[mirror_ubuntu-kernels.git] / arch / x86 / kernel / i8259.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/linkage.h>
#include <linux/errno.h>
#include <linux/signal.h>
#include <linux/sched.h>
#include <linux/ioport.h>
#include <linux/interrupt.h>
#include <linux/timex.h>
#include <linux/random.h>
#include <linux/init.h>
#include <linux/kernel_stat.h>
#include <linux/syscore_ops.h>
#include <linux/bitops.h>
#include <linux/acpi.h>
#include <linux/io.h>
#include <linux/delay.h>

#include <linux/atomic.h>
#include <asm/timer.h>
#include <asm/hw_irq.h>
#include <asm/pgtable.h>
#include <asm/desc.h>
#include <asm/apic.h>
#include <asm/i8259.h>

/*
 * This is the 'legacy' 8259A Programmable Interrupt Controller,
 * present in the majority of PC/AT boxes.
 * plus some generic x86 specific things if generic specifics makes
 * any sense at all.
 */
static void init_8259A(int auto_eoi);

static int i8259A_auto_eoi;
DEFINE_RAW_SPINLOCK(i8259A_lock);

/*
 * 8259A PIC functions to handle ISA devices:
 */

/*
 * This contains the irq mask for both 8259A irq controllers,
 */
unsigned int cached_irq_mask = 0xffff;

/*
 * Not all IRQs can be routed through the IO-APIC, eg. on certain (older)
 * boards the timer interrupt is not really connected to any IO-APIC pin,
 * it's fed to the master 8259A's IR0 line only.
 *
 * Any '1' bit in this mask means the IRQ is routed through the IO-APIC.
 * this 'mixed mode' IRQ handling costs nothing because it's only used
 * at IRQ setup time.
 */
unsigned long io_apic_irqs;

static void mask_8259A_irq(unsigned int irq)
{
	unsigned int mask = 1 << irq;
	unsigned long flags;

	raw_spin_lock_irqsave(&i8259A_lock, flags);
	cached_irq_mask |= mask;
	if (irq & 8)
		outb(cached_slave_mask, PIC_SLAVE_IMR);
	else
		outb(cached_master_mask, PIC_MASTER_IMR);
	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
}

static void disable_8259A_irq(struct irq_data *data)
{
	mask_8259A_irq(data->irq);
}

static void unmask_8259A_irq(unsigned int irq)
{
	unsigned int mask = ~(1 << irq);
	unsigned long flags;

	raw_spin_lock_irqsave(&i8259A_lock, flags);
	cached_irq_mask &= mask;
	if (irq & 8)
		outb(cached_slave_mask, PIC_SLAVE_IMR);
	else
		outb(cached_master_mask, PIC_MASTER_IMR);
	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
}

static void enable_8259A_irq(struct irq_data *data)
{
	unmask_8259A_irq(data->irq);
}

static int i8259A_irq_pending(unsigned int irq)
{
	unsigned int mask = 1<<irq;
	unsigned long flags;
	int ret;

	raw_spin_lock_irqsave(&i8259A_lock, flags);
	if (irq < 8)
		ret = inb(PIC_MASTER_CMD) & mask;
	else
		ret = inb(PIC_SLAVE_CMD) & (mask >> 8);
	raw_spin_unlock_irqrestore(&i8259A_lock, flags);

	return ret;
}

static void make_8259A_irq(unsigned int irq)
{
	disable_irq_nosync(irq);
	io_apic_irqs &= ~(1<<irq);
	irq_set_chip_and_handler(irq, &i8259A_chip, handle_level_irq);
	enable_irq(irq);
}

/*
 * This function assumes to be called rarely. Switching between
 * 8259A registers is slow.
 * This has to be protected by the irq controller spinlock
 * before being called.
 */
static inline int i8259A_irq_real(unsigned int irq)
{
	int value;
	int irqmask = 1<<irq;

	if (irq < 8) {
		outb(0x0B, PIC_MASTER_CMD);	/* ISR register */
		value = inb(PIC_MASTER_CMD) & irqmask;
		outb(0x0A, PIC_MASTER_CMD);	/* back to the IRR register */
		return value;
	}
	outb(0x0B, PIC_SLAVE_CMD);	/* ISR register */
	value = inb(PIC_SLAVE_CMD) & (irqmask >> 8);
	outb(0x0A, PIC_SLAVE_CMD);	/* back to the IRR register */
	return value;
}

/*
 * Careful! The 8259A is a fragile beast, it pretty
 * much _has_ to be done exactly like this (mask it
 * first, _then_ send the EOI, and the order of EOI
 * to the two 8259s is important!
 */
static void mask_and_ack_8259A(struct irq_data *data)
{
	unsigned int irq = data->irq;
	unsigned int irqmask = 1 << irq;
	unsigned long flags;

