powerpc: wii: hollywood interrupt controller support

Add support for the dual interrupt controller included in the "Hollywood"
chipset of the Nintendo Wii video game console.
This interrupt controller serves both the Broadway processor (as a cascade)
and the Starlet processor, and is used to manage interrupts for the
non-classic hardware.

Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 241 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/embedded6xx/hlwd-pic.c b/arch/powerpc/platforms/embedded6xx/hlwd-pic.c
new file mode 100644
index 000000000000..dd20bff33207
--- /dev/null
+++ b/arch/powerpc/platforms/embedded6xx/hlwd-pic.c
@@ -0,0 +1,241 @@
+/*
+ * arch/powerpc/platforms/embedded6xx/hlwd-pic.c
+ *
+ * Nintendo Wii "Hollywood" interrupt controller support.
+ * Copyright (C) 2009 The GameCube Linux Team
+ * Copyright (C) 2009 Albert Herranz
+ *
+ * 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.
+ *
+ */
+#define DRV_MODULE_NAME "hlwd-pic"
+#define pr_fmt(fmt) DRV_MODULE_NAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <linux/of.h>
+#include <asm/io.h>
+
+#include "hlwd-pic.h"
+
+#define HLWD_NR_IRQS	32
+
+/*
+ * Each interrupt has a corresponding bit in both
+ * the Interrupt Cause (ICR) and Interrupt Mask (IMR) registers.
+ *
+ * Enabling/disabling an interrupt line involves asserting/clearing
+ * the corresponding bit in IMR. ACK'ing a request simply involves
+ * asserting the corresponding bit in ICR.
+ */
+#define HW_BROADWAY_ICR		0x00
+#define HW_BROADWAY_IMR		0x04
+
+
+/*
+ * IRQ chip hooks.
+ *
+ */
+
+static void hlwd_pic_mask_and_ack(unsigned int virq)
+{
+	int irq = virq_to_hw(virq);
+	void __iomem *io_base = get_irq_chip_data(virq);
+	u32 mask = 1 << irq;
+
+	clrbits32(io_base + HW_BROADWAY_IMR, mask);
+	out_be32(io_base + HW_BROADWAY_ICR, mask);
+}
+
+static void hlwd_pic_ack(unsigned int virq)
+{
+	int irq = virq_to_hw(virq);
+	void __iomem *io_base = get_irq_chip_data(virq);
+
+	out_be32(io_base + HW_BROADWAY_ICR, 1 << irq);
+}
+
+static void hlwd_pic_mask(unsigned int virq)
+{
+	int irq = virq_to_hw(virq);
+	void __iomem *io_base = get_irq_chip_data(virq);
+
+	clrbits32(io_base + HW_BROADWAY_IMR, 1 << irq);
+}
+
+static void hlwd_pic_unmask(unsigned int virq)
+{
+	int irq = virq_to_hw(virq);
+	void __iomem *io_base = get_irq_chip_data(virq);
+
+	setbits32(io_base + HW_BROADWAY_IMR, 1 << irq);
+}
+
+
+static struct irq_chip hlwd_pic = {
+	.name		= "hlwd-pic",
+	.ack		= hlwd_pic_ack,
+	.mask_ack	= hlwd_pic_mask_and_ack,
+	.mask		= hlwd_pic_mask,
+	.unmask		= hlwd_pic_unmask,
+};
+
+/*
+ * IRQ host hooks.
