linux-kernel - Re: [PATCH v3 05/14] remoteproc: Refactor function rproc_fw

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Date:   Fri, 8 May 2020 15:27:56 -0600
From:   Mathieu Poirier <mathieu.poirier@...aro.org>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>
Cc:     ohad@...ery.com, loic.pallardy@...com, arnaud.pouliquen@...com,
        s-anna@...com, linux-remoteproc@...r.kernel.org, corbet@....net,
        linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 05/14] remoteproc: Refactor function rproc_fw_boot()

On Tue, May 05, 2020 at 05:33:41PM -0700, Bjorn Andersson wrote:
> On Fri 24 Apr 13:01 PDT 2020, Mathieu Poirier wrote:
> 
> > Refactor function rproc_fw_boot() in order to better reflect the work
> > that is done when supporting scenarios where the remoteproc core is
> > synchronising with a remote processor.
> > 
> > Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> > ---
> >  drivers/remoteproc/remoteproc_core.c | 10 ++++++----
> >  1 file changed, 6 insertions(+), 4 deletions(-)
> > 
> > diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> > index a02593b75bec..e90a21de9de1 100644
> > --- a/drivers/remoteproc/remoteproc_core.c
> > +++ b/drivers/remoteproc/remoteproc_core.c
> > @@ -1370,9 +1370,9 @@ static int rproc_start(struct rproc *rproc, const struct firmware *fw)
> >  }
> >  
> >  /*
> > - * take a firmware and boot a remote processor with it.
> > + * boot or synchronise with a remote processor.
> >   */
> > -static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
> > +static int rproc_actuate_device(struct rproc *rproc, const struct firmware *fw)
> 
> Per patch 4 this function will if rproc_needs_syncing() be called with
> fw == NULL, it's not obvious to me that the various operations on "fw"
> in this function are valid anymore.

That is right, all firmware related operations in this function are found in
remoteproc_internal.h where the value of rproc->sync_with_mcu is checked before
moving forward. That allows us to avoid introducing a new function similar to
rproc_fw_boot() but without firmware operations or peppering the code with if
statements.

> 
> >  {
> >  	struct device *dev = &rproc->dev;
> >  	const char *name = rproc->firmware;
> > @@ -1382,7 +1382,9 @@ static int rproc_fw_boot(struct rproc *rproc, const struct firmware *fw)
> >  	if (ret)
> >  		return ret;
> >  
> > -	dev_info(dev, "Booting fw image %s, size %zd\n", name, fw->size);
> > +	if (!rproc_needs_syncing(rproc))
> 
> Can't we make this check on fw, to make the relationship "if we where
> passed a firmware object, we're going to load and boot that firmware"?

It can but I specifically decided to use rproc_needs_syncing() to be consistent
with the rest of the patchset.  That way all we need to do is grep for
rproc_needs_syncing to get all the places where a decision about synchronising
with a remote processor is made.

> 
> Regards,
> Bjorn
> 
> > +		dev_info(dev, "Booting fw image %s, size %zd\n",
> > +			 name, fw->size);
> >  
> >  	/*
> >  	 * if enabling an IOMMU isn't relevant for this rproc, this is
> > @@ -1818,7 +1820,7 @@ int rproc_boot(struct rproc *rproc)
> >  		}
> >  	}
> >  
> > -	ret = rproc_fw_boot(rproc, firmware_p);
> > +	ret = rproc_actuate_device(rproc, firmware_p);
> >  
> >  	release_firmware(firmware_p);
> >  
> > -- 
> > 2.20.1
> >