/*
 * linux/arch/arm/mach-omap2/irq.c
 *
 * Interrupt handler for OMAP2 boards.
 *
 * Copyright (C) 2005 Nokia Corporation
 * Author: Paul Mundt <paul.mundt@nokia.com>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License. See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>

#include <asm/exception.h>
#include <asm/mach/irq.h>
#include <linux/irqdomain.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>

#include "soc.h"
#include "iomap.h"
#include "common.h"

/* selected INTC register offsets */

#define INTC_REVISION		0x0000
#define INTC_SYSCONFIG		0x0010
#define INTC_SYSSTATUS		0x0014
#define INTC_SIR		0x0040
#define INTC_CONTROL		0x0048
#define INTC_PROTECTION		0x004C
#define INTC_IDLE		0x0050
#define INTC_THRESHOLD		0x0068
#define INTC_MIR0		0x0084
#define INTC_MIR_CLEAR0		0x0088
#define INTC_MIR_SET0		0x008c
#define INTC_PENDING_IRQ0	0x0098
#define INTC_ILR0		0x0100
/* Number of IRQ state bits in each MIR register */
#define IRQ_BITS_PER_REG	32

#define OMAP2_IRQ_BASE		OMAP2_L4_IO_ADDRESS(OMAP24XX_IC_BASE)
#define OMAP3_IRQ_BASE		OMAP2_L4_IO_ADDRESS(OMAP34XX_IC_BASE)
#define INTCPS_SIR_IRQ_OFFSET	0x0040	/* omap2/3 active interrupt offset */
#define ACTIVEIRQ_MASK		0x7f	/* omap2/3 active interrupt bits */
#define INTCPS_NR_MIR_REGS	3
#define INTCPS_NR_IRQS		96

/*
 * OMAP2 has a number of different interrupt controllers, each interrupt
 * controller is identified as its own "bank". Register definitions are
 * fairly consistent for each bank, but not all registers are implemented
 * for each bank.. when in doubt, consult the TRM.
 */
static struct omap_irq_bank {
	void __iomem *base_reg;
	unsigned int nr_irqs;
} __attribute__ ((aligned(4))) irq_banks[] = {
	{
		/* MPU INTC */
		.nr_irqs	= 96,
	},
};

static struct irq_domain *domain;
static void __iomem *omap_irq_base;

/* Structure to save interrupt controller context */
struct omap3_intc_regs {
	u32 sysconfig;
	u32 protection;
	u32 idle;
	u32 threshold;
	u32 ilr[INTCPS_NR_IRQS];
	u32 mir[INTCPS_NR_MIR_REGS];
};

/* INTC bank register get/set */

static void intc_bank_write_reg(u32 val, struct omap_irq_bank *bank, u16 reg)
{
	writel_relaxed(val, bank->base_reg + reg);
}

static u32 intc_bank_read_reg(struct omap_irq_bank *bank, u16 reg)
{
	return readl_relaxed(bank->base_reg + reg);
}

/* XXX: FIQ and additional INTC support (only MPU at the moment) */
static void omap_ack_irq(struct irq_data *d)
{
	intc_bank_write_reg(0x1, &irq_banks[0], INTC_CONTROL);
}

static void omap_mask_ack_irq(struct irq_data *d)
{
	irq_gc_mask_disable_reg(d);
	omap_ack_irq(d);
}

static void __init omap_irq_bank_init_one(struct omap_irq_bank *bank)
{
	unsigned long tmp;

	tmp = intc_bank_read_reg(bank, INTC_REVISION) & 0xff;
	pr_info("IRQ: Found an INTC at 0x%p (revision %ld.%ld) with %d interrupts\n",
		bank->base_reg, tmp >> 4, tmp & 0xf, bank->nr_irqs);

	tmp = intc_bank_read_reg(bank, INTC_SYSCONFIG);
	tmp |= 1 << 1;	/* soft reset */
	intc_bank_write_reg(tmp, bank, INTC_SYSCONFIG);

	while (!(intc_bank_read_reg(bank, INTC_SYSSTATUS) & 0x1))
		/* Wait for reset to complete */;

