/*
 * Interrupt handling for Marvell mv64360/mv64460 host bridges (Discovery)
 *
 * Author: Dale Farnsworth <dale@farnsworth.org>
 *
 * 2007 (c) MontaVista, Software, Inc.  This file is licensed under
 * the terms of the GNU General Public License version 2.  This program
 * is licensed "as is" without any warranty of any kind, whether express
 * or implied.
 */

#include <linux/stddef.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>

#include <asm/byteorder.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/irq.h>

#include "mv64x60.h"

/* Interrupt Controller Interface Registers */
#define MV64X60_IC_MAIN_CAUSE_LO	0x0004
#define MV64X60_IC_MAIN_CAUSE_HI	0x000c
#define MV64X60_IC_CPU0_INTR_MASK_LO	0x0014
#define MV64X60_IC_CPU0_INTR_MASK_HI	0x001c
#define MV64X60_IC_CPU0_SELECT_CAUSE	0x0024

#define MV64X60_HIGH_GPP_GROUPS		0x0f000000
#define MV64X60_SELECT_CAUSE_HIGH	0x40000000

/* General Purpose Pins Controller Interface Registers */
#define MV64x60_GPP_INTR_CAUSE		0x0008
#define MV64x60_GPP_INTR_MASK		0x000c

#define MV64x60_LEVEL1_LOW		0
#define MV64x60_LEVEL1_HIGH		1
#define MV64x60_LEVEL1_GPP		2

#define MV64x60_LEVEL1_MASK		0x00000060
#define MV64x60_LEVEL1_OFFSET		5

#define MV64x60_LEVEL2_MASK		0x0000001f

#define MV64x60_NUM_IRQS		96

static DEFINE_SPINLOCK(mv64x60_lock);

static void __iomem *mv64x60_irq_reg_base;
static void __iomem *mv64x60_gpp_reg_base;

/*
 * Interrupt Controller Handling
 *
 * The interrupt controller handles three groups of interrupts:
 *   main low:	IRQ0-IRQ31
 *   main high:	IRQ32-IRQ63
 *   gpp:	IRQ64-IRQ95
 *
 * This code handles interrupts in two levels.  Level 1 selects the
 * interrupt group, and level 2 selects an IRQ within that group.
 * Each group has its own irq_chip structure.
 */

static u32 mv64x60_cached_low_mask;
static u32 mv64x60_cached_high_mask = MV64X60_HIGH_GPP_GROUPS;
static u32 mv64x60_cached_gpp_mask;

static struct irq_host *mv64x60_irq_host;

/*
 * mv64x60_chip_low functions
 */

static void mv64x60_mask_low(unsigned int virq)
{
	int level2 = irq_map[virq].hwirq & MV64x60_LEVEL2_MASK;
	unsigned long flags;

	spin_lock_irqsave(&mv64x60_lock, flags);
	mv64x60_cached_low_mask &= ~(1 << level2);
	out_le32(mv64x60_irq_reg_base + MV64X60_IC_CPU0_INTR_MASK_LO,
		 mv64x60_cached_low_mask);
	spin_unlock_irqrestore(&mv64x60_lock, flags);
	(void)in_le32(mv64x60_irq_reg_base + MV64X60_IC_CPU0_INTR_MASK_LO);
}

static void mv64x60_unmask_low(unsigned int virq)
{
	int level2 = irq_map[virq].hwirq & MV64x60_LEVEL2_MASK;
	unsigned long flags;

	spin_lock_irqsave(&mv64x60_lock, flags);
	mv64x60_cached_low_mask |= 1 << level2;
	out_le32(mv64x60_irq_reg_base + MV64X60_IC_CPU0_INTR_MASK_LO,
		 mv64x60_cached_low_mask);
	spin_unlock_irqrestore(&mv64x60_lock, flags);
	(void)in_le32(mv64x60_irq_reg_base + MV64X60_IC_CPU0_INTR_MASK_LO);
}

static struct irq_chip mv64x60_chip_low = {
	.name		= "mv64x60_low",
	.mask		= mv64x60_mask_low,
	.mask_ack	= mv64x60_mask_low,
	.unmask		= mv64x60_unmask_low,
};