+ *
+ */
+
+static struct irq_host *hlwd_irq_host;
+
+static int hlwd_pic_map(struct irq_host *h, unsigned int virq,
+			   irq_hw_number_t hwirq)
+{
+	set_irq_chip_data(virq, h->host_data);
+	get_irq_desc(virq)->status |= IRQ_LEVEL;
+	set_irq_chip_and_handler(virq, &hlwd_pic, handle_level_irq);
+	return 0;
+}
+
+static void hlwd_pic_unmap(struct irq_host *h, unsigned int irq)
+{
+	set_irq_chip_data(irq, NULL);
+	set_irq_chip(irq, NULL);
+}
+
+static struct irq_host_ops hlwd_irq_host_ops = {
+	.map = hlwd_pic_map,
+	.unmap = hlwd_pic_unmap,
+};
+
+static unsigned int __hlwd_pic_get_irq(struct irq_host *h)
+{
+	void __iomem *io_base = h->host_data;
+	int irq;
+	u32 irq_status;
+
+	irq_status = in_be32(io_base + HW_BROADWAY_ICR) &
+		     in_be32(io_base + HW_BROADWAY_IMR);
+	if (irq_status == 0)
+		return NO_IRQ;	/* no more IRQs pending */
+
+	irq = __ffs(irq_status);
+	return irq_linear_revmap(h, irq);
+}
+
+static void hlwd_pic_irq_cascade(unsigned int cascade_virq,
+				      struct irq_desc *desc)
+{
+	struct irq_host *irq_host = get_irq_data(cascade_virq);
+	unsigned int virq;
+
+	spin_lock(&desc->lock);
+	desc->chip->mask(cascade_virq); /* IRQ_LEVEL */
+	spin_unlock(&desc->lock);
+
+	virq = __hlwd_pic_get_irq(irq_host);
+	if (virq != NO_IRQ)
+		generic_handle_irq(virq);
+	else
+		pr_err("spurious interrupt!\n");
+
+	spin_lock(&desc->lock);
+	desc->chip->ack(cascade_virq); /* IRQ_LEVEL */
+	if (!(desc->status & IRQ_DISABLED) && desc->chip->unmask)
+		desc->chip->unmask(cascade_virq);
+	spin_unlock(&desc->lock);
+}
+
+/*
+ * Platform hooks.
+ *
+ */
+
+static void __hlwd_quiesce(void __iomem *io_base)
+{
+	/* mask and ack all IRQs */
+	out_be32(io_base + HW_BROADWAY_IMR, 0);
+	out_be32(io_base + HW_BROADWAY_ICR, 0xffffffff);
+}
+
+struct irq_host *hlwd_pic_init(struct device_node *np)
+{
+	struct irq_host *irq_host;
+	struct resource res;
+	void __iomem *io_base;
+	int retval;
+
+	retval = of_address_to_resource(np, 0, &res);
+	if (retval) {
+		pr_err("no io memory range found\n");
+		return NULL;
+	}
+	io_base = ioremap(res.start, resource_size(&res));
+	if (!io_base) {
+		pr_err("ioremap failed\n");
+		return NULL;
+	}
+
+	pr_info("controller at 0x%08x mapped to 0x%p\n", res.start, io_base);
+
+	__hlwd_quiesce(io_base);
+
+	irq_host = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, HLWD_NR_IRQS,
+				  &hlwd_irq_host_ops, -1);
+	if (!irq_host) {
+		pr_err("failed to allocate irq_host\n");
+		return NULL;
+	}
+	irq_host->host_data = io_base;
+
+	return irq_host;
+}
+
+unsigned int hlwd_pic_get_irq(void)
+{
+	return __hlwd_pic_get_irq(hlwd_irq_host);
+}
+
+/*
+ * Probe function.
+ *
+ */
+
+void hlwd_pic_probe(void)
+{
+	struct irq_host *host;
+	struct device_node *np;
+	const u32 *interrupts;
+	int cascade_virq;
+
+	for_each_compatible_node(np, NULL, "nintendo,hollywood-pic") {
+		interrupts = of_get_property(np, "interrupts", NULL);
+		if (interrupts) {
+			host = hlwd_pic_init(np);
+			BUG_ON(!host);
+			cascade_virq = irq_of_parse_and_map(np, 0);
+			set_irq_data(cascade_virq, host);
+			set_irq_chained_handler(cascade_virq,
+						hlwd_pic_irq_cascade);
+			hlwd_irq_host = host;
+			break;
+		}
+	}
+}
+
+/**
+ * hlwd_quiesce() - quiesce hollywood irq controller
+ *
+ * Mask and ack all interrupt sources.
+ *
+ */
+void hlwd_quiesce(void)
+{
+	void __iomem *io_base = hlwd_irq_host->host_data;
+
+	__hlwd_quiesce(io_base);
+}
+