	/* Enable autoidle */
	intc_bank_write_reg(1 << 0, bank, INTC_SYSCONFIG);
}

int omap_irq_pending(void)
{
	int i;

	for (i = 0; i < ARRAY_SIZE(irq_banks); i++) {
		struct omap_irq_bank *bank = irq_banks + i;
		int irq;

		for (irq = 0; irq < bank->nr_irqs; irq += 32)
			if (intc_bank_read_reg(bank, INTC_PENDING_IRQ0 +
					       ((irq >> 5) << 5)))
				return 1;
	}
	return 0;
}

static __init void
omap_alloc_gc(void __iomem *base, unsigned int irq_start, unsigned int num)
{
	struct irq_chip_generic *gc;
	struct irq_chip_type *ct;

	gc = irq_alloc_generic_chip("INTC", 1, irq_start, base,
					handle_level_irq);
	ct = gc->chip_types;
	ct->chip.irq_ack = omap_mask_ack_irq;
	ct->chip.irq_mask = irq_gc_mask_disable_reg;
	ct->chip.irq_unmask = irq_gc_unmask_enable_reg;
	ct->chip.flags |= IRQCHIP_SKIP_SET_WAKE;

	ct->regs.enable = INTC_MIR_CLEAR0;
	ct->regs.disable = INTC_MIR_SET0;
	irq_setup_generic_chip(gc, IRQ_MSK(num), IRQ_GC_INIT_MASK_CACHE,
				IRQ_NOREQUEST | IRQ_NOPROBE, 0);
}

static void __init omap_init_irq(u32 base, int nr_irqs,
				 struct device_node *node)
{
	unsigned long nr_of_irqs = 0;
	unsigned int nr_banks = 0;
	int i, j, irq_base;

	omap_irq_base = ioremap(base, SZ_4K);
	if (WARN_ON(!omap_irq_base))
		return;

	irq_base = irq_alloc_descs(-1, 0, nr_irqs, 0);
	if (irq_base < 0) {
		pr_warn("Couldn't allocate IRQ numbers\n");
		irq_base = 0;
	}

	domain = irq_domain_add_legacy(node, nr_irqs, irq_base, 0,
				       &irq_domain_simple_ops, NULL);

	for (i = 0; i < ARRAY_SIZE(irq_banks); i++) {
		struct omap_irq_bank *bank = irq_banks + i;

		bank->nr_irqs = nr_irqs;

		/* Static mapping, never released */
		bank->base_reg = ioremap(base, SZ_4K);
		if (!bank->base_reg) {
			pr_err("Could not ioremap irq bank%i\n", i);
			continue;
		}

		omap_irq_bank_init_one(bank);

		for (j = 0; j < bank->nr_irqs; j += 32)
			omap_alloc_gc(bank->base_reg + j, j + irq_base, 32);

		nr_of_irqs += bank->nr_irqs;
		nr_banks++;
	}

	pr_info("Total of %ld interrupts on %d active controller%s\n",
		nr_of_irqs, nr_banks, nr_banks > 1 ? "s" : "");
}

void __init omap2_init_irq(void)
{
	omap_init_irq(OMAP24XX_IC_BASE, 96, NULL);
}

void __init omap3_init_irq(void)
{
	omap_init_irq(OMAP34XX_IC_BASE, 96, NULL);
}

void __init ti81xx_init_irq(void)
{
	omap_init_irq(OMAP34XX_IC_BASE, 128, NULL);
}

static inline void omap_intc_handle_irq(void __iomem *base_addr, struct pt_regs *regs)
{
	u32 irqnr;
	int handled_irq = 0;

	do {
		irqnr = readl_relaxed(base_addr + 0x98);
		if (irqnr)
			goto out;

		irqnr = readl_relaxed(base_addr + 0xb8);
		if (irqnr)
			goto out;

		irqnr = readl_relaxed(base_addr + 0xd8);
#if IS_ENABLED(CONFIG_SOC_TI81XX) || IS_ENABLED(CONFIG_SOC_AM33XX)
		if (irqnr)
			goto out;
		irqnr = readl_relaxed(base_addr + 0xf8);
#endif

out:
		if (!irqnr)
			break;

		irqnr = readl_relaxed(base_addr + INTCPS_SIR_IRQ_OFFSET);
		irqnr &= ACTIVEIRQ_MASK;

		if (irqnr) {
			irqnr = irq_find_mapping(domain, irqnr);
			handle_IRQ(irqnr, regs);
			handled_irq = 1;
		}
	} while (irqnr);

