[PATCH v3] sh_eth: ensure pm_runtime cannot suspend the device during init

[PATCH v3] sh_eth: ensure pm_runtime cannot suspend the device during init

[Ben Dooks]

The pm_rumtime work queue is causing the device to be suspended during
initialisation, thus the initialisation may not be able to access registers
properly. As the code is called from a work queue, it is possible that this
is not seen from certain configurations/builds due to the asynchronos
nature of the code.

Another issue has also been found where the network device registration
calls back into the driver thus causing further pm_runtime calls that
also caused issues with the MDIO bus code.

Use pm_runtime_get_sync() and pm_runtime_put() to ensure that the
pm system does not suspend it during the probe() call and remove the
now unnecessary pm_runtime_resume() call.

This fixes the external abort that can cause /sbin/init or other such
init processed to die.

Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>

---
Cc: sergei.shtylyov@cogentembedded.com
Cc: laurent.pinchart+renesas@ideasonboard.com
cc: netdev@vger.kernel.org

Note, Laurent this should probably be applied before your
current series as it may require changes to the exit sequence.

Fixes from v1:
	- use pm_runtime_put() over pm_runtime_put_sync() as
	  we do not need to guaranteed the device has powered
          off after probe.

Fixed from v2:
	- call pm_runtime_put() in error path
---
 drivers/net/ethernet/renesas/sh_eth.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index 4f76b5e..610da51 100644
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -2841,6 +2841,9 @@ static int sh_eth_drv_probe(struct platform_device *pdev)
 		goto out;
 	}
 
+	pm_runtime_enable(&pdev->dev);
+	pm_runtime_get_sync(&pdev->dev);
+
 	/* The sh Ether-specific entries in the device structure. */
 	ndev->base_addr = res->start;
 	devno = pdev->id;
@@ -2868,8 +2871,6 @@ static int sh_eth_drv_probe(struct platform_device *pdev)
 
 	spin_lock_init(&mdp->lock);
 	mdp->pdev = pdev;
-	pm_runtime_enable(&pdev->dev);
-	pm_runtime_resume(&pdev->dev);
 
 	if (pdev->dev.of_node)
 		pd = sh_eth_parse_dt(&pdev->dev);
@@ -2961,6 +2962,7 @@ static int sh_eth_drv_probe(struct platform_device *pdev)
 	pr_info("Base address at 0x%x, %pM, IRQ %d.\n",
 		(u32)ndev->base_addr, ndev->dev_addr, ndev->irq);
 
+	pm_runtime_put(&pdev->dev);
 	platform_set_drvdata(pdev, ndev);
 
 	return ret;
@@ -2976,6 +2978,7 @@ out_release:
 	if (ndev)
 		free_netdev(ndev);
 
+	pm_runtime_put(&pdev->dev);
 out:
 	return ret;
 }
-- 
1.9.0

Re: [PATCH v3] sh_eth: ensure pm_runtime cannot suspend the device during init

[Laurent Pinchart]

Hi Ben,

Thank you for the patch.

On Thursday 20 March 2014 18:34:37 Ben Dooks wrote:
> The pm_rumtime work queue is causing the device to be suspended during
> initialisation, thus the initialisation may not be able to access registers
> properly. As the code is called from a work queue, it is possible that this
> is not seen from certain configurations/builds due to the asynchronos
> nature of the code.
> 
> Another issue has also been found where the network device registration
> calls back into the driver thus causing further pm_runtime calls that
> also caused issues with the MDIO bus code.
> 
> Use pm_runtime_get_sync() and pm_runtime_put() to ensure that the
> pm system does not suspend it during the probe() call and remove the
> now unnecessary pm_runtime_resume() call.
> 
> This fixes the external abort that can cause /sbin/init or other such
> init processed to die.
> 
> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
> 
> ---
> Cc: sergei.shtylyov@cogentembedded.com
> Cc: laurent.pinchart+renesas@ideasonboard.com
> cc: netdev@vger.kernel.org
> 
> Note, Laurent this should probably be applied before your
> current series as it may require changes to the exit sequence.

Would you like me to include the patch in that series when I'll send a pull 
request ?

> Fixes from v1:
> 	- use pm_runtime_put() over pm_runtime_put_sync() as
> 	  we do not need to guaranteed the device has powered
>           off after probe.
> 
> Fixed from v2:
> 	- call pm_runtime_put() in error path
> ---
>  drivers/net/ethernet/renesas/sh_eth.c | 7 +++++--
>  1 file changed, 5 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/ethernet/renesas/sh_eth.c
> b/drivers/net/ethernet/renesas/sh_eth.c index 4f76b5e..610da51 100644
> --- a/drivers/net/ethernet/renesas/sh_eth.c
> +++ b/drivers/net/ethernet/renesas/sh_eth.c
> @@ -2841,6 +2841,9 @@ static int sh_eth_drv_probe(struct platform_device
> *pdev) goto out;
>  	}
> 
> +	pm_runtime_enable(&pdev->dev);
> +	pm_runtime_get_sync(&pdev->dev);
> +
>  	/* The sh Ether-specific entries in the device structure. */
>  	ndev->base_addr = res->start;
>  	devno = pdev->id;
> @@ -2868,8 +2871,6 @@ static int sh_eth_drv_probe(struct platform_device
> *pdev)
> 
>  	spin_lock_init(&mdp->lock);
>  	mdp->pdev = pdev;
> -	pm_runtime_enable(&pdev->dev);
> -	pm_runtime_resume(&pdev->dev);
> 
>  	if (pdev->dev.of_node)
>  		pd = sh_eth_parse_dt(&pdev->dev);
> @@ -2961,6 +2962,7 @@ static int sh_eth_drv_probe(struct platform_device
> *pdev) pr_info("Base address at 0x%x, %pM, IRQ %d.\n",
>  		(u32)ndev->base_addr, ndev->dev_addr, ndev->irq);
> 
> +	pm_runtime_put(&pdev->dev);
>  	platform_set_drvdata(pdev, ndev);
> 
>  	return ret;
> @@ -2976,6 +2978,7 @@ out_release:
>  	if (ndev)
>  		free_netdev(ndev);
> 
> +	pm_runtime_put(&pdev->dev);

