Hi Peng,
On 9/23/2019 6:14 PM, Peng Fan wrote:
> From: Peng Fan <[email protected]>
>
> This mailbox driver implements a mailbox which signals transmitted data
> via an ARM smc (secure monitor call) instruction. The mailbox receiver
> is implemented in firmware and can synchronously return data when it
> returns execution to the non-secure world again.
> An asynchronous receive path is not implemented.
> This allows the usage of a mailbox to trigger firmware actions on SoCs
> which either don't have a separate management processor or on which such
> a core is not available. A user of this mailbox could be the SCP
> interface.
>
> Modified from Andre Przywara's v2 patch
> https://lore.kernel.org/patchwork/patch/812999/
>
> Cc: Andre Przywara <[email protected]>
> Signed-off-by: Peng Fan <[email protected]>
> ---
[snip]
> +typedef unsigned long (smc_mbox_fn)(unsigned int, unsigned long,
> + unsigned long, unsigned long,
> + unsigned long, unsigned long,
> + unsigned long);
> +static smc_mbox_fn *invoke_smc_mbox_fn;
Sorry for spotting this so late, the only thing that concerns me here
with this singleton is if we happen to have both an arm,smc-mbox and
arm,hvc-mbox configured in the system, this would not work. I do not
believe this could be a functional use case, but we should probably
guard against that or better yet, move that into the arm_smc_chan_data
private structure?
--
Florian
Hi Florian
> Subject: Re: [PATCH V8 2/2] mailbox: introduce ARM SMC based mailbox
>
> Hi Peng,
>
> On 9/23/2019 6:14 PM, Peng Fan wrote:
> > From: Peng Fan <[email protected]>
> >
> > This mailbox driver implements a mailbox which signals transmitted
> > data via an ARM smc (secure monitor call) instruction. The mailbox
> > receiver is implemented in firmware and can synchronously return data
> > when it returns execution to the non-secure world again.
> > An asynchronous receive path is not implemented.
> > This allows the usage of a mailbox to trigger firmware actions on SoCs
> > which either don't have a separate management processor or on which
> > such a core is not available. A user of this mailbox could be the SCP
> > interface.
> >
> > Modified from Andre Przywara's v2 patch
> > https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Flore
> > .kernel.org%2Fpatchwork%2Fpatch%2F812999%2F&data=02%7C01%7
> Cpeng.fa
> >
> n%40nxp.com%7C296c7cd2225e4ca32bb808d74099afb2%7C686ea1d3bc2b4
> c6fa92cd
> >
> 99c5c301635%7C0%7C0%7C637048901144091126&sdata=JDo%2Be7Tt
> hoi4jve0O
> > S8qe3%2Fpji4g8CgRxL7ntCQx3Fg%3D&reserved=0
> >
> > Cc: Andre Przywara <[email protected]>
> > Signed-off-by: Peng Fan <[email protected]>
> > ---
>
> [snip]
>
> > +typedef unsigned long (smc_mbox_fn)(unsigned int, unsigned long,
> > + unsigned long, unsigned long,
> > + unsigned long, unsigned long,
> > + unsigned long);
> > +static smc_mbox_fn *invoke_smc_mbox_fn;
>
> Sorry for spotting this so late, the only thing that concerns me here with this
> singleton is if we happen to have both an arm,smc-mbox and arm,hvc-mbox
> configured in the system, this would not work.
Yes. Thanks for spotting this.
I do not believe this could be a
> functional use case, but we should probably guard against that or better yet,
> move that into the arm_smc_chan_data private structure?
Agree. Will Fix in v9.
Thanks,
Peng.
> --
> Florian