Re: [PATCH V12 04/10] irqchip: create library file for LoongArch irqchip driver

[Marc Zyngier <maz@kernel.org>]

On Wed, 15 Jun 2022 07:07:24 +0100,
Jianmin Lv <lvjianmin@loongson.cn> wrote:
> 
> The library file contains following content:
> - Implement acpi_get_gsi_domain_id callback.
> - Implement initialization of vector group entries and APIs
>   for building hierachy irqdomains.
> 
> Signed-off-by: Jianmin Lv <lvjianmin@loongson.cn>
> ---
>  drivers/irqchip/Makefile                   |   2 +-
>  drivers/irqchip/irq-loongarch-pic-common.c | 122 +++++++++++++++++++++++++++++
>  drivers/irqchip/irq-loongarch-pic-common.h |  39 +++++++++
>  3 files changed, 162 insertions(+), 1 deletion(-)
>  create mode 100644 drivers/irqchip/irq-loongarch-pic-common.c
>  create mode 100644 drivers/irqchip/irq-loongarch-pic-common.h
> 
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index 6894a13..2d0d871 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -103,7 +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_IRQ_LOONGARCH_CPU)		+= irq-loongarch-cpu.o irq-loongarch-pic-common.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-pic-common.c b/drivers/irqchip/irq-loongarch-pic-common.c
> new file mode 100644
> index 0000000..2f75362
> --- /dev/null
> +++ b/drivers/irqchip/irq-loongarch-pic-common.c
> @@ -0,0 +1,122 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2022 Loongson Limited, All Rights Reserved.
> + */
> +
> +#include <linux/irq.h>
> +#include <linux/pci.h>
> +#include <linux/acpi.h>
> +#include "irq-loongarch-pic-common.h"
> +
> +static struct acpi_vector_group vector_group[MAX_IO_PICS];
> +
> +struct acpi_madt_bio_pic *acpi_pchpic[MAX_IO_PICS];
> +
> +struct fwnode_handle *liointc_handle;
> +struct fwnode_handle *pch_lpc_handle;
> +struct fwnode_handle *pch_msi_handle[MAX_IO_PICS];
> +struct fwnode_handle *pch_pic_handle[MAX_IO_PICS];

Why aren't these in individual drivers, and then have accessors to
retrieve them?

> +
> +static int find_pch_pic(u32 gsi)
> +{
> +	int i, start, end;
> +
> +	/* Find the PCH_PIC that manages this GSI. */
> +	for (i = 0; i < MAX_IO_PICS; i++) {
> +		struct acpi_madt_bio_pic *irq_cfg = acpi_pchpic[i];
> +
> +		if (!irq_cfg)
> +			return -1;
> +
> +		start = irq_cfg->gsi_base;
> +		end   = irq_cfg->gsi_base + irq_cfg->size;
> +		if (gsi >= start && gsi < end)
> +			return i;
> +	}
> +
> +	pr_err("ERROR: Unable to locate PCH_PIC for GSI %d\n", gsi);
> +	return -1;
> +}

Same thing. This really should be in the PCH driver, and be called by
lpic_get_gsi_domain().

> +
> +struct fwnode_handle *lpic_get_gsi_domain_id(u32 gsi)
> +{
> +	int id;
> +	struct fwnode_handle *domain_handle = NULL;
> +
> +	switch (gsi) {
> +	case GSI_MIN_CPU_IRQ ... GSI_MAX_CPU_IRQ:
> +		if (liointc_handle)
> +			domain_handle = liointc_handle;
> +		break;
> +
> +	case GSI_MIN_LPC_IRQ ... GSI_MAX_LPC_IRQ:
> +		if (pch_lpc_handle)
> +			domain_handle = pch_lpc_handle;
> +		break;
> +
> +	case GSI_MIN_PCH_IRQ ... GSI_MAX_PCH_IRQ:
> +		id = find_pch_pic(gsi);
> +		if (id >= 0 && pch_pic_handle[id])
> +			domain_handle = pch_pic_handle[id];
> +
> +		break;
> +	}
> +
> +	return domain_handle;
> +}
> +
> +static int pci_mcfg_parse(struct acpi_table_header *header)
> +{
> +	struct acpi_table_mcfg *mcfg;
> +	struct acpi_mcfg_allocation *mptr;
> +	int i, n;
> +
> +	if (header->length < sizeof(struct acpi_table_mcfg))
> +		return -EINVAL;
> +
> +	n = (header->length - sizeof(struct acpi_table_mcfg)) /
> +					sizeof(struct acpi_mcfg_allocation);
> +	mcfg = (struct acpi_table_mcfg *)header;
> +	mptr = (struct acpi_mcfg_allocation *) &mcfg[1];
> +
> +	for (i = 0; i < n; i++, mptr++)
> +		vector_group[mptr->pci_segment].node = (mptr->address >> 44) & 0xf;
> +
> +	return 0;
> +}
> +
> +void __init init_vector_parent_group(void)
> +{
> +	acpi_table_parse(ACPI_SIG_MCFG, pci_mcfg_parse);
> +}

I really don't think the PCI code should be anywhere near
this. Frankly, this file looks like a dumping ground for totally
unrelated stuff.

> +
> +void acpi_set_vector_parent(int node, struct irq_domain *parent)
> +{
> +	int i;
> +
> +	if (cpu_has_flatmode)
> +		node = cpu_to_node(node * CORES_PER_EIO_NODE);
> +
> +	for (i = 0; i < MAX_IO_PICS; i++) {
> +		if (node == vector_group[i].node) {
> +			vector_group[i].parent = parent;
> +			return;
> +		}
> +	}
> +}
> +
> +struct irq_domain *acpi_get_msi_parent(int index)
> +{
> +	return vector_group[index].parent;
> +}
> +
> +struct irq_domain *acpi_get_pch_parent(int node)
> +{
> +	int i;
> +
> +	for (i = 0; i < MAX_IO_PICS; i++) {
> +		if (node == vector_group[i].node)
> +			return vector_group[i].parent;
> +	}
> +	return NULL;
> +}

Same thing. There is nothing "common" here. All this should be split
in the various drivers, where they belong.

	M.

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