Re: [PATCH 2/3] pinctrl: stm32: protect configuration registers with a hwspinlock

[Benjamin Gaignard <benjamin.gaignard@xxxxxxxxxx>]

Le lun. 19 nov. 2018 à 13:20, Linus Walleij <linus.walleij@xxxxxxxxxx> a écrit :
>
> On Tue, Nov 13, 2018 at 10:51 AM Benjamin Gaignard
> <benjamin.gaignard@xxxxxxxxxx> wrote:
>
> > If a hwspinlock if defined in device tree use it to protect
> > configuration registers.
> >
> > Signed-off-by: Benjamin Gaignard <benjamin.gaignard@xxxxxx>
>
> Patch applied with Alex' ACK.

Thanks

>
> Out of curiosity: what is it protecting against?
> I would guess simultaneous access from another CPU
> but the commit doesn't say.
>
> Simultaneous access from two CPUs makes it extra important
> that all register access is read-modify-write, so I'd have a second
> check over the code to make sure this is the case.

Yes it is to protect configuration registers from being used at the same by
cortexA and cortexM.

>
> Yours,
> Linus Walleij