linux-kernel - Re: [PATCH v2] remoteproc: stm32: fix probe error case

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Message-ID: <392808fa-1504-233f-234b-0cca21886c17@st.com>
Date:   Tue, 12 Nov 2019 14:09:40 +0000
From:   Fabien DESSENNE <fabien.dessenne@...com>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
CC:     Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre TORGUE <alexandre.torgue@...com>,
        Ohad Ben-Cohen <ohad@...ery.com>,
        "linux-stm32@...md-mailman.stormreply.com" 
        <linux-stm32@...md-mailman.stormreply.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-remoteproc@...r.kernel.org" <linux-remoteproc@...r.kernel.org>,
        Loic PALLARDY <loic.pallardy@...com>,
        Arnaud POULIQUEN <arnaud.pouliquen@...com>
Subject: Re: [PATCH v2] remoteproc: stm32: fix probe error case

Hi Bjorn,


On 11/11/2019 11:04 PM, Bjorn Andersson wrote:
> On Mon 07 Oct 00:39 PDT 2019, 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@...com>
>> ---
>> Changes since v1: test IS_ERR() before checking PTR_ERR()
>> ---
>>   drivers/remoteproc/stm32_rproc.c | 10 ++++++++--
>>   1 file changed, 8 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/remoteproc/stm32_rproc.c b/drivers/remoteproc/stm32_rproc.c
>> index 2cf4b29..a507332 100644
>> --- a/drivers/remoteproc/stm32_rproc.c
>> +++ b/drivers/remoteproc/stm32_rproc.c
>> @@ -310,7 +310,7 @@ 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;
>> @@ -329,10 +329,14 @@ 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)
>> +				return -EPROBE_DEFER;
> If for some reason you get EPROBE_DEFER when i > 0 you need to
> mbox_free_channel() channels [0..i) before returning.

The mailbox framework returns EPROBE_DIFFER to inform that the mailbox 
provider has not registered yet. I do not expected to have a success 
followed by a EPROBE_DEFER error.

But in the very special case where we use two different mailbox 
providers this may happen.

I will send an updated version, thanks for pointing this.

BR

Fabien

>
> Regards,
> Bjorn
>
>>   			dev_warn(dev, "cannot get %s mbox\n", name);
>>   			ddata->mb[i].chan = NULL;
>>   		}
>>   	}
>> +
>> +	return 0;
>>   }
>>   
>>   static int stm32_rproc_set_hold_boot(struct rproc *rproc, bool hold)
>> @@ -596,7 +600,9 @@ 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
>>