[PATCH v4] remoteproc: stm32: fix probe error case

[PATCH v4] remoteproc: stm32: fix probe error case

[Fabien Dessenne]

If the rproc driver is probed before the mailbox driver and if the rproc
Device Tree node has some mailbox properties, the rproc driver probe
shall be deferred instead of being probed without mailbox support.

Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
---
Changes since v3: on error, free mailboxes from stm32_rproc_request_mbox()
Changes since v2: free other requested mailboxes after one request fails
Changes since v1: test IS_ERR() before checking PTR_ERR()
---
 drivers/remoteproc/stm32_rproc.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
index 2cf4b29..bcebb78 100644
--- a/drivers/remoteproc/stm32_rproc.c
+++ b/drivers/remoteproc/stm32_rproc.c
@@ -310,11 +310,12 @@ static const struct stm32_mbox stm32_rproc_mbox[MBOX_NB_MBX] = {
 	}
 };
 
-static void stm32_rproc_request_mbox(struct rproc *rproc)
+static int stm32_rproc_request_mbox(struct rproc *rproc)
 {
 	struct stm32_rproc *ddata = rproc->priv;
 	struct device *dev = &rproc->dev;
 	unsigned int i;
+	int j;
 	const unsigned char *name;
 	struct mbox_client *cl;
 
@@ -329,10 +330,20 @@ static void stm32_rproc_request_mbox(struct rproc *rproc)
 
 		ddata->mb[i].chan = mbox_request_channel_byname(cl, name);
 		if (IS_ERR(ddata->mb[i].chan)) {
+			if (PTR_ERR(ddata->mb[i].chan) == -EPROBE_DEFER)
+				goto err_probe;
 			dev_warn(dev, "cannot get %s mbox\n", name);
 			ddata->mb[i].chan = NULL;
 		}
 	}
+
+	return 0;
+
+err_probe:
+	for (j = i - 1; j >= 0; j--)
+		if (ddata->mb[j].chan)
+			mbox_free_channel(ddata->mb[j].chan);
+	return -EPROBE_DEFER;
 }
 
 static int stm32_rproc_set_hold_boot(struct rproc *rproc, bool hold)
@@ -596,7 +607,9 @@ static int stm32_rproc_probe(struct platform_device *pdev)
 	if (ret)
 		goto free_rproc;
 
-	stm32_rproc_request_mbox(rproc);
+	ret = stm32_rproc_request_mbox(rproc);
+	if (ret)
+		goto free_rproc;
 
 	ret = rproc_add(rproc);
 	if (ret)
-- 
2.7.4


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Re: [PATCH v4] remoteproc: stm32: fix probe error case

[Mathieu Poirier]

Hi Fabien,

On Fri, Nov 15, 2019 at 11:03:08AM +0100, Fabien Dessenne wrote:
> If the rproc driver is probed before the mailbox driver and if the rproc
> Device Tree node has some mailbox properties, the rproc driver probe
> shall be deferred instead of being probed without mailbox support.
> 
> Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
> ---
> Changes since v3: on error, free mailboxes from stm32_rproc_request_mbox()
> Changes since v2: free other requested mailboxes after one request fails
> Changes since v1: test IS_ERR() before checking PTR_ERR()
> ---
>  drivers/remoteproc/stm32_rproc.c | 17 +++++++++++++++--
>  1 file changed, 15 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
> index 2cf4b29..bcebb78 100644
> --- a/drivers/remoteproc/stm32_rproc.c
> +++ b/drivers/remoteproc/stm32_rproc.c
> @@ -310,11 +310,12 @@ static const struct stm32_mbox stm32_rproc_mbox[MBOX_NB_MBX] = {
>  	}
>  };
>  
> -static void stm32_rproc_request_mbox(struct rproc *rproc)
> +static int stm32_rproc_request_mbox(struct rproc *rproc)
>  {
>  	struct stm32_rproc *ddata = rproc->priv;
>  	struct device *dev = &rproc->dev;
>  	unsigned int i;
> +	int j;
>  	const unsigned char *name;
>  	struct mbox_client *cl;
>  
> @@ -329,10 +330,20 @@ static void stm32_rproc_request_mbox(struct rproc *rproc)
>  
>  		ddata->mb[i].chan = mbox_request_channel_byname(cl, name);
>  		if (IS_ERR(ddata->mb[i].chan)) {
> +			if (PTR_ERR(ddata->mb[i].chan) == -EPROBE_DEFER)
> +				goto err_probe;
>  			dev_warn(dev, "cannot get %s mbox\n", name);
>  			ddata->mb[i].chan = NULL;
>  		}
>  	}
> +
> +	return 0;
> +
> +err_probe:
> +	for (j = i - 1; j >= 0; j--)
> +		if (ddata->mb[j].chan)
> +			mbox_free_channel(ddata->mb[j].chan);

Do you need to set ddata->mb[i].chan to NULL as it is done in
stm32_rproc_free_mbox?

Also I'm wondering about the error path for this function.  If something goes
wrong in mbox_request_channel_byname() none of the previously allocated channels
are freed and no further actions is taken.  Should we simply abort the probing
of the rproc if any of channels can't be probed?

