/*
 * sun4c irq support
 *
 *  djhr: Hacked out of irq.c into a CPU dependent version.
 *
 *  Copyright (C) 1995 David S. Miller (davem@caip.rutgers.edu)
 *  Copyright (C) 1995 Miguel de Icaza (miguel@nuclecu.unam.mx)
 *  Copyright (C) 1995 Pete A. Zaitcev (zaitcev@yahoo.com)
 *  Copyright (C) 1996 Dave Redman (djhr@tadpole.co.uk)
 */

#include <linux/init.h>

#include <asm/oplib.h>
#include <asm/timer.h>
#include <asm/irq.h>
#include <asm/io.h>

#include "irq.h"

/* Sun4c interrupts are typically laid out as follows:
 *
 *  1 - Software interrupt, SBUS level 1
 *  2 - SBUS level 2
 *  3 - ESP SCSI, SBUS level 3
 *  4 - Software interrupt
 *  5 - Lance ethernet, SBUS level 4
 *  6 - Software interrupt
 *  7 - Graphics card, SBUS level 5
 *  8 - SBUS level 6
 *  9 - SBUS level 7
 * 10 - Counter timer
 * 11 - Floppy
 * 12 - Zilog uart
 * 13 - CS4231 audio
 * 14 - Profiling timer
 * 15 - NMI
 *
 * The interrupt enable bits in the interrupt mask register are
 * really only used to enable/disable the timer interrupts, and
 * for signalling software interrupts.  There is also a master
 * interrupt enable bit in this register.
 *
 * Interrupts are enabled by setting the SUN4C_INT_* bits, they
 * are disabled by clearing those bits.
 */

/*
 * Bit field defines for the interrupt registers on various
 * Sparc machines.
 */

/* The sun4c interrupt register. */
#define SUN4C_INT_ENABLE  0x01     /* Allow interrupts. */
#define SUN4C_INT_E14     0x80     /* Enable level 14 IRQ. */
#define SUN4C_INT_E10     0x20     /* Enable level 10 IRQ. */
#define SUN4C_INT_E8      0x10     /* Enable level 8 IRQ. */
#define SUN4C_INT_E6      0x08     /* Enable level 6 IRQ. */
#define SUN4C_INT_E4      0x04     /* Enable level 4 IRQ. */
#define SUN4C_INT_E1      0x02     /* Enable level 1 IRQ. */

/*
 * Pointer to the interrupt enable byte
 * Used by entry.S
 */
unsigned char __iomem *interrupt_enable;

static void sun4c_mask_irq(struct irq_data *data)
{
	unsigned long mask = (unsigned long)data->chip_data;

	if (mask) {
		unsigned long flags;

		local_irq_save(flags);
		mask = sbus_readb(interrupt_enable) & ~mask;
		sbus_writeb(mask, interrupt_enable);
		local_irq_restore(flags);
	}
}

static void sun4c_unmask_irq(struct irq_data *data)
{
	unsigned long mask = (unsigned long)data->chip_data;

	if (mask) {
		unsigned long flags;

		local_irq_save(flags);
		mask = sbus_readb(interrupt_enable) | mask;
		sbus_writeb(mask, interrupt_enable);
		local_irq_restore(flags);
	}
}

static unsigned int sun4c_startup_irq(struct irq_data *data)
{
	irq_link(data->irq);
	sun4c_unmask_irq(data);

	return 0;
}

static void sun4c_shutdown_irq(struct irq_data *data)
{
	sun4c_mask_irq(data);
	irq_unlink(data->irq);
}

static struct irq_chip sun4c_irq = {
	.name		= "sun4c",
	.irq_startup	= sun4c_startup_irq,
	.irq_shutdown	= sun4c_shutdown_irq,
	.irq_mask	= sun4c_mask_irq,
	.irq_unmask	= sun4c_unmask_irq,
};

static unsigned int sun4c_build_device_irq(struct platform_device *op,
					   unsigned int real_irq)
{
	 unsigned int irq;

	if (real_irq >= 16) {
		prom_printf("Bogus sun4c IRQ %u\n", real_irq);
		prom_halt();
	}

	irq = irq_alloc(real_irq, real_irq);
	if (irq) {
		unsigned long mask = 0UL;

