +
> +	ret = pm_runtime_force_resume(dev);
> +
> +	if (ret)
> +		return ret;
> +
> +	pm_runtime_get_sync(dev);
> +	ret = sdhci_resume_host(host);
> +	pm_runtime_mark_last_busy(dev);
> +	pm_runtime_put_autosuspend(dev);
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(sdhci_pltfm_rpm_resume);
>  #endif	/* CONFIG_PM */
>  
>  static int __init sdhci_pltfm_drv_init(void)
> diff --git a/drivers/mmc/host/sdhci-pltfm.h b/drivers/mmc/host/sdhci-pltfm.h
> index 04bc248..ac5f6ea 100644
> --- a/drivers/mmc/host/sdhci-pltfm.h
> +++ b/drivers/mmc/host/sdhci-pltfm.h
> @@ -114,6 +114,8 @@ static inline void *sdhci_pltfm_priv(struct sdhci_pltfm_host *host)
>  extern int sdhci_pltfm_suspend(struct device *dev);
>  extern int sdhci_pltfm_resume(struct device *dev);
>  extern const struct dev_pm_ops sdhci_pltfm_pmops;
> +extern int sdhci_pltfm_rpm_suspend(struct device *dev);
> +extern int sdhci_pltfm_rpm_resume(struct device *dev);
>  #define SDHCI_PLTFM_PMOPS (&sdhci_pltfm_pmops)
>  #else
>  #define SDHCI_PLTFM_PMOPS NULL
> -- 
> 2.4.1
>