/*
 * mv64x60_chip_high functions
 */

static void mv64x60_mask_high(unsigned int virq)
{
	int level2 = irq_map[virq].hwirq & MV64x60_LEVEL2_MASK;
	unsigned long flags;

	spin_lock_irqsave(&mv64x60_lock, flags);
	mv64x60_cached_high_mask &= ~(1 << level2);
	out_le32(mv64x60_irq_reg_base + MV64X60_IC_CPU0_INTR_MASK_HI,
		 mv64x60_cached_high_mask);
	spin_unlock_irqrestore(&mv64x60_lock, flags);
	(void)in_le32(mv64x60_irq_reg_base + MV64X60_IC_CPU0_INTR_MASK_HI);
}

static void mv64x60_unmask_high(unsigned int virq)
{
	int level2 = irq_map[virq].hwirq & MV64x60_LEVEL2_MASK;
	unsigned long flags;

	spin_lock_irqsave(&mv64x60_lock, flags);
	mv64x60_cached_high_mask |= 1 << level2;
	out_le32(mv64x60_irq_reg_base + MV64X60_IC_CPU0_INTR_MASK_HI,
		 mv64x60_cached_high_mask);
	spin_unlock_irqrestore(&mv64x60_lock, flags);
	(void)in_le32(mv64x60_irq_reg_base + MV64X60_IC_CPU0_INTR_MASK_HI);
}

static struct irq_chip mv64x60_chip_high = {
	.name		= "mv64x60_high",
	.mask		= mv64x60_mask_high,
	.mask_ack	= mv64x60_mask_high,
	.unmask		= mv64x60_unmask_high,
};

/*
 * mv64x60_chip_gpp functions
 */

static void mv64x60_mask_gpp(unsigned int virq)
{
	int level2 = irq_map[virq].hwirq & MV64x60_LEVEL2_MASK;
	unsigned long flags;

	spin_lock_irqsave(&mv64x60_lock, flags);
	mv64x60_cached_gpp_mask &= ~(1 << level2);
	out_le32(mv64x60_gpp_reg_base + MV64x60_GPP_INTR_MASK,
		 mv64x60_cached_gpp_mask);
	spin_unlock_irqrestore(&mv64x60_lock, flags);
	(void)in_le32(mv64x60_gpp_reg_base + MV64x60_GPP_INTR_MASK);
}

static void mv64x60_mask_ack_gpp(unsigned int virq)
{
	int level2 = irq_map[virq].hwirq & MV64x60_LEVEL2_MASK;
	unsigned long flags;

	spin_lock_irqsave(&mv64x60_lock, flags);
	mv64x60_cached_gpp_mask &= ~(1 << level2);
	out_le32(mv64x60_gpp_reg_base + MV64x60_GPP_INTR_MASK,
		 mv64x60_cached_gpp_mask);
	out_le32(mv64x60_gpp_reg_base + MV64x60_GPP_INTR_CAUSE,
		 ~(1 << level2));
	spin_unlock_irqrestore(&mv64x60_lock, flags);
	(void)in_le32(mv64x60_gpp_reg_base + MV64x60_GPP_INTR_CAUSE);
}

static void mv64x60_unmask_gpp(unsigned int virq)
{
	int level2 = irq_map[virq].hwirq & MV64x60_LEVEL2_MASK;
	unsigned long flags;

	spin_lock_irqsave(&mv64x60_lock, flags);
	mv64x60_cached_gpp_mask |= 1 << level2;
	out_le32(mv64x60_gpp_reg_base + MV64x60_GPP_INTR_MASK,
		 mv64x60_cached_gpp_mask);
	spin_unlock_irqrestore(&mv64x60_lock, flags);
	(void)in_le32(mv64x60_gpp_reg_base + MV64x60_GPP_INTR_MASK);
}

static struct irq_chip mv64x60_chip_gpp = {
	.name		= "mv64x60_gpp",
	.mask		= mv64x60_mask_gpp,
	.mask_ack	= mv64x60_mask_ack_gpp,
	.unmask		= mv64x60_unmask_gpp,
};

