[RFC PATCH v2 09/11] powerpc: gamecube/wii: flipper interrupt controller support

[Albert Herranz]

Add support for the interrupt controller included in the "Flipper"
chipset of the Nintendo GameCube video game console.
The same interrupt controller is also present in the "Hollywood" chipset
of the Nintendo Wii.

Signed-off-by: Albert Herranz <albert_herranz at yahoo.es>
---
v1 -> v2
- Build always Flipper interrupt controller when GAMECUBE_COMMON and
  get rid of FLIPPER_PIC option. Suggestion by Grant Likely.
- Use NO_IRQ instead of -1. Suggestion by Benjamin Herrenschmidt.
- Write 0xffffffff instead of ~0 to clear interrupts.
  Suggestion by Segher Boessenkool.
- Use __fls instead of open coded asm. Suggestion by Segher Boessenkool.
- Use a write instead of a read/modify/write to ack interrupts.
  Suggestion by Segher Boessenkool and Benjamin Herrenschmidt.
- Use name instead of typename for struct irq_chip.
- Adapt to updated device tree.

 arch/powerpc/platforms/embedded6xx/Makefile      |    1 +
 arch/powerpc/platforms/embedded6xx/flipper-pic.c |  263 ++++++++++++++++++++++
 arch/powerpc/platforms/embedded6xx/flipper-pic.h |   25 ++
 3 files changed, 289 insertions(+), 0 deletions(-)
 create mode 100644 arch/powerpc/platforms/embedded6xx/flipper-pic.c
 create mode 100644 arch/powerpc/platforms/embedded6xx/flipper-pic.h

