arch/arm/mach-ixp23xx/core.c - kernel/prism - Git at Google

 /*
  * arch/arm/mach-ixp23xx/core.c
  *
  * Core routines for IXP23xx chips
  *
  * Author: Deepak Saxena <dsaxena@plexity.net>
  *
  * Copyright 2005 (c) MontaVista Software, Inc.
  *
  * Based on 2.4 code Copyright 2004 (c) Intel Corporation
  *
  * 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/init.h>
 #include <linux/spinlock.h>
 #include <linux/sched.h>
 #include <linux/interrupt.h>
 #include <linux/serial.h>
 #include <linux/tty.h>
 #include <linux/bitops.h>
 #include <linux/serial_8250.h>
 #include <linux/serial_core.h>
 #include <linux/device.h>
 #include <linux/mm.h>
 #include <linux/time.h>
 #include <linux/timex.h>

 #include <asm/types.h>
 #include <asm/setup.h>
 #include <asm/memory.h>
 #include <mach/hardware.h>
 #include <asm/irq.h>
 #include <asm/system.h>
 #include <asm/tlbflush.h>
 #include <asm/pgtable.h>

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


 /*************************************************************************
  * Chip specific mappings shared by all IXP23xx systems
  *************************************************************************/
 static struct map_desc ixp23xx_io_desc[] __initdata = {
 	{ /* XSI-CPP CSRs */
 	 	.virtual	= IXP23XX_XSI2CPP_CSR_VIRT,
 	 	.pfn		= __phys_to_pfn(IXP23XX_XSI2CPP_CSR_PHYS),
 	 	.length		= IXP23XX_XSI2CPP_CSR_SIZE,
 		.type		= MT_DEVICE,
 	}, { /* Expansion Bus Config */
 	 	.virtual	= IXP23XX_EXP_CFG_VIRT,
 	 	.pfn		= __phys_to_pfn(IXP23XX_EXP_CFG_PHYS),
 	 	.length		= IXP23XX_EXP_CFG_SIZE,
 		.type		= MT_DEVICE,
 	}, { /* UART, Interrupt ctrl, GPIO, timers, NPEs, MACS,.... */
 	 	.virtual	= IXP23XX_PERIPHERAL_VIRT,
 	 	.pfn		= __phys_to_pfn(IXP23XX_PERIPHERAL_PHYS),
 	 	.length		= IXP23XX_PERIPHERAL_SIZE,
 		.type		= MT_DEVICE,
 	}, { /* CAP CSRs */
 	 	.virtual	= IXP23XX_CAP_CSR_VIRT,
 	 	.pfn		= __phys_to_pfn(IXP23XX_CAP_CSR_PHYS),
 	 	.length		= IXP23XX_CAP_CSR_SIZE,
 		.type		= MT_DEVICE,
 	}, { /* MSF CSRs */
 	 	.virtual	= IXP23XX_MSF_CSR_VIRT,
 	 	.pfn		= __phys_to_pfn(IXP23XX_MSF_CSR_PHYS),
 	 	.length		= IXP23XX_MSF_CSR_SIZE,
 		.type		= MT_DEVICE,
 	}, { /* PCI I/O Space */
 	 	.virtual	= IXP23XX_PCI_IO_VIRT,
 	 	.pfn		= __phys_to_pfn(IXP23XX_PCI_IO_PHYS),
 	 	.length		= IXP23XX_PCI_IO_SIZE,
 		.type		= MT_DEVICE,
 	}, { /* PCI Config Space */
 	 	.virtual	= IXP23XX_PCI_CFG_VIRT,
 	 	.pfn		= __phys_to_pfn(IXP23XX_PCI_CFG_PHYS),
 	 	.length		= IXP23XX_PCI_CFG_SIZE,
 		.type		= MT_DEVICE,
 	}, { /* PCI local CFG CSRs */
 	 	.virtual	= IXP23XX_PCI_CREG_VIRT,
 	 	.pfn		= __phys_to_pfn(IXP23XX_PCI_CREG_PHYS),
 	 	.length		= IXP23XX_PCI_CREG_SIZE,
 		.type		= MT_DEVICE,
 	}, { /* PCI MEM Space */
 	 	.virtual	= IXP23XX_PCI_MEM_VIRT,
 	 	.pfn		= __phys_to_pfn(IXP23XX_PCI_MEM_PHYS),
 	 	.length		= IXP23XX_PCI_MEM_SIZE,
 		.type		= MT_DEVICE,
 	}
 };

 void __init ixp23xx_map_io(void)
 {
 	iotable_init(ixp23xx_io_desc, ARRAY_SIZE(ixp23xx_io_desc));
 }


