/*
 * This file define the irq handler for MSP SLM subsystem interrupts.
 *
 * Copyright 2005-2007 PMC-Sierra, Inc, derived from irq_cpu.c
 * Author: Andrew Hughes, Andrew_Hughes@pmc-sierra.com
 *
 * This program is free software; you can redistribute  it and/or modify it
 * under  the terms of  the GNU General  Public License as published by the
 * Free Software Foundation;  either version 2 of the  License, or (at your
 * option) any later version.
 */

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

#include <asm/system.h>

#include <msp_cic_int.h>
#include <msp_regs.h>

/*
 * NOTE: We are only enabling support for VPE0 right now.
 */

static inline void unmask_msp_cic_irq(unsigned int irq)
{

	/* check for PER interrupt range */
	if (irq < MSP_PER_INTBASE)
		*CIC_VPE0_MSK_REG |= (1 << (irq - MSP_CIC_INTBASE));
	else
		*PER_INT_MSK_REG |= (1 << (irq - MSP_PER_INTBASE));
}

static inline void mask_msp_cic_irq(unsigned int irq)
{
	/* check for PER interrupt range */
	if (irq < MSP_PER_INTBASE)
		*CIC_VPE0_MSK_REG &= ~(1 << (irq - MSP_CIC_INTBASE));
	else
		*PER_INT_MSK_REG &= ~(1 << (irq - MSP_PER_INTBASE));
}

/*
 * While we ack the interrupt interrupts are disabled and thus we don't need
 * to deal with concurrency issues.  Same for msp_cic_irq_end.
 */
static inline void ack_msp_cic_irq(unsigned int irq)
{
	mask_msp_cic_irq(irq);

	/*
	 * only really necessary for 18, 16-14 and sometimes 3:0 (since
	 * these can be edge sensitive) but it doesn't hurt for the others.
	 */

	/* check for PER interrupt range */
	if (irq < MSP_PER_INTBASE)
		*CIC_STS_REG = (1 << (irq - MSP_CIC_INTBASE));
	else
		*PER_INT_STS_REG = (1 << (irq - MSP_PER_INTBASE));
}

static struct irq_chip msp_cic_irq_controller = {
	.name = "MSP_CIC",
	.ack = ack_msp_cic_irq,
	.mask = ack_msp_cic_irq,
	.mask_ack = ack_msp_cic_irq,
	.unmask = unmask_msp_cic_irq,
};


void __init msp_cic_irq_init(void)
{
	int i;

	/* Mask/clear interrupts. */
	*CIC_VPE0_MSK_REG = 0x00000000;
	*PER_INT_MSK_REG  = 0x00000000;
	*CIC_STS_REG      = 0xFFFFFFFF;
	*PER_INT_STS_REG  = 0xFFFFFFFF;

#if defined(CONFIG_PMC_MSP7120_GW) || \
    defined(CONFIG_PMC_MSP7120_EVAL)
	/*
	 * The MSP7120 RG and EVBD boards use IRQ[6:4] for PCI.
	 * These inputs map to EXT_INT_POL[6:4] inside the CIC.
	 * They are to be active low, level sensitive.
	 */
	*CIC_EXT_CFG_REG &= 0xFFFF8F8F;
#endif

	/* initialize all the IRQ descriptors */
	for (i = MSP_CIC_INTBASE; i < MSP_PER_INTBASE + 32; i++)
		set_irq_chip_and_handler(i, &msp_cic_irq_controller,
					 handle_level_irq);
}

void msp_cic_irq_dispatch(void)
{
	u32 pending;
	int intbase;

	intbase = MSP_CIC_INTBASE;
	pending = *CIC_STS_REG & *CIC_VPE0_MSK_REG;

	/* check for PER interrupt */
	if (pending == (1 << (MSP_INT_PER - MSP_CIC_INTBASE))) {
		intbase = MSP_PER_INTBASE;
		pending = *PER_INT_STS_REG & *PER_INT_MSK_REG;
	}

	/* check for spurious interrupt */
	if (pending == 0x00000000) {
		printk(KERN_ERR
			"Spurious %s interrupt? status %08x, mask %08x\n",
			(intbase == MSP_CIC_INTBASE) ? "CIC" : "PER",
			(intbase == MSP_CIC_INTBASE) ?
				*CIC_STS_REG : *PER_INT_STS_REG,
			(intbase == MSP_CIC_INTBASE) ?
				*CIC_VPE0_MSK_REG : *PER_INT_MSK_REG);
		return;
	}

	/* check for the timer and dispatch it first */
	if ((intbase == MSP_CIC_INTBASE) &&
	    (pending & (1 << (MSP_INT_VPE0_TIMER - MSP_CIC_INTBASE))))
		do_IRQ(MSP_INT_VPE0_TIMER);
	else
		do_IRQ(ffs(pending) + intbase - 1);
}