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@@ -0,0 +1,139 @@
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+/*
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+ * Driver for MIPS Goldfish Programmable Interrupt Controller.
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+ *
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+ * Author: Miodrag Dinic <miodrag.dinic@mips.com>
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+ *
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+ * This program is free software; you can redistribute it and/or modify it
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+ * under the terms of the GNU General Public License as published by the
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+ * Free Software Foundation; either version 2 of the License, or (at your
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+ * option) any later version.
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+ */
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+
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+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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+
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+#include <linux/interrupt.h>
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+#include <linux/irq.h>
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+#include <linux/irqchip.h>
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+#include <linux/irqchip/chained_irq.h>
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+#include <linux/irqdomain.h>
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+#include <linux/of_address.h>
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+#include <linux/of_irq.h>
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+
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+#define GFPIC_NR_IRQS 32
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+
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+/* 8..39 Cascaded Goldfish PIC interrupts */
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+#define GFPIC_IRQ_BASE 8
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+
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+#define GFPIC_REG_IRQ_PENDING 0x04
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+#define GFPIC_REG_IRQ_DISABLE_ALL 0x08
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+#define GFPIC_REG_IRQ_DISABLE 0x0c
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+#define GFPIC_REG_IRQ_ENABLE 0x10
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+
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+struct goldfish_pic_data {
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+ void __iomem *base;
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+ struct irq_domain *irq_domain;
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+};
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+
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+static void goldfish_pic_cascade(struct irq_desc *desc)
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+{
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+ struct goldfish_pic_data *gfpic = irq_desc_get_handler_data(desc);
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+ struct irq_chip *host_chip = irq_desc_get_chip(desc);
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+ u32 pending, hwirq, virq;
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+
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+ chained_irq_enter(host_chip, desc);
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+
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+ pending = readl(gfpic->base + GFPIC_REG_IRQ_PENDING);
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+ while (pending) {
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+ hwirq = __fls(pending);
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+ virq = irq_linear_revmap(gfpic->irq_domain, hwirq);
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+ generic_handle_irq(virq);
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+ pending &= ~(1 << hwirq);
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+ }
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+
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+ chained_irq_exit(host_chip, desc);
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+}
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+
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+static const struct irq_domain_ops goldfish_irq_domain_ops = {
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+ .xlate = irq_domain_xlate_onecell,
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+};
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+
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+static int __init goldfish_pic_of_init(struct device_node *of_node,
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+ struct device_node *parent)
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+{
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+ struct goldfish_pic_data *gfpic;
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+ struct irq_chip_generic *gc;
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+ struct irq_chip_type *ct;
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+ unsigned int parent_irq;
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+ int ret = 0;
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+
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+ gfpic = kzalloc(sizeof(*gfpic), GFP_KERNEL);
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+ if (!gfpic) {
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+ ret = -ENOMEM;
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+ goto out_err;
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+ }
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+
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+ parent_irq = irq_of_parse_and_map(of_node, 0);
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+ if (!parent_irq) {
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+ pr_err("Failed to map parent IRQ!\n");
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+ ret = -EINVAL;
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+ goto out_free;
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+ }
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+
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+ gfpic->base = of_iomap(of_node, 0);
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+ if (!gfpic->base) {
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+ pr_err("Failed to map base address!\n");
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+ ret = -ENOMEM;
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+ goto out_unmap_irq;
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+ }
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+
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+ /* Mask interrupts. */
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+ writel(1, gfpic->base + GFPIC_REG_IRQ_DISABLE_ALL);
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+
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+ gc = irq_alloc_generic_chip("GFPIC", 1, GFPIC_IRQ_BASE, gfpic->base,
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+ handle_level_irq);
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+ if (!gc) {
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+ pr_err("Failed to allocate chip structures!\n");
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+ ret = -ENOMEM;
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+ goto out_iounmap;
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+ }
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+
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+ ct = gc->chip_types;
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+ ct->regs.enable = GFPIC_REG_IRQ_ENABLE;
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+ ct->regs.disable = GFPIC_REG_IRQ_DISABLE;
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+ ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
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+ ct->chip.irq_mask = irq_gc_mask_disable_reg;
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+
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+ irq_setup_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS), 0,
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+ IRQ_NOPROBE | IRQ_LEVEL, 0);
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+
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+ gfpic->irq_domain = irq_domain_add_legacy(of_node, GFPIC_NR_IRQS,
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+ GFPIC_IRQ_BASE, 0,
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+ &goldfish_irq_domain_ops,
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+ NULL);
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+ if (!gfpic->irq_domain) {
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+ pr_err("Failed to add irqdomain!\n");
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+ ret = -ENOMEM;
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+ goto out_destroy_generic_chip;
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+ }
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+
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+ irq_set_chained_handler_and_data(parent_irq,
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+ goldfish_pic_cascade, gfpic);
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+
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+ pr_info("Successfully registered.\n");
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+ return 0;
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+
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+out_destroy_generic_chip:
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+ irq_destroy_generic_chip(gc, IRQ_MSK(GFPIC_NR_IRQS),
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+ IRQ_NOPROBE | IRQ_LEVEL, 0);
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+out_iounmap:
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+ iounmap(gfpic->base);
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+out_unmap_irq:
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+ irq_dispose_mapping(parent_irq);
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+out_free:
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+ kfree(gfpic);
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+out_err:
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+ pr_err("Failed to initialize! (errno = %d)\n", ret);
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+ return ret;
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+}
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+
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+IRQCHIP_DECLARE(google_gf_pic, "google,goldfish-pic", goldfish_pic_of_init);
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