Re: [PATCH 1/2] irqchip: irq-mst: Add MStar interrupt controller support

Marc Zyngier
2020-08-19T08:14:32Z

On 2020-08-19 04:42, Mark-PK Tsai wrote:
> Add MStar interrupt controller support using hierarchy irq
> domain.
>
> Signed-off-by: Mark-PK Tsai <mark-pk.tsai@mediatek.com>
> ---
> drivers/irqchip/Kconfig | 7 ++
> drivers/irqchip/Makefile | 1 +
> drivers/irqchip/irq-mst-intc.c | 195 +++++++++++++++++++++++++++++++++
> 3 files changed, 203 insertions(+)
> create mode 100644 drivers/irqchip/irq-mst-intc.c
>
> diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
> index bb70b7177f94..c3a9d880a4ea 100644
> --- a/drivers/irqchip/Kconfig
> +++ b/drivers/irqchip/Kconfig
> @@ -571,4 +571,11 @@ config LOONGSON_PCH_MSI
> help
> Support for the Loongson PCH MSI Controller.
>
> +config MST_IRQ
> + bool "MStar Interrupt Controller"
> + select IRQ_DOMAIN
> + select IRQ_DOMAIN_HIERARCHY
> + help
> + Support MStar Interrupt Controller.

What selects it? Can it have a default for the relevant platforms?

> +
> endmenu
> diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
> index 133f9c45744a..e2688a62403e 100644
> --- a/drivers/irqchip/Makefile
> +++ b/drivers/irqchip/Makefile
> @@ -111,3 +111,4 @@ obj-$(CONFIG_LOONGSON_HTPIC) +=
> irq-loongson-htpic.o
> obj-$(CONFIG_LOONGSON_HTVEC) += irq-loongson-htvec.o
> obj-$(CONFIG_LOONGSON_PCH_PIC) += irq-loongson-pch-pic.o
> obj-$(CONFIG_LOONGSON_PCH_MSI) += irq-loongson-pch-msi.o
> +obj-$(CONFIG_MST_IRQ) += irq-mst-intc.o
> diff --git a/drivers/irqchip/irq-mst-intc.c
> b/drivers/irqchip/irq-mst-intc.c
> new file mode 100644
> index 000000000000..38d567741860
> --- /dev/null
> +++ b/drivers/irqchip/irq-mst-intc.c
> @@ -0,0 +1,195 @@
> +// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
> +/*
> + * Copyright (c) 2020 MediaTek Inc.
> + * Author Mark-PK Tsai <mark-pk.tsai@mediatek.com>
> + */
> +#include <linux/interrupt.h>
> +#include <linux/io.h>
> +#include <linux/irq.h>
> +#include <linux/irqchip.h>
> +#include <linux/irqdomain.h>
> +#include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +
> +#define INTC_MASK 0x0
> +#define INTC_EOI 0x20
> +
> +struct mst_intc_chip_data {
> + raw_spinlock_t lock;
> + unsigned int irq_start, nr_irqs;
> + void __iomem *base;
> + bool no_eoi;

nit: please align the fields of the data structure on a vertical line.

> +};
> +
> +static void mst_poke_irq(struct irq_data *d, u32 offset)

Given that this is supposed to be the opposite of "clear", this
should be mst_set_irq().

> +{
> + irq_hw_number_t hwirq = irqd_to_hwirq(d);
> + struct mst_intc_chip_data *cd = irq_data_get_irq_chip_data(d);
> + u16 val, mask;
> +
> + mask = 1 << (hwirq % 16);
> + offset += (hwirq / 16) * 4;
> +
> + raw_spin_lock(&cd->lock);
> + val = readw_relaxed(cd->base + offset) | mask;
> + writew_relaxed(val, cd->base + offset);
> + raw_spin_unlock(&cd->lock);

Small improvement, but you still miss the fact that a masking
operation can also occur from an interrupt handler, and this
will cause a deadlock. You need to disable interrupts as well.