/*
 * mv64x60_host_ops functions
 */

static struct irq_chip *mv64x60_chips[] = {
	[MV64x60_LEVEL1_LOW]  = &mv64x60_chip_low,
	[MV64x60_LEVEL1_HIGH] = &mv64x60_chip_high,
	[MV64x60_LEVEL1_GPP]  = &mv64x60_chip_gpp,
};

static int mv64x60_host_map(struct irq_host *h, unsigned int virq,
			  irq_hw_number_t hwirq)
{
	int level1;

	irq_to_desc(virq)->status |= IRQ_LEVEL;

	level1 = (hwirq & MV64x60_LEVEL1_MASK) >> MV64x60_LEVEL1_OFFSET;
	BUG_ON(level1 > MV64x60_LEVEL1_GPP);
	set_irq_chip_and_handler(virq, mv64x60_chips[level1], handle_level_irq);

	return 0;
}

static struct irq_host_ops mv64x60_host_ops = {
	.map   = mv64x60_host_map,
};

/*
 * Global functions
 */

void __init mv64x60_init_irq(void)
{
	struct device_node *np;
	phys_addr_t paddr;
	unsigned int size;
	const unsigned int *reg;
	unsigned long flags;

	np = of_find_compatible_node(NULL, NULL, "marvell,mv64360-gpp");
	reg = of_get_property(np, "reg", &size);
	paddr = of_translate_address(np, reg);
	mv64x60_gpp_reg_base = ioremap(paddr, reg[1]);
	of_node_put(np);

	np = of_find_compatible_node(NULL, NULL, "marvell,mv64360-pic");
	reg = of_get_property(np, "reg", &size);
	paddr = of_translate_address(np, reg);
	mv64x60_irq_reg_base = ioremap(paddr, reg[1]);

	mv64x60_irq_host = irq_alloc_host(np, IRQ_HOST_MAP_LINEAR,
					  MV64x60_NUM_IRQS,
					  &mv64x60_host_ops, MV64x60_NUM_IRQS);

	spin_lock_irqsave(&mv64x60_lock, flags);
	out_le32(mv64x60_gpp_reg_base + MV64x60_GPP_INTR_MASK,
		 mv64x60_cached_gpp_mask);
	out_le32(mv64x60_irq_reg_base + MV64X60_IC_CPU0_INTR_MASK_LO,
		 mv64x60_cached_low_mask);
	out_le32(mv64x60_irq_reg_base + MV64X60_IC_CPU0_INTR_MASK_HI,
		 mv64x60_cached_high_mask);

	out_le32(mv64x60_gpp_reg_base + MV64x60_GPP_INTR_CAUSE, 0);
	out_le32(mv64x60_irq_reg_base + MV64X60_IC_MAIN_CAUSE_LO, 0);
	out_le32(mv64x60_irq_reg_base + MV64X60_IC_MAIN_CAUSE_HI, 0);
	spin_unlock_irqrestore(&mv64x60_lock, flags);
}

unsigned int mv64x60_get_irq(void)
{
	u32 cause;
	int level1;
	irq_hw_number_t hwirq;
	int virq = NO_IRQ;

	cause = in_le32(mv64x60_irq_reg_base + MV64X60_IC_CPU0_SELECT_CAUSE);
	if (cause & MV64X60_SELECT_CAUSE_HIGH) {
		cause &= mv64x60_cached_high_mask;
		level1 = MV64x60_LEVEL1_HIGH;
		if (cause & MV64X60_HIGH_GPP_GROUPS) {
			cause = in_le32(mv64x60_gpp_reg_base +
					MV64x60_GPP_INTR_CAUSE);
			cause &= mv64x60_cached_gpp_mask;
			level1 = MV64x60_LEVEL1_GPP;
		}
	} else {
		cause &= mv64x60_cached_low_mask;
		level1 = MV64x60_LEVEL1_LOW;
	}
	if (cause) {
		hwirq = (level1 << MV64x60_LEVEL1_OFFSET) | __ilog2(cause);
		virq = irq_linear_revmap(mv64x60_irq_host, hwirq);
	}

	return virq;
}