Subject: Re: [PATCH 1/2] soc: ti: Use remoteproc auto_boot feature
To: Sarangdhar Joshi <spjoshi@codeaurora.org>,
        Ohad Ben-Cohen <ohad@wizery.com>,
        Bjorn Andersson <bjorn.andersson@linaro.org>,
        Santosh Shilimkar <ssantosh@kernel.org>
References: <1481846632-4778-1-git-send-email-spjoshi@codeaurora.org>
 <1f5b2631-f744-a5c1-55c1-82eb27d5cbd7@ti.com>
 <9092e066-b2ad-ee42-de5f-d66b84a10cfd@codeaurora.org>
CC: <linux-remoteproc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <linux-arm-kernel@lists.infradead.org>,
        <linux-arm-msm@vger.kernel.org>, Stephen Boyd <sboyd@codeaurora.org>,
        Trilok Soni <tsoni@codeaurora.org>, Dave Gerlach <d-gerlach@ti.com>
From: Suman Anna <s-anna@ti.com>
Message-ID: <1f847af8-6bde-4645-aea4-7e9b02306e39@ti.com>
Date: Fri, 23 Dec 2016 11:05:58 -0600
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Hi Sarang,

>>
>> On 12/15/2016 06:03 PM, Sarangdhar Joshi wrote:
>>> The function wkup_m3_rproc_boot_thread waits for asynchronous
>>> firmware loading to complete successfully before calling
>>> rproc_boot(). The same can be achieved by just setting
>>> rproc->auto_boot flag. Change this. As a result this change
>>> removes wkup_m3_rproc_boot_thread and moves m3_ipc->sync_complete
>>> initialization to the wkup_m3_ipc_probe().
>>>
>>> Other than the current usage, the firmware_loading_complete is
>>> only used in rproc_del() where it's no longer needed.  This
>>> change is in preparation for removing firmware_loading_complete
>>> completely.
>>
>> Based on the comments so far, I am assuming that you are dropping this
>> series.
> 
> No, may not be dropping this. Will try to handle it differently in
> rproc_del() (probably by making use of some state flag).
>>
>> In any case, this series did break our PM stack. We definitely don't
>> want to auto-boot the wkup_m3_rproc device, that responsibility will
>> need to stay with the wkup_m3_ipc driver.
> 
> Which scenario did it break? Booting up rproc device before
> wkup_m3_ipc_probe() causes issues?

Yes, our state machine requires the wkup_m3_ipc driver to control the
boot of the wkup_m3 remoteproc. The wkup_m3 is not a typical remoteproc,
it is our PM master and is responsible for putting the host processor
into suspend and waking it up in system suspend/cpuidle paths.
The remoteproc infrastructure is only used for load/boot, but the Linux
PM state machine and communication is all controlled by the wkup_m3_ipc
driver.

> 
> Nevertheless, I think Bjorn's suggestion of just dropping the call to
> wait_for_completion() and keeping kthread looks good, also because of
> the fact that rproc_boot() anyways calls request_firmware() and no
> longer needed to wait on asynchronous loading of firmware.

Yeah, I will have to test this, but looking at current code, this should
mostly be ok because of the remoteproc core changes w.r.t resource table
parsing.

regards
Suman