[PATCH v4 4/4] irqchip: Add bcm2836 interrupt controller for Raspberry Pi 2.
Eric Anholt
eric at anholt.net
Thu Aug 6 16:00:33 PDT 2015
This interrupt controller is the new root interrupt controller with
the timer, PMU events, and IPIs, and the bcm2835's interrupt
controller is chained off of it to handle the peripherals.
I wrote the interrupt chip support, while Andrea Merello wrote the IPI
code.
Signed-off-by: Eric Anholt <eric at anholt.net>
Signed-off-by: Andrea Merello <andrea.merello at gmail.com>
Acked-by: Stephen Warren <swarren at wwwdotorg.org>
---
v2: Rename functions/globals to bcm2836_arm_local. Treat per-cpu
interrupts as per-cpu in mask/unmask. Add comments about how
registers work.
v3: Drop debug printfs from PMU interrupt masking.
v4: Use cpu notifiers to unmask IPIs only when Linux wants the CPU up.
drivers/irqchip/Makefile | 1 +
drivers/irqchip/irq-bcm2836.c | 275 ++++++++++++++++++++++++++++++++++++++++++
2 files changed, 276 insertions(+)
create mode 100644 drivers/irqchip/irq-bcm2836.c
diff --git a/drivers/irqchip/Makefile b/drivers/irqchip/Makefile
index b8d4e96..9727681 100644
--- a/drivers/irqchip/Makefile
+++ b/drivers/irqchip/Makefile
@@ -1,6 +1,7 @@
obj-$(CONFIG_IRQCHIP) += irqchip.o
obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2835.o
+obj-$(CONFIG_ARCH_BCM2835) += irq-bcm2836.o
obj-$(CONFIG_ARCH_EXYNOS) += exynos-combiner.o
obj-$(CONFIG_ARCH_HIP04) += irq-hip04.o
obj-$(CONFIG_ARCH_MMP) += irq-mmp.o
diff --git a/drivers/irqchip/irq-bcm2836.c b/drivers/irqchip/irq-bcm2836.c
new file mode 100644
index 0000000..052bd83
--- /dev/null
+++ b/drivers/irqchip/irq-bcm2836.c
@@ -0,0 +1,275 @@
+/*
+ * Root interrupt controller for the BCM2836 (Raspberry Pi 2).
+ *
+ * Copyright 2015 Broadcom
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/cpu.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <asm/exception.h>
+
+/*
+ * The low 2 bits identify the CPU that the GPU IRQ goes to, and the
+ * next 2 bits identify the CPU that the GPU FIQ goes to.
+ */
+#define LOCAL_GPU_ROUTING 0x00c
+/* When setting bits 0-3, enables PMU interrupts on that CPU. */
+#define LOCAL_PM_ROUTING_SET 0x010
+/* When setting bits 0-3, disables PMU interrupts on that CPU. */
+#define LOCAL_PM_ROUTING_CLR 0x014
+/*
+ * The low 4 bits of this are the CPU's timer IRQ enables, and the
+ * next 4 bits are the CPU's timer FIQ enables (which override the IRQ
+ * bits).
+ */
+#define LOCAL_TIMER_INT_CONTROL0 0x040
+/*
+ * The low 4 bits of this are the CPU's per-mailbox IRQ enables, and
+ * the next 4 bits are the CPU's per-mailbox FIQ enables (which
+ * override the IRQ bits).
+ */
+#define LOCAL_MAILBOX_INT_CONTROL0 0x050
+/*
+ * The CPU's interrupt status register. Bits are defined by the the
+ * LOCAL_IRQ_* bits below.
+ */
+#define LOCAL_IRQ_PENDING0 0x060
+/* Same status bits as above, but for FIQ. */
+#define LOCAL_FIQ_PENDING0 0x070
+/*
+ * Mailbox0 write-to-set bits. There are 16 mailboxes, 4 per CPU, and
+ * these bits are organized by mailbox number and then CPU number. We
+ * use mailbox 0 for IPIs. The mailbox's interrupt is raised while
+ * any bit is set.
