intc.c

linux 内核源代码

/*
 * Shared interrupt handling code for IPR and INTC2 types of IRQs.
 *
 * Copyright (C) 2007 Magnus Damm
 *
 * Based on intc2.c and ipr.c
 *
 * Copyright (C) 1999  Niibe Yutaka & Takeshi Yaegashi
 * Copyright (C) 2000  Kazumoto Kojima
 * Copyright (C) 2001  David J. Mckay ([e-mail])
 * Copyright (C) 2003  Takashi Kusuda <[e-mail]>
 * Copyright (C) 2005, 2006  Paul Mundt
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 */
#include <linux/init.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/io.h>
#include <linux/interrupt.h>
#include <linux/bootmem.h>

#define _INTC_MK(fn, mode, addr_e, addr_d, width, shift) \
	((shift) | ((width) << 5) | ((fn) << 9) | ((mode) << 13) | \
	 ((addr_e) << 16) | ((addr_d << 24)))

#define _INTC_SHIFT(h) (h & 0x1f)
#define _INTC_WIDTH(h) ((h >> 5) & 0xf)
#define _INTC_FN(h) ((h >> 9) & 0xf)
#define _INTC_MODE(h) ((h >> 13) & 0x7)
#define _INTC_ADDR_E(h) ((h >> 16) & 0xff)
#define _INTC_ADDR_D(h) ((h >> 24) & 0xff)

struct intc_handle_int {
	unsigned int irq;
	unsigned long handle;
};

struct intc_desc_int {
	unsigned long *reg;
#ifdef CONFIG_SMP
	unsigned long *smp;
#endif
	unsigned int nr_reg;
	struct intc_handle_int *prio;
	unsigned int nr_prio;
	struct intc_handle_int *sense;
	unsigned int nr_sense;
	struct irq_chip chip;
};

#ifdef CONFIG_SMP
#define IS_SMP(x) x.smp
#define INTC_REG(d, x, c) (d->reg[(x)] + ((d->smp[(x)] & 0xff) * c))
#define SMP_NR(d, x) ((d->smp[(x)] >> 8) ? (d->smp[(x)] >> 8) : 1)
#else
#define IS_SMP(x) 0
#define INTC_REG(d, x, c) (d->reg[(x)])
#define SMP_NR(d, x) 1
#endif

static unsigned int intc_prio_level[NR_IRQS]; /* for now */

static inline struct intc_desc_int *get_intc_desc(unsigned int irq)
{
	struct irq_chip *chip = get_irq_chip(irq);
	return (void *)((char *)chip - offsetof(struct intc_desc_int, chip));
}

static inline unsigned int set_field(unsigned int value,
				     unsigned int field_value,
				     unsigned int handle)
{
	unsigned int width = _INTC_WIDTH(handle);
	unsigned int shift = _INTC_SHIFT(handle);

	value &= ~(((1 << width) - 1) << shift);
	value |= field_value << shift;
	return value;
}

static void write_8(unsigned long addr, unsigned long h, unsigned long data)
{
	ctrl_outb(set_field(0, data, h), addr);
}

static void write_16(unsigned long addr, unsigned long h, unsigned long data)
{
	ctrl_outw(set_field(0, data, h), addr);
}

static void write_32(unsigned long addr, unsigned long h, unsigned long data)
{
	ctrl_outl(set_field(0, data, h), addr);
}

static void modify_8(unsigned long addr, unsigned long h, unsigned long data)
{
	ctrl_outb(set_field(ctrl_inb(addr), data, h), addr);
}

static void modify_16(unsigned long addr, unsigned long h, unsigned long data)
{
	ctrl_outw(set_field(ctrl_inw(addr), data, h), addr);
}

static void modify_32(unsigned long addr, unsigned long h, unsigned long data)
{
	ctrl_outl(set_field(ctrl_inl(addr), data, h), addr);
}

enum {	REG_FN_ERR = 0, REG_FN_WRITE_BASE = 1, REG_FN_MODIFY_BASE = 5 };

static void (*intc_reg_fns[])(unsigned long addr,
			      unsigned long h,
			      unsigned long data) = {
	[REG_FN_WRITE_BASE + 0] = write_8,
	[REG_FN_WRITE_BASE + 1] = write_16,
	[REG_FN_WRITE_BASE + 3] = write_32,
	[REG_FN_MODIFY_BASE + 0] = modify_8,
	[REG_FN_MODIFY_BASE + 1] = modify_16,
	[REG_FN_MODIFY_BASE + 3] = modify_32,
};

enum {	MODE_ENABLE_REG = 0, /* Bit(s) set -> interrupt enabled */
	MODE_MASK_REG,       /* Bit(s) set -> interrupt disabled */
	MODE_DUAL_REG,       /* Two registers, set bit to enable / disable */
	MODE_PRIO_REG,       /* Priority value written to enable interrupt */
	MODE_PCLR_REG,       /* Above plus all bits set to disable interrupt */
};

static void intc_mode_field(unsigned long addr,
			    unsigned long handle,
			    void (*fn)(unsigned long,
				       unsigned long,
				       unsigned long),
			    unsigned int irq)
{
	fn(addr, handle, ((1 << _INTC_WIDTH(handle)) - 1));
}

static void intc_mode_zero(unsigned long addr,
			   unsigned long handle,
			   void (*fn)(unsigned long,
				       unsigned long,
				       unsigned long),
			   unsigned int irq)
{
	fn(addr, handle, 0);
}