Do we also need a pm_runtime_disable() here ?

>  out:
>  	return ret;
>  }

-- 
Regards,

Laurent Pinchart

Re: [PATCH v3] sh_eth: ensure pm_runtime cannot suspend the device during init

[Sergei Shtylyov]

Hello.

On 03/20/2014 09:01 PM, Laurent Pinchart wrote:

>> The pm_rumtime work queue is causing the device to be suspended during
>> initialisation, thus the initialisation may not be able to access registers
>> properly. As the code is called from a work queue, it is possible that this
>> is not seen from certain configurations/builds due to the asynchronos
>> nature of the code.

>> Another issue has also been found where the network device registration
>> calls back into the driver thus causing further pm_runtime calls that
>> also caused issues with the MDIO bus code.

>> Use pm_runtime_get_sync() and pm_runtime_put() to ensure that the
>> pm system does not suspend it during the probe() call and remove the
>> now unnecessary pm_runtime_resume() call.

>> This fixes the external abort that can cause /sbin/init or other such
>> init processed to die.

>> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
>> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>

>> ---
>> Cc: sergei.shtylyov@cogentembedded.com
>> Cc: laurent.pinchart+renesas@ideasonboard.com
>> cc: netdev@vger.kernel.org

>> Note, Laurent this should probably be applied before your
>> current series as it may require changes to the exit sequence.

> Would you like me to include the patch in that series when I'll send a pull
> request ?

>> Fixes from v1:
>> 	- use pm_runtime_put() over pm_runtime_put_sync() as
>> 	  we do not need to guaranteed the device has powered
>>            off after probe.

>> Fixed from v2:
>> 	- call pm_runtime_put() in error path
>> ---
>>   drivers/net/ethernet/renesas/sh_eth.c | 7 +++++--
>>   1 file changed, 5 insertions(+), 2 deletions(-)

>> diff --git a/drivers/net/ethernet/renesas/sh_eth.c
>> b/drivers/net/ethernet/renesas/sh_eth.c index 4f76b5e..610da51 100644
>> --- a/drivers/net/ethernet/renesas/sh_eth.c
>> +++ b/drivers/net/ethernet/renesas/sh_eth.c
[...]
>> @@ -2976,6 +2978,7 @@ out_release:
>>   	if (ndev)
>>   		free_netdev(ndev);
>>
>> +	pm_runtime_put(&pdev->dev);

> Do we also need a pm_runtime_disable() here ?

    I've looked at other drivers and it looks like we do.

>>   out:
>>   	return ret;
>>   }

WBR, Sergei

Re: [PATCH v3] sh_eth: ensure pm_runtime cannot suspend the device during init

[Ben Dooks]

On 20/03/14 20:09, Sergei Shtylyov wrote:
> Hello.
>
> On 03/20/2014 09:01 PM, Laurent Pinchart wrote:
>
>>> The pm_rumtime work queue is causing the device to be suspended during
>>> initialisation, thus the initialisation may not be able to access
>>> registers
>>> properly. As the code is called from a work queue, it is possible
>>> that this
>>> is not seen from certain configurations/builds due to the asynchronos
>>> nature of the code.
>
>>> Another issue has also been found where the network device registration
>>> calls back into the driver thus causing further pm_runtime calls that
>>> also caused issues with the MDIO bus code.
>
>>> Use pm_runtime_get_sync() and pm_runtime_put() to ensure that the
>>> pm system does not suspend it during the probe() call and remove the
>>> now unnecessary pm_runtime_resume() call.
>
>>> This fixes the external abort that can cause /sbin/init or other such
>>> init processed to die.
>
>>> Signed-off-by: Ben Dooks <ben.dooks@codethink.co.uk>
>>> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
>
>>> ---
>>> Cc: sergei.shtylyov@cogentembedded.com
>>> Cc: laurent.pinchart+renesas@ideasonboard.com
>>> cc: netdev@vger.kernel.org
>
>>> Note, Laurent this should probably be applied before your
>>> current series as it may require changes to the exit sequence.
>
>> Would you like me to include the patch in that series when I'll send a
>> pull
>> request ?
>
>>> Fixes from v1:
>>>     - use pm_runtime_put() over pm_runtime_put_sync() as
>>>       we do not need to guaranteed the device has powered
>>>            off after probe.
>
>>> Fixed from v2:
>>>     - call pm_runtime_put() in error path

Thanks, that looks like another issue that got missed.
I will submit v3


-- 
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius