linux-kernel - Re: [PATCH] rpmsg: core: add support to power domains for devices

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Message-ID: <4e1b6773-c4da-4638-eee7-2f996d387903@st.com>
Date:   Wed, 26 Sep 2018 14:48:14 +0200
From:   Arnaud Pouliquen <arnaud.pouliquen@...com>
To:     Suman Anna <s-anna@...com>,
        Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
        <ohad@...ery.com>, <bjorn.andersson@...aro.org>
CC:     <linux-remoteproc@...r.kernel.org>,
        <linux-arm-msm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Loic Pallardy <loic.pallardy@...com>
Subject: Re: [PATCH] rpmsg: core: add support to power domains for devices

Hi Suman,


On 09/25/2018 09:02 PM, Suman Anna wrote:
> Hi Arnaud,
> 
>> On 09/25/2018 02:25 AM, Suman Anna wrote:
>>> Hi Srinivas,
>>>
>>> On 06/15/2018 04:59 AM, Srinivas Kandagatla wrote:
>>>> Some of the rpmsg devices need to switch on power domains to communicate
>>>> with remote processor. For example on Qualcomm DB820c platform LPASS
>>>> power domain needs to switched on for any kind of audio services.
>>>> This patch adds the missing power domain support in rpmsg core.
>>>>
>>>> Without this patch attempting to play audio via QDSP on DB820c would
>>>> reboot the system.
>>>>
>>>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@...aro.org>
>>>> ---
>>>>  drivers/rpmsg/rpmsg_core.c | 7 +++++++
>>>>  1 file changed, 7 insertions(+)
>>>>
>>>> diff --git a/drivers/rpmsg/rpmsg_core.c b/drivers/rpmsg/rpmsg_core.c
>>>> index b714a543a91d..8122807db380 100644
>>>> --- a/drivers/rpmsg/rpmsg_core.c
>>>> +++ b/drivers/rpmsg/rpmsg_core.c
>>>> @@ -15,6 +15,7 @@
>>>>  #include <linux/module.h>
>>>>  #include <linux/rpmsg.h>
>>>>  #include <linux/of_device.h>
>>>> +#include <linux/pm_domain.h>
>>>>  #include <linux/slab.h>
>>>>  
>>>>  #include "rpmsg_internal.h"
>>>> @@ -449,6 +450,10 @@ static int rpmsg_dev_probe(struct device *dev)
>>>>  	struct rpmsg_endpoint *ept = NULL;
>>>>  	int err;
>>>>  
>>>> +	err = dev_pm_domain_attach(dev, true);
>>>> +	if (err)
>>>> +		goto out;
>>>
>>> This patch has broken the virtio-rpmsg stack based rpmsg devices. These
>>> devices are non-DT and the rpmsg_dev_probe() is now failing with -19
>>> (-ENODEV) error code.
>>>
>>> Loic, Arnaud,
>>> Can one of you double-confirm this behavior on ST platforms as well?
>>> The patch came through 4.14.71 stable release and broke our downstream
>>> kernels.
> 
>> I do not reproduce issue on 4.14.0 + your patch,  on my ST platform (not
>> able to test on the LTS branch).
>> By looking the source code, seems that your issue is related to
>> genpd_dev_pm_attach that returns -ENODEV because you have
>> no remoteproc device node...
>> Do you have a rproc node defined in your DT? we have one.
> 
> The dev here is not the remoteproc dev but the rpmsg device which does
> not have an OF node, and so I get the ENODEV due to the check on
> dev->of_node in genpd_dev_pm_attach. I do have DT remoteproc nodes.
> 
> Are you publishing an rpmsg device from the remote side and are they
> being probed? Issue is seen only during the probe phase, you will not
> see any errors if the rpmsg devices are just being published and created.
Sorry something was wrong in my fw used yesterday for testing...so
forget my previous status.

I re-tested it and I have the same issue (-ENODEV) with rpmsg device
probed on ns announcement rpmsg from remote side.
So we confirm the issue.

Regards
Arnaud

> 
> regards
> Suman
> 
>>
>> Regards
>> Arnaud
>>
>>>
>>> regards
>>> Suman
>>>
>>>> +
>>>>  	if (rpdrv->callback) {
>>>>  		strncpy(chinfo.name, rpdev->id.name, RPMSG_NAME_SIZE);
>>>>  		chinfo.src = rpdev->src;
>>>> @@ -490,6 +495,8 @@ static int rpmsg_dev_remove(struct device *dev)
>>>>  
>>>>  	rpdrv->remove(rpdev);
>>>>  
>>>> +	dev_pm_domain_detach(dev, true);
>>>> +
>>>>  	if (rpdev->ept)
>>>>  		rpmsg_destroy_ept(rpdev->ept);
>>>>  
>>>>
>>>
>