		switch (real_irq) {
		case 1:
			mask = SUN4C_INT_E1;
			break;
		case 8:
			mask = SUN4C_INT_E8;
			break;
		case 10:
			mask = SUN4C_INT_E10;
			break;
		case 14:
			mask = SUN4C_INT_E14;
			break;
		default:
			/* All the rest are either always enabled,
			 * or are for signalling software interrupts.
			 */
			break;
		}
		irq_set_chip_and_handler_name(irq, &sun4c_irq,
		                              handle_level_irq, "level");
		irq_set_chip_data(irq, (void *)mask);
	}
	return irq;
}

struct sun4c_timer_info {
	u32		l10_count;
	u32		l10_limit;
	u32		l14_count;
	u32		l14_limit;
};

static struct sun4c_timer_info __iomem *sun4c_timers;

static void sun4c_clear_clock_irq(void)
{
	sbus_readl(&sun4c_timers->l10_limit);
}

static void sun4c_load_profile_irq(int cpu, unsigned int limit)
{
	/* Errm.. not sure how to do this.. */
}

static void __init sun4c_init_timers(irq_handler_t counter_fn)
{
	const struct linux_prom_irqs *prom_irqs;
	struct device_node *dp;
	unsigned int irq;
	const u32 *addr;
	int err;

	dp = of_find_node_by_name(NULL, "counter-timer");
	if (!dp) {
		prom_printf("sun4c_init_timers: Unable to find counter-timer\n");
		prom_halt();
	}

	addr = of_get_property(dp, "address", NULL);
	if (!addr) {
		prom_printf("sun4c_init_timers: No address property\n");
		prom_halt();
	}

	sun4c_timers = (void __iomem *) (unsigned long) addr[0];

	prom_irqs = of_get_property(dp, "intr", NULL);
	of_node_put(dp);
	if (!prom_irqs) {
		prom_printf("sun4c_init_timers: No intr property\n");
		prom_halt();
	}

	/* Have the level 10 timer tick at 100HZ.  We don't touch the
	 * level 14 timer limit since we are letting the prom handle
	 * them until we have a real console driver so L1-A works.
	 */
	sbus_writel((((1000000/HZ) + 1) << 10), &sun4c_timers->l10_limit);

	master_l10_counter = &sun4c_timers->l10_count;

	irq = sun4c_build_device_irq(NULL, prom_irqs[0].pri);
	err = request_irq(irq, counter_fn, IRQF_TIMER, "timer", NULL);
	if (err) {
		prom_printf("sun4c_init_timers: request_irq() fails with %d\n", err);
		prom_halt();
	}

	/* disable timer interrupt */
	sun4c_mask_irq(irq_get_irq_data(irq));
}

#ifdef CONFIG_SMP
static void sun4c_nop(void)
{
}
#endif

void __init sun4c_init_IRQ(void)
{
	struct device_node *dp;
	const u32 *addr;

	dp = of_find_node_by_name(NULL, "interrupt-enable");
	if (!dp) {
		prom_printf("sun4c_init_IRQ: Unable to find interrupt-enable\n");
		prom_halt();
	}

	addr = of_get_property(dp, "address", NULL);
	of_node_put(dp);
	if (!addr) {
		prom_printf("sun4c_init_IRQ: No address property\n");
		prom_halt();
	}

	interrupt_enable = (void __iomem *) (unsigned long) addr[0];

	BTFIXUPSET_CALL(clear_clock_irq, sun4c_clear_clock_irq, BTFIXUPCALL_NORM);
	BTFIXUPSET_CALL(load_profile_irq, sun4c_load_profile_irq, BTFIXUPCALL_NOP);

	sparc_irq_config.init_timers      = sun4c_init_timers;
	sparc_irq_config.build_device_irq = sun4c_build_device_irq;

#ifdef CONFIG_SMP
	BTFIXUPSET_CALL(set_cpu_int, sun4c_nop, BTFIXUPCALL_NOP);
	BTFIXUPSET_CALL(clear_cpu_int, sun4c_nop, BTFIXUPCALL_NOP);
	BTFIXUPSET_CALL(set_irq_udt, sun4c_nop, BTFIXUPCALL_NOP);
#endif
	sbus_writeb(SUN4C_INT_ENABLE, interrupt_enable);
	/* Cannot enable interrupts until OBP ticker is disabled. */
}