+ */
+#define LOCAL_MAILBOX0_SET0 0x080
+/* Mailbox0 write-to-clear bits. */
+#define LOCAL_MAILBOX0_CLR0 0x0c0
+
+#define LOCAL_IRQ_CNTPSIRQ 0
+#define LOCAL_IRQ_CNTPNSIRQ 1
+#define LOCAL_IRQ_CNTHPIRQ 2
+#define LOCAL_IRQ_CNTVIRQ 3
+#define LOCAL_IRQ_MAILBOX0 4
+#define LOCAL_IRQ_MAILBOX1 5
+#define LOCAL_IRQ_MAILBOX2 6
+#define LOCAL_IRQ_MAILBOX3 7
+#define LOCAL_IRQ_GPU_FAST 8
+#define LOCAL_IRQ_PMU_FAST 9
+#define LAST_IRQ LOCAL_IRQ_PMU_FAST
+
+struct bcm2836_arm_irqchip_intc {
+ struct irq_domain *domain;
+ void __iomem *base;
+};
+
+static struct bcm2836_arm_irqchip_intc intc __read_mostly;
+
+static void bcm2836_arm_irqchip_mask_per_cpu_irq(unsigned int reg_offset,
+ unsigned int bit,
+ int cpu)
+{
+ void __iomem *reg = intc.base + reg_offset + 4 * cpu;
+
+ writel(readl(reg) & ~BIT(bit), reg);
+}
+
+static void bcm2836_arm_irqchip_unmask_per_cpu_irq(unsigned int reg_offset,
+ unsigned int bit,
+ int cpu)
+{
+ void __iomem *reg = intc.base + reg_offset + 4 * cpu;
+
+ writel(readl(reg) | BIT(bit), reg);
+}
+
+static void bcm2836_arm_irqchip_mask_timer_irq(struct irq_data *d)
+{
+ bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
+ d->hwirq - LOCAL_IRQ_CNTPSIRQ,
+ smp_processor_id());
+}
+
+static void bcm2836_arm_irqchip_unmask_timer_irq(struct irq_data *d)
+{
+ bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_TIMER_INT_CONTROL0,
+ d->hwirq - LOCAL_IRQ_CNTPSIRQ,
+ smp_processor_id());
+}
+
+static struct irq_chip bcm2836_arm_irqchip_timer = {
+ .name = "bcm2836-timer",
+ .irq_mask = bcm2836_arm_irqchip_mask_timer_irq,
+ .irq_unmask = bcm2836_arm_irqchip_unmask_timer_irq
+};
+
+static void bcm2836_arm_irqchip_mask_pmu_irq(struct irq_data *d)
+{
+ writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_CLR);
+}
+
+static void bcm2836_arm_irqchip_unmask_pmu_irq(struct irq_data *d)
+{
+ writel(1 << smp_processor_id(), intc.base + LOCAL_PM_ROUTING_SET);
+}
+
+static struct irq_chip bcm2836_arm_irqchip_pmu = {
+ .name = "bcm2836-pmu",
+ .irq_mask = bcm2836_arm_irqchip_mask_pmu_irq,
+ .irq_unmask = bcm2836_arm_irqchip_unmask_pmu_irq
+};
+
+static void bcm2836_arm_irqchip_mask_gpu_irq(struct irq_data *d)
+{
+}
+
+static void bcm2836_arm_irqchip_unmask_gpu_irq(struct irq_data *d)
+{
+}
+
+static struct irq_chip bcm2836_arm_irqchip_gpu = {
+ .name = "bcm2836-gpu",
+ .irq_mask = bcm2836_arm_irqchip_mask_gpu_irq,
+ .irq_unmask = bcm2836_arm_irqchip_unmask_gpu_irq
+};
+
+static void bcm2836_arm_irqchip_register_irq(int hwirq, struct irq_chip *chip)
+{
+ int irq = irq_create_mapping(intc.domain, hwirq);
+
+ irq_set_percpu_devid(irq);
+ irq_set_chip_and_handler(irq, chip, handle_percpu_devid_irq);
+ irq_set_status_flags(irq, IRQ_NOAUTOEN);
+}
+
+static void __exception_irq_entry bcm2836_arm_irqchip_handle_irq(
+ struct pt_regs *regs)
+{
+ int cpu = smp_processor_id();
+ u32 stat;
+
+ stat = readl_relaxed(intc.base + LOCAL_IRQ_PENDING0 + 4 * cpu);
+ if (stat & 0x10) {
+#ifdef CONFIG_SMP
+ void __iomem *mailbox0 = (intc.base +
+ LOCAL_MAILBOX0_CLR0 + 16 * cpu);
+ u32 mbox_val = readl(mailbox0);
+ u32 ipi = ffs(mbox_val) - 1;
+
+ writel(1 << ipi, mailbox0);
+ handle_IPI(ipi, regs);
+#endif
+ } else {
+ u32 hwirq = ffs(stat) - 1;
+
+ handle_IRQ(irq_linear_revmap(intc.domain, hwirq), regs);
+ }
+}
+
+#ifdef CONFIG_SMP
+static void bcm2836_arm_irqchip_send_ipi(const struct cpumask *mask,
+ unsigned int ipi)
+{
+ int cpu;
+ void __iomem *mailbox0_base = intc.base + LOCAL_MAILBOX0_SET0;
+
+ /*
+ * Ensure that stores to normal memory are visible to the
+ * other CPUs before issuing the IPI.
