--- /dev/null
+Synopsys DesignWare APB interrupt controller (dw_apb_ictl)
+
+Synopsys DesignWare provides interrupt controller IP for APB known as
+dw_apb_ictl. The IP is used as secondary interrupt controller in some SoCs with
+APB bus, e.g. Marvell Armada 1500.
+
+Required properties:
+- compatible: shall be "snps,dw-apb-ictl"
+- reg: physical base address of the controller and length of memory mapped
+ region starting with ENABLE_LOW register
+- interrupt-controller: identifies the node as an interrupt controller
+- #interrupt-cells: number of cells to encode an interrupt-specifier, shall be 1
+- interrupts: interrupt reference to primary interrupt controller
+- interrupt-parent: (optional) reference specific primary interrupt controller
+
+The interrupt sources map to the corresponding bits in the interrupt
+registers, i.e.
+- 0 maps to bit 0 of low interrupts,
+- 1 maps to bit 1 of low interrupts,
+- 32 maps to bit 0 of high interrupts,
+- 33 maps to bit 1 of high interrupts,
+- (optional) fast interrupts start at 64.
+
+Example:
+ aic: interrupt-controller@3000 {
+ compatible = "snps,dw-apb-ictl";
+ reg = <0x3000 0xc00>;
+ interrupt-controller;
+ #interrupt-cells = <1>;
+ interrupt-parent = <&gic>;
+ interrupts = <GIC_SPI 3 IRQ_TYPE_LEVEL_HIGH>;
+ };
--- /dev/null
+/*
+ * Synopsys DW APB ICTL irqchip driver.
+ *
+ * Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
+ *
+ * based on GPL'ed 2.6 kernel sources
+ * (c) Marvell International Ltd.
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ */
+
+#include <linux/io.h>
+#include <linux/irq.h>
+#include <linux/irqchip/chained_irq.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
+
+#include "irqchip.h"
+
+#define APB_INT_ENABLE_L 0x00
+#define APB_INT_ENABLE_H 0x04
+#define APB_INT_MASK_L 0x08
+#define APB_INT_MASK_H 0x0c
+#define APB_INT_FINALSTATUS_L 0x30
+#define APB_INT_FINALSTATUS_H 0x34
+
+static void dw_apb_ictl_handler(unsigned int irq, struct irq_desc *desc)
+{
+ struct irq_chip *chip = irq_get_chip(irq);
+ struct irq_chip_generic *gc = irq_get_handler_data(irq);
+ struct irq_domain *d = gc->private;
+ u32 stat;
+ int n;
+
+ chained_irq_enter(chip, desc);
+
+ for (n = 0; n < gc->num_ct; n++) {
+ stat = readl_relaxed(gc->reg_base +
+ APB_INT_FINALSTATUS_L + 4 * n);
+ while (stat) {
+ u32 hwirq = ffs(stat) - 1;
+ generic_handle_irq(irq_find_mapping(d,
+ gc->irq_base + hwirq + 32 * n));
+ stat &= ~(1 << hwirq);
+ }
+ }
+
+ chained_irq_exit(chip, desc);
+}
+
+static int __init dw_apb_ictl_init(struct device_node *np,
+ struct device_node *parent)
+{
+ unsigned int clr = IRQ_NOREQUEST | IRQ_NOPROBE | IRQ_NOAUTOEN;
+ struct resource r;
+ struct irq_domain *domain;
+ struct irq_chip_generic *gc;
+ void __iomem *iobase;
+ int ret, nrirqs, irq;
+ u32 reg;
+
+ /* Map the parent interrupt for the chained handler */
+ irq = irq_of_parse_and_map(np, 0);
+ if (irq <= 0) {
+ pr_err("%s: unable to parse irq\n", np->full_name);
+ return -EINVAL;
+ }
+
+ ret = of_address_to_resource(np, 0, &r);
+ if (ret) {
+ pr_err("%s: unable to get resource\n", np->full_name);
+ return ret;
+ }
+
+ if (!request_mem_region(r.start, resource_size(&r), np->full_name)) {
+ pr_err("%s: unable to request mem region\n", np->full_name);
+ return -ENOMEM;
+ }
+
+ iobase = ioremap(r.start, resource_size(&r));
+ if (!iobase) {
+ pr_err("%s: unable to map resource\n", np->full_name);
+ ret = -ENOMEM;
+ goto err_release;
+ }
+
+ /*
+ * DW IP can be configured to allow 2-64 irqs. We can determine
+ * the number of irqs supported by writing into enable register
+ * and look for bits not set, as corresponding flip-flops will
+ * have been removed by sythesis tool.
+ */
+
+ /* mask and enable all interrupts */
+ writel(~0, iobase + APB_INT_MASK_L);
+ writel(~0, iobase + APB_INT_MASK_H);
+ writel(~0, iobase + APB_INT_ENABLE_L);
+ writel(~0, iobase + APB_INT_ENABLE_H);
+
+ reg = readl(iobase + APB_INT_ENABLE_H);
+ if (reg)
+ nrirqs = 32 + fls(reg);
+ else
+ nrirqs = fls(readl(iobase + APB_INT_ENABLE_L));
+
+ domain = irq_domain_add_linear(np, nrirqs,
+ &irq_generic_chip_ops, NULL);
+ if (!domain) {
+ pr_err("%s: unable to add irq domain\n", np->full_name);
+ ret = -ENOMEM;
+ goto err_unmap;
+ }
+
+ ret = irq_alloc_domain_generic_chips(domain, 32, (nrirqs > 32) ? 2 : 1,
+ np->name, handle_level_irq, clr, 0,
+ IRQ_GC_INIT_MASK_CACHE);
+ if (ret) {
+ pr_err("%s: unable to alloc irq domain gc\n", np->full_name);
+ goto err_unmap;
+ }
+
+ gc = irq_get_domain_generic_chip(domain, 0);
+ gc->private = domain;
+ gc->reg_base = iobase;
+
+ gc->chip_types[0].regs.mask = APB_INT_MASK_L;
+ gc->chip_types[0].chip.irq_mask = irq_gc_mask_set_bit;
+ gc->chip_types[0].chip.irq_unmask = irq_gc_mask_clr_bit;
+
+ if (nrirqs > 32) {
+ gc->chip_types[1].regs.mask = APB_INT_MASK_H;
+ gc->chip_types[1].chip.irq_mask = irq_gc_mask_set_bit;
+ gc->chip_types[1].chip.irq_unmask = irq_gc_mask_clr_bit;
+ }
+
+ irq_set_handler_data(irq, gc);
+ irq_set_chained_handler(irq, dw_apb_ictl_handler);
+
+ return 0;
+
+err_unmap:
+ iounmap(iobase);
+err_release:
+ release_mem_region(r.start, resource_size(&r));
+ return ret;
+}
+IRQCHIP_DECLARE(dw_apb_ictl,
+ "snps,dw-apb-ictl", dw_apb_ictl_init);
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