MIPS: JZ4740: Add IRQ handler code

Add support for IRQ handling on a JZ4740 SoC.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/1465/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 167 insertions, 0 deletions

diff --git a/arch/mips/jz4740/irq.c b/arch/mips/jz4740/irq.c
new file mode 100644
index 000000000000..7d33ff83580f
--- /dev/null
+++ b/arch/mips/jz4740/irq.c
@@ -0,0 +1,167 @@
+/*
+ *  Copyright (C) 2009-2010, Lars-Peter Clausen <lars@metafoo.de>
+ *  JZ4740 platform IRQ support
+ *
+ *  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.
+ *
+ *  You should have received a copy of the GNU General Public License along
+ *  with this program; if not, write to the Free Software Foundation, Inc.,
+ *  675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/types.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/timex.h>
+#include <linux/slab.h>
+#include <linux/delay.h>
+
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+#include <asm/io.h>
+#include <asm/mipsregs.h>
+#include <asm/irq_cpu.h>
+
+#include <asm/mach-jz4740/base.h>
+
+static void __iomem *jz_intc_base;
+static uint32_t jz_intc_wakeup;
+static uint32_t jz_intc_saved;
+
+#define JZ_REG_INTC_STATUS	0x00
+#define JZ_REG_INTC_MASK	0x04
+#define JZ_REG_INTC_SET_MASK	0x08
+#define JZ_REG_INTC_CLEAR_MASK	0x0c
+#define JZ_REG_INTC_PENDING	0x10
+
+#define IRQ_BIT(x) BIT((x) - JZ4740_IRQ_BASE)
+
+static void intc_irq_unmask(unsigned int irq)
+{
+	writel(IRQ_BIT(irq), jz_intc_base + JZ_REG_INTC_CLEAR_MASK);
+}
+
+static void intc_irq_mask(unsigned int irq)
+{
+	writel(IRQ_BIT(irq), jz_intc_base + JZ_REG_INTC_SET_MASK);
+}
+
+static int intc_irq_set_wake(unsigned int irq, unsigned int on)
+{
+	if (on)
+		jz_intc_wakeup |= IRQ_BIT(irq);
+	else
+		jz_intc_wakeup &= ~IRQ_BIT(irq);
+
+	return 0;
+}
+
+static struct irq_chip intc_irq_type = {
+	.name =		"INTC",
+	.mask =		intc_irq_mask,
+	.mask_ack =	intc_irq_mask,
+	.unmask =	intc_irq_unmask,
+	.set_wake =	intc_irq_set_wake,
+};
+
+static irqreturn_t jz4740_cascade(int irq, void *data)
+{
+	uint32_t irq_reg;
+
+	irq_reg = readl(jz_intc_base + JZ_REG_INTC_PENDING);
+
+	if (irq_reg)
+		generic_handle_irq(__fls(irq_reg) + JZ4740_IRQ_BASE);
+
+	return IRQ_HANDLED;
+}
+
+static struct irqaction jz4740_cascade_action = {
+	.handler = jz4740_cascade,
+	.name = "JZ4740 cascade interrupt",
+};
+
+void __init arch_init_irq(void)
+{
+	int i;
+	mips_cpu_irq_init();
+
+	jz_intc_base = ioremap(JZ4740_INTC_BASE_ADDR, 0x14);
+
+	for (i = JZ4740_IRQ_BASE; i < JZ4740_IRQ_BASE + 32; i++) {
+		intc_irq_mask(i);
+		set_irq_chip_and_handler(i, &intc_irq_type, handle_level_irq);
+	}
+
+	setup_irq(2, &jz4740_cascade_action);
+}
+
+asmlinkage void plat_irq_dispatch(void)
+{
+	unsigned int pending = read_c0_status() & read_c0_cause() & ST0_IM;
+	if (pending & STATUSF_IP2)
+		do_IRQ(2);
+	else if (pending & STATUSF_IP3)
+		do_IRQ(3);
+	else
+		spurious_interrupt();
+}
+
+void jz4740_intc_suspend(void)
+{
+	jz_intc_saved = readl(jz_intc_base + JZ_REG_INTC_MASK);
+	writel(~jz_intc_wakeup, jz_intc_base + JZ_REG_INTC_SET_MASK);
+	writel(jz_intc_wakeup, jz_intc_base + JZ_REG_INTC_CLEAR_MASK);
+}
+
+void jz4740_intc_resume(void)
+{
+	writel(~jz_intc_saved, jz_intc_base + JZ_REG_INTC_CLEAR_MASK);
+	writel(jz_intc_saved, jz_intc_base + JZ_REG_INTC_SET_MASK);
+}
+
+#ifdef CONFIG_DEBUG_FS
+
+static inline void intc_seq_reg(struct seq_file *s, const char *name,
+	unsigned int reg)
+{
+	seq_printf(s, "%s:\t\t%08x\n", name, readl(jz_intc_base + reg));
+}
+
+static int intc_regs_show(struct seq_file *s, void *unused)
+{
+	intc_seq_reg(s, "Status", JZ_REG_INTC_STATUS);
+	intc_seq_reg(s, "Mask", JZ_REG_INTC_MASK);
+	intc_seq_reg(s, "Pending", JZ_REG_INTC_PENDING);
+
+	return 0;
+}
+
+static int intc_regs_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, intc_regs_show, NULL);
+}
+
+static const struct file_operations intc_regs_operations = {
+	.open		= intc_regs_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init intc_debugfs_init(void)
+{
+	(void) debugfs_create_file("jz_regs_intc", S_IFREG | S_IRUGO,
+				NULL, NULL, &intc_regs_operations);
+	return 0;
+}
+subsys_initcall(intc_debugfs_init);
+
+#endif