linux-kernel - Re: [PATCH v4 9/9] remoteproc: Properly handle firmware name when attaching

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Message-ID: <20200623200918.GA407764@builder.lan>
Date:   Tue, 23 Jun 2020 13:09:18 -0700
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>
Cc:     ohad@...ery.com, linux-remoteproc@...r.kernel.org,
        linux-kernel@...r.kernel.org, loic.pallardy@...com,
        arnaud.pouliquen@...com, s-anna@...com
Subject: Re: [PATCH v4 9/9] remoteproc: Properly handle firmware name when
 attaching

On Tue 23 Jun 12:48 PDT 2020, Mathieu Poirier wrote:

> On Mon, Jun 22, 2020 at 12:33:19AM -0700, Bjorn Andersson wrote:
> > On Mon 01 Jun 10:51 PDT 2020, Mathieu Poirier wrote:
> > 
> > > This patch prevents the firmware image name from being displayed when
> > > the remoteproc core is attaching to a remote processor. This is needed
> > > needed since there is no guarantee about the nature of the firmware
> > > image that is loaded by the external entity.
> > > 
> > > Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
> > 
> > How about renaming the bool "firmware_unknown"?
> 
> My hope was to use the same variable, i.e "autonomous", for the RUNNING ->
> DETACHED and CRASHED -> DETACHED scenarios to reduce the amount of
> variables we need to keep track of when the functionality is implemented in
> upcoming pachsets.
> 

Sounds like a good goal, let's keep it as is for now!

Thanks,
Bjorn

> Thanks for the review,
> Mathieu
> 
> > 
> > Apart from that, I think this looks good.
> > 
> > Regards,
> > Bjorn
> > 
> > > ---
> > >  drivers/remoteproc/remoteproc_core.c  | 18 ++++++++++++++++++
> > >  drivers/remoteproc/remoteproc_sysfs.c | 16 ++++++++++++++--
> > >  include/linux/remoteproc.h            |  2 ++
> > >  3 files changed, 34 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> > > index 0e23284fbd25..a8adc712e7f6 100644
> > > --- a/drivers/remoteproc/remoteproc_core.c
> > > +++ b/drivers/remoteproc/remoteproc_core.c
> > > @@ -1642,6 +1642,14 @@ static int rproc_stop(struct rproc *rproc, bool crashed)
> > >  
> > >  	rproc->state = RPROC_OFFLINE;
> > >  
> > > +	/*
> > > +	 * The remote processor has been stopped and is now offline, which means
> > > +	 * that the next time it is brought back online the remoteproc core will
> > > +	 * be responsible to load its firmware.  As such it is no longer
> > > +	 * autonomous.
> > > +	 */
> > > +	rproc->autonomous = false;
> > > +
> > >  	dev_info(dev, "stopped remote processor %s\n", rproc->name);
> > >  
> > >  	return 0;
> > > @@ -2166,6 +2174,16 @@ int rproc_add(struct rproc *rproc)
> > >  	/* create debugfs entries */
> > >  	rproc_create_debug_dir(rproc);
> > >  
> > > +	/*
> > > +	 * Remind ourselves the remote processor has been attached to rather
> > > +	 * than booted by the remoteproc core.  This is important because the
> > > +	 * RPROC_DETACHED state will be lost as soon as the remote processor
> > > +	 * has been attached to.  Used in firmware_show() and reset in
> > > +	 * rproc_stop().
> > > +	 */
> > > +	if (rproc->state == RPROC_DETACHED)
> > > +		rproc->autonomous = true;
> > > +
> > >  	/* if rproc is marked always-on, request it to boot */
> > >  	if (rproc->auto_boot) {
> > >  		ret = rproc_trigger_auto_boot(rproc);
> > > diff --git a/drivers/remoteproc/remoteproc_sysfs.c b/drivers/remoteproc/remoteproc_sysfs.c
> > > index 8b462c501465..4ee158431f67 100644
> > > --- a/drivers/remoteproc/remoteproc_sysfs.c
> > > +++ b/drivers/remoteproc/remoteproc_sysfs.c
> > > @@ -14,8 +14,20 @@ static ssize_t firmware_show(struct device *dev, struct device_attribute *attr,
> > >  			  char *buf)
> > >  {
> > >  	struct rproc *rproc = to_rproc(dev);
> > > -
> > > -	return sprintf(buf, "%s\n", rproc->firmware);
> > > +	const char *firmware = rproc->firmware;
> > > +
> > > +	/*
> > > +	 * If the remote processor has been started by an external
> > > +	 * entity we have no idea of what image it is running.  As such
> > > +	 * simply display a generic string rather then rproc->firmware.
> > > +	 *
> > > +	 * Here we rely on the autonomous flag because a remote processor
> > > +	 * may have been attached to and currently in a running state.
> > > +	 */
> > > +	if (rproc->autonomous)
> > > +		firmware = "unknown";
> > > +
> > > +	return sprintf(buf, "%s\n", firmware);
> > >  }
> > >  
> > >  /* Change firmware name via sysfs */
> > > diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > > index bf6a310ba870..cf5e31556780 100644
> > > --- a/include/linux/remoteproc.h
> > > +++ b/include/linux/remoteproc.h
> > > @@ -491,6 +491,7 @@ struct rproc_dump_segment {
> > >   * @table_sz: size of @cached_table
> > >   * @has_iommu: flag to indicate if remote processor is behind an MMU
> > >   * @auto_boot: flag to indicate if remote processor should be auto-started
> > > + * @autonomous: true if an external entity has booted the remote processor
> > >   * @dump_segments: list of segments in the firmware
> > >   * @nb_vdev: number of vdev currently handled by rproc
> > >   */
> > > @@ -524,6 +525,7 @@ struct rproc {
> > >  	size_t table_sz;
> > >  	bool has_iommu;
> > >  	bool auto_boot;
> > > +	bool autonomous;
> > >  	struct list_head dump_segments;
> > >  	int nb_vdev;
> > >  	u8 elf_class;
> > > -- 
> > > 2.20.1
> > >