linux-kernel - Re: [PATCH 1/2] soc: ti: Use remoteproc auto

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Date:   Thu, 22 Dec 2016 05:02:46 -0800
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Suman Anna <s-anna@...com>
Cc:     Sarangdhar Joshi <spjoshi@...eaurora.org>,
        Ohad Ben-Cohen <ohad@...ery.com>,
        Santosh Shilimkar <ssantosh@...nel.org>,
        linux-remoteproc@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-arm-msm@...r.kernel.org, Stephen Boyd <sboyd@...eaurora.org>,
        Trilok Soni <tsoni@...eaurora.org>,
        Dave Gerlach <d-gerlach@...com>
Subject: Re: [PATCH 1/2] soc: ti: Use remoteproc auto_boot feature

On Wed 21 Dec 19:16 PST 2016, Suman Anna wrote:

> 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.
> 

Following up on those comments only revealed that we have several other
similar race conditions, so I'm hoping that Sarangdhar will continue to
work on fixing those - and in this process get rid of this completion.

> 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.
> 

Reviewing the wkup_m3 situation again I see that as we have moved the
resource table parsing to the rproc_boot() path there's no longer any
need for the wkup_m3_ipc driver to wait for the remoteproc-core-internal
completion.

If rproc_get_by_phandle() returns non-NULL it is initialized. We still
don't want to call rproc_boot() from wkup_m3_ipc_probe(), so let's keep
the wkup_m3_rproc_boot_thread().

Sarangdhar, could you update the wkup_m3_ipc patch to just drop the
wait_for_completion() call?

Regards,
Bjorn