Regardless of the above and without surprise:

Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org> 

> +	return -EPROBE_DEFER;
>  }
>  
>  static int stm32_rproc_set_hold_boot(struct rproc *rproc, bool hold)
> @@ -596,7 +607,9 @@ static int stm32_rproc_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto free_rproc;
>  
> -	stm32_rproc_request_mbox(rproc);
> +	ret = stm32_rproc_request_mbox(rproc);
> +	if (ret)
> +		goto free_rproc;
>  
>  	ret = rproc_add(rproc);
>  	if (ret)
> -- 
> 2.7.4
> 
> 
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel


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Re: [PATCH v4] remoteproc: stm32: fix probe error case

[Fabien DESSENNE]

Hi Mathieu


On 15/11/2019 7:55 PM, Mathieu Poirier wrote:
> Hi Fabien,
>
> On Fri, Nov 15, 2019 at 11:03:08AM +0100, Fabien Dessenne wrote:
>> If the rproc driver is probed before the mailbox driver and if the rproc
>> Device Tree node has some mailbox properties, the rproc driver probe
>> shall be deferred instead of being probed without mailbox support.
>>
>> Signed-off-by: Fabien Dessenne <fabien.dessenne@st.com>
>> ---
>> Changes since v3: on error, free mailboxes from stm32_rproc_request_mbox()
>> Changes since v2: free other requested mailboxes after one request fails
>> Changes since v1: test IS_ERR() before checking PTR_ERR()
>> ---
>>   drivers/remoteproc/stm32_rproc.c | 17 +++++++++++++++--
>>   1 file changed, 15 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
>> index 2cf4b29..bcebb78 100644
>> --- a/drivers/remoteproc/stm32_rproc.c
>> +++ b/drivers/remoteproc/stm32_rproc.c
>> @@ -310,11 +310,12 @@ static const struct stm32_mbox stm32_rproc_mbox[MBOX_NB_MBX] = {
>>   	}
>>   };
>>   
>> -static void stm32_rproc_request_mbox(struct rproc *rproc)
>> +static int stm32_rproc_request_mbox(struct rproc *rproc)
>>   {
>>   	struct stm32_rproc *ddata = rproc->priv;
>>   	struct device *dev = &rproc->dev;
>>   	unsigned int i;
>> +	int j;
>>   	const unsigned char *name;
>>   	struct mbox_client *cl;
>>   
>> @@ -329,10 +330,20 @@ static void stm32_rproc_request_mbox(struct rproc *rproc)
>>   
>>   		ddata->mb[i].chan = mbox_request_channel_byname(cl, name);
>>   		if (IS_ERR(ddata->mb[i].chan)) {
>> +			if (PTR_ERR(ddata->mb[i].chan) == -EPROBE_DEFER)
>> +				goto err_probe;
>>   			dev_warn(dev, "cannot get %s mbox\n", name);
>>   			ddata->mb[i].chan = NULL;
>>   		}
>>   	}
>> +
>> +	return 0;
>> +
>> +err_probe:
>> +	for (j = i - 1; j >= 0; j--)
>> +		if (ddata->mb[j].chan)
>> +			mbox_free_channel(ddata->mb[j].chan);
> Do you need to set ddata->mb[i].chan to NULL as it is done in
> stm32_rproc_free_mbox?

This is probably useless : when we hit this error, we exit the probe 
function without any need to track the channels status. Later when the 
probe deferral triggers the probe call again, rproc_alloc() is called 
and zero-allocates the private data (=channels, ...)

The assignment to NULL in stm32_rproc_free_mbox is probably useless too, 
but I prefer to not clean it up now.


>
> Also I'm wondering about the error path for this function.  If something goes
> wrong in mbox_request_channel_byname() none of the previously allocated channels
> are freed and no further actions is taken.  Should we simply abort the probing
> of the rproc if any of channels can't be probed?

The mailboxes are optional (specified as DT optional properties) so we 
shall not break on mbox_request_channel() errors.


>
> Regardless of the above and without surprise:
>
> Tested-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Thank you :)
>
>> +	return -EPROBE_DEFER;
>>   }
>>   
>>   static int stm32_rproc_set_hold_boot(struct rproc *rproc, bool hold)
>> @@ -596,7 +607,9 @@ static int stm32_rproc_probe(struct platform_device *pdev)
>>   	if (ret)
>>   		goto free_rproc;
>>   
>> -	stm32_rproc_request_mbox(rproc);
>> +	ret = stm32_rproc_request_mbox(rproc);
>> +	if (ret)
>> +		goto free_rproc;
>>   
>>   	ret = rproc_add(rproc);
>>   	if (ret)
>> -- 
>> 2.7.4
>>
>>
>> _______________________________________________
>> linux-arm-kernel mailing list
>> linux-arm-kernel@lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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Re: [PATCH v4] remoteproc: stm32: fix probe error case

[Bjorn Andersson]

On Fri 15 Nov 02:03 PST 2019, Fabien Dessenne wrote:
> +
> +	return 0;
> +
> +err_probe:
> +	for (j = i - 1; j >= 0; j--)

It's idiomatic to just use 'i' itself here. But I applied this as is,
with Mathieu's t-b.

Thanks,
Bjorn

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