/*
 * arch/ppc/syslib/cpc700_pic.c
 *
 * Interrupt controller support for IBM Spruce
 *
 * Authors: Mark Greer, Matt Porter, and Johnnie Peters
 *	    mgreer@mvista.com
 *          mporter@mvista.com
 *          jpeters@mvista.com
 *
 * 2001-2002 (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/init.h>
#include <linux/sched.h>
#include <linux/signal.h>
#include <linux/irq.h>

#include <asm/io.h>
#include <asm/system.h>
#include <asm/irq.h>

#include "cpc700.h"

static void
cpc700_unmask_irq(unsigned int irq)
{
	unsigned int tr_bits;

	/*
	 * IRQ 31 is largest IRQ supported.
	 * IRQs 17-19 are reserved.
	 */
	if ((irq <= 31) && ((irq < 17) || (irq > 19))) {
		tr_bits = CPC700_IN_32(CPC700_UIC_UICTR);

		if ((tr_bits & (1 << (31 - irq))) == 0) {
			/* level trigger interrupt, clear bit in status
			 * register */
			CPC700_OUT_32(CPC700_UIC_UICSR, 1 << (31 - irq));
		}

		/* Know IRQ fits in entry 0 of ppc_cached_irq_mask[] */
		ppc_cached_irq_mask[0] |= CPC700_UIC_IRQ_BIT(irq);
	
		CPC700_OUT_32(CPC700_UIC_UICER, ppc_cached_irq_mask[0]);
	}
	return;
}

static void
cpc700_mask_irq(unsigned int irq)
{
	/*
	 * IRQ 31 is largest IRQ supported.
	 * IRQs 17-19 are reserved.
	 */
	if ((irq <= 31) && ((irq < 17) || (irq > 19))) {
		/* Know IRQ fits in entry 0 of ppc_cached_irq_mask[] */
		ppc_cached_irq_mask[0] &=
			~CPC700_UIC_IRQ_BIT(irq);

		CPC700_OUT_32(CPC700_UIC_UICER, ppc_cached_irq_mask[0]);
	}
	return;
}

static void
cpc700_mask_and_ack_irq(unsigned int irq)
{
	u_int	bit;

	/*
	 * IRQ 31 is largest IRQ supported.
	 * IRQs 17-19 are reserved.
	 */
	if ((irq <= 31) && ((irq < 17) || (irq > 19))) {
		/* Know IRQ fits in entry 0 of ppc_cached_irq_mask[] */
		bit = CPC700_UIC_IRQ_BIT(irq);

		ppc_cached_irq_mask[0] &= ~bit;
		CPC700_OUT_32(CPC700_UIC_UICER, ppc_cached_irq_mask[0]);
		CPC700_OUT_32(CPC700_UIC_UICSR, bit); /* Write 1 clears IRQ */
	}
	return;
}

static struct hw_interrupt_type cpc700_pic = {
	.typename = "CPC700 PIC",
	.enable = cpc700_unmask_irq,
	.disable = cpc700_mask_irq,
	.ack = cpc700_mask_and_ack_irq,
};

__init static void
cpc700_pic_init_irq(unsigned int irq)
{
	unsigned int tmp;

	/* Set interrupt sense */
	tmp = CPC700_IN_32(CPC700_UIC_UICTR);
	if (cpc700_irq_assigns[irq][0] == 0) {
		tmp &= ~CPC700_UIC_IRQ_BIT(irq);
	} else {
		tmp |= CPC700_UIC_IRQ_BIT(irq);
	}
	CPC700_OUT_32(CPC700_UIC_UICTR, tmp);

	/* Set interrupt polarity */
	tmp = CPC700_IN_32(CPC700_UIC_UICPR);
	if (cpc700_irq_assigns[irq][1]) {
		tmp |= CPC700_UIC_IRQ_BIT(irq);
	} else {
		tmp &= ~CPC700_UIC_IRQ_BIT(irq);
	}
	CPC700_OUT_32(CPC700_UIC_UICPR, tmp);

	/* Set interrupt critical */
	tmp = CPC700_IN_32(CPC700_UIC_UICCR);
	tmp |= CPC700_UIC_IRQ_BIT(irq);
	CPC700_OUT_32(CPC700_UIC_UICCR, tmp);
		
	return;
}

__init void
cpc700_init_IRQ(void)
{
	int i;

	ppc_cached_irq_mask[0] = 0;
	CPC700_OUT_32(CPC700_UIC_UICER, 0x00000000);    /* Disable all irq's */
	CPC700_OUT_32(CPC700_UIC_UICSR, 0xffffffff);    /* Clear cur intrs */
	CPC700_OUT_32(CPC700_UIC_UICCR, 0xffffffff);    /* Gen INT not MCP */
	CPC700_OUT_32(CPC700_UIC_UICPR, 0x00000000);    /* Active low */
	CPC700_OUT_32(CPC700_UIC_UICTR, 0x00000000);    /* Level Sensitive */
	CPC700_OUT_32(CPC700_UIC_UICVR, CPC700_UIC_UICVCR_0_HI);
						        /* IRQ 0 is highest */

	for (i = 0; i < 17; i++) {
		irq_desc[i].handler = &cpc700_pic;
		cpc700_pic_init_irq(i);
	}

	for (i = 20; i < 32; i++) {
		irq_desc[i].handler = &cpc700_pic;
		cpc700_pic_init_irq(i);
	}

	return;
}


/*
 * Find the highest IRQ that generating an interrupt, if any.
 */
int
cpc700_get_irq(struct pt_regs *regs)
{
	int irq = 0;
	u_int irq_status, irq_test = 1;

	irq_status = CPC700_IN_32(CPC700_UIC_UICMSR);

	do
	{
		if (irq_status & irq_test)
			break;
		irq++;
		irq_test <<= 1;
	} while (irq < NR_IRQS);
	

	if (irq == NR_IRQS)
	    irq = 33;

	return (31 - irq);
}