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

Marc Zyngier
2022-07-07T12:59:17Z

On Sun, 03 Jul 2022 09:45:31 +0100,
Jianmin Lv <lvjianmin@loongson.cn> 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@loongson.cn>
> ---
> 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.

M.

--
Without deviation from the norm, progress is not possible.