 /***************************************************************************
  * IXP23xx Interrupt Handling
  ***************************************************************************/
 enum ixp23xx_irq_type {
 	IXP23XX_IRQ_LEVEL, IXP23XX_IRQ_EDGE
 };

 static void ixp23xx_config_irq(unsigned int, enum ixp23xx_irq_type);

 static int ixp23xx_irq_set_type(unsigned int irq, unsigned int type)
 {
 	int line = irq - IRQ_IXP23XX_GPIO6 + 6;
 	u32 int_style;
 	enum ixp23xx_irq_type irq_type;
 	volatile u32 *int_reg;

 	/*
 	 * Only GPIOs 6-15 are wired to interrupts on IXP23xx
 	 */
 	if (line < 6 || line > 15)
 		return -EINVAL;

 	switch (type) {
 	case IRQ_TYPE_EDGE_BOTH:
 		int_style = IXP23XX_GPIO_STYLE_TRANSITIONAL;
 		irq_type = IXP23XX_IRQ_EDGE;
 		break;
 	case IRQ_TYPE_EDGE_RISING:
 		int_style = IXP23XX_GPIO_STYLE_RISING_EDGE;
 		irq_type = IXP23XX_IRQ_EDGE;
 		break;
 	case IRQ_TYPE_EDGE_FALLING:
 		int_style = IXP23XX_GPIO_STYLE_FALLING_EDGE;
 		irq_type = IXP23XX_IRQ_EDGE;
 		break;
 	case IRQ_TYPE_LEVEL_HIGH:
 		int_style = IXP23XX_GPIO_STYLE_ACTIVE_HIGH;
 		irq_type = IXP23XX_IRQ_LEVEL;
 		break;
 	case IRQ_TYPE_LEVEL_LOW:
 		int_style = IXP23XX_GPIO_STYLE_ACTIVE_LOW;
 		irq_type = IXP23XX_IRQ_LEVEL;
 		break;
 	default:
 		return -EINVAL;
 	}

 	ixp23xx_config_irq(irq, irq_type);

 	if (line >= 8) {	/* pins 8-15 */
 		line -= 8;
 		int_reg = (volatile u32 *)IXP23XX_GPIO_GPIT2R;
 	} else {		/* pins 0-7 */
 		int_reg = (volatile u32 *)IXP23XX_GPIO_GPIT1R;
 	}

 	/*
 	 * Clear pending interrupts
 	 */
 	*IXP23XX_GPIO_GPISR = (1 << line);

 	/* Clear the style for the appropriate pin */
 	*int_reg &= ~(IXP23XX_GPIO_STYLE_MASK <<
 			(line * IXP23XX_GPIO_STYLE_SIZE));

 	/* Set the new style */
 	*int_reg |= (int_style << (line * IXP23XX_GPIO_STYLE_SIZE));

 	return 0;
 }

 static void ixp23xx_irq_mask(unsigned int irq)
 {
 	volatile unsigned long *intr_reg;

 	if (irq >= 56)
 		irq += 8;

 	intr_reg = IXP23XX_INTR_EN1 + (irq / 32);
 	*intr_reg &= ~(1 << (irq % 32));
 }

 static void ixp23xx_irq_ack(unsigned int irq)
 {
 	int line = irq - IRQ_IXP23XX_GPIO6 + 6;

 	if ((line < 6) || (line > 15))
 		return;

