1 files changed, 340 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-bcm2836.c b/drivers/irqchip/irq-bcm2836.c
new file mode 100644
index 0000000000..e5f1059b98
--- /dev/null
+++ b/drivers/irqchip/irq-bcm2836.c
@@ -0,0 +1,340 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Root interrupt controller for the BCM2836 (Raspberry Pi 2).
+ *
+ * Copyright 2015 Broadcom
+ */
+
+#include <linux/cpu.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/irqchip/irq-bcm2836.h>
+
+#include <asm/exception.h>
+
+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_dummy_op(struct irq_data *d)
+{
+}
+
+static struct irq_chip bcm2836_arm_irqchip_dummy = {
+	.name		= "bcm2836-dummy",
+	.irq_eoi	= bcm2836_arm_irqchip_dummy_op,
+};
+
+static int bcm2836_map(struct irq_domain *d, unsigned int irq,
+		       irq_hw_number_t hw)
+{
+	struct irq_chip *chip;
+
+	switch (hw) {
+	case LOCAL_IRQ_MAILBOX0:
+		chip = &bcm2836_arm_irqchip_dummy;
+		break;
+	case LOCAL_IRQ_CNTPSIRQ:
+	case LOCAL_IRQ_CNTPNSIRQ:
+	case LOCAL_IRQ_CNTHPIRQ:
+	case LOCAL_IRQ_CNTVIRQ:
+		chip = &bcm2836_arm_irqchip_timer;
+		break;
+	case LOCAL_IRQ_GPU_FAST:
+		chip = &bcm2836_arm_irqchip_gpu;
+		break;
+	case LOCAL_IRQ_PMU_FAST:
+		chip = &bcm2836_arm_irqchip_pmu;
+		break;
+	default:
+		pr_warn_once("Unexpected hw irq: %lu\n", hw);
+		return -EINVAL;
+	}
+
+	irq_set_percpu_devid(irq);
+	irq_domain_set_info(d, irq, hw, chip, d->host_data,
+			    handle_percpu_devid_irq, NULL, NULL);
+	irq_set_status_flags(irq, IRQ_NOAUTOEN);
+
+	return 0;
+}
+
+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) {
+		u32 hwirq = ffs(stat) - 1;
+
+		generic_handle_domain_irq(intc.domain, hwirq);
+	}
+}
+
+#ifdef CONFIG_SMP
+static struct irq_domain *ipi_domain;
+
+static void bcm2836_arm_irqchip_handle_ipi(struct irq_desc *desc)
+{
+	struct irq_chip *chip = irq_desc_get_chip(desc);
+	int cpu = smp_processor_id();
+	u32 mbox_val;
+
+	chained_irq_enter(chip, desc);
+
+	mbox_val = readl_relaxed(intc.base + LOCAL_MAILBOX0_CLR0 + 16 * cpu);
+	if (mbox_val) {
+		int hwirq = ffs(mbox_val) - 1;
+		generic_handle_domain_irq(ipi_domain, hwirq);
+	}
+
+	chained_irq_exit(chip, desc);
+}
+
+static void bcm2836_arm_irqchip_ipi_ack(struct irq_data *d)
+{
+	int cpu = smp_processor_id();
+
+	writel_relaxed(BIT(d->hwirq),
+		       intc.base + LOCAL_MAILBOX0_CLR0 + 16 * cpu);
+}
+
+static void bcm2836_arm_irqchip_ipi_send_mask(struct irq_data *d,
+					      const struct cpumask *mask)
+{
+	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.