> +}
> +
> +static void mst_clear_irq(struct irq_data *d, u32 offset)
> +{
> + irq_hw_number_t hwirq = irqd_to_hwirq(d);
> + struct mst_intc_chip_data *cd = irq_data_get_irq_chip_data(d);
> + u16 val, mask;
> +
> + mask = 1 << (hwirq % 16);
> + offset += (hwirq / 16) * 4;
> +
> + raw_spin_lock(&cd->lock);
> + val = readw_relaxed(cd->base + offset) & ~mask;
> + writew_relaxed(val, cd->base + offset);
> + raw_spin_unlock(&cd->lock);
> +}
> +
> +static void mst_intc_mask_irq(struct irq_data *d)
> +{
> + mst_poke_irq(d, INTC_MASK);
> + irq_chip_mask_parent(d);
> +}
> +
> +static void mst_intc_unmask_irq(struct irq_data *d)
> +{
> + mst_clear_irq(d, INTC_MASK);
> + irq_chip_unmask_parent(d);
> +}
> +
> +static void mst_intc_eoi_irq(struct irq_data *d)
> +{
> + struct mst_intc_chip_data *cd = irq_data_get_irq_chip_data(d);
> +
> + if (!cd->no_eoi)
> + mst_poke_irq(d, INTC_EOI);
> +
> + irq_chip_eoi_parent(d);
> +}
> +
> +static struct irq_chip mst_intc_chip = {
> + .name = "mst-intc",
> + .irq_mask = mst_intc_mask_irq,
> + .irq_unmask = mst_intc_unmask_irq,
> + .irq_eoi = mst_intc_eoi_irq,
> + .irq_get_irqchip_state = irq_chip_get_parent_state,
> + .irq_set_irqchip_state = irq_chip_set_parent_state,
> + .irq_set_affinity = irq_chip_set_affinity_parent,
> + .irq_set_vcpu_affinity = irq_chip_set_vcpu_affinity_parent,
> + .irq_set_type = irq_chip_set_type_parent,
> + .irq_retrigger = irq_chip_retrigger_hierarchy,
> + .flags = IRQCHIP_SET_TYPE_MASKED |
> + IRQCHIP_SKIP_SET_WAKE |
> + IRQCHIP_MASK_ON_SUSPEND,
> +};
> +
> +static int mst_intc_domain_translate(struct irq_domain *d,
> + struct irq_fwspec *fwspec,
> + unsigned long *hwirq,
> + unsigned int *type)
> +{
> + if (is_of_node(fwspec->fwnode)) {
> + if (fwspec->param_count != 3)
> + return -EINVAL;
> +
> + /* No PPI should point to this domain */
> + if (fwspec->param[0] != 0)
> + return -EINVAL;
> +
> + *hwirq = fwspec->param[1];
> + *type = fwspec->param[2] & IRQ_TYPE_SENSE_MASK;
> + return 0;
> + }
> +
> + return -EINVAL;
> +}
> +
> +static int mst_intc_domain_alloc(struct irq_domain *domain, unsigned
> int virq,
> + unsigned int nr_irqs, void *data)
> +{
> + int i;
> + irq_hw_number_t hwirq;
> + struct irq_fwspec parent_fwspec, *fwspec = data;
> + struct mst_intc_chip_data *cd = (struct mst_intc_chip_data
> *)domain->host_data;

No cast necessary here.

> +
> + /* Not GIC compliant */
> + if (fwspec->param_count != 3)
> + return -EINVAL;
> +
> + /* No PPI should point to this domain */
> + if (fwspec->param[0])
> + return -EINVAL;
> +
> + if (fwspec->param[1] >= cd->nr_irqs)

This condition is bogus, as it doesn't take into account the nr_irqs
parameter.

> + return -EINVAL;
> +
> + hwirq = fwspec->param[1];
> + for (i = 0; i < nr_irqs; i++)
> + irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
> + &mst_intc_chip,
> + domain->host_data);
> +
> + parent_fwspec = *fwspec;
> + parent_fwspec.fwnode = domain->parent->fwnode;
> + parent_fwspec.param[1] = cd->irq_start + hwirq;
> + return irq_domain_alloc_irqs_parent(domain, virq, nr_irqs,
> &parent_fwspec);
> +}
> +
> +static const struct irq_domain_ops mst_intc_domain_ops = {
> + .translate = mst_intc_domain_translate,
> + .alloc = mst_intc_domain_alloc,
> + .free = irq_domain_free_irqs_common,
> +};
> +
> +int __init
> +mst_intc_of_init(struct device_node *dn, struct device_node *parent)
> +{
> + struct irq_domain *domain, *domain_parent;
> + struct mst_intc_chip_data *cd;
> + unsigned int irq_start, irq_end;

unsigned int != u32.

> +
> + domain_parent = irq_find_host(parent);
> + if (!domain_parent) {
> + pr_err("mst-intc: interrupt-parent not found\n");
> + return -EINVAL;
> + }
> +
> + if (of_property_read_u32_index(dn, "mstar,irqs-map-range", 0,
> &irq_start) ||
> + of_property_read_u32_index(dn, "mstar,irqs-map-range", 1,
> &irq_end))
> + return -EINVAL;
> +
> + cd = kzalloc(sizeof(*cd), GFP_KERNEL);
> + if (!cd)
> + return -ENOMEM;
> +
> + cd->base = of_iomap(dn, 0);
> + if (!cd->base) {
> + kfree(cd);
> + return -ENOMEM;
> + }
> +
> + cd->no_eoi = of_property_read_bool(dn, "mstar,intc-no-eoi");
> + raw_spin_lock_init(&cd->lock);
> + cd->irq_start = irq_start;
> + cd->nr_irqs = irq_end - irq_start + 1;
> + domain = irq_domain_add_hierarchy(domain_parent, 0, cd->nr_irqs, dn,
> + &mst_intc_domain_ops, cd);
> + if (!domain) {
> + iounmap(cd->base);
> + kfree(cd);
> + return -ENOMEM;
> + }
> +
> + return 0;
> +}
> +
> +IRQCHIP_DECLARE(mst_intc, "mstar,mst-intc", mst_intc_of_init);

Thanks,

M.
--
Jazz is not dead. It just smells funny...