ARM: S5P64X0: External Interrupt Support

Add external interrupt support for S5P64X0.The external interrupt
group 0(0 to 15) is used for wake-up source in stop and sleep mode.
Add generic irq chip support

Signed-off-by: Padmavathi Venna <padma.v@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/mach-s5p64x0/Makefile

@@ -13,7 +13,7 @@ obj-				:=
 # Core support for S5P64X0 system
 
 obj-$(CONFIG_ARCH_S5P64X0)	+= cpu.o init.o clock.o dma.o gpiolib.o
-obj-$(CONFIG_ARCH_S5P64X0)	+= setup-i2c0.o
+obj-$(CONFIG_ARCH_S5P64X0)	+= setup-i2c0.o irq-eint.o
 obj-$(CONFIG_CPU_S5P6440)	+= clock-s5p6440.o
 obj-$(CONFIG_CPU_S5P6450)	+= clock-s5p6450.o
 

arch/arm/mach-s5p64x0/include/mach/regs-gpio.h

@@ -34,4 +34,14 @@
 #define S5P6450_GPQ_BASE		(S5P_VA_GPIO + 0x0180)
 #define S5P6450_GPS_BASE		(S5P_VA_GPIO + 0x0300)
 
+/* External interrupt control registers for group0 */
+
+#define EINT0CON0_OFFSET		(0x900)
+#define EINT0MASK_OFFSET		(0x920)
+#define EINT0PEND_OFFSET		(0x924)
+
+#define S5P64X0_EINT0CON0		(S5P_VA_GPIO + EINT0CON0_OFFSET)
+#define S5P64X0_EINT0MASK		(S5P_VA_GPIO + EINT0MASK_OFFSET)
+#define S5P64X0_EINT0PEND		(S5P_VA_GPIO + EINT0PEND_OFFSET)
+
 #endif /* __ASM_ARCH_REGS_GPIO_H */

