Re: [PATCH v5 3/5] remoteproc: Add prepare/unprepare callbacks

[Paul Cercueil <paul@xxxxxxxxxxxxxxx>]

Hi Arnaud,


Le mar., févr. 18, 2020 at 17:31, Arnaud POULIQUEN 
<arnaud.pouliquen@xxxxxx> a écrit :
> Hi Paul,
>
> I still wonder about the use of pm_runtime mechanism as a more 
> generic alternative...

The use of pm_runtime is perfect if CONFIG_PM is enabled, but otherwise 
it's a bit cumbersome, as the clocks must be enabled in the probe.

-Paul

> Else just a minor remark inline.
>
> On 2/11/20 3:26 PM, 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.
> >
> >  Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx>
> >  ---
> >
> >  Notes:
> >      v2-v4: No change
> >      v5: Move calls to prepare/unprepare to 
> > rproc_fw_boot/rproc_shutdown
> >
> >   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 fe5c7a2f9767..022b927e176b 100644
> >  --- a/drivers/remoteproc/remoteproc_core.c
> >  +++ b/drivers/remoteproc/remoteproc_core.c
> >  @@ -1373,6 +1373,14 @@ static int rproc_fw_boot(struct rproc 
> > *rproc, const struct firmware *fw)
> >
> >   	dev_info(dev, "Booting fw image %s, size %zd\n", name, fw->size);
> >
> >  +	if (rproc->ops->prepare) {
> >  +		ret = rproc->ops->prepare(rproc);
> >  +		if (ret) {
> >  +			dev_err(dev, "Failed to prepare rproc: %d\n", ret);
> >  +			return ret;
> >  +		}
> >  +	}
> >  +
> >   	/*
> >   	 * if enabling an IOMMU isn't relevant for this rproc, this is
> >   	 * just a nop
> >  @@ -1380,7 +1388,7 @@ static int rproc_fw_boot(struct rproc *rproc, 
> > const struct firmware *fw)
> >   	ret = rproc_enable_iommu(rproc);
> >   	if (ret) {
> >   		dev_err(dev, "can't enable iommu: %d\n", ret);
> >  -		return ret;
> >  +		goto unprepare_rproc;
> >   	}
> >
> >   	rproc->bootaddr = rproc_get_boot_addr(rproc, fw);
> >  @@ -1424,6 +1432,9 @@ static int rproc_fw_boot(struct rproc *rproc, 
> > const struct firmware *fw)
> >   	rproc->table_ptr = NULL;
> >   disable_iommu:
> >   	rproc_disable_iommu(rproc);
> >  +unprepare_rproc:
> >  +	if (rproc->ops->unprepare)
> >  +		rproc->ops->unprepare(rproc);
> >   	return ret;
> >   }
> >
> >  @@ -1823,6 +1834,9 @@ void rproc_shutdown(struct rproc *rproc)
> >
> >   	rproc_disable_iommu(rproc);
> >
> >  +	if (rproc->ops->unprepare)
> >  +		rproc->ops->unprepare(rproc);
> >  +
> >   	/* Free the copy of the resource table */
> >   	kfree(rproc->cached_table);
> >   	rproc->cached_table = NULL;
> >  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
>
> Would be nice here to precise that these functions are optional
> you can look at rproc_ops struct for example.
>
> Regards,
> Arnaud
>
> >    * @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);