On 10/30/20 8:57 PM, Mathieu Poirier wrote:
> Introduce function __rproc_detach() to perform the same kind of
> operation as rproc_stop(), but instead of switching off the
> remote processor using rproc->ops->stop(), it uses
> rproc->ops->detach(). That way it is possible for the core
> to release the resources associated with a remote processor while
> the latter is kept operating.
>
> Signed-off-by: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
> Reviewed-by: Peng Fan <peng.fan@xxxxxxx>
> ---
> drivers/remoteproc/remoteproc_core.c | 31 ++++++++++++++++++++++++++++
> 1 file changed, 31 insertions(+)
>
> diff --git a/drivers/remoteproc/remoteproc_core.c b/drivers/remoteproc/remoteproc_core.c
> index ed1f9ca4248b..62e88ff65009 100644
> --- a/drivers/remoteproc/remoteproc_core.c
> +++ b/drivers/remoteproc/remoteproc_core.c
> @@ -1664,6 +1664,37 @@ static int rproc_stop(struct rproc *rproc, bool crashed)
> return 0;
> }
>
> +/*
> + * __rproc_detach(): Does the opposite of rproc_attach()
> + */
> +static int __maybe_unused __rproc_detach(struct rproc *rproc)
> +{
> + struct device *dev = &rproc->dev;
> + int ret;
> +
> + /* No need to continue if a detach() operation has not been provided */
> + if (!rproc->ops->detach)
> + return -EINVAL;
> +
> + /* Stop any subdevices for the remote processor */
> + rproc_stop_subdevices(rproc, false);
How to determine whether a subdevice should be stopped or detached?
For instance, in ST, we have a resource manager subdev which maintains clocks and regulators
for peripherals used by the remote processor.
In case of detachment we would need to maintain clock and regulators.
> +
> + /* Tell the remote processor the core isn't available anymore */
> + ret = rproc->ops->detach(rproc);
> + if (ret) {
> + dev_err(dev, "can't detach from rproc: %d\n", ret);
> + rproc_start_subdevices(rproc);
> + return ret;
> + }
> +
> + rproc_unprepare_subdevices(rproc);
Same here, is prepare/unprepare can depend on the operation?
Seems that adding rproc_attach_subdevices/rproc_detach_subdevices could be not sufficient
to address prepare/unprepare.
Alternative could be:
- extra parameter for the subdev ops to indicate attach/detach action...?
- intermediate rproc state : ATTACHING, DETACHING
- other?
That's said, I don't think that it is blocking for the ST resource manager.
In this particular case, regulators and clocks can be permanently activated
as a back-up solution (always-on).
So, if no other company has a problem with that, we can keep this implementation for now.
Regards,
Arnaud
> +
> + rproc->state = RPROC_DETACHED;
> +
> + dev_info(dev, "detached remote processor %s\n", rproc->name);
> +
> + return 0;
> +}
>
> /**
> * rproc_trigger_recovery() - recover a remoteproc
>
