Re: [PATCH 1/2] rpmsg: qcom_smd: Fix fallback to qcom,ipc parse

[barnabas.czeman@mainlining.org]

On 2025-04-21 12:38, Dmitry Baryshkov wrote:
> On Mon, Apr 21, 2025 at 04:04:16AM +0200, Barnabás Czémán wrote:
>> mbox_request_channel() returning value was changed in case of error.
>> It uses returning value of of_parse_phandle_with_args().
>> It is returning with -ENOENT instead of -ENODEV when no mboxes 
>> property
>> exists.
> 
> Why? What is the rationale?
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/of/base.c#n1390
mailbox: use error ret code of of_parse_phandle_with_args() this commit 
was changed the return value
from ENODEV to use retrun value of of_parse_phandle_with_args what is 
returnung with EINVAL or ENOENT.
It makes skipping fallback path to parse qcom,ipc if there is no mboxes 
property defined.
As far as I know qcom,ipc now only needed for rpm smd-edge on some SoCs 
like 8939, 8916, 8976, 8917.
arm64: dts: qcom: msm8939: revert use of APCS mbox for RPM
> 
>> 
>> Fixes: 24fdd5074b20 ("mailbox: use error ret code of 
>> of_parse_phandle_with_args()")
>> Signed-off-by: Barnabás Czémán <barnabas.czeman@mainlining.org>
>> ---
>>  drivers/rpmsg/qcom_smd.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/rpmsg/qcom_smd.c b/drivers/rpmsg/qcom_smd.c
>> index 
>> 40d386809d6b78e209861c23d934e1b9fd743606..e552a9af578e48cfd854a228a4d91e4fa04bf29d 
>> 100644
>> --- a/drivers/rpmsg/qcom_smd.c
>> +++ b/drivers/rpmsg/qcom_smd.c
>> @@ -1368,7 +1368,7 @@ static int qcom_smd_parse_edge(struct device 
>> *dev,
>>  	edge->mbox_client.knows_txdone = true;
>>  	edge->mbox_chan = mbox_request_channel(&edge->mbox_client, 0);
>>  	if (IS_ERR(edge->mbox_chan)) {
>> -		if (PTR_ERR(edge->mbox_chan) != -ENODEV) {
>> +		if (PTR_ERR(edge->mbox_chan) != -ENOENT) {
>>  			ret = PTR_ERR(edge->mbox_chan);
>>  			goto put_node;
>>  		}
>> 
>> --
>> 2.49.0
>>