Re: [PATCH V12 03/10] irqchip: Add LoongArch CPU interrupt controller support

From: Marc Zyngier
Date: Sat Jun 18 2022 - 07:01:25 EST


On Wed, 15 Jun 2022 07:07:23 +0100,
Jianmin Lv <lvjianmin@xxxxxxxxxxx> wrote:
>
> From: Huacai Chen <chenhuacai@xxxxxxxxxxx>
>
> LoongArch CPUINTC stands for CSR.ECFG/CSR.ESTAT and related interrupt
> controller that described in Section 7.4 of "LoongArch Reference Manual,
> Vol 1". For more information please refer Documentation/loongarch/irq-
> chip-model.rst.
>
> LoongArch CPUINTC has 13 interrupt sources: SWI0~1, HWI0~7, IPI, TI
> (Timer) and PCOV (PMC). IRQ mappings of HWI0~7 are configurable (can be
> created from DT/ACPI), but IPI, TI (Timer) and PCOV (PMC) are hardcoded
> bits, so we define get_xxx_irq() for them.
>
> Change-Id: I53fb0be768daeeecc90d0ccc0bb0becd3d4e6984

Please drop this Change-Id. The upstream kernel doesn't use Gerrit.

> Co-developed-by: Jianmin Lv <lvjianmin@xxxxxxxxxxx>
> Signed-off-by: Jianmin Lv <lvjianmin@xxxxxxxxxxx>
> Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> ---
> drivers/acpi/bus.c | 3 +
> drivers/irqchip/Kconfig | 10 +++
> drivers/irqchip/Makefile | 1 +
> drivers/irqchip/irq-loongarch-cpu.c | 134 ++++++++++++++++++++++++++++++++++++
> include/linux/acpi.h | 1 +
> 5 files changed, 149 insertions(+)
> create mode 100644 drivers/irqchip/irq-loongarch-cpu.c
>
> 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;

This should be part of the patch that deals with the ACPI-specific
part of the architecture, which is the following patch.

> default:
> pr_info("Unknown interrupt routing model\n");
> return -ENODEV;
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 4ab1038..4126b1c 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -546,6 +546,16 @@ config EXYNOS_IRQ_COMBINER
> Say yes here to add support for the IRQ combiner devices embedded
> in Samsung Exynos chips.
>
> +config IRQ_LOONGARCH_CPU
> + bool
> + select GENERIC_IRQ_CHIP
> + select IRQ_DOMAIN
> + select GENERIC_IRQ_EFFECTIVE_AFF_MASK
> + help
> + Support for the LoongArch CPU Interrupt Controller. For details of
> + irq chip hierarchy on LoongArch platforms please read the document
> + Documentation/loongarch/irq-chip-model.rst.
> +
> config LOONGSON_LIOINTC
> bool "Loongson Local I/O Interrupt Controller"
> depends on MACH_LOONGSON64
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index 5b67450..6894a13 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -103,6 +103,7 @@ obj-$(CONFIG_LS1X_IRQ) += irq-ls1x.o
> obj-$(CONFIG_TI_SCI_INTR_IRQCHIP) += irq-ti-sci-intr.o
> obj-$(CONFIG_TI_SCI_INTA_IRQCHIP) += irq-ti-sci-inta.o
> obj-$(CONFIG_TI_PRUSS_INTC) += irq-pruss-intc.o
> +obj-$(CONFIG_IRQ_LOONGARCH_CPU) += irq-loongarch-cpu.o
> obj-$(CONFIG_LOONGSON_LIOINTC) += irq-loongson-liointc.o
> obj-$(CONFIG_LOONGSON_HTPIC) += irq-loongson-htpic.o
> obj-$(CONFIG_LOONGSON_HTVEC) += irq-loongson-htvec.o
> diff --git a/drivers/irqchip/irq-loongarch-cpu.c b/drivers/irqchip/irq-loongarch-cpu.c
> new file mode 100644
> index 0000000..c382bd9
> --- /dev/null
> +++ b/drivers/irqchip/irq-loongarch-cpu.c
> @@ -0,0 +1,134 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * Copyright (C) 2020-2022 Loongson Technology Corporation Limited
> + */
> +
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip.h>
> +#include <linux/irqdomain.h>
> +
> +#include <asm/loongarch.h>
> +#include <asm/setup.h>
> +#include "irq-loongarch-pic-common.h"
> +
> +static struct irq_domain *irq_domain;
> +
> +static void mask_loongarch_irq(struct irq_data *d)
> +{
> + clear_csr_ecfg(ECFGF(d->hwirq));
> +}
> +
> +static void unmask_loongarch_irq(struct irq_data *d)
> +{
> + set_csr_ecfg(ECFGF(d->hwirq));
> +}
> +
> +static struct irq_chip cpu_irq_controller = {
> + .name = "LoongArch",

Why is it "LoongArch" and not "CPUINTC", which would make a lot more
sense?

