Re: [PATCH V15 14/15] irqchip: Add LoongArch CPU interrupt controller support

From: Huacai Chen
Date: Fri Jul 15 2022 - 11:12:16 EST


Hi, Jianmin,

On Fri, Jul 15, 2022 at 3:11 PM 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 expose the fwnode_handle to map them, and get mapped irq
> by irq_create_mapping when using them.
>
> Co-developed-by: Jianmin Lv <lvjianmin@xxxxxxxxxxx>
> Signed-off-by: Jianmin Lv <lvjianmin@xxxxxxxxxxx>
> Signed-off-by: Huacai Chen <chenhuacai@xxxxxxxxxxx>
> ---
> arch/loongarch/include/asm/irq.h | 8 +--
> arch/loongarch/kernel/irq.c | 15 ++++-
> arch/loongarch/kernel/time.c | 14 ++++-
> drivers/irqchip/Kconfig | 10 +++
> drivers/irqchip/Makefile | 1 +
> drivers/irqchip/irq-loongarch-cpu.c | 119 ++++++++++++++++++++++++++++++++++++
> 6 files changed, 157 insertions(+), 10 deletions(-)
> create mode 100644 drivers/irqchip/irq-loongarch-cpu.c
>
> diff --git a/arch/loongarch/include/asm/irq.h b/arch/loongarch/include/asm/irq.h
> index a826ac4..ca46856 100644
> --- a/arch/loongarch/include/asm/irq.h
> +++ b/arch/loongarch/include/asm/irq.h
> @@ -35,9 +35,6 @@ static inline bool on_irq_stack(int cpu, unsigned long sp)
> return (low <= sp && sp <= high);
> }
>
> -int get_ipi_irq(void);
> -int get_pmc_irq(void);
> -int get_timer_irq(void);
> void spurious_interrupt(void);
>
> #define NR_IRQS_LEGACY 16
> @@ -94,13 +91,10 @@ struct acpi_vector_group {
> struct acpi_madt_msi_pic;
> struct acpi_madt_lpc_pic;
>
> -struct irq_domain *loongarch_cpu_irq_init(void);
> -
> int liointc_acpi_init(struct irq_domain *parent,
> struct acpi_madt_lio_pic *acpi_liointc);
> int eiointc_acpi_init(struct irq_domain *parent,
> struct acpi_madt_eio_pic *acpi_eiointc);
> -
> int htvec_acpi_init(struct irq_domain *parent,
> struct acpi_madt_ht_pic *acpi_htvec);
> int pch_lpc_acpi_init(struct irq_domain *parent,
> @@ -120,7 +114,7 @@ int pch_pic_acpi_init(struct irq_domain *parent,
> extern struct acpi_madt_msi_pic *acpi_pchmsi[MAX_IO_PICS];
> extern struct acpi_madt_bio_pic *acpi_pchpic[MAX_IO_PICS];
>
> -extern struct irq_domain *cpu_domain;
> +extern struct fwnode_handle *cpuintc_handle;
> extern struct fwnode_handle *liointc_handle;
> extern struct fwnode_handle *pch_lpc_handle;
> extern struct fwnode_handle *pch_pic_handle[MAX_IO_PICS];
> diff --git a/arch/loongarch/kernel/irq.c b/arch/loongarch/kernel/irq.c
> index 06f2a15..99924d8 100644
> --- a/arch/loongarch/kernel/irq.c
> +++ b/arch/loongarch/kernel/irq.c
> @@ -25,7 +25,6 @@
> DEFINE_PER_CPU_SHARED_ALIGNED(irq_cpustat_t, irq_stat);
> EXPORT_PER_CPU_SYMBOL(irq_stat);
>
> -struct irq_domain *cpu_domain;
> struct acpi_vector_group pch_group[MAX_IO_PICS];
> struct acpi_vector_group msi_group[MAX_IO_PICS];
>
> @@ -89,6 +88,16 @@ static void __init init_vec_parent_group(void)
> acpi_table_parse(ACPI_SIG_MCFG, early_pci_mcfg_parse);
> }
>
> +static int __init get_ipi_irq(void)
> +{
> + struct irq_domain *d = irq_find_matching_fwnode(cpuintc_handle, DOMAIN_BUS_ANY);
> +
> + if (d)
> + return irq_create_mapping(d, EXCCODE_IPI - EXCCODE_INT_START);
> +
> + return -EINVAL;
> +}
> +
> void __init init_IRQ(void)
> {
> int i;
> @@ -105,7 +114,9 @@ void __init init_IRQ(void)
> init_vec_parent_group();
> irqchip_init();