 	*IXP23XX_GPIO_GPISR = (1 << line);
 }

 /*
  * Level triggered interrupts on GPIO lines can only be cleared when the
  * interrupt condition disappears.
  */
 static void ixp23xx_irq_level_unmask(unsigned int irq)
 {
 	volatile unsigned long *intr_reg;

 	ixp23xx_irq_ack(irq);

 	if (irq >= 56)
 		irq += 8;

 	intr_reg = IXP23XX_INTR_EN1 + (irq / 32);
 	*intr_reg |= (1 << (irq % 32));
 }

 static void ixp23xx_irq_edge_unmask(unsigned int irq)
 {
 	volatile unsigned long *intr_reg;

 	if (irq >= 56)
 		irq += 8;

 	intr_reg = IXP23XX_INTR_EN1 + (irq / 32);
 	*intr_reg |= (1 << (irq % 32));
 }

 static struct irq_chip ixp23xx_irq_level_chip = {
 	.ack		= ixp23xx_irq_mask,
 	.mask		= ixp23xx_irq_mask,
 	.unmask		= ixp23xx_irq_level_unmask,
 	.set_type	= ixp23xx_irq_set_type
 };

 static struct irq_chip ixp23xx_irq_edge_chip = {
 	.ack		= ixp23xx_irq_ack,
 	.mask		= ixp23xx_irq_mask,
 	.unmask		= ixp23xx_irq_edge_unmask,
 	.set_type	= ixp23xx_irq_set_type
 };

 static void ixp23xx_pci_irq_mask(unsigned int irq)
 {
 	*IXP23XX_PCI_XSCALE_INT_ENABLE &= ~(1 << (IRQ_IXP23XX_INTA + 27 - irq));
 }

 static void ixp23xx_pci_irq_unmask(unsigned int irq)
 {
 	*IXP23XX_PCI_XSCALE_INT_ENABLE |= (1 << (IRQ_IXP23XX_INTA + 27 - irq));
 }

 /*
  * TODO: Should this just be done at ASM level?
  */
 static void pci_handler(unsigned int irq, struct irq_desc *desc)
 {
 	u32 pci_interrupt;
 	unsigned int irqno;

 	pci_interrupt = *IXP23XX_PCI_XSCALE_INT_STATUS;

 	desc->chip->ack(irq);

 	/* See which PCI_INTA, or PCI_INTB interrupted */
 	if (pci_interrupt & (1 << 26)) {
 		irqno = IRQ_IXP23XX_INTB;
 	} else if (pci_interrupt & (1 << 27)) {
 		irqno = IRQ_IXP23XX_INTA;
 	} else {
 		BUG();
 	}

 	generic_handle_irq(irqno);

 	desc->chip->unmask(irq);
 }

 static struct irq_chip ixp23xx_pci_irq_chip = {
 	.ack	= ixp23xx_pci_irq_mask,
 	.mask	= ixp23xx_pci_irq_mask,
 	.unmask	= ixp23xx_pci_irq_unmask
 };

 static void ixp23xx_config_irq(unsigned int irq, enum ixp23xx_irq_type type)
 {
 	switch (type) {
 	case IXP23XX_IRQ_LEVEL:
 		set_irq_chip(irq, &ixp23xx_irq_level_chip);
 		set_irq_handler(irq, handle_level_irq);
 		break;
 	case IXP23XX_IRQ_EDGE:
 		set_irq_chip(irq, &ixp23xx_irq_edge_chip);
 		set_irq_handler(irq, handle_edge_irq);
 		break;
 	}
 	set_irq_flags(irq, IRQF_VALID);
 }

 void __init ixp23xx_init_irq(void)
 {
 	int irq;

 	/* Route everything to IRQ */
 	*IXP23XX_INTR_SEL1 = 0x0;
 	*IXP23XX_INTR_SEL2 = 0x0;
 	*IXP23XX_INTR_SEL3 = 0x0;
 	*IXP23XX_INTR_SEL4 = 0x0;

 	/* Mask all sources */
 	*IXP23XX_INTR_EN1 = 0x0;
 	*IXP23XX_INTR_EN2 = 0x0;
 	*IXP23XX_INTR_EN3 = 0x0;
 	*IXP23XX_INTR_EN4 = 0x0;