> + .irq_mask = mask_loongarch_irq,
> + .irq_unmask = unmask_loongarch_irq,
> +};
> +
> +static void handle_cpu_irq(struct pt_regs *regs)
> +{
> + int hwirq;
> + unsigned int estat = read_csr_estat() & CSR_ESTAT_IS;
> +
> + while ((hwirq = ffs(estat))) {
> + estat &= ~BIT(hwirq - 1);
> + generic_handle_domain_irq(irq_domain, hwirq - 1);
> + }
> +}
> +
> +int get_ipi_irq(void)
> +{
> + return irq_create_mapping(irq_domain, EXCCODE_IPI - EXCCODE_INT_START);
> +}
> +
> +int get_pmc_irq(void)
> +{
> + return irq_create_mapping(irq_domain, EXCCODE_PMC - EXCCODE_INT_START);
> +}
> +
> +int get_timer_irq(void)
> +{
> + return irq_create_mapping(irq_domain, EXCCODE_TIMER - EXCCODE_INT_START);
> +}
> +
> +static int loongarch_cpu_intc_map(struct irq_domain *d, unsigned int irq,
> + irq_hw_number_t hwirq)
> +{
> + irq_set_noprobe(irq);
> + irq_set_chip_and_handler(irq, &cpu_irq_controller, handle_percpu_irq);
> +
> + return 0;
> +}
> +
> +static const struct irq_domain_ops loongarch_cpu_intc_irq_domain_ops = {
> + .map = loongarch_cpu_intc_map,
> + .xlate = irq_domain_xlate_onecell,
> +};
> +
> +struct irq_domain * __init loongarch_cpu_irq_init(void)
> +{
> + struct fwnode_handle *domain_handle;
> +
> + /* Mask interrupts. */
> + clear_csr_ecfg(ECFG0_IM);
> + clear_csr_estat(ESTATF_IP);
> +
> + domain_handle = irq_domain_alloc_fwnode(NULL);

Please don't use NULL here, as this is supposed to be a physical
address. If you don't have any physical address at hand (because this
driver isn't using MMIO), use irq_domain_alloc_named_fwnode() instead.

> + irq_domain = irq_domain_create_linear(domain_handle, EXCCODE_INT_NUM,
> + &loongarch_cpu_intc_irq_domain_ops, NULL);
> +
> + if (!irq_domain)
> + panic("Failed to add irqdomain for LoongArch CPU");
> +
> + set_handle_irq(&handle_cpu_irq);
> + acpi_set_irq_model(ACPI_IRQ_MODEL_LPIC, lpic_get_gsi_domain_id);

lpic_get_gsi_domain_id only gets defined in the following patch, so
the series cannot be bisected. Please fix this (the series should
compile every step of the way).

> +
> + return irq_domain;
> +}
> +
> +static int __init
> +liointc_parse_madt(union acpi_subtable_headers *header,
> + const unsigned long end)
> +{
> + struct acpi_madt_lio_pic *liointc_entry = (struct acpi_madt_lio_pic *)header;
> +
> + return liointc_acpi_init(irq_domain, liointc_entry);
> +}
> +
> +static int __init
> +eiointc_parse_madt(union acpi_subtable_headers *header,
> + const unsigned long end)
> +{
> + struct acpi_madt_eio_pic *eiointc_entry = (struct acpi_madt_eio_pic *)header;
> +
> + return eiointc_acpi_init(irq_domain, eiointc_entry);
> +}
> +static int __init acpi_cascade_irqdomain_init(void)
> +{
> + acpi_table_parse_madt(ACPI_MADT_TYPE_LIO_PIC,
> + liointc_parse_madt, 0);
> + acpi_table_parse_madt(ACPI_MADT_TYPE_EIO_PIC,
> + eiointc_parse_madt, 0);
> + return 0;
> +}
> +static int __init coreintc_acpi_init_v1(union acpi_subtable_headers *header,
> + const unsigned long end)
> +{
> + if (irq_domain)
> + return 0;
> +
> + init_vector_parent_group();
> + loongarch_cpu_irq_init();
> + acpi_cascade_irqdomain_init();
> + return 0;
> +}
> +IRQCHIP_ACPI_DECLARE(coreintc_v1, ACPI_MADT_TYPE_CORE_PIC,
> + NULL, ACPI_MADT_CORE_PIC_VERSION_V1,
> + coreintc_acpi_init_v1);
> diff --git a/include/linux/acpi.h b/include/linux/acpi.h
> index 957e23f..d2f5108 100644
> --- a/include/linux/acpi.h
> +++ b/include/linux/acpi.h
> @@ -105,6 +105,7 @@ enum acpi_irq_model_id {
> ACPI_IRQ_MODEL_IOSAPIC,
> ACPI_IRQ_MODEL_PLATFORM,
> ACPI_IRQ_MODEL_GIC,
> + ACPI_IRQ_MODEL_LPIC,

This hunk should be moved to the patch that introduces
lpic_get_gsi_domain_id.

Thanks,

M.

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