/* 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_set_bit;
	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);