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Date:   Sat, 18 Jun 2022 11:59:32 +0100
Message-ID: <87czf6p78r.wl-maz@kernel.org>
From:   Marc Zyngier <maz@kernel.org>
To:     Jianmin Lv <lvjianmin@loongson.cn>
Cc:     Thomas Gleixner <tglx@linutronix.de>, linux-kernel@vger.kernel.org,
        Hanjun Guo <guohanjun@huawei.com>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Jiaxun Yang <jiaxun.yang@flygoat.com>,
        Huacai Chen <chenhuacai@loongson.cn>
Subject: Re: [PATCH V12 03/10] irqchip: Add LoongArch CPU interrupt controller support
In-Reply-To: <1655273250-23495-4-git-send-email-lvjianmin@loongson.cn>
References: <1655273250-23495-1-git-send-email-lvjianmin@loongson.cn>
        <1655273250-23495-4-git-send-email-lvjianmin@loongson.cn>
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On Wed, 15 Jun 2022 07:07:23 +0100,
Jianmin Lv <lvjianmin@loongson.cn> wrote:
> 
> From: Huacai Chen <chenhuacai@loongson.cn>
> 
> 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@loongson.cn>
> Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
> ---
>  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.