+ */
+ dsb();
+
+ for_each_cpu(cpu, mask) {
+ writel(1 << ipi, mailbox0_base + 16 * cpu);
+ }
+}
+
+/* Unmasks the IPI on the CPU when it's online. */
+static int bcm2836_arm_irqchip_cpu_notify(struct notifier_block *nfb,
+ unsigned long action, void *hcpu)
+{
+ unsigned int cpu = (unsigned long)hcpu;
+ unsigned int int_reg = LOCAL_MAILBOX_INT_CONTROL0;
+ unsigned int mailbox = 0;
+
+ if (action == CPU_STARTING || action == CPU_STARTING_FROZEN)
+ bcm2836_arm_irqchip_unmask_per_cpu_irq(int_reg, mailbox, cpu);
+ else if (action == CPU_DYING)
+ bcm2836_arm_irqchip_mask_per_cpu_irq(int_reg, mailbox, cpu);
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block bcm2836_arm_irqchip_cpu_notifier = {
+ .notifier_call = bcm2836_arm_irqchip_cpu_notify,
+ .priority = 100,
+};
+#endif
+
+static const struct irq_domain_ops bcm2836_arm_irqchip_intc_ops = {
+ .xlate = irq_domain_xlate_onecell
+};
+
+static void
+bcm2836_arm_irqchip_smp_init(void)
+{
+#ifdef CONFIG_SMP
+ /* Unmask IPIs to the boot CPU. */
+ bcm2836_arm_irqchip_cpu_notify(&bcm2836_arm_irqchip_cpu_notifier,
+ CPU_STARTING,
+ (void *)smp_processor_id());
+ register_cpu_notifier(&bcm2836_arm_irqchip_cpu_notifier);
+
+ set_smp_cross_call(bcm2836_arm_irqchip_send_ipi);
+#endif
+}
+
+static int __init bcm2836_arm_irqchip_l1_intc_of_init(struct device_node *node,
+ struct device_node *parent)
+{
+ intc.base = of_iomap(node, 0);
+ if (!intc.base) {
+ panic("%s: unable to map local interrupt registers\n",
+ node->full_name);
+ }
+
+ intc.domain = irq_domain_add_linear(node, LAST_IRQ + 1,
+ &bcm2836_arm_irqchip_intc_ops,
+ NULL);
+ if (!intc.domain)
+ panic("%s: unable to create IRQ domain\n", node->full_name);
+
+ bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTPSIRQ,
+ &bcm2836_arm_irqchip_timer);
+ bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTPNSIRQ,
+ &bcm2836_arm_irqchip_timer);
+ bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTHPIRQ,
+ &bcm2836_arm_irqchip_timer);
+ bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_CNTVIRQ,
+ &bcm2836_arm_irqchip_timer);
+ bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_GPU_FAST,
+ &bcm2836_arm_irqchip_gpu);
+ bcm2836_arm_irqchip_register_irq(LOCAL_IRQ_PMU_FAST,
+ &bcm2836_arm_irqchip_pmu);
+
+ bcm2836_arm_irqchip_smp_init();
+
+ set_handle_irq(bcm2836_arm_irqchip_handle_irq);
+ return 0;
+}
+
+IRQCHIP_DECLARE(bcm2836_arm_irqchip_l1_intc, "brcm,bcm2836-l1-intc",
+ bcm2836_arm_irqchip_l1_intc_of_init);
--
2.1.4
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