1 files changed, 136 insertions, 0 deletions
diff --git a/drivers/irqchip/irq-nvic.c b/drivers/irqchip/irq-nvic.c
new file mode 100644
index 0000000000..ba6332b00a
--- /dev/null
+++ b/drivers/irqchip/irq-nvic.c
@@ -0,0 +1,136 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * drivers/irq/irq-nvic.c
+ *
+ * Copyright (C) 2008 ARM Limited, All Rights Reserved.
+ * Copyright (C) 2013 Pengutronix
+ *
+ * Support for the Nested Vectored Interrupt Controller found on the
+ * ARMv7-M CPUs (Cortex-M3/M4)
+ */
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/irq.h>
+#include <linux/irqchip.h>
+#include <linux/irqdomain.h>
+
+#include <asm/v7m.h>
+#include <asm/exception.h>
+
+#define NVIC_ISER		0x000
+#define NVIC_ICER		0x080
+#define NVIC_IPR		0x400
+
+#define NVIC_MAX_BANKS		16
+/*
+ * Each bank handles 32 irqs. Only the 16th (= last) bank handles only
+ * 16 irqs.
+ */
+#define NVIC_MAX_IRQ		((NVIC_MAX_BANKS - 1) * 32 + 16)
+
+static struct irq_domain *nvic_irq_domain;
+
+static void __irq_entry nvic_handle_irq(struct pt_regs *regs)
+{
+	unsigned long icsr = readl_relaxed(BASEADDR_V7M_SCB + V7M_SCB_ICSR);
+	irq_hw_number_t hwirq = (icsr & V7M_SCB_ICSR_VECTACTIVE) - 16;
+
+	generic_handle_domain_irq(nvic_irq_domain, hwirq);
+}
+
+static int nvic_irq_domain_alloc(struct irq_domain *domain, unsigned int virq,
+				unsigned int nr_irqs, void *arg)
+{
+	int i, ret;
+	irq_hw_number_t hwirq;
+	unsigned int type = IRQ_TYPE_NONE;
+	struct irq_fwspec *fwspec = arg;
+
+	ret = irq_domain_translate_onecell(domain, fwspec, &hwirq, &type);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < nr_irqs; i++)
+		irq_map_generic_chip(domain, virq + i, hwirq + i);
+
+	return 0;
+}
+
+static const struct irq_domain_ops nvic_irq_domain_ops = {
+	.translate = irq_domain_translate_onecell,
+	.alloc = nvic_irq_domain_alloc,
+	.free = irq_domain_free_irqs_top,
+};
+
+static int __init nvic_of_init(struct device_node *node,
+			       struct device_node *parent)
+{
+	unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
+	unsigned int irqs, i, ret, numbanks;
+	void __iomem *nvic_base;
+
+	numbanks = (readl_relaxed(V7M_SCS_ICTR) &
+		    V7M_SCS_ICTR_INTLINESNUM_MASK) + 1;
+
+	nvic_base = of_iomap(node, 0);
+	if (!nvic_base) {
+		pr_warn("unable to map nvic registers\n");
+		return -ENOMEM;
+	}
+
+	irqs = numbanks * 32;
+	if (irqs > NVIC_MAX_IRQ)
+		irqs = NVIC_MAX_IRQ;
+
+	nvic_irq_domain =
+		irq_domain_add_linear(node, irqs, &nvic_irq_domain_ops, NULL);
+
+	if (!nvic_irq_domain) {
+		pr_warn("Failed to allocate irq domain\n");
+		iounmap(nvic_base);
+		return -ENOMEM;
+	}
+
+	ret = irq_alloc_domain_generic_chips(nvic_irq_domain, 32, 1,
+					     "nvic_irq", handle_fasteoi_irq,
+					     clr, 0, IRQ_GC_INIT_MASK_CACHE);
+	if (ret) {
+		pr_warn("Failed to allocate irq chips\n");
+		irq_domain_remove(nvic_irq_domain);
+		iounmap(nvic_base);
+		return ret;
+	}
+
+	for (i = 0; i < numbanks; ++i) {
+		struct irq_chip_generic *gc;
+
+		gc = irq_get_domain_generic_chip(nvic_irq_domain, 32 * i);
+		gc->reg_base = nvic_base + 4 * i;
+		gc->chip_types[0].regs.enable = NVIC_ISER;
+		gc->chip_types[0].regs.disable = NVIC_ICER;
+		gc->chip_types[0].chip.irq_mask = irq_gc_mask_disable_reg;
+		gc->chip_types[0].chip.irq_unmask = irq_gc_unmask_enable_reg;
+		/* This is a no-op as end of interrupt is signaled by the
+		 * exception return sequence.
+		 */
+		gc->chip_types[0].chip.irq_eoi = irq_gc_noop;
+
+		/* disable interrupts */
+		writel_relaxed(~0, gc->reg_base + NVIC_ICER);
+	}
+
+	/* Set priority on all interrupts */
+	for (i = 0; i < irqs; i += 4)
+		writel_relaxed(0, nvic_base + NVIC_IPR + i);
+
+	set_handle_irq(nvic_handle_irq);
+	return 0;
+}
+IRQCHIP_DECLARE(armv7m_nvic, "arm,armv7m-nvic", nvic_of_init);