Re: [PATCH v4 03/16] firmware: arm_scmi: Add transport optional init/exit support

Cristian Marussi
2021-06-16T09:06:22Z

Hi Jonathan,

thanks for having a look at this series.

On Mon, Jun 14, 2021 at 02:29:56PM +0100, Jonathan Cameron wrote:
> On Fri, 11 Jun 2021 17:59:24 +0100
> Cristian Marussi <cristian.marussi@arm.com> wrote:
>
> > Some SCMI transport could need to perform some transport specific setup
> > before they can be used by the SCMI core transport layer: typically this
> > early setup consists in registering with some other kernel subsystem.
> >
> > Add the optional capability for a transport to provide a couple of .init
> > and .exit functions that are assured to be called early during the SCMI
> > core initialization phase, well before the SCMI core probing step.
> >
> > [ Peter: Adapted RFC patch by Cristian for submission to upstream. ]
> > Signed-off-by: Peter Hilber <peter.hilber@opensynergy.com>
> > [ Cristian: Fixed scmi_transports_exit point of invocation ]
> > Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
>
> Drive by comment inline. Feel free to ignore ;)
>
> Jonathan
>
> > ---
> > drivers/firmware/arm_scmi/common.h | 8 ++++
> > drivers/firmware/arm_scmi/driver.c | 59 ++++++++++++++++++++++++++++++
> > 2 files changed, 67 insertions(+)
> >
> > diff --git a/drivers/firmware/arm_scmi/common.h b/drivers/firmware/arm_scmi/common.h
> > index 7c2b9fd7e929..6bb734e0e3ac 100644
> > --- a/drivers/firmware/arm_scmi/common.h
> > +++ b/drivers/firmware/arm_scmi/common.h
> > @@ -321,6 +321,12 @@ struct scmi_device *scmi_child_dev_find(struct device *parent,
> > /**
> > * struct scmi_desc - Description of SoC integration
> > *
> > + * @init: An optional function that a transport can provide to initialize some
> > + * transport-specific setup during SCMI core initialization, so ahead of
> > + * SCMI core probing.
> > + * @exit: An optional function that a transport can provide to de-initialize
> > + * some transport-specific setup during SCMI core de-initialization, so
> > + * after SCMI core removal.
> > * @ops: Pointer to the transport specific ops structure
> > * @max_rx_timeout_ms: Timeout for communication with SoC (in Milliseconds)
> > * @max_msg: Maximum number of messages that can be pending
> > @@ -328,6 +334,8 @@ struct scmi_device *scmi_child_dev_find(struct device *parent,
> > * @max_msg_size: Maximum size of data per message that can be handled.
> > */
> > struct scmi_desc {
> > + int (*init)(void);
> > + void (*exit)(void);
> > const struct scmi_transport_ops *ops;
> > int max_rx_timeout_ms;
> > int max_msg;
> > diff --git a/drivers/firmware/arm_scmi/driver.c b/drivers/firmware/arm_scmi/driver.c
> > index f15d75af87ea..20f8f0581f3a 100644
> > --- a/drivers/firmware/arm_scmi/driver.c
> > +++ b/drivers/firmware/arm_scmi/driver.c
> > @@ -1594,10 +1594,67 @@ static struct platform_driver scmi_driver = {
> > .remove = scmi_remove,
> > };
> >
> > +/**
> > + * __scmi_transports_setup - Common helper to call transport-specific
> > + * .init/.exit code if provided.
> > + *
> > + * @init: A flag to distinguish between init and exit.
> > + *
> > + * Note that, if provided, we invoke .init/.exit functions for all the
> > + * transports currently compiled in.
> > + *
> > + * Return: 0 on Success.
> > + */
> > +static inline int __scmi_transports_setup(bool init)
> > +{
> > + int ret = 0;
> > + const struct of_device_id *trans;
> > +
> > + for (trans = scmi_of_match; trans->data; trans++) {
> > + const struct scmi_desc *tdesc = trans->data;
> > +
> > + if ((init && !tdesc->init) || (!init && !tdesc->exit))
> > + continue;
> > +
> > + pr_debug("SCMI %sInitializing %s transport\n",
> > + init ? "" : "De-", trans->compatible);
>
> Clever formatting can makes grepping for messages harder.
>
> Perhaps
> if (init)
> pr_debug("SCMI Initializing %s transport\n",
> trans->compatible);
> else
> pr_debug("SCMI Deinitializing %s transport\n",
> trans->compatible);
>
> would be nicer even though it burns some lines. Also avoids somewhat
> ugly capitalization : De-Initializing xxx transport.
>
> You could combine it with the convenient if(init) below
>

Right, I'll rework to avoid issues grepping.

Thanks,
Cristian