[PATCH] dmaengine: shdma: Move DMA stop to (runtime) suspend callbacks

[PATCH] dmaengine: shdma: Move DMA stop to (runtime) suspend callbacks

[Geert Uytterhoeven]

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@glider.be>
---
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

Re: [PATCH] dmaengine: shdma: Move DMA stop to (runtime) suspend callbacks

[Sergei Shtylyov]

Hello.

On 02/26/2015 01:26 PM, Geert Uytterhoeven 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@glider.be>
> ---
> 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
[...]
> @@ -929,13 +929,12 @@ static int sh_dmae_remove(struct platform_device *pdev)
>   }
>
>   static struct platform_driver sh_dmae_driver = {
> -	.driver 	= {
> +	.driver		= {

    Hm, don't understand what was changed on this line...

WBR, Sergei

Re: [PATCH] dmaengine: shdma: Move DMA stop to (runtime) suspend callbacks

[Geert Uytterhoeven]

On Thu, Feb 26, 2015 at 2:21 PM, Sergei Shtylyov
<sergei.shtylyov@cogentembedded.com> wrote:
>>   static struct platform_driver sh_dmae_driver = {
>> -       .driver         = {
>> +       .driver         = {
>
>
>    Hm, don't understand what was changed on this line...

One silly space that should have been a TAB.

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH] dmaengine: shdma: Move DMA stop to (runtime) suspend callbacks

[Ulf Hansson]

On 26 February 2015 at 11:26, Geert Uytterhoeven
<geert+renesas@glider.be> 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@glider.be>

Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>

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
>

Re: [PATCH] dmaengine: shdma: Move DMA stop to (runtime) suspend callbacks

[Vinod Koul]

On Thu, Feb 26, 2015 at 11:26:34AM +0100, Geert Uytterhoeven 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@glider.be>
Applied, thanks

-- 
~Vinod