arch/arm/mach-s5p64x0/irq-eint.c

@@ -0,0 +1,152 @@
+/* arch/arm/mach-s5p64x0/irq-eint.c
+ *
+ * Copyright (c) 2011 Samsung Electronics Co., Ltd
+ *		http://www.samsung.com/
+ *
+ * Based on linux/arch/arm/mach-s3c64xx/irq-eint.c
+ *
+ * S5P64X0 - Interrupt handling for External Interrupts.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/gpio.h>
+#include <linux/irq.h>
+#include <linux/io.h>
+
+#include <plat/regs-irqtype.h>
+#include <plat/gpio-cfg.h>
+
+#include <mach/regs-gpio.h>
+#include <mach/regs-clock.h>
+
+#define eint_offset(irq)	((irq) - IRQ_EINT(0))
+
+static int s5p64x0_irq_eint_set_type(struct irq_data *data, unsigned int type)
+{
+	int offs = eint_offset(data->irq);
+	int shift;
+	u32 ctrl, mask;
+	u32 newvalue = 0;
+
+	if (offs > 15)
+		return -EINVAL;
+
+	switch (type) {
+	case IRQ_TYPE_NONE:
+		printk(KERN_WARNING "No edge setting!\n");
+		break;
+	case IRQ_TYPE_EDGE_RISING:
+		newvalue = S3C2410_EXTINT_RISEEDGE;
+		break;
+	case IRQ_TYPE_EDGE_FALLING:
+		newvalue = S3C2410_EXTINT_FALLEDGE;
+		break;
+	case IRQ_TYPE_EDGE_BOTH:
+		newvalue = S3C2410_EXTINT_BOTHEDGE;
+		break;
+	case IRQ_TYPE_LEVEL_LOW:
+		newvalue = S3C2410_EXTINT_LOWLEV;
+		break;
+	case IRQ_TYPE_LEVEL_HIGH:
+		newvalue = S3C2410_EXTINT_HILEV;
+		break;
+	default:
+		printk(KERN_ERR "No such irq type %d", type);
+		return -EINVAL;
+	}
+
+	shift = (offs / 2) * 4;
+	mask = 0x7 << shift;
+
+	ctrl = __raw_readl(S5P64X0_EINT0CON0) & ~mask;
+	ctrl |= newvalue << shift;
+	__raw_writel(ctrl, S5P64X0_EINT0CON0);
+
+	/* Configure the GPIO pin for 6450 or 6440 based on CPU ID */
+	if (0x50000 == (__raw_readl(S5P64X0_SYS_ID) & 0xFF000))
+		s3c_gpio_cfgpin(S5P6450_GPN(offs), S3C_GPIO_SFN(2));
+	else
+		s3c_gpio_cfgpin(S5P6440_GPN(offs), S3C_GPIO_SFN(2));
+
+	return 0;
+}
+
+/*
+ * s5p64x0_irq_demux_eint
+ *
+ * This function demuxes the IRQ from the group0 external interrupts,
+ * from IRQ_EINT(0) to IRQ_EINT(15). It is designed to be inlined into
+ * the specific handlers s5p64x0_irq_demux_eintX_Y.
+ */
+static inline void s5p64x0_irq_demux_eint(unsigned int start, unsigned int end)
+{
+	u32 status = __raw_readl(S5P64X0_EINT0PEND);
+	u32 mask = __raw_readl(S5P64X0_EINT0MASK);
+	unsigned int irq;
+
+	status &= ~mask;
+	status >>= start;
+	status &= (1 << (end - start + 1)) - 1;
+
+	for (irq = IRQ_EINT(start); irq <= IRQ_EINT(end); irq++) {
+		if (status & 1)
+			generic_handle_irq(irq);
+		status >>= 1;
+	}
+}
+
+static void s5p64x0_irq_demux_eint0_3(unsigned int irq, struct irq_desc *desc)
+{
+	s5p64x0_irq_demux_eint(0, 3);
+}
+
+static void s5p64x0_irq_demux_eint4_11(unsigned int irq, struct irq_desc *desc)
+{
+	s5p64x0_irq_demux_eint(4, 11);
+}
+
+static void s5p64x0_irq_demux_eint12_15(unsigned int irq,
+					struct irq_desc *desc)
+{
+	s5p64x0_irq_demux_eint(12, 15);
+}
+
+static int s5p64x0_alloc_gc(void)
+{
+	struct irq_chip_generic *gc;
+	struct irq_chip_type *ct;
+
+	gc = irq_alloc_generic_chip("s5p64x0-eint", 1, S5P_IRQ_EINT_BASE,
+				    S5P_VA_GPIO, handle_level_irq);
+	if (!gc) {
+		printk(KERN_ERR "%s: irq_alloc_generic_chip for group 0"
+			"external interrupts failed\n", __func__);
+		return -EINVAL;
+	}
+
+	ct = gc->chip_types;
+	ct->chip.irq_ack = irq_gc_ack;
+	ct->chip.irq_mask = irq_gc_mask_set_bit;
+	ct->chip.irq_unmask = irq_gc_mask_clr_bit;
+	ct->chip.irq_set_type = s5p64x0_irq_eint_set_type;
+	ct->regs.ack = EINT0PEND_OFFSET;
+	ct->regs.mask = EINT0MASK_OFFSET;
+	irq_setup_generic_chip(gc, IRQ_MSK(16), IRQ_GC_INIT_MASK_CACHE,
+			       IRQ_NOREQUEST | IRQ_NOPROBE, 0);
+	return 0;
+}
+
+static int __init s5p64x0_init_irq_eint(void)
+{
+	int ret = s5p64x0_alloc_gc();
+	irq_set_chained_handler(IRQ_EINT0_3, s5p64x0_irq_demux_eint0_3);
+	irq_set_chained_handler(IRQ_EINT4_11, s5p64x0_irq_demux_eint4_11);
+	irq_set_chained_handler(IRQ_EINT12_15, s5p64x0_irq_demux_eint12_15);
+
+	return ret;
+}
+arch_initcall(s5p64x0_init_irq_eint);