irq.c

/*
 * 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/init.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <mach/hardware.h>
#include <asm/mach/irq.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
/* Number of IRQ state bits in each MIR register */
#define IRQ_BITS_PER_REG	32

/*
 * 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 */
		.base_reg	= 0,
		.nr_irqs	= 96,
	},
};

/* 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];
};

static struct omap3_intc_regs intc_context[ARRAY_SIZE(irq_banks)];

/* INTC bank register get/set */

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

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

static int previous_irq;

/*
 * On 34xx we can get occasional spurious interrupts if the ack from
 * an interrupt handler does not get posted before we unmask. Warn about
 * the interrupt handlers that need to flush posted writes.
 */
static int omap_check_spurious(unsigned int irq)
{
	u32 sir, spurious;

	sir = intc_bank_read_reg(&irq_banks[0], INTC_SIR);
	spurious = sir >> 7;

	if (spurious) {
		printk(KERN_WARNING "Spurious irq %i: 0x%08x, please flush "
					"posted write for irq %i\n",
					irq, sir, previous_irq);
		return spurious;
	}

	return 0;
}

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

static void omap_mask_irq(unsigned int irq)
{
	int offset = irq & (~(IRQ_BITS_PER_REG - 1));

	if (cpu_is_omap34xx()) {
		int spurious = 0;

		/*
		 * INT_34XX_GPT12_IRQ is also the spurious irq. Maybe because
		 * it is the highest irq number?
		 */
		if (irq == INT_34XX_GPT12_IRQ)
			spurious = omap_check_spurious(irq);

		if (!spurious)
			previous_irq = irq;
	}

	irq &= (IRQ_BITS_PER_REG - 1);

	intc_bank_write_reg(1 << irq, &irq_banks[0], INTC_MIR_SET0 + offset);
}

static void omap_unmask_irq(unsigned int irq)
{
	int offset = irq & (~(IRQ_BITS_PER_REG - 1));

	irq &= (IRQ_BITS_PER_REG - 1);

	intc_bank_write_reg(1 << irq, &irq_banks[0], INTC_MIR_CLEAR0 + offset);
}

static void omap_mask_ack_irq(unsigned int irq)
{
	omap_mask_irq(irq);
	omap_ack_irq(irq);
}

static struct irq_chip omap_irq_chip = {
	.name	= "INTC",
	.ack	= omap_mask_ack_irq,
	.mask	= omap_mask_irq,
	.unmask	= omap_unmask_irq,
};

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;
	printk(KERN_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;
}

void __init omap_init_irq(void)
{
	unsigned long nr_of_irqs = 0;
	unsigned int nr_banks = 0;
	int i;

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

		if (cpu_is_omap24xx())
			base = OMAP24XX_IC_BASE;
		else if (cpu_is_omap34xx())
			base = OMAP34XX_IC_BASE;

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

		omap_irq_bank_init_one(bank);

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

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

	for (i = 0; i < nr_of_irqs; i++) {
		set_irq_chip(i, &omap_irq_chip);
		set_irq_handler(i, handle_level_irq);
		set_irq_flags(i, IRQF_VALID);
	}
}

#ifdef CONFIG_ARCH_OMAP3
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(0);
}

void omap3_intc_prepare_idle(void)
{
	/* Disable autoidle as it can stall interrupt controller */
	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);
}
#endif /* CONFIG_ARCH_OMAP3 */