linux-kernel - Re: [RFC PATCH v2] soc: qcom: rmtfs_mem: Control remoteproc from rmtfs

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Date:   Wed, 31 Oct 2018 19:34:57 +0530
From:   Sibi Sankar <sibis@...eaurora.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     briannorris@...omium.org, david.brown@...aro.org,
        robh+dt@...nel.org, mark.rutland@....com, andy.gross@...aro.org,
        akdwived@...eaurora.org, clew@...eaurora.org,
        linux-kernel@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        linux-soc@...r.kernel.org, linux-arm-msm-owner@...r.kernel.org
Subject: Re: [RFC PATCH v2] soc: qcom: rmtfs_mem: Control remoteproc from
 rmtfs_mem

Hi Bjorn,
Thanks for the review!

On 2018-10-22 01:46, Bjorn Andersson wrote:
> On Sun 30 Sep 08:56 PDT 2018, Sibi Sankar wrote:
> 
>> From: Bjorn Andersson <bjorn.andersson@...aro.org>
>> 
>> rmtfs_mem provides access to physical storage and is crucial for the
>> operation of the Qualcomm modem subsystem.
>> 
>> The rmtfs_mem implementation must be available before the modem
>> subsystem is booted and a solution where the modem remoteproc will
>> verify that the rmtfs_mem is available has been discussed in the past.
>> But this would not handle the case where the rmtfs_mem provider is
>> restarted, which would cause fatal loss of access to the storage 
>> device
>> for the modem.
>> 
>> The suggestion is therefore to link the rmtfs_mem to its associated
>> remote processor instance and control it based on the availability of
>> the rmtfs_mem implementation.
>> 
>> Signed-off-by: Bjorn Andersson <bjorn.andersson@...aro.org>
>> [sibis: Added qmi lookup for Remote file system service]
>> Signed-off-by: Sibi Sankar <sibis@...eaurora.org>
> 
> Thanks Sibi,
> 
> This looks clean and straight forward, but I think the logic should be
> moved into the qcom_q6v5_mss driver itself - as we now only care about
> the QMI service being present, not the rmtfs_memory driver.
> 

Will move it to qcom_q6v5_mss in the next re-spin.

The only drawback I found is that occasionally we receive the
the watchdog immediately after we kill the rmtfs application.
But eventually it gets handled as expected.

SDM845 Logs:
2360 root       0:00 rmtfs
/ # kill 2360

remoteproc: watchdog received: sys_m_smsm_mpss.c:285:APPS force stop
remoteproc0: crash detected in 4080000.remoteproc: type watchdog
qcom-q6v5-mss 4080000.remoteproc: timed out on wait
qcom-q6v5-mss 4080000.remoteproc: port failed halt
remoteproc remoteproc0: stopped remote processor 4080000.remoteproc


> There's nothing left of my original patch, so please credit yourself as
> author of v3.
> 
> [..]
>> diff --git a/drivers/soc/qcom/rmtfs_mem.c 
>> b/drivers/soc/qcom/rmtfs_mem.c
> [..]
>> @@ -181,6 +217,22 @@ static int qcom_rmtfs_mem_probe(struct 
>> platform_device *pdev)
>>  	rmtfs_mem->client_id = client_id;
>>  	rmtfs_mem->size = rmem->size;
>> 
>> +	ret = of_property_read_u32(node, "rproc", &rproc_phandle);
>> +	if (!ret) {
>> +		rmtfs_mem->rproc = rproc_get_by_phandle(rproc_phandle);
>> +		if (!rmtfs_mem->rproc)
>> +			return -EPROBE_DEFER;
>> +	}
>> +
>> +	ret = qmi_handle_init(&rmtfs_mem->rmtfs_hdl, 0,
>> +			      &rmtfs_lookup_ops, NULL);
>> +	if (ret < 0)
>> +		goto put_rproc;
>> +
>> +	ret = qmi_add_lookup(&rmtfs_mem->rmtfs_hdl, 14, 0, 0);
> 
> The 14 here deserves a define and the whole thing would benefit from a
> comment describing the remoteproc's dependency on the RMTFS service
> being present.
> 

Will add it in the respin

>> +	if (ret < 0)
>> +		goto err_release_qmi_handle;
>> +
>>  	device_initialize(&rmtfs_mem->dev);
>>  	rmtfs_mem->dev.parent = &pdev->dev;
>>  	rmtfs_mem->dev.groups = qcom_rmtfs_mem_groups;
> 
> Looking forward to v3!
> 

Done :)

> Regards,
> Bjorn

-- Sibi Sankar --
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project.