> #ifdef CONFIG_SMP
> - ipi_irq = EXCCODE_IPI - EXCCODE_INT_START;
> + ipi_irq = get_ipi_irq();
> + if (ipi_irq < 0)
> + panic("IPI IRQ mapping failed\n");
> irq_set_percpu_devid(ipi_irq);
> r = request_percpu_irq(ipi_irq, loongson3_ipi_interrupt, "IPI", &ipi_dummy_dev);
> if (r < 0)
> diff --git a/arch/loongarch/kernel/time.c b/arch/loongarch/kernel/time.c
> index fe68238..79dc5ed 100644
> --- a/arch/loongarch/kernel/time.c
> +++ b/arch/loongarch/kernel/time.c
> @@ -123,6 +123,16 @@ void sync_counter(void)
> csr_write64(-init_timeval, LOONGARCH_CSR_CNTC);
> }
>
> +static int get_timer_irq(void)
> +{
> + struct irq_domain *d = irq_find_matching_fwnode(cpuintc_handle, DOMAIN_BUS_ANY);
> +
> + if (d)
> + return irq_create_mapping(d, EXCCODE_TIMER - EXCCODE_INT_START);
> +
> + return -EINVAL;
> +}
> +
> int constant_clockevent_init(void)
> {
> unsigned int irq;
> @@ -132,7 +142,9 @@ int constant_clockevent_init(void)
> struct clock_event_device *cd;
> static int timer_irq_installed = 0;
>
> - irq = EXCCODE_TIMER - EXCCODE_INT_START;
> + irq = get_timer_irq();
> + if (irq < 0)
> + pr_err("Failed to map irq %d (timer)\n", irq);
>
> cd = &per_cpu(constant_clockevent_device, cpu);
>
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index 8f077d3..f53164c 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 0cfd4f0..e559007 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-$(CONFIG_LOONGSON_EIOINTC) += irq-loongson-eiointc.o
> obj-$(CONFIG_LOONGSON_HTPIC) += irq-loongson-htpic.o
> diff --git a/drivers/irqchip/irq-loongarch-cpu.c b/drivers/irqchip/irq-loongarch-cpu.c
> new file mode 100644
> index 0000000..476f407
> --- /dev/null
> +++ b/drivers/irqchip/irq-loongarch-cpu.c
> @@ -0,0 +1,119 @@
> +// 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>
> +
> +static struct irq_domain *irq_domain;
> +struct fwnode_handle *cpuintc_handle;
> +
> +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 = "CPUINTC",
> + .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);
> + }
> +}
> +
> +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,
> +};
> +
> +static int __init loongarch_cpu_irq_init(void)
> +{
> + /* Mask interrupts. */
> + clear_csr_ecfg(ECFG0_IM);
> + clear_csr_estat(ESTATF_IP);
> +
> + cpuintc_handle = irq_domain_alloc_fwnode(NULL);
> + irq_domain = irq_domain_create_linear(cpuintc_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);
> +
> + return 0;
> +}
> +
> +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;
> +
> + 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);

I think loongarch_cpu_irq_init() and coreintc_acpi_init_v1() can be
merged like below, which makes code simpler.

static int __init loongarch_cpu_irq_init(union acpi_subtable_headers
*header, const unsigned long end)
{
struct fwnode_handle *domain_handle;

if (irq_domain)
return 0;

/* Mask interrupts. */
clear_csr_ecfg(ECFG0_IM);
clear_csr_estat(ESTATF_IP);

domain_handle = irq_domain_alloc_fwnode(NULL);
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");

acpi_cascade_irqdomain_init();
set_handle_irq(&handle_cpu_irq);

return 0;
}
IRQCHIP_ACPI_DECLARE(cpuintc_v1, ACPI_MADT_TYPE_CORE_PIC,
NULL, ACPI_MADT_CORE_PIC_VERSION_V1, loongarch_cpu_irq_init);

Thanks,
Huacai
> --
> 1.8.3.1
>
>