 	/*
 	 * Configure all IRQs for level-sensitive operation
 	 */
 	for (irq = 0; irq <= NUM_IXP23XX_RAW_IRQS; irq++) {
 		ixp23xx_config_irq(irq, IXP23XX_IRQ_LEVEL);
 	}

 	for (irq = IRQ_IXP23XX_INTA; irq <= IRQ_IXP23XX_INTB; irq++) {
 		set_irq_chip(irq, &ixp23xx_pci_irq_chip);
 		set_irq_handler(irq, handle_level_irq);
 		set_irq_flags(irq, IRQF_VALID);
 	}

 	set_irq_chained_handler(IRQ_IXP23XX_PCI_INT_RPH, pci_handler);
 }


 /*************************************************************************
  * Timer-tick functions for IXP23xx
  *************************************************************************/
 #define CLOCK_TICKS_PER_USEC	(CLOCK_TICK_RATE / USEC_PER_SEC)

 static unsigned long next_jiffy_time;

 static unsigned long
 ixp23xx_gettimeoffset(void)
 {
 	unsigned long elapsed;

 	elapsed = *IXP23XX_TIMER_CONT - (next_jiffy_time - LATCH);

 	return elapsed / CLOCK_TICKS_PER_USEC;
 }

 static irqreturn_t
 ixp23xx_timer_interrupt(int irq, void *dev_id)
 {
 	/* Clear Pending Interrupt by writing '1' to it */
 	*IXP23XX_TIMER_STATUS = IXP23XX_TIMER1_INT_PEND;
 	while ((signed long)(*IXP23XX_TIMER_CONT - next_jiffy_time) >= LATCH) {
 		timer_tick();
 		next_jiffy_time += LATCH;
 	}

 	return IRQ_HANDLED;
 }

 static struct irqaction ixp23xx_timer_irq = {
 	.name		= "IXP23xx Timer Tick",
 	.handler	= ixp23xx_timer_interrupt,
 	.flags		= IRQF_DISABLED | IRQF_TIMER | IRQF_IRQPOLL,
 };

 void __init ixp23xx_init_timer(void)
 {
 	/* Clear Pending Interrupt by writing '1' to it */
 	*IXP23XX_TIMER_STATUS = IXP23XX_TIMER1_INT_PEND;

 	/* Setup the Timer counter value */
 	*IXP23XX_TIMER1_RELOAD =
 		(LATCH & ~IXP23XX_TIMER_RELOAD_MASK) | IXP23XX_TIMER_ENABLE;

 	*IXP23XX_TIMER_CONT = 0;
 	next_jiffy_time = LATCH;

 	/* Connect the interrupt handler and enable the interrupt */
 	setup_irq(IRQ_IXP23XX_TIMER1, &ixp23xx_timer_irq);
 }

 struct sys_timer ixp23xx_timer = {
 	.init		= ixp23xx_init_timer,
 	.offset		= ixp23xx_gettimeoffset,
 };


 /*************************************************************************
  * IXP23xx Platform Initialization
  *************************************************************************/
 static struct resource ixp23xx_uart_resources[] = {
 	{
 		.start		= IXP23XX_UART1_PHYS,
 		.end		= IXP23XX_UART1_PHYS + 0x0fff,
 		.flags		= IORESOURCE_MEM
 	}, {
 		.start		= IXP23XX_UART2_PHYS,
 		.end		= IXP23XX_UART2_PHYS + 0x0fff,
 		.flags		= IORESOURCE_MEM
 	}
 };

 static struct plat_serial8250_port ixp23xx_uart_data[] = {
 	{
 		.mapbase	= IXP23XX_UART1_PHYS,
 		.membase	= (char *)(IXP23XX_UART1_VIRT + 3),
 		.irq		= IRQ_IXP23XX_UART1,
 		.flags		= UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
 		.iotype		= UPIO_MEM,
 		.regshift	= 2,
 		.uartclk	= IXP23XX_UART_XTAL,
 	}, {
 		.mapbase	= IXP23XX_UART2_PHYS,
 		.membase	= (char *)(IXP23XX_UART2_VIRT + 3),
 		.irq		= IRQ_IXP23XX_UART2,
 		.flags		= UPF_BOOT_AUTOCONF | UPF_SKIP_TEST,
 		.iotype		= UPIO_MEM,
 		.regshift	= 2,
 		.uartclk	= IXP23XX_UART_XTAL,
 	},
 	{ },
 };

 static struct platform_device ixp23xx_uart = {
 	.name			= "serial8250",
 	.id			= 0,
 	.dev.platform_data	= ixp23xx_uart_data,
 	.num_resources		= 2,
 	.resource		= ixp23xx_uart_resources,
 };

 static struct platform_device *ixp23xx_devices[] __initdata = {
 	&ixp23xx_uart,
 };

 void __init ixp23xx_sys_init(void)
 {
 	*IXP23XX_EXP_UNIT_FUSE |= 0xf;
 	platform_add_devices(ixp23xx_devices, ARRAY_SIZE(ixp23xx_devices));
 }
	/*
	* arch/arm/mach-ixp23xx/core.c
	*
	* Core routines for IXP23xx chips
	*
	* Author: Deepak Saxena <dsaxena@plexity.net>
	*
	* Copyright 2005 (c) MontaVista Software, Inc.
	*
	* Based on 2.4 code Copyright 2004 (c) Intel Corporation
	*
	* 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/init.h>
	#include <linux/spinlock.h>
	#include <linux/sched.h>
	#include <linux/interrupt.h>
	#include <linux/serial.h>
	#include <linux/tty.h>
	#include <linux/bitops.h>
	#include <linux/serial_8250.h>
	#include <linux/serial_core.h>
	#include <linux/device.h>
	#include <linux/mm.h>
	#include <linux/time.h>
	#include <linux/timex.h>

	#include <asm/types.h>
	#include <asm/setup.h>
	#include <asm/memory.h>
	#include <mach/hardware.h>
	#include <asm/irq.h>
	#include <asm/system.h>
	#include <asm/tlbflush.h>
	#include <asm/pgtable.h>

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


	/*************************************************************************
	* Chip specific mappings shared by all IXP23xx systems
	*************************************************************************/
	static struct map_desc ixp23xx_io_desc[] __initdata = {
	{ /* XSI-CPP CSRs */
	.virtual = IXP23XX_XSI2CPP_CSR_VIRT,
	.pfn = __phys_to_pfn(IXP23XX_XSI2CPP_CSR_PHYS),
	.length = IXP23XX_XSI2CPP_CSR_SIZE,
	.type = MT_DEVICE,
	}, { /* Expansion Bus Config */
	.virtual = IXP23XX_EXP_CFG_VIRT,
	.pfn = __phys_to_pfn(IXP23XX_EXP_CFG_PHYS),
	.length = IXP23XX_EXP_CFG_SIZE,
	.type = MT_DEVICE,
	}, { /* UART, Interrupt ctrl, GPIO, timers, NPEs, MACS,.... */
	.virtual = IXP23XX_PERIPHERAL_VIRT,
	.pfn = __phys_to_pfn(IXP23XX_PERIPHERAL_PHYS),
	.length = IXP23XX_PERIPHERAL_SIZE,
	.type = MT_DEVICE,
	}, { /* CAP CSRs */
	.virtual = IXP23XX_CAP_CSR_VIRT,
	.pfn = __phys_to_pfn(IXP23XX_CAP_CSR_PHYS),
	.length = IXP23XX_CAP_CSR_SIZE,
	.type = MT_DEVICE,
	}, { /* MSF CSRs */
	.virtual = IXP23XX_MSF_CSR_VIRT,
	.pfn = __phys_to_pfn(IXP23XX_MSF_CSR_PHYS),
	.length = IXP23XX_MSF_CSR_SIZE,
	.type = MT_DEVICE,
	}, { /* PCI I/O Space */
	.virtual = IXP23XX_PCI_IO_VIRT,
	.pfn = __phys_to_pfn(IXP23XX_PCI_IO_PHYS),
	.length = IXP23XX_PCI_IO_SIZE,
	.type = MT_DEVICE,
	}, { /* PCI Config Space */
	.virtual = IXP23XX_PCI_CFG_VIRT,
	.pfn = __phys_to_pfn(IXP23XX_PCI_CFG_PHYS),
	.length = IXP23XX_PCI_CFG_SIZE,
	.type = MT_DEVICE,
	}, { /* PCI local CFG CSRs */
	.virtual = IXP23XX_PCI_CREG_VIRT,
	.pfn = __phys_to_pfn(IXP23XX_PCI_CREG_PHYS),
	.length = IXP23XX_PCI_CREG_SIZE,
	.type = MT_DEVICE,
	}, { /* PCI MEM Space */
	.virtual = IXP23XX_PCI_MEM_VIRT,
	.pfn = __phys_to_pfn(IXP23XX_PCI_MEM_PHYS),
	.length = IXP23XX_PCI_MEM_SIZE,
	.type = MT_DEVICE,
	}
	};

	void __init ixp23xx_map_io(void)
	{
	iotable_init(ixp23xx_io_desc, ARRAY_SIZE(ixp23xx_io_desc));
	}


	/***************************************************************************
	* IXP23xx Interrupt Handling
	***************************************************************************/
	enum ixp23xx_irq_type {
	IXP23XX_IRQ_LEVEL, IXP23XX_IRQ_EDGE
	};

	static void ixp23xx_config_irq(unsigned int, enum ixp23xx_irq_type);

	static int ixp23xx_irq_set_type(unsigned int irq, unsigned int type)
	{
	int line = irq - IRQ_IXP23XX_GPIO6 + 6;
	u32 int_style;
	enum ixp23xx_irq_type irq_type;
	volatile u32 *int_reg;

	/*
	* Only GPIOs 6-15 are wired to interrupts on IXP23xx
	*/
	if (line < 6 \|\| line > 15)
	return -EINVAL;

	switch (type) {
	case IRQ_TYPE_EDGE_BOTH:
	int_style = IXP23XX_GPIO_STYLE_TRANSITIONAL;
	irq_type = IXP23XX_IRQ_EDGE;
	break;
	case IRQ_TYPE_EDGE_RISING:
	int_style = IXP23XX_GPIO_STYLE_RISING_EDGE;
	irq_type = IXP23XX_IRQ_EDGE;
	break;
	case IRQ_TYPE_EDGE_FALLING:
	int_style = IXP23XX_GPIO_STYLE_FALLING_EDGE;
	irq_type = IXP23XX_IRQ_EDGE;
	break;
	case IRQ_TYPE_LEVEL_HIGH:
	int_style = IXP23XX_GPIO_STYLE_ACTIVE_HIGH;
	irq_type = IXP23XX_IRQ_LEVEL;
	break;
	case IRQ_TYPE_LEVEL_LOW:
	int_style = IXP23XX_GPIO_STYLE_ACTIVE_LOW;
	irq_type = IXP23XX_IRQ_LEVEL;
	break;
	default:
	return -EINVAL;
	}

	ixp23xx_config_irq(irq, irq_type);

	if (line >= 8) { /* pins 8-15 */
	line -= 8;
	int_reg = (volatile u32 *)IXP23XX_GPIO_GPIT2R;
	} else { /* pins 0-7 */
	int_reg = (volatile u32 *)IXP23XX_GPIO_GPIT1R;
	}

	/*
	* Clear pending interrupts
	*/
	*IXP23XX_GPIO_GPISR = (1 << line);

	/* Clear the style for the appropriate pin */
	*int_reg &= ~(IXP23XX_GPIO_STYLE_MASK <<
	(line * IXP23XX_GPIO_STYLE_SIZE));

	/* Set the new style */
	int_reg \|= (int_style << (line IXP23XX_GPIO_STYLE_SIZE));

	return 0;
	}

	static void ixp23xx_irq_mask(unsigned int irq)
	{
	volatile unsigned long *intr_reg;

	if (irq >= 56)
	irq += 8;

	intr_reg = IXP23XX_INTR_EN1 + (irq / 32);
	*intr_reg &= ~(1 << (irq % 32));
	}

	static void ixp23xx_irq_ack(unsigned int irq)
	{
	int line = irq - IRQ_IXP23XX_GPIO6 + 6;

	if ((line < 6) \|\| (line > 15))
	return;

	*IXP23XX_GPIO_GPISR = (1 << line);
	}

	/*
	* Level triggered interrupts on GPIO lines can only be cleared when the
	* interrupt condition disappears.
	*/
	static void ixp23xx_irq_level_unmask(unsigned int irq)
	{
	volatile unsigned long *intr_reg;

	ixp23xx_irq_ack(irq);

	if (irq >= 56)
	irq += 8;

	intr_reg = IXP23XX_INTR_EN1 + (irq / 32);
	*intr_reg \|= (1 << (irq % 32));
	}

	static void ixp23xx_irq_edge_unmask(unsigned int irq)
	{
	volatile unsigned long *intr_reg;

	if (irq >= 56)
	irq += 8;

	intr_reg = IXP23XX_INTR_EN1 + (irq / 32);
	*intr_reg \|= (1 << (irq % 32));
	}

	static struct irq_chip ixp23xx_irq_level_chip = {
	.ack = ixp23xx_irq_mask,
	.mask = ixp23xx_irq_mask,
	.unmask = ixp23xx_irq_level_unmask,
	.set_type = ixp23xx_irq_set_type
	};

	static struct irq_chip ixp23xx_irq_edge_chip = {
	.ack = ixp23xx_irq_ack,
	.mask = ixp23xx_irq_mask,
	.unmask = ixp23xx_irq_edge_unmask,
	.set_type = ixp23xx_irq_set_type
	};

	static void ixp23xx_pci_irq_mask(unsigned int irq)
	{
	*IXP23XX_PCI_XSCALE_INT_ENABLE &= ~(1 << (IRQ_IXP23XX_INTA + 27 - irq));
	}

	static void ixp23xx_pci_irq_unmask(unsigned int irq)
	{
	*IXP23XX_PCI_XSCALE_INT_ENABLE \|= (1 << (IRQ_IXP23XX_INTA + 27 - irq));
	}

	/*
	* TODO: Should this just be done at ASM level?
	*/
	static void pci_handler(unsigned int irq, struct irq_desc *desc)
	{
	u32 pci_interrupt;
	unsigned int irqno;

	pci_interrupt = *IXP23XX_PCI_XSCALE_INT_STATUS;

	desc->chip->ack(irq);

	/* See which PCI_INTA, or PCI_INTB interrupted */
	if (pci_interrupt & (1 << 26)) {
	irqno = IRQ_IXP23XX_INTB;
	} else if (pci_interrupt & (1 << 27)) {
	irqno = IRQ_IXP23XX_INTA;
	} else {
	BUG();
	}

	generic_handle_irq(irqno);

	desc->chip->unmask(irq);
	}

	static struct irq_chip ixp23xx_pci_irq_chip = {
	.ack = ixp23xx_pci_irq_mask,
	.mask = ixp23xx_pci_irq_mask,
	.unmask = ixp23xx_pci_irq_unmask
	};

	static void ixp23xx_config_irq(unsigned int irq, enum ixp23xx_irq_type type)
	{
	switch (type) {
	case IXP23XX_IRQ_LEVEL:
	set_irq_chip(irq, &ixp23xx_irq_level_chip);
	set_irq_handler(irq, handle_level_irq);
	break;
	case IXP23XX_IRQ_EDGE:
	set_irq_chip(irq, &ixp23xx_irq_edge_chip);
	set_irq_handler(irq, handle_edge_irq);
	break;
	}
	set_irq_flags(irq, IRQF_VALID);
	}

	void __init ixp23xx_init_irq(void)
	{
	int irq;

	/* Route everything to IRQ */
	*IXP23XX_INTR_SEL1 = 0x0;
	*IXP23XX_INTR_SEL2 = 0x0;
	*IXP23XX_INTR_SEL3 = 0x0;
	*IXP23XX_INTR_SEL4 = 0x0;

	/* Mask all sources */
	*IXP23XX_INTR_EN1 = 0x0;
	*IXP23XX_INTR_EN2 = 0x0;
	*IXP23XX_INTR_EN3 = 0x0;
	*IXP23XX_INTR_EN4 = 0x0;

	/*
	* Configure all IRQs for level-sensitive operation
	*/
	for (irq = 0; irq <= NUM_IXP23XX_RAW_IRQS; irq++) {
	ixp23xx_config_irq(irq, IXP23XX_IRQ_LEVEL);
	}

	for (irq = IRQ_IXP23XX_INTA; irq <= IRQ_IXP23XX_INTB; irq++) {
	set_irq_chip(irq, &ixp23xx_pci_irq_chip);
	set_irq_handler(irq, handle_level_irq);
	set_irq_flags(irq, IRQF_VALID);
	}

