Re: [PATCH v4 3/5] drivers: psci: refactor psci_cpu_init_idle in preparation for ACPI LPI support

[Sudeep Holla]

On 09/06/16 14:24, Lorenzo Pieralisi wrote:
> On Tue, Apr 19, 2016 at 01:30:11PM +0100, Sudeep Holla wrote:
> > Inorder to accomodate bot DT and ACPI LPI support in psci_cpu_init_idle,
> > move the device tree specific into psci_dt_cpu_init_idle.
> >
> > Cc: Mark Rutland <mark.rutland@xxxxxxx>
> > Cc: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
> > Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> > Signed-off-by: Sudeep Holla <sudeep.holla@xxxxxxx>
> > ---
> >   drivers/firmware/psci.c | 23 +++++++++--------------
> >   1 file changed, 9 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/firmware/psci.c b/drivers/firmware/psci.c
> > index 11bfee8b79a9..af6c5c839568 100644
> > --- a/drivers/firmware/psci.c
> > +++ b/drivers/firmware/psci.c
> > @@ -250,11 +250,11 @@ static int __init psci_features(u32 psci_func_id)
> >   #ifdef CONFIG_CPU_IDLE
> >   static DEFINE_PER_CPU_READ_MOSTLY(u32 *, psci_power_state);
> >
> > -static int psci_dt_cpu_init_idle(struct device_node *cpu_node, int cpu)
> > +static int psci_dt_cpu_init_idle(unsigned int cpu)
>
> Unfortunately you would break ARM 32-bit if you did that.

Ah right, I failed to catch this. Thanks for spotting this.

[...]

> >   int psci_cpu_init_idle(unsigned int cpu)
> >   {
> > -	struct device_node *cpu_node;
> > -	int ret;
> > -
> > -	cpu_node = of_get_cpu_node(cpu, NULL);
> > -	if (!cpu_node)
> > -		return -ENODEV;
> > -
> > -	ret = psci_dt_cpu_init_idle(cpu_node, cpu);
> > -
> > -	of_node_put(cpu_node);
> > -
> > -	return ret;
> > +	return psci_dt_cpu_init_idle(cpu);
>
> How about leaving code as is and you wrap the cpu_node retrieval:
>
> if (!acpi_disabled) {
> 	acpi_idle_init();
> } else {
> 	cpu_node = of_get_cpu_node(cpu, NULL);
> 	if (!cpu_node)
> 		return -ENODEV;
>
> 	ret = psci_dt_cpu_init_idle(cpu_node, cpu);
>
> 	of_node_put(cpu_node);
> }
>
> ?
>
> Alternatively, you could create an intermediate stub
> __psci_dt_cpu_init_idle(), that will be used for CONFIG_ARM
> cpuidle_ops.init and psci_dt_cpu_init_idle() after retrieving
> the cpu_node, which I think is slightly cleaner.

I like this approach more.

--
Regards,
Sudeep