diff --git a/arch/powerpc/platforms/embedded6xx/Makefile b/arch/powerpc/platforms/embedded6xx/Makefile
index 0ab7492..b80f47c 100644
--- a/arch/powerpc/platforms/embedded6xx/Makefile
+++ b/arch/powerpc/platforms/embedded6xx/Makefile
@@ -8,3 +8,4 @@ obj-$(CONFIG_PPC_HOLLY)		+= holly.o
 obj-$(CONFIG_PPC_PRPMC2800)	+= prpmc2800.o
 obj-$(CONFIG_PPC_C2K)		+= c2k.o
 obj-$(CONFIG_USBGECKO_UDBG)	+= usbgecko_udbg.o
+obj-$(CONFIG_GAMECUBE_COMMON)	+= flipper-pic.o
diff --git a/arch/powerpc/platforms/embedded6xx/flipper-pic.c b/arch/powerpc/platforms/embedded6xx/flipper-pic.c
new file mode 100644
index 0000000..d596328
--- /dev/null
+++ b/arch/powerpc/platforms/embedded6xx/flipper-pic.c
@@ -0,0 +1,263 @@
+/*
+ * arch/powerpc/platforms/embedded6xx/flipper-pic.c
+ *
+ * Nintendo GameCube/Wii "Flipper" interrupt controller support.
+ * Copyright (C) 2004-2009 The GameCube Linux Team
+ * Copyright (C) 2007,2008,2009 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 "flipper-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 "flipper-pic.h"
+
+#define FLIPPER_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 setting/clearing
+ * the corresponding bit in IMR.
+ * Except for the RSW interrupt, all interrupts get deasserted automatically
+ * when the source deasserts the interrupt.
+ */
+#define FLIPPER_ICR		0x00
+#define FLIPPER_ICR_RSS		(1<<16) /* reset switch state */
+
+#define FLIPPER_IMR		0x04
+
+#define FLIPPER_RESET		0x24
+
+
+/*
+ * IRQ chip hooks.
+ *
+ */
+
+static void flipper_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 + FLIPPER_IMR, mask);
+	/* this is at least needed for RSW */
+	out_be32(io_base + FLIPPER_ICR, mask);
+}
+
+static void flipper_pic_ack(unsigned int virq)
+{
+	int irq = virq_to_hw(virq);
+	void __iomem *io_base = get_irq_chip_data(virq);
+
+	/* this is at least needed for RSW */
+	out_be32(io_base + FLIPPER_ICR, 1 << irq);
+}
+
+static void flipper_pic_mask(unsigned int virq)
+{
+	int irq = virq_to_hw(virq);
+	void __iomem *io_base = get_irq_chip_data(virq);
+
+	clrbits32(io_base + FLIPPER_IMR, 1 << irq);
+}
+
+static void flipper_pic_unmask(unsigned int virq)
+{
+	int irq = virq_to_hw(virq);
+	void __iomem *io_base = get_irq_chip_data(virq);
+
+	setbits32(io_base + FLIPPER_IMR, 1 << irq);
+}
+
+
+static struct irq_chip flipper_pic = {
+	.name		= "flipper-pic",
+	.ack		= flipper_pic_ack,
+	.mask_ack	= flipper_pic_mask_and_ack,
+	.mask		= flipper_pic_mask,
+	.unmask		= flipper_pic_unmask,
+};
+
+/*
+ * IRQ host hooks.
+ *
+ */
+
+static struct irq_host *flipper_irq_host;
+
+static int flipper_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, &flipper_pic, handle_level_irq);
+	return 0;
+}
+
+static void flipper_pic_unmap(struct irq_host *h, unsigned int irq)
+{
+	set_irq_chip_data(irq, NULL);
+	set_irq_chip(irq, NULL);
+}
+
+static int flipper_pic_match(struct irq_host *h, struct device_node *np)
+{
+	return 1;
+}
+
+
+static struct irq_host_ops flipper_irq_host_ops = {
+	.map = flipper_pic_map,
+	.unmap = flipper_pic_unmap,
+	.match = flipper_pic_match,
+};
+
+/*
+ * Platform hooks.
+ *
+ */
+
+static void __flipper_quiesce(void __iomem *io_base)
+{
+	/* mask and ack all IRQs */
+	out_be32(io_base + FLIPPER_IMR, 0x00000000);
+	out_be32(io_base + FLIPPER_ICR, 0xffffffff);
+}
+
+struct irq_host * __init flipper_pic_init(struct device_node *np)
+{
+	struct device_node *pi;
+	struct irq_host *irq_host = NULL;
+	struct resource res;
+	void __iomem *io_base;
+	int retval;
+
+	pi = of_get_parent(np);
+	if (!pi) {
+		pr_err("no parent found\n");
+		goto out;
+	}
+	if (!of_device_is_compatible(pi, "nintendo,flipper-pi")) {
+		pr_err("unexpected parent compatible\n");
+		goto out;
+	}
+
+	retval = of_address_to_resource(pi, 0, &res);
+	if (retval) {
+		pr_err("no io memory range found\n");
+		goto out;
+	}
+	io_base = ioremap(res.start, resource_size(&res));
+
+	pr_info("controller at 0x%08x mapped to 0x%p\n", res.start, io_base);
+
+	__flipper_quiesce(io_base);
+
+	irq_host = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR, FLIPPER_NR_IRQS,
+				  &flipper_irq_host_ops, -1);
+	if (!irq_host) {
+		pr_err("failed to allocate irq_host\n");
+		return NULL;
+	}
+
+	irq_host->host_data = io_base;
+
+out:
+	return irq_host;
+}
+
+unsigned int flipper_pic_get_irq(void)
+{
+	void __iomem *io_base = flipper_irq_host->host_data;
+	int irq;
+	u32 irq_status;
+
+	irq_status = in_be32(io_base + FLIPPER_ICR) &
+		     in_be32(io_base + FLIPPER_IMR);
+	if (irq_status == 0)
+		return NO_IRQ;	/* no more IRQs pending */
+
+	irq = __ffs(irq_status);
+	return irq_linear_revmap(flipper_irq_host, irq);
+}
+
+/*
+ * Probe function.
+ *
+ */
+
+void __init flipper_pic_probe(void)
+{
+	struct device_node *np;
+
+	np = of_find_compatible_node(NULL, NULL, "nintendo,flipper-pic");
+	BUG_ON(!np);
+
+	flipper_irq_host = flipper_pic_init(np);
+	BUG_ON(!flipper_irq_host);
+
+	irq_set_default_host(flipper_irq_host);
+
+	of_node_put(np);
+}
+
+/*
+ * Misc functions related to the flipper chipset.
+ *
+ */
+
+/**
+ * flipper_quiesce() - quiesce flipper irq controller
+ *
+ * Mask and ack all interrupt sources.
+ *
+ */
+void flipper_quiesce(void)
+{
+	void __iomem *io_base = flipper_irq_host->host_data;
+
+	__flipper_quiesce(io_base);
+}
+
+/*
+ * Resets the platform.
+ */
+void flipper_platform_reset(void)
+{
+	void __iomem *io_base;
+
+	if (flipper_irq_host && flipper_irq_host->host_data) {
+		io_base = flipper_irq_host->host_data;
+		out_8(io_base + FLIPPER_RESET, 0x00);
+	}
+}
+
+/*
+ * Returns non-zero if the reset button is pressed.
+ */
+int flipper_is_reset_button_pressed(void)
+{
+	void __iomem *io_base;
+	u32 icr;
+
+	if (flipper_irq_host && flipper_irq_host->host_data) {
+		io_base = flipper_irq_host->host_data;
+		icr = in_be32(io_base + FLIPPER_ICR);
+		return !(icr & FLIPPER_ICR_RSS);
+	}
+	return 0;
+}
+
diff --git a/arch/powerpc/platforms/embedded6xx/flipper-pic.h b/arch/powerpc/platforms/embedded6xx/flipper-pic.h
new file mode 100644
index 0000000..e339186
--- /dev/null
+++ b/arch/powerpc/platforms/embedded6xx/flipper-pic.h
@@ -0,0 +1,25 @@
+/*
+ * arch/powerpc/platforms/embedded6xx/flipper-pic.h
+ *
+ * Nintendo GameCube/Wii "Flipper" interrupt controller support.
+ * Copyright (C) 2004-2009 The GameCube Linux Team
+ * Copyright (C) 2007,2008,2009 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.
+ *
+ */
+
+#ifndef __FLIPPER_PIC_H
+#define __FLIPPER_PIC_H
+
+unsigned int flipper_pic_get_irq(void);
+void __init flipper_pic_probe(void);
+
+void flipper_quiesce(void);
+void flipper_platform_reset(void);
+int flipper_is_reset_button_pressed(void);
+
+#endif
-- 
1.6.3.3