sh: maskreg IRQ support.

Formerly implemented by ADX, we can use this generically,
so move it over.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>

arch/sh/Kconfig

@@ -313,6 +313,9 @@ config CPU_HAS_INTEVT
 config CPU_HAS_PINT_IRQ
 	bool
 
+config CPU_HAS_MASKREG_IRQ
+	bool
+
 config CPU_HAS_INTC2_IRQ
 	bool
 

arch/sh/kernel/cpu/irq/Makefile

@@ -3,5 +3,6 @@
 #
 obj-y	+= ipr.o imask.o
 
-obj-$(CONFIG_CPU_HAS_PINT_IRQ)	+= pint.o
-obj-$(CONFIG_CPU_HAS_INTC2_IRQ)	+= intc2.o
+obj-$(CONFIG_CPU_HAS_PINT_IRQ)		+= pint.o
+obj-$(CONFIG_CPU_HAS_MASKREG_IRQ)	+= maskreg.o
+obj-$(CONFIG_CPU_HAS_INTC2_IRQ)		+= intc2.o

arch/sh/kernel/cpu/irq/maskreg.c

@@ -0,0 +1,99 @@
+/*
+ * Interrupt handling for Simple external interrupt mask register
+ *
+ * Copyright (C) 2001 A&D Co., Ltd. <http://www.aandd.co.jp>
+ *
+ * This is for the machine which have single 16 bit register
+ * for masking external IRQ individually.
+ * Each bit of the register is for masking each interrupt.
+ *
+ * This file may be copied or modified under the terms of the GNU
+ * General Public License.  See linux/COPYING for more information.
+ */
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/irq.h>
+#include <asm/system.h>
+#include <asm/io.h>
+
+/* address of external interrupt mask register */
+unsigned long irq_mask_register;
+
+/* forward declaration */
+static unsigned int startup_maskreg_irq(unsigned int irq);
+static void shutdown_maskreg_irq(unsigned int irq);
+static void enable_maskreg_irq(unsigned int irq);
+static void disable_maskreg_irq(unsigned int irq);
+static void mask_and_ack_maskreg(unsigned int);
+static void end_maskreg_irq(unsigned int irq);
+
+/* hw_interrupt_type */
+static struct hw_interrupt_type maskreg_irq_type = {
+	.typename = "Mask Register",
+	.startup = startup_maskreg_irq,
+	.shutdown = shutdown_maskreg_irq,
+	.enable = enable_maskreg_irq,
+	.disable = disable_maskreg_irq,
+	.ack = mask_and_ack_maskreg,
+	.end = end_maskreg_irq
+};
+
+/* actual implementatin */
+static unsigned int startup_maskreg_irq(unsigned int irq)
+{
+	enable_maskreg_irq(irq);
+	return 0; /* never anything pending */
+}
+
+static void shutdown_maskreg_irq(unsigned int irq)
+{
+	disable_maskreg_irq(irq);
+}
+
+static void disable_maskreg_irq(unsigned int irq)
+{
+	unsigned long flags;
+	unsigned short val, mask = 0x01 << irq;
+
+	BUG_ON(!irq_mask_register);
+
+	/* Set "irq"th bit */
+	local_irq_save(flags);
+	val = ctrl_inw(irq_mask_register);
+	val |= mask;
+	ctrl_outw(val, irq_mask_register);
+	local_irq_restore(flags);
+}
+
+static void enable_maskreg_irq(unsigned int irq)
+{
+	unsigned long flags;
+	unsigned short val, mask = ~(0x01 << irq);
+
+	BUG_ON(!irq_mask_register);
+
+	/* Clear "irq"th bit */
+	local_irq_save(flags);
+	val = ctrl_inw(irq_mask_register);
+	val &= mask;
+	ctrl_outw(val, irq_mask_register);
+	local_irq_restore(flags);
+}
+
+static void mask_and_ack_maskreg(unsigned int irq)
+{
+	disable_maskreg_irq(irq);
+}
+
+static void end_maskreg_irq(unsigned int irq)
+{
+	if (!(irq_desc[irq].status & (IRQ_DISABLED|IRQ_INPROGRESS)))
+		enable_maskreg_irq(irq);
+}
+
+void make_maskreg_irq(unsigned int irq)
+{
+	disable_irq_nosync(irq);
+	irq_desc[irq].handler = &maskreg_irq_type;
+	disable_maskreg_irq(irq);
+}