	set_irq_chained_handler(IRQ_IXP23XX_PCI_INT_RPH, pci_handler);
	}


	/*************************************************************************
	* Timer-tick functions for IXP23xx
	*************************************************************************/
	#define CLOCK_TICKS_PER_USEC (CLOCK_TICK_RATE / USEC_PER_SEC)

	static unsigned long next_jiffy_time;

	static unsigned long
	ixp23xx_gettimeoffset(void)
	{
	unsigned long elapsed;

	elapsed = *IXP23XX_TIMER_CONT - (next_jiffy_time - LATCH);

	return elapsed / CLOCK_TICKS_PER_USEC;
	}

	static irqreturn_t
	ixp23xx_timer_interrupt(int irq, void *dev_id)
	{
	/* Clear Pending Interrupt by writing '1' to it */
	*IXP23XX_TIMER_STATUS = IXP23XX_TIMER1_INT_PEND;
	while ((signed long)(*IXP23XX_TIMER_CONT - next_jiffy_time) >= LATCH) {
	timer_tick();
	next_jiffy_time += LATCH;
	}

	return IRQ_HANDLED;
	}

	static struct irqaction ixp23xx_timer_irq = {
	.name = "IXP23xx Timer Tick",
	.handler = ixp23xx_timer_interrupt,
	.flags = IRQF_DISABLED \| IRQF_TIMER \| IRQF_IRQPOLL,
	};

	void __init ixp23xx_init_timer(void)
	{
	/* Clear Pending Interrupt by writing '1' to it */
	*IXP23XX_TIMER_STATUS = IXP23XX_TIMER1_INT_PEND;

	/* Setup the Timer counter value */
	*IXP23XX_TIMER1_RELOAD =
	(LATCH & ~IXP23XX_TIMER_RELOAD_MASK) \| IXP23XX_TIMER_ENABLE;

	*IXP23XX_TIMER_CONT = 0;
	next_jiffy_time = LATCH;

	/* Connect the interrupt handler and enable the interrupt */
	setup_irq(IRQ_IXP23XX_TIMER1, &ixp23xx_timer_irq);
	}

	struct sys_timer ixp23xx_timer = {
	.init = ixp23xx_init_timer,
	.offset = ixp23xx_gettimeoffset,
	};


	/*************************************************************************
	* IXP23xx Platform Initialization
	*************************************************************************/
	static struct resource ixp23xx_uart_resources[] = {
	{
	.start = IXP23XX_UART1_PHYS,
	.end = IXP23XX_UART1_PHYS + 0x0fff,
	.flags = IORESOURCE_MEM
	}, {
	.start = IXP23XX_UART2_PHYS,
	.end = IXP23XX_UART2_PHYS + 0x0fff,
	.flags = IORESOURCE_MEM
	}
	};

	static struct plat_serial8250_port ixp23xx_uart_data[] = {
	{
	.mapbase = IXP23XX_UART1_PHYS,
	.membase = (char *)(IXP23XX_UART1_VIRT + 3),
	.irq = IRQ_IXP23XX_UART1,
	.flags = UPF_BOOT_AUTOCONF \| UPF_SKIP_TEST,
	.iotype = UPIO_MEM,
	.regshift = 2,
	.uartclk = IXP23XX_UART_XTAL,
	}, {
	.mapbase = IXP23XX_UART2_PHYS,
	.membase = (char *)(IXP23XX_UART2_VIRT + 3),
	.irq = IRQ_IXP23XX_UART2,
	.flags = UPF_BOOT_AUTOCONF \| UPF_SKIP_TEST,
	.iotype = UPIO_MEM,
	.regshift = 2,
	.uartclk = IXP23XX_UART_XTAL,
	},
	{ },
	};

	static struct platform_device ixp23xx_uart = {
	.name = "serial8250",
	.id = 0,
	.dev.platform_data = ixp23xx_uart_data,
	.num_resources = 2,
	.resource = ixp23xx_uart_resources,
	};

	static struct platform_device *ixp23xx_devices[] __initdata = {
	&ixp23xx_uart,
	};

	void __init ixp23xx_sys_init(void)
	{
	*IXP23XX_EXP_UNIT_FUSE \|= 0xf;
	platform_add_devices(ixp23xx_devices, ARRAY_SIZE(ixp23xx_devices));
	}