MIPS: Lemote 2F: Add IRQ support

The generic i8259_irq() will make kernel hang on booting, so Loongson 2F
needs its own polling method.

IP6 is shared by the bonito interrupt and perfcounter interrupts.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: zhangfx@lemote.com
Cc: yanh@lemote.com 
Cc: huhb@lemote.com
Cc: Nicholas Mc Guire <hofrat@hofr.at>
Cc: Arnaud Patard <apatard@mandriva.com>
Cc: loongson-dev@googlegroups.com
Cc: linux-mips@linux-mips.org
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 132 insertions, 0 deletions

diff --git a/arch/mips/loongson/lemote-2f/irq.c b/arch/mips/loongson/lemote-2f/irq.c
new file mode 100644
index 000000000000..50e7bb6012b7
--- /dev/null
+++ b/arch/mips/loongson/lemote-2f/irq.c
@@ -0,0 +1,132 @@
+/*
+ * Copyright (C) 2007 Lemote Inc.
+ * Author: Fuxin Zhang, zhangfx@lemote.com
+ *
+ *  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.
+ */
+
+#include <linux/interrupt.h>
+
+#include <asm/irq_cpu.h>
+#include <asm/i8259.h>
+#include <asm/mipsregs.h>
+
+#include <loongson.h>
+#include <machine.h>
+
+#define LOONGSON_TIMER_IRQ	(MIPS_CPU_IRQ_BASE + 7)	/* cpu timer */
+#define LOONGSON_PERFCNT_IRQ	(MIPS_CPU_IRQ_BASE + 6)	/* cpu perf counter */
+#define LOONGSON_NORTH_BRIDGE_IRQ	(MIPS_CPU_IRQ_BASE + 6)	/* bonito */
+#define LOONGSON_UART_IRQ	(MIPS_CPU_IRQ_BASE + 3)	/* cpu serial port */
+#define LOONGSON_SOUTH_BRIDGE_IRQ	(MIPS_CPU_IRQ_BASE + 2)	/* i8259 */
+
+#define LOONGSON_INT_BIT_INT0		(1 << 11)
+#define LOONGSON_INT_BIT_INT1		(1 << 12)
+
+/*
+ * The generic i8259_irq() make the kernel hang on booting.  Since we cannot
+ * get the irq via the IRR directly, we access the ISR instead.
+ */
+static inline int mach_i8259_irq(void)
+{
+	int irq, isr;
+
+	irq = -1;
+
+	if ((LOONGSON_INTISR & LOONGSON_INTEN) & LOONGSON_INT_BIT_INT0) {
+		spin_lock(&i8259A_lock);
+		isr = inb(PIC_MASTER_CMD) &
+			~inb(PIC_MASTER_IMR) & ~(1 << PIC_CASCADE_IR);
+		if (!isr)
+			isr = (inb(PIC_SLAVE_CMD) & ~inb(PIC_SLAVE_IMR)) << 8;
+		irq = ffs(isr) - 1;
+		if (unlikely(irq == 7)) {
+			/*
+			 * This may be a spurious interrupt.
+			 *
+			 * Read the interrupt status register (ISR). If the most
+			 * significant bit is not set then there is no valid
+			 * interrupt.
+			 */
+			outb(0x0B, PIC_MASTER_ISR);	/* ISR register */
+			if (~inb(PIC_MASTER_ISR) & 0x80)
+				irq = -1;
+		}
+		spin_unlock(&i8259A_lock);
+	}
+
+	return irq;
+}
+
+static void i8259_irqdispatch(void)
+{
+	int irq;
+
+	irq = mach_i8259_irq();
+	if (irq >= 0)
+		do_IRQ(irq);
+	else
+		spurious_interrupt();
+}
+
+void mach_irq_dispatch(unsigned int pending)
+{
+	if (pending & CAUSEF_IP7)
+		do_IRQ(LOONGSON_TIMER_IRQ);
+	else if (pending & CAUSEF_IP6) {	/* North Bridge, Perf counter */
+#ifdef CONFIG_OPROFILE
+		do_IRQ(LOONGSON2_PERFCNT_IRQ);
+#endif
+		bonito_irqdispatch();
+	} else if (pending & CAUSEF_IP3)	/* CPU UART */
+		do_IRQ(LOONGSON_UART_IRQ);
+	else if (pending & CAUSEF_IP2)	/* South Bridge */
+		i8259_irqdispatch();
+	else
+		spurious_interrupt();
+}
+
+void __init set_irq_trigger_mode(void)
+{
+	/* setup cs5536 as high level trigger */
+	LOONGSON_INTPOL = LOONGSON_INT_BIT_INT0 | LOONGSON_INT_BIT_INT1;
+	LOONGSON_INTEDGE &= ~(LOONGSON_INT_BIT_INT0 | LOONGSON_INT_BIT_INT1);
+}
+
+static irqreturn_t ip6_action(int cpl, void *dev_id)
+{
+	return IRQ_HANDLED;
+}
+
+struct irqaction ip6_irqaction = {
+	.handler = ip6_action,
+	.name = "cascade",
+	.flags = IRQF_SHARED,
+};
+
+struct irqaction cascade_irqaction = {
+	.handler = no_action,
+	.name = "cascade",
+};
+
+void __init mach_init_irq(void)
+{
+	/* init all controller
+	 *   0-15         ------> i8259 interrupt
+	 *   16-23        ------> mips cpu interrupt
+	 *   32-63        ------> bonito irq
+	 */
+
+	/* Sets the first-level interrupt dispatcher. */
+	mips_cpu_irq_init();
+	init_i8259_irqs();
+	bonito_irq_init();
+
+	/* setup north bridge irq (bonito) */
+	setup_irq(LOONGSON_NORTH_BRIDGE_IRQ, &ip6_irqaction);
+	/* setup source bridge irq (i8259) */
+	setup_irq(LOONGSON_SOUTH_BRIDGE_IRQ, &cascade_irqaction);
+}