/*
 * arch/arm/mach-ixp4xx/common.c
 *
 * Generic code shared across all IXP4XX platforms
 *
 * Maintainer: Deepak Saxena <dsaxena@plexity.net>
 *
 * Copyright 2002 (c) Intel Corporation
 * Copyright 2003-2004 (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/kernel.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/serial.h>
#include <linux/sched.h>
#include <linux/tty.h>
#include <linux/platform_device.h>
#include <linux/serial_core.h>
#include <linux/bootmem.h>
#include <linux/interrupt.h>
#include <linux/bitops.h>
#include <linux/time.h>
#include <linux/timex.h>
#include <linux/clocksource.h>

#include <asm/hardware.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/pgtable.h>
#include <asm/page.h>
#include <asm/irq.h>

#include <asm/mach/map.h>
#include <asm/mach/irq.h>
#include <asm/mach/time.h>

/*************************************************************************
 * IXP4xx chipset I/O mapping
 *************************************************************************/
static struct map_desc ixp4xx_io_desc[] __initdata = {
	{	/* UART, Interrupt ctrl, GPIO, timers, NPEs, MACs, USB .... */
		.virtual	= IXP4XX_PERIPHERAL_BASE_VIRT,
		.pfn		= __phys_to_pfn(IXP4XX_PERIPHERAL_BASE_PHYS),
		.length		= IXP4XX_PERIPHERAL_REGION_SIZE,
		.type		= MT_DEVICE
	}, {	/* Expansion Bus Config Registers */
		.virtual	= IXP4XX_EXP_CFG_BASE_VIRT,
		.pfn		= __phys_to_pfn(IXP4XX_EXP_CFG_BASE_PHYS),
		.length		= IXP4XX_EXP_CFG_REGION_SIZE,
		.type		= MT_DEVICE
	}, {	/* PCI Registers */
		.virtual	= IXP4XX_PCI_CFG_BASE_VIRT,
		.pfn		= __phys_to_pfn(IXP4XX_PCI_CFG_BASE_PHYS),
		.length		= IXP4XX_PCI_CFG_REGION_SIZE,
		.type		= MT_DEVICE
	},
#ifdef CONFIG_DEBUG_LL
	{	/* Debug UART mapping */
		.virtual	= IXP4XX_DEBUG_UART_BASE_VIRT,
		.pfn		= __phys_to_pfn(IXP4XX_DEBUG_UART_BASE_PHYS),
		.length		= IXP4XX_DEBUG_UART_REGION_SIZE,
		.type		= MT_DEVICE
	}
#endif
};

void __init ixp4xx_map_io(void)
{
  	iotable_init(ixp4xx_io_desc, ARRAY_SIZE(ixp4xx_io_desc));
}


/*************************************************************************
 * IXP4xx chipset IRQ handling
 *
 * TODO: GPIO IRQs should be marked invalid until the user of the IRQ
 *       (be it PCI or something else) configures that GPIO line
 *       as an IRQ.
 **************************************************************************/
enum ixp4xx_irq_type {
	IXP4XX_IRQ_LEVEL, IXP4XX_IRQ_EDGE
};

static void ixp4xx_config_irq(unsigned irq, enum ixp4xx_irq_type type);

/*
 * IRQ -> GPIO mapping table
 */
static signed char irq2gpio[32] = {
	-1, -1, -1, -1, -1, -1,  0,  1,
	-1, -1, -1, -1, -1, -1, -1, -1,
	-1, -1, -1,  2,  3,  4,  5,  6,
	 7,  8,  9, 10, 11, 12, -1, -1,
};

static int ixp4xx_set_irq_type(unsigned int irq, unsigned int type)
{
	int line = irq2gpio[irq];
	u32 int_style;
	enum ixp4xx_irq_type irq_type;
	volatile u32 *int_reg;

	/*
	 * Only for GPIO IRQs
	 */
	if (line < 0)
		return -EINVAL;

	switch (type){
	case IRQT_BOTHEDGE:
		int_style = IXP4XX_GPIO_STYLE_TRANSITIONAL;
		irq_type = IXP4XX_IRQ_EDGE;
		break;
	case IRQT_RISING:
		int_style = IXP4XX_GPIO_STYLE_RISING_EDGE;
		irq_type = IXP4XX_IRQ_EDGE;
		break;
	case IRQT_FALLING:
		int_style = IXP4XX_GPIO_STYLE_FALLING_EDGE;
		irq_type = IXP4XX_IRQ_EDGE;
		break;
	case IRQT_HIGH:
		int_style = IXP4XX_GPIO_STYLE_ACTIVE_HIGH;
		irq_type = IXP4XX_IRQ_LEVEL;
		break;
	case IRQT_LOW:
		int_style = IXP4XX_GPIO_STYLE_ACTIVE_LOW;
		irq_type = IXP4XX_IRQ_LEVEL;
		break;
	default:
		return -EINVAL;
	}
	ixp4xx_config_irq(irq, irq_type);

	if (line >= 8) {	/* pins 8-15 */
		line -= 8;
		int_reg = IXP4XX_GPIO_GPIT2R;
	} else {		/* pins 0-7 */
		int_reg = IXP4XX_GPIO_GPIT1R;
	}

	/* Clear the style for the appropriate pin */
	*int_reg &= ~(IXP4XX_GPIO_STYLE_CLEAR <<
	    		(line * IXP4XX_GPIO_STYLE_SIZE));

	*IXP4XX_GPIO_GPISR = (1 << line);

	/* Set the new style */
	*int_reg |= (int_style << (line * IXP4XX_GPIO_STYLE_SIZE));

	/* Configure the line as an input */
	gpio_line_config(line, IXP4XX_GPIO_IN);

	return 0;
}

static void ixp4xx_irq_mask(unsigned int irq)
{
	if (cpu_is_ixp46x() && irq >= 32)
		*IXP4XX_ICMR2 &= ~(1 << (irq - 32));
	else
		*IXP4XX_ICMR &= ~(1 << irq);
}

static void ixp4xx_irq_unmask(unsigned int irq)
{
	if (cpu_is_ixp46x() && irq >= 32)
		*IXP4XX_ICMR2 |= (1 << (irq - 32));
	else
		*IXP4XX_ICMR |= (1 << irq);
}

static void ixp4xx_irq_ack(unsigned int irq)
{
	int line = (irq < 32) ? irq2gpio[irq] : -1;

	if (line >= 0)
		*IXP4XX_GPIO_GPISR = (1 << line);
}

/*
 * Level triggered interrupts on GPIO lines can only be cleared when the
 * interrupt condition disappears.
 */
static void ixp4xx_irq_level_unmask(unsigned int irq)
{
	ixp4xx_irq_ack(irq);
	ixp4xx_irq_unmask(irq);
}

static struct irqchip ixp4xx_irq_level_chip = {
	.ack		= ixp4xx_irq_mask,
	.mask		= ixp4xx_irq_mask,
	.unmask		= ixp4xx_irq_level_unmask,
	.set_type	= ixp4xx_set_irq_type,
};

static struct irqchip ixp4xx_irq_edge_chip = {
	.ack		= ixp4xx_irq_ack,
	.mask		= ixp4xx_irq_mask,
	.unmask		= ixp4xx_irq_unmask,
	.set_type	= ixp4xx_set_irq_type,
};

static void ixp4xx_config_irq(unsigned irq, enum ixp4xx_irq_type type)
{
	switch (type) {
	case IXP4XX_IRQ_LEVEL:
		set_irq_chip(irq, &ixp4xx_irq_level_chip);
		set_irq_handler(irq, do_level_IRQ);
		break;
	case IXP4XX_IRQ_EDGE:
		set_irq_chip(irq, &ixp4xx_irq_edge_chip);
		set_irq_handler(irq, do_edge_IRQ);
		break;
	}
	set_irq_flags(irq, IRQF_VALID);
}

void __init ixp4xx_init_irq(void)
{
	int i = 0;

	/* Route all sources to IRQ instead of FIQ */
	*IXP4XX_ICLR = 0x0;

	/* Disable all interrupt */
	*IXP4XX_ICMR = 0x0; 

	if (cpu_is_ixp46x()) {
		/* Route upper 32 sources to IRQ instead of FIQ */
		*IXP4XX_ICLR2 = 0x00;

		/* Disable upper 32 interrupts */
		*IXP4XX_ICMR2 = 0x00;
	}

        /* Default to all level triggered */
	for(i = 0; i < NR_IRQS; i++)
		ixp4xx_config_irq(i, IXP4XX_IRQ_LEVEL);
}


