Re: [PATCH 1/2] irqchip: irq-mt58xx: Add mt58xx interrupt controller support

From: Marc Zyngier
Date: Mon Aug 03 2020 - 04:04:45 EST

On 2020-08-03 07:22, Mark-PK Tsai wrote:
Add mt58xx interrupt controller support using hierarchy irq
domain.

Signed-off-by: Mark-PK Tsai <mark-pk.tsai@xxxxxxxxxxxx>
---
drivers/irqchip/Kconfig | 7 ++
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-mt58xx.c | 196 +++++++++++++++++++++++++++++++++++
3 files changed, 204 insertions(+)
create mode 100644 drivers/irqchip/irq-mt58xx.c

diff --git a/drivers/irqchip/Kconfig b/drivers/irqchip/Kconfig
index 216b3b8392b5..00453af78be0 100644
--- a/drivers/irqchip/Kconfig
+++ b/drivers/irqchip/Kconfig
@@ -572,4 +572,11 @@ config LOONGSON_PCH_MSI
help
Support for the Loongson PCH MSI Controller.

+config MT58XX_IRQ
+ bool "MT58XX IRQ"
+ select IRQ_DOMAIN
+ select IRQ_DOMAIN_HIERARCHY
+ help
+ Support Mediatek MT58XX Interrupt Controller.
+
endmenu
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index 133f9c45744a..5062e9bfa92d 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_MT58XX_IRQ) += irq-mt58xx.o
diff --git a/drivers/irqchip/irq-mt58xx.c b/drivers/irqchip/irq-mt58xx.c
new file mode 100644
index 000000000000..e45ad023afa6
--- /dev/null
+++ b/drivers/irqchip/irq-mt58xx.c
@@ -0,0 +1,196 @@
+// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
+/*
+ * Copyright (c) 2020 MediaTek Inc.
+ * Author Mark-PK Tsai <mark-pk.tsai@xxxxxxxxxxxx>
+ */
+
+#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>
+
+#define INTC_MASK 0x0
+#define INTC_EOI 0x20
+
+struct mtk_intc_chip_data {
+ char *name;
+ struct irq_chip chip;

There is no need to embed a full struct irqchip per controller, see below.

+ unsigned int irq_start, nr_irqs;
+ void __iomem *base;
+};
+
+static void mtk_poke_irq(struct irq_data *d, u32 offset)
+{
+ struct mtk_intc_chip_data *cd = irq_data_get_irq_chip_data(d);
+ void __iomem *base = cd->base;
+ u8 index = (u8)irqd_to_hwirq(d);

Why the restrictive type? Why isn't unsigned int good enough?

+ u16 val, mask;
+
+ mask = 1 << (index % 16);
+ val = readw_relaxed(base + offset + (index / 16) * 4) | mask;
+ writew_relaxed(val, base + offset + (index / 16) * 4);

RMW without locking, you will end-up with corruption.
Please store the address calculation in a temporaty variable to make it
more readable

+}
+
+static void mtk_clear_irq(struct irq_data *d, u32 offset)
+{
+ struct mtk_intc_chip_data *cd = irq_data_get_irq_chip_data(d);
+ void __iomem *base = cd->base;
+ u8 index = (u8)irqd_to_hwirq(d);
+ u16 val, mask;
+
+ mask = 1 << (index % 16);
+ val = readw_relaxed(base + offset + (index / 16) * 4) & ~mask;
+ writew_relaxed(val, base + offset + (index / 16) * 4);

Same comments.

+}
+
+static void mtk_intc_mask_irq(struct irq_data *d)
+{
+ mtk_poke_irq(d, INTC_MASK);
+ irq_chip_mask_parent(d);
+}
+
+static void mtk_intc_unmask_irq(struct irq_data *d)
+{
+ mtk_clear_irq(d, INTC_MASK);
+ irq_chip_unmask_parent(d);
+}
+
+static void mtk_intc_eoi_irq(struct irq_data *d)
+{
+ mtk_poke_irq(d, INTC_EOI);
+ irq_chip_eoi_parent(d);
+}
+
+static struct irq_chip mtk_intc_chip = {
+ .irq_mask = mtk_intc_mask_irq,
+ .irq_unmask = mtk_intc_unmask_irq,
+ .irq_eoi = mtk_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,

How about retrigger?

+ .irq_set_type = irq_chip_set_type_parent,
+ .flags = IRQCHIP_SET_TYPE_MASKED |
+ IRQCHIP_SKIP_SET_WAKE |
+ IRQCHIP_MASK_ON_SUSPEND,
+};
+
+static int mt58xx_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 mt58xx_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 mtk_intc_chip_data *cd = (struct mtk_intc_chip_data
*)domain->host_data;
+
+ /* 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)
+ return -EINVAL;
+
+ hwirq = fwspec->param[1];
+ for (i = 0; i < nr_irqs; i++)
+ irq_domain_set_hwirq_and_chip(domain, virq + i, hwirq + i,
+ &cd->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 mt58xx_intc_domain_ops = {
+ .translate = mt58xx_intc_domain_translate,
+ .alloc = mt58xx_intc_domain_alloc,
+ .free = irq_domain_free_irqs_common,
+};
+
+int __init
+mt58xx_intc_of_init(struct device_node *dn, struct device_node *parent)
+{
+ static int nr_intc;
+ struct irq_domain *domain, *domain_parent;
+ struct mtk_intc_chip_data *cd;
+ unsigned int irq_start, irq_end;
+
+ domain_parent = irq_find_host(parent);
+ if (!domain_parent) {
+ pr_err("mt58xx-intc: interrupt-parent not found\n");
+ return -EINVAL;
+ }
+
+ cd = kzalloc(sizeof(*cd), GFP_KERNEL);
+ if (!cd)
+ return -ENOMEM;
+
+ cd->chip = mtk_intc_chip;
+ if (of_property_read_u32_index(dn, "mediatek,irqs-map-range", 0,
&irq_start) ||
+ of_property_read_u32_index(dn, "mediatek,irqs-map-range", 1, &irq_end)) {
+ kfree(cd);
+ return -EINVAL;
+ }
+
+ if (of_property_read_bool(dn, "mediatek,intc-no-eoi"))
+ cd->chip.irq_eoi = irq_chip_eoi_parent;

No. Just add a flag to your chip data structure, and check for this
flag in your irq_eoi callback. Or provide two distinct irq_chip
structures that will only differ by the irq_eoi method.

+
+ cd->irq_start = irq_start;
+ cd->nr_irqs = irq_end - irq_start + 1;
+ cd->chip.name = kasprintf(GFP_KERNEL, "mt58xx-intc-%d", nr_intc++);

Neither. That's not useful, and is a waste of memory. Stick to constant
names in the irq_chip structure.

+ if (!cd->chip.name) {
+ kfree(cd);
+ return -ENOMEM;
+ }
+
+ cd->base = of_iomap(dn, 0);
+ if (!cd->base) {
+ kfree(cd->chip.name);
+ kfree(cd);
+ return -ENOMEM;
+ }
+
+ domain = irq_domain_add_hierarchy(domain_parent, 0, cd->nr_irqs,
+ dn, &mt58xx_intc_domain_ops, cd);
+ if (!domain) {
+ kfree(cd->chip.name);
+ iounmap(cd->base);
+ kfree(cd);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+IRQCHIP_DECLARE(mt58xx_intc, "mediatek,mt58xx-intc", mt58xx_intc_of_init);

On a side note, the merge window has just opened. Please refrain from
reposting this until -rc1.

Thanks,

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