Re: [PATCH V14 14/15] irqchip / ACPI: Introduce ACPI_IRQ_MODEL_LPIC for LoongArch

[Jianmin Lv]

On 2022/7/8 上午11:17, Jianmin Lv wrote:
> On 2022/7/7 下午8:59, Marc Zyngier wrote:
> > On Sun, 03 Jul 2022 09:45:31 +0100,
> > Jianmin Lv <lvjianmin@xxxxxxxxxxx> wrote:
> > > For LoongArch, ACPI_IRQ_MODEL_LPIC is introduced, and then the
> > > callback acpi_get_gsi_domain_id and acpi_gsi_to_irq_fallback are
> > > implemented.
> > >
> > > The acpi_get_gsi_domain_id callback returns related fwnode handle
> > > of irqdomain for different GSI range.
> > >
> > > The acpi_gsi_to_irq_fallback will create new mapping for gsi when
> > > the mapping of it is not found.
> > >
> > > Signed-off-by: Jianmin Lv <lvjianmin@xxxxxxxxxxx>
> > > ---
> > >   drivers/acpi/bus.c                  |  3 +++
> > >   drivers/irqchip/irq-loongarch-cpu.c | 37 
> > > +++++++++++++++++++++++++++++++++++++
> > >   include/linux/acpi.h                |  1 +
> > >   3 files changed, 41 insertions(+)
> > >
> > > diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c
> > > index 86fa61a..63fbf00 100644
> > > --- a/drivers/acpi/bus.c
> > > +++ b/drivers/acpi/bus.c
> > > @@ -1145,6 +1145,9 @@ static int __init acpi_bus_init_irq(void)
> > >       case ACPI_IRQ_MODEL_PLATFORM:
> > >           message = "platform specific model";
> > >           break;
> > > +    case ACPI_IRQ_MODEL_LPIC:
> > > +        message = "LPIC";
> > > +        break;
> > >       default:
> > >           pr_info("Unknown interrupt routing model\n");
> > >           return -ENODEV;
> > > diff --git a/drivers/irqchip/irq-loongarch-cpu.c 
> > > b/drivers/irqchip/irq-loongarch-cpu.c
> > > index c2f7411..1b241d7 100644
> > > --- a/drivers/irqchip/irq-loongarch-cpu.c
> > > +++ b/drivers/irqchip/irq-loongarch-cpu.c
> > > @@ -15,6 +15,41 @@
> > >   static struct irq_domain *irq_domain;
> > > +static int lpic_gsi_to_irq(u32 gsi)
> > > +{
> > > +    /* Only pch irqdomain transferring is required for LoongArch. */
> > > +    if (gsi >= GSI_MIN_PCH_IRQ && gsi <= GSI_MAX_PCH_IRQ)
> > > +        return acpi_register_gsi(NULL, gsi, ACPI_LEVEL_SENSITIVE, 
> > > ACPI_ACTIVE_HIGH);
> > > +    return -1;
> >
> > The expected return value on failure is 0 (which indicates that no
> > interrupt was mapped). Here, things will break as acpi_gsi_to_irq()
> > stores the result as unsigned, and compares the result to 0.
>
> Ok, thanks, I'll change the return value to 0 on failure and change 
> return type to unsigned int.

Hi, Marc, if the return type is changed to unsigned int, the return type 
of the fallback handler in the patch:
ACPI: irq: Allow acpi_gsi_to_irq() to have an arch-specific fallback

should be changed to unsigned int too, yes?

> >     M.