/*************************************************************************
 * IXP4xx timer tick
 * We use OS timer1 on the CPU for the timer tick and the timestamp 
 * counter as a source of real clock ticks to account for missed jiffies.
 *************************************************************************/

static unsigned volatile last_jiffy_time;

#define CLOCK_TICKS_PER_USEC	((CLOCK_TICK_RATE + USEC_PER_SEC/2) / USEC_PER_SEC)

static irqreturn_t ixp4xx_timer_interrupt(int irq, void *dev_id, struct pt_regs *regs)
{
	write_seqlock(&xtime_lock);

	/* Clear Pending Interrupt by writing '1' to it */
	*IXP4XX_OSST = IXP4XX_OSST_TIMER_1_PEND;

	/*
	 * Catch up with the real idea of time
	 */
	while ((signed long)(*IXP4XX_OSTS - last_jiffy_time) >= LATCH) {
		timer_tick(regs);
		last_jiffy_time += LATCH;
	}

	write_sequnlock(&xtime_lock);

	return IRQ_HANDLED;
}

static struct irqaction ixp4xx_timer_irq = {
	.name		= "IXP4xx Timer Tick",
	.flags		= IRQF_DISABLED | IRQF_TIMER,
	.handler	= ixp4xx_timer_interrupt,
};

static void __init ixp4xx_timer_init(void)
{
	/* Clear Pending Interrupt by writing '1' to it */
	*IXP4XX_OSST = IXP4XX_OSST_TIMER_1_PEND;

	/* Setup the Timer counter value */
	*IXP4XX_OSRT1 = (LATCH & ~IXP4XX_OST_RELOAD_MASK) | IXP4XX_OST_ENABLE;

	/* Reset time-stamp counter */
	*IXP4XX_OSTS = 0;
	last_jiffy_time = 0;

	/* Connect the interrupt handler and enable the interrupt */
	setup_irq(IRQ_IXP4XX_TIMER1, &ixp4xx_timer_irq);
}

struct sys_timer ixp4xx_timer = {
	.init		= ixp4xx_timer_init,
};

static struct resource ixp46x_i2c_resources[] = {
	[0] = {
		.start 	= 0xc8011000,
		.end	= 0xc801101c,
		.flags	= IORESOURCE_MEM,
	},
	[1] = {
		.start 	= IRQ_IXP4XX_I2C,
		.end	= IRQ_IXP4XX_I2C,
		.flags	= IORESOURCE_IRQ
	}
};

/*
 * I2C controller. The IXP46x uses the same block as the IOP3xx, so
 * we just use the same device name.
 */
static struct platform_device ixp46x_i2c_controller = {
	.name		= "IOP3xx-I2C",
	.id		= 0,
	.num_resources	= 2,
	.resource	= ixp46x_i2c_resources
};

static struct platform_device *ixp46x_devices[] __initdata = {
	&ixp46x_i2c_controller
};

unsigned long ixp4xx_exp_bus_size;
EXPORT_SYMBOL(ixp4xx_exp_bus_size);

void __init ixp4xx_sys_init(void)
{
	ixp4xx_exp_bus_size = SZ_16M;

	if (cpu_is_ixp46x()) {
		int region;

		platform_add_devices(ixp46x_devices,
				ARRAY_SIZE(ixp46x_devices));

		for (region = 0; region < 7; region++) {
			if((*(IXP4XX_EXP_REG(0x4 * region)) & 0x200)) {
				ixp4xx_exp_bus_size = SZ_32M;
				break;
			}
		}
	}

	printk("IXP4xx: Using %luMiB expansion bus window size\n",
			ixp4xx_exp_bus_size >> 20);
}

cycle_t ixp4xx_get_cycles(void)
{
	return *IXP4XX_OSTS;
}

static struct clocksource clocksource_ixp4xx = {
	.name 		= "OSTS",
	.rating		= 200,
	.read		= ixp4xx_get_cycles,
	.mask		= CLOCKSOURCE_MASK(32),
	.shift 		= 20,
	.is_continuous 	= 1,
};

unsigned long ixp4xx_timer_freq = FREQ;
static int __init ixp4xx_clocksource_init(void)
{
	clocksource_ixp4xx.mult =
		clocksource_hz2mult(ixp4xx_timer_freq,
				    clocksource_ixp4xx.shift);
	clocksource_register(&clocksource_ixp4xx);

	return 0;
}

device_initcall(ixp4xx_clocksource_init);