	/* If an irq is masked or deasserted while active, we will
	 * keep ending up here with no irq handled. So remove it from
	 * the INTC with an ack.*/
	if (!handled_irq)
		omap_ack_irq(NULL);
}

asmlinkage void __exception_irq_entry omap2_intc_handle_irq(struct pt_regs *regs)
{
	void __iomem *base_addr = OMAP2_IRQ_BASE;
	omap_intc_handle_irq(base_addr, regs);
}

int __init intc_of_init(struct device_node *node,
			     struct device_node *parent)
{
	struct resource res;
	u32 nr_irq = 96;

	if (WARN_ON(!node))
		return -ENODEV;

	if (of_address_to_resource(node, 0, &res)) {
		WARN(1, "unable to get intc registers\n");
		return -EINVAL;
	}

	if (of_property_read_u32(node, "ti,intc-size", &nr_irq))
		pr_warn("unable to get intc-size, default to %d\n", nr_irq);

	omap_init_irq(res.start, nr_irq, of_node_get(node));

	return 0;
}

static const struct of_device_id irq_match[] __initconst = {
	{ .compatible = "ti,omap2-intc", .data = intc_of_init, },
	{ }
};

void __init omap_intc_of_init(void)
{
	of_irq_init(irq_match);
}

#if defined(CONFIG_ARCH_OMAP3) || defined(CONFIG_SOC_AM33XX)
static struct omap3_intc_regs intc_context[ARRAY_SIZE(irq_banks)];

void omap_intc_save_context(void)
{
	int ind = 0, i = 0;
	for (ind = 0; ind < ARRAY_SIZE(irq_banks); ind++) {
		struct omap_irq_bank *bank = irq_banks + ind;
		intc_context[ind].sysconfig =
			intc_bank_read_reg(bank, INTC_SYSCONFIG);
		intc_context[ind].protection =
			intc_bank_read_reg(bank, INTC_PROTECTION);
		intc_context[ind].idle =
			intc_bank_read_reg(bank, INTC_IDLE);
		intc_context[ind].threshold =
			intc_bank_read_reg(bank, INTC_THRESHOLD);
		for (i = 0; i < INTCPS_NR_IRQS; i++)
			intc_context[ind].ilr[i] =
				intc_bank_read_reg(bank, (0x100 + 0x4*i));
		for (i = 0; i < INTCPS_NR_MIR_REGS; i++)
			intc_context[ind].mir[i] =
				intc_bank_read_reg(&irq_banks[0], INTC_MIR0 +
				(0x20 * i));
	}
}

void omap_intc_restore_context(void)
{
	int ind = 0, i = 0;

	for (ind = 0; ind < ARRAY_SIZE(irq_banks); ind++) {
		struct omap_irq_bank *bank = irq_banks + ind;
		intc_bank_write_reg(intc_context[ind].sysconfig,
					bank, INTC_SYSCONFIG);
		intc_bank_write_reg(intc_context[ind].sysconfig,
					bank, INTC_SYSCONFIG);
		intc_bank_write_reg(intc_context[ind].protection,
					bank, INTC_PROTECTION);
		intc_bank_write_reg(intc_context[ind].idle,
					bank, INTC_IDLE);
		intc_bank_write_reg(intc_context[ind].threshold,
					bank, INTC_THRESHOLD);
		for (i = 0; i < INTCPS_NR_IRQS; i++)
			intc_bank_write_reg(intc_context[ind].ilr[i],
				bank, (0x100 + 0x4*i));
		for (i = 0; i < INTCPS_NR_MIR_REGS; i++)
			intc_bank_write_reg(intc_context[ind].mir[i],
				 &irq_banks[0], INTC_MIR0 + (0x20 * i));
	}
	/* MIRs are saved and restore with other PRCM registers */
}

void omap3_intc_suspend(void)
{
	/* A pending interrupt would prevent OMAP from entering suspend */
	omap_ack_irq(NULL);
}

void omap3_intc_prepare_idle(void)
{
	/*
	 * Disable autoidle as it can stall interrupt controller,
	 * cf. errata ID i540 for 3430 (all revisions up to 3.1.x)
	 */
	intc_bank_write_reg(0, &irq_banks[0], INTC_SYSCONFIG);
}

void omap3_intc_resume_idle(void)
{
	/* Re-enable autoidle */
	intc_bank_write_reg(1, &irq_banks[0], INTC_SYSCONFIG);
}

asmlinkage void __exception_irq_entry omap3_intc_handle_irq(struct pt_regs *regs)
{
	void __iomem *base_addr = OMAP3_IRQ_BASE;
	omap_intc_handle_irq(base_addr, regs);
}
#endif /* CONFIG_ARCH_OMAP3 */