linux-kernel - Re: [PATCH v4 3/5] remoteproc: Add prepare/unprepare callbacks

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Message-ID: <20200120201944.GO1511@yoga>
Date:   Mon, 20 Jan 2020 12:19:44 -0800
From:   Bjorn Andersson <bjorn.andersson@...aro.org>
To:     Paul Cercueil <paul@...pouillou.net>
Cc:     Ohad Ben-Cohen <ohad@...ery.com>, Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>, od@...c.me,
        linux-remoteproc@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH v4 3/5] remoteproc: Add prepare/unprepare callbacks

On Wed 15 Jan 13:15 PST 2020, Paul Cercueil wrote:

> Hi Bjorn,
> 
> 
> Le sam., déc. 21, 2019 at 12:20, Bjorn Andersson
> <bjorn.andersson@...aro.org> a écrit :
> > On Tue 10 Dec 08:40 PST 2019, Paul Cercueil wrote:
> > 
> > >  The .prepare() callback is called before the firmware is loaded to
> > >  memory. This is useful for instance in the case where some setup is
> > >  required for the memory to be accessible.
> > > 
> > 
> > Would it make sense to somehow tie this prepare/unprepare to the actual
> > struct rproc_mem_entry that needs the resource enabled?
> 
> Do you need such granularity?
> 

I don't have such needs, but given some of the memory structure that
Suman and Loic has been talking about I would expect that such need
exists.

> In my case, the three memories need the same clock to be enabled.
> 

But we can update your driver to associate your one clock with the
memory objects if/when we end up implementing this later.

Regards,
Bjorn

> -Paul
> 
> 
> > 
> > >  Signed-off-by: Paul Cercueil <paul@...pouillou.net>
> > >  ---
> > > 
> > >  Notes:
> > >      v2-v4: No change
> > > 
> > >   drivers/remoteproc/remoteproc_core.c | 16 +++++++++++++++-
> > >   include/linux/remoteproc.h           |  4 ++++
> > >   2 files changed, 19 insertions(+), 1 deletion(-)
> > > 
> > >  diff --git a/drivers/remoteproc/remoteproc_core.c
> > > b/drivers/remoteproc/remoteproc_core.c
> > >  index 0a9fc7fdd1c3..3ea5f675a148 100644
> > >  --- a/drivers/remoteproc/remoteproc_core.c
> > >  +++ b/drivers/remoteproc/remoteproc_core.c
> > >  @@ -1299,11 +1299,19 @@ static int rproc_start(struct rproc *rproc,
> > > const struct firmware *fw)
> > >   	struct device *dev = &rproc->dev;
> > >   	int ret;
> > > 
> > >  +	if (rproc->ops->prepare) {
> > >  +		ret = rproc->ops->prepare(rproc);
> > >  +		if (ret) {
> > >  +			dev_err(dev, "Failed to prepare rproc: %d\n", ret);
> > >  +			return ret;
> > >  +		}
> > >  +	}
> > >  +
> > >   	/* load the ELF segments to memory */
> > >   	ret = rproc_load_segments(rproc, fw);
> > >   	if (ret) {
> > >   		dev_err(dev, "Failed to load program segments: %d\n", ret);
> > >  -		return ret;
> > >  +		goto unprepare_rproc;
> > >   	}
> > > 
> > >   	/*
> > >  @@ -1354,6 +1362,9 @@ static int rproc_start(struct rproc *rproc,
> > > const struct firmware *fw)
> > >   	rproc_unprepare_subdevices(rproc);
> > >   reset_table_ptr:
> > >   	rproc->table_ptr = rproc->cached_table;
> > >  +unprepare_rproc:
> > >  +	if (rproc->ops->unprepare)
> > >  +		rproc->ops->unprepare(rproc);
> > > 
> > >   	return ret;
> > >   }
> > >  @@ -1483,6 +1494,9 @@ static int rproc_stop(struct rproc *rproc,
> > > bool crashed)
> > > 
> > >   	rproc->state = RPROC_OFFLINE;
> > > 
> > >  +	if (rproc->ops->unprepare)
> > >  +		rproc->ops->unprepare(rproc);
> > >  +
> > >   	dev_info(dev, "stopped remote processor %s\n", rproc->name);
> > > 
> > >   	return 0;
> > >  diff --git a/include/linux/remoteproc.h b/include/linux/remoteproc.h
> > >  index 5f201f0c86c3..a6272d1ba384 100644
> > >  --- a/include/linux/remoteproc.h
> > >  +++ b/include/linux/remoteproc.h
> > >  @@ -355,6 +355,8 @@ enum rsc_handling_status {
> > > 
> > >   /**
> > >    * struct rproc_ops - platform-specific device handlers
> > >  + * @prepare:	prepare the device for power up (before the firmware
> > > is loaded)
> > >  + * @unprepare:	unprepare the device after it is stopped
> > >    * @start:	power on the device and boot it
> > >    * @stop:	power off the device
> > >    * @kick:	kick a virtqueue (virtqueue id given as a parameter)
> > >  @@ -371,6 +373,8 @@ enum rsc_handling_status {
> > >    * @get_boot_addr:	get boot address to entry point specified in
> > > firmware
> > >    */
> > >   struct rproc_ops {
> > >  +	int (*prepare)(struct rproc *rproc);
> > >  +	void (*unprepare)(struct rproc *rproc);
> > >   	int (*start)(struct rproc *rproc);
> > >   	int (*stop)(struct rproc *rproc);
> > >   	void (*kick)(struct rproc *rproc, int vqid);
> > >  --
> > >  2.24.0
> > > 
> 
>