On 26 February 2015 at 11:26, Geert Uytterhoeven
<geert+renesas@xxxxxxxxx> wrote:
> During system reboot, the sh-dma-engine device may be runtime-suspended,
> causing a crash:
>
> Unhandled fault: imprecise external abort (0x1406) at 0x0002c02c
> Internal error: : 1406 [#1] SMP ARM
> ...
> PC is at sh_dmae_ctl_stop+0x28/0x64
> LR is at sh_dmae_ctl_stop+0x24/0x64
>
> If the sh-dma-engine is runtime-suspended, its module clock is turned
> off, and its registers cannot be accessed.
>
> To fix this, move the call to sh_dmae_ctl_stop(), which touches the
> DMAOR register, to the sh_dmae_suspend() and sh_dmae_runtime_suspend()
> callbacks. This makes PM operations more symmetric, as both
> sh_dmae_resume() and sh_dmae_runtime_resume() already call sh_dmae_rst()
> to re-initialize the DMAOR register.
>
> Remove sh_dmae_shutdown(), as it became empty.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Reviewed-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
Kind regards
Uffe
> ---
> This is v3 of "dmaengine: shdma: Runtime-resume device in .shutdown()"
>
> v3:
> - Move the call to sh_dmae_ctl_stop() to sh_dmae_suspend() and
> sh_dmae_runtime_suspend() instead of runtime-resuming the device in
> .shutdown(),
>
> v2:
> - Do nothing if we're runtime suspended.
> ---
> drivers/dma/sh/shdmac.c | 15 +++++++--------
> 1 file changed, 7 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/dma/sh/shdmac.c b/drivers/dma/sh/shdmac.c
> index b2431aa300331270..9f1d4c7dbab83890 100644
> --- a/drivers/dma/sh/shdmac.c
> +++ b/drivers/dma/sh/shdmac.c
> @@ -582,15 +582,12 @@ static void sh_dmae_chan_remove(struct sh_dmae_device *shdev)
> }
> }
>
> -static void sh_dmae_shutdown(struct platform_device *pdev)
> -{
> - struct sh_dmae_device *shdev = platform_get_drvdata(pdev);
> - sh_dmae_ctl_stop(shdev);
> -}
> -
> #ifdef CONFIG_PM
> static int sh_dmae_runtime_suspend(struct device *dev)
> {
> + struct sh_dmae_device *shdev = dev_get_drvdata(dev);
> +
> + sh_dmae_ctl_stop(shdev);
> return 0;
> }
>
> @@ -605,6 +602,9 @@ static int sh_dmae_runtime_resume(struct device *dev)
> #ifdef CONFIG_PM_SLEEP
> static int sh_dmae_suspend(struct device *dev)
> {
> + struct sh_dmae_device *shdev = dev_get_drvdata(dev);
> +
> + sh_dmae_ctl_stop(shdev);
> return 0;
> }
>
> @@ -929,13 +929,12 @@ static int sh_dmae_remove(struct platform_device *pdev)
> }
>
> static struct platform_driver sh_dmae_driver = {
> - .driver = {
> + .driver = {
> .pm = &sh_dmae_pm,
> .name = SH_DMAE_DRV_NAME,
> .of_match_table = sh_dmae_of_match,
> },
> .remove = sh_dmae_remove,
> - .shutdown = sh_dmae_shutdown,
> };
>
> static int __init sh_dmae_init(void)
> --
> 1.9.1
>
--
To unsubscribe from this list: send the line "unsubscribe dmaengine" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