static void intc_mode_prio(unsigned long addr,
			   unsigned long handle,
			   void (*fn)(unsigned long,
				       unsigned long,
				       unsigned long),
			   unsigned int irq)
{
	fn(addr, handle, intc_prio_level[irq]);
}

static void (*intc_enable_fns[])(unsigned long addr,
				 unsigned long handle,
				 void (*fn)(unsigned long,
					    unsigned long,
					    unsigned long),
				 unsigned int irq) = {
	[MODE_ENABLE_REG] = intc_mode_field,
	[MODE_MASK_REG] = intc_mode_zero,
	[MODE_DUAL_REG] = intc_mode_field,
	[MODE_PRIO_REG] = intc_mode_prio,
	[MODE_PCLR_REG] = intc_mode_prio,
};

static void (*intc_disable_fns[])(unsigned long addr,
				  unsigned long handle,
				  void (*fn)(unsigned long,
					     unsigned long,
					     unsigned long),
				  unsigned int irq) = {
	[MODE_ENABLE_REG] = intc_mode_zero,
	[MODE_MASK_REG] = intc_mode_field,
	[MODE_DUAL_REG] = intc_mode_field,
	[MODE_PRIO_REG] = intc_mode_zero,
	[MODE_PCLR_REG] = intc_mode_field,
};

static inline void _intc_enable(unsigned int irq, unsigned long handle)
{
	struct intc_desc_int *d = get_intc_desc(irq);
	unsigned long addr;
	unsigned int cpu;

	for (cpu = 0; cpu < SMP_NR(d, _INTC_ADDR_E(handle)); cpu++) {
		addr = INTC_REG(d, _INTC_ADDR_E(handle), cpu);
		intc_enable_fns[_INTC_MODE(handle)](addr, handle, intc_reg_fns\
						    [_INTC_FN(handle)], irq);
	}
}

static void intc_enable(unsigned int irq)
{
	_intc_enable(irq, (unsigned long)get_irq_chip_data(irq));
}

static void intc_disable(unsigned int irq)
{
	struct intc_desc_int *d = get_intc_desc(irq);
	unsigned long handle = (unsigned long) get_irq_chip_data(irq);
	unsigned long addr;
	unsigned int cpu;

	for (cpu = 0; cpu < SMP_NR(d, _INTC_ADDR_D(handle)); cpu++) {
		addr = INTC_REG(d, _INTC_ADDR_D(handle), cpu);
		intc_disable_fns[_INTC_MODE(handle)](addr, handle,intc_reg_fns\
						     [_INTC_FN(handle)], irq);
	}
}

static struct intc_handle_int *intc_find_irq(struct intc_handle_int *hp,
					     unsigned int nr_hp,
					     unsigned int irq)
{
	int i;

	/* this doesn't scale well, but...
	 *
	 * this function should only be used for cerain uncommon
	 * operations such as intc_set_priority() and intc_set_sense()
	 * and in those rare cases performance doesn't matter that much.
	 * keeping the memory footprint low is more important.
	 *
	 * one rather simple way to speed this up and still keep the
	 * memory footprint down is to make sure the array is sorted
	 * and then perform a bisect to lookup the irq.
	 */

	for (i = 0; i < nr_hp; i++) {
		if ((hp + i)->irq != irq)
			continue;

		return hp + i;
	}

	return NULL;
}

int intc_set_priority(unsigned int irq, unsigned int prio)
{
	struct intc_desc_int *d = get_intc_desc(irq);
	struct intc_handle_int *ihp;

	if (!intc_prio_level[irq] || prio <= 1)
		return -EINVAL;

	ihp = intc_find_irq(d->prio, d->nr_prio, irq);
	if (ihp) {
		if (prio >= (1 << _INTC_WIDTH(ihp->handle)))
			return -EINVAL;

		intc_prio_level[irq] = prio;

		/*
		 * only set secondary masking method directly
		 * primary masking method is using intc_prio_level[irq]
		 * priority level will be set during next enable()
		 */

		if (_INTC_FN(ihp->handle) != REG_FN_ERR)
			_intc_enable(irq, ihp->handle);
	}
	return 0;
}

#define VALID(x) (x | 0x80)

static unsigned char intc_irq_sense_table[IRQ_TYPE_SENSE_MASK + 1] = {
	[IRQ_TYPE_EDGE_FALLING] = VALID(0),
	[IRQ_TYPE_EDGE_RISING] = VALID(1),
	[IRQ_TYPE_LEVEL_LOW] = VALID(2),
	[IRQ_TYPE_LEVEL_HIGH] = VALID(3),
};

static int intc_set_sense(unsigned int irq, unsigned int type)
{
	struct intc_desc_int *d = get_intc_desc(irq);
	unsigned char value = intc_irq_sense_table[type & IRQ_TYPE_SENSE_MASK];
	struct intc_handle_int *ihp;
	unsigned long addr;

	if (!value)
		return -EINVAL;

	ihp = intc_find_irq(d->sense, d->nr_sense, irq);
	if (ihp) {
		addr = INTC_REG(d, _INTC_ADDR_E(ihp->handle), 0);
		intc_reg_fns[_INTC_FN(ihp->handle)](addr, ihp->handle, value);
	}
	return 0;
}

static unsigned int __init intc_get_reg(struct intc_desc_int *d,
				 unsigned long address)
{
	unsigned int k;

	for (k = 0; k < d->nr_reg; k++) {
		if (d->reg[k] == address)
			return k;
	}

	BUG();
	return 0;
}