+	 */
+	smp_wmb();
+
+	for_each_cpu(cpu, mask)
+		writel_relaxed(BIT(d->hwirq), mailbox0_base + 16 * cpu);
+}
+
+static struct irq_chip bcm2836_arm_irqchip_ipi = {
+	.name		= "IPI",
+	.irq_mask	= bcm2836_arm_irqchip_dummy_op,
+	.irq_unmask	= bcm2836_arm_irqchip_dummy_op,
+	.irq_ack	= bcm2836_arm_irqchip_ipi_ack,
+	.ipi_send_mask	= bcm2836_arm_irqchip_ipi_send_mask,
+};
+
+static int bcm2836_arm_irqchip_ipi_alloc(struct irq_domain *d,
+					 unsigned int virq,
+					 unsigned int nr_irqs, void *args)
+{
+	int i;
+
+	for (i = 0; i < nr_irqs; i++) {
+		irq_set_percpu_devid(virq + i);
+		irq_domain_set_info(d, virq + i, i, &bcm2836_arm_irqchip_ipi,
+				    d->host_data,
+				    handle_percpu_devid_irq,
+				    NULL, NULL);
+	}
+
+	return 0;
+}
+
+static void bcm2836_arm_irqchip_ipi_free(struct irq_domain *d,
+					 unsigned int virq,
+					 unsigned int nr_irqs)
+{
+	/* Not freeing IPIs */
+}
+
+static const struct irq_domain_ops ipi_domain_ops = {
+	.alloc	= bcm2836_arm_irqchip_ipi_alloc,
+	.free	= bcm2836_arm_irqchip_ipi_free,
+};
+
+static int bcm2836_cpu_starting(unsigned int cpu)
+{
+	bcm2836_arm_irqchip_unmask_per_cpu_irq(LOCAL_MAILBOX_INT_CONTROL0, 0,
+					       cpu);
+	return 0;
+}
+
+static int bcm2836_cpu_dying(unsigned int cpu)
+{
+	bcm2836_arm_irqchip_mask_per_cpu_irq(LOCAL_MAILBOX_INT_CONTROL0, 0,
+					     cpu);
+	return 0;
+}
+
+#define BITS_PER_MBOX	32
+
+static void __init bcm2836_arm_irqchip_smp_init(void)
+{
+	struct irq_fwspec ipi_fwspec = {
+		.fwnode		= intc.domain->fwnode,
+		.param_count	= 1,
+		.param		= {
+			[0]	= LOCAL_IRQ_MAILBOX0,
+		},
+	};
+	int base_ipi, mux_irq;
+
+	mux_irq = irq_create_fwspec_mapping(&ipi_fwspec);
+	if (WARN_ON(mux_irq <= 0))
+		return;
+
+	ipi_domain = irq_domain_create_linear(intc.domain->fwnode,
+					      BITS_PER_MBOX, &ipi_domain_ops,
+					      NULL);
+	if (WARN_ON(!ipi_domain))
+		return;
+
+	ipi_domain->flags |= IRQ_DOMAIN_FLAG_IPI_SINGLE;
+	irq_domain_update_bus_token(ipi_domain, DOMAIN_BUS_IPI);
+
+	base_ipi = irq_domain_alloc_irqs(ipi_domain, BITS_PER_MBOX, NUMA_NO_NODE, NULL);
+	if (WARN_ON(!base_ipi))
+		return;
+
+	set_smp_ipi_range(base_ipi, BITS_PER_MBOX);
+
+	irq_set_chained_handler_and_data(mux_irq,
+					 bcm2836_arm_irqchip_handle_ipi, NULL);
+
+	/* Unmask IPIs to the boot CPU. */
+	cpuhp_setup_state(CPUHP_AP_IRQ_BCM2836_STARTING,
+			  "irqchip/bcm2836:starting", bcm2836_cpu_starting,
+			  bcm2836_cpu_dying);
+}
+#else
+#define bcm2836_arm_irqchip_smp_init()	do { } while(0)
+#endif
+
+static const struct irq_domain_ops bcm2836_arm_irqchip_intc_ops = {
+	.xlate = irq_domain_xlate_onetwocell,
+	.map = bcm2836_map,
+};
+
+/*
+ * The LOCAL_IRQ_CNT* timer firings are based off of the external
+ * oscillator with some scaling.  The firmware sets up CNTFRQ to
+ * report 19.2Mhz, but doesn't set up the scaling registers.
+ */
+static void bcm2835_init_local_timer_frequency(void)
+{
+	/*
+	 * Set the timer to source from the 19.2Mhz crystal clock (bit
+	 * 8 unset), and only increment by 1 instead of 2 (bit 9
+	 * unset).
+	 */
+	writel(0, intc.base + LOCAL_CONTROL);
+
+	/*
+	 * Set the timer prescaler to 1:1 (timer freq = input freq *
+	 * 2**31 / prescaler)
+	 */
+	writel(0x80000000, intc.base + LOCAL_PRESCALER);
+}
+
+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("%pOF: unable to map local interrupt registers\n", node);
+	}
+
+	bcm2835_init_local_timer_frequency();
+
+	intc.domain = irq_domain_add_linear(node, LAST_IRQ + 1,
+					    &bcm2836_arm_irqchip_intc_ops,
+					    NULL);
+	if (!intc.domain)
+		panic("%pOF: unable to create IRQ domain\n", node);
+
+	irq_domain_update_bus_token(intc.domain, DOMAIN_BUS_WIRED);
+
+	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);