Re: [RFC PATCH v2 30/31] kvx: Add power controller driver

[Yann Sionneau]

Hello Krzysztof, Arnd, all,

On 1/22/23 12:54, Krzysztof Kozlowski wrote:
> On 20/01/2023 15:10, Yann Sionneau wrote:
> > From: Jules Maselbas <jmaselbas@xxxxxxxxx>
> >
> > The Power Controller (pwr-ctrl) control cores reset and wake-up
> > procedure.
> > +
> > +int __init kvx_pwr_ctrl_probe(void)
> > +{
> > +	struct device_node *ctrl;
> > +
> > +	ctrl = get_pwr_ctrl_node();
> > +	if (!ctrl) {
> > +		pr_err("Failed to get power controller node\n");
> > +		return -EINVAL;
> > +	}
> > +
> > +	if (!of_device_is_compatible(ctrl, "kalray,kvx-pwr-ctrl")) {
> > +		pr_err("Failed to get power controller node\n");
> No. Drivers go to drivers, not to arch directory. This should be a
> proper driver instead of some fake stub doing its own driver matching.
> You need to rework this.

I am working on a v3 patchset, therefore I am working on a solution for 
this "pwr-ctrl" driver that needs to go somewhere else than arch/kvx/.

The purpose of this "driver" is just to expose a void 
kvx_pwr_ctrl_cpu_poweron(unsigned int cpu) function, used by 
kernel/smpboot.c function __cpu_up() in order to start secondary CPUs in 
SMP config.

Doing this, on our SoC, requires writing 3 registers in a memory-mapped 
device named "power controller".

I made some researches in drivers/ but I am not sure yet what's a good 
place that fits what our device is doing (booting secondary CPUs).

* drivers/power/reset seems to be for resetting the entire SoC

* drivers/power/supply seems to be to control power supplies ICs/periph.

* drivers/reset seems to be for device reset

* drivers/pmdomain maybe ?

* drivers/soc ?

* drivers/platform ?

* drivers/misc ?

What do you think?

Thanks.

Regards,

--

Yann