	raw_spin_lock_irqsave(&i8259A_lock, flags);
	/*
	 * Lightweight spurious IRQ detection. We do not want
	 * to overdo spurious IRQ handling - it's usually a sign
	 * of hardware problems, so we only do the checks we can
	 * do without slowing down good hardware unnecessarily.
	 *
	 * Note that IRQ7 and IRQ15 (the two spurious IRQs
	 * usually resulting from the 8259A-1|2 PICs) occur
	 * even if the IRQ is masked in the 8259A. Thus we
	 * can check spurious 8259A IRQs without doing the
	 * quite slow i8259A_irq_real() call for every IRQ.
	 * This does not cover 100% of spurious interrupts,
	 * but should be enough to warn the user that there
	 * is something bad going on ...
	 */
	if (cached_irq_mask & irqmask)
		goto spurious_8259A_irq;
	cached_irq_mask |= irqmask;

handle_real_irq:
	if (irq & 8) {
		inb(PIC_SLAVE_IMR);	/* DUMMY - (do we need this?) */
		outb(cached_slave_mask, PIC_SLAVE_IMR);
		/* 'Specific EOI' to slave */
		outb(0x60+(irq&7), PIC_SLAVE_CMD);
		 /* 'Specific EOI' to master-IRQ2 */
		outb(0x60+PIC_CASCADE_IR, PIC_MASTER_CMD);
	} else {
		inb(PIC_MASTER_IMR);	/* DUMMY - (do we need this?) */
		outb(cached_master_mask, PIC_MASTER_IMR);
		outb(0x60+irq, PIC_MASTER_CMD);	/* 'Specific EOI to master */
	}
	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
	return;

spurious_8259A_irq:
	/*
	 * this is the slow path - should happen rarely.
	 */
	if (i8259A_irq_real(irq))
		/*
		 * oops, the IRQ _is_ in service according to the
		 * 8259A - not spurious, go handle it.
		 */
		goto handle_real_irq;

	{
		static int spurious_irq_mask;
		/*
		 * At this point we can be sure the IRQ is spurious,
		 * lets ACK and report it. [once per IRQ]
		 */
		if (!(spurious_irq_mask & irqmask)) {
			printk(KERN_DEBUG
			       "spurious 8259A interrupt: IRQ%d.\n", irq);
			spurious_irq_mask |= irqmask;
		}
		atomic_inc(&irq_err_count);
		/*
		 * Theoretically we do not have to handle this IRQ,
		 * but in Linux this does not cause problems and is
		 * simpler for us.
		 */
		goto handle_real_irq;
	}
}

struct irq_chip i8259A_chip = {
	.name		= "XT-PIC",
	.irq_mask	= disable_8259A_irq,
	.irq_disable	= disable_8259A_irq,
	.irq_unmask	= enable_8259A_irq,
	.irq_mask_ack	= mask_and_ack_8259A,
};

static char irq_trigger[2];
/**
 * ELCR registers (0x4d0, 0x4d1) control edge/level of IRQ
 */
static void restore_ELCR(char *trigger)
{
	outb(trigger[0], 0x4d0);
	outb(trigger[1], 0x4d1);
}

static void save_ELCR(char *trigger)
{
	/* IRQ 0,1,2,8,13 are marked as reserved */
	trigger[0] = inb(0x4d0) & 0xF8;
	trigger[1] = inb(0x4d1) & 0xDE;
}

static void i8259A_resume(void)
{
	init_8259A(i8259A_auto_eoi);
	restore_ELCR(irq_trigger);
}

static int i8259A_suspend(void)
{
	save_ELCR(irq_trigger);
	return 0;
}

static void i8259A_shutdown(void)
{
	/* Put the i8259A into a quiescent state that
	 * the kernel initialization code can get it
	 * out of.
	 */
	outb(0xff, PIC_MASTER_IMR);	/* mask all of 8259A-1 */
	outb(0xff, PIC_SLAVE_IMR);	/* mask all of 8259A-2 */
}

static struct syscore_ops i8259_syscore_ops = {
	.suspend = i8259A_suspend,
	.resume = i8259A_resume,
	.shutdown = i8259A_shutdown,
};

static void mask_8259A(void)
{
	unsigned long flags;

	raw_spin_lock_irqsave(&i8259A_lock, flags);

	outb(0xff, PIC_MASTER_IMR);	/* mask all of 8259A-1 */
	outb(0xff, PIC_SLAVE_IMR);	/* mask all of 8259A-2 */

	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
}

static void unmask_8259A(void)
{
	unsigned long flags;

	raw_spin_lock_irqsave(&i8259A_lock, flags);

	outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */
	outb(cached_slave_mask, PIC_SLAVE_IMR);	  /* restore slave IRQ mask */

	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
}

static int probe_8259A(void)
{
	unsigned long flags;
	unsigned char probe_val = ~(1 << PIC_CASCADE_IR);
	unsigned char new_val;
	/*
	 * Check to see if we have a PIC.
	 * Mask all except the cascade and read
	 * back the value we just wrote. If we don't
	 * have a PIC, we will read 0xff as opposed to the
	 * value we wrote.
	 */
	raw_spin_lock_irqsave(&i8259A_lock, flags);

	outb(0xff, PIC_SLAVE_IMR);	/* mask all of 8259A-2 */
	outb(probe_val, PIC_MASTER_IMR);
	new_val = inb(PIC_MASTER_IMR);
	if (new_val != probe_val) {
		printk(KERN_INFO "Using NULL legacy PIC\n");
		legacy_pic = &null_legacy_pic;
	}

	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
	return nr_legacy_irqs();
}

static void init_8259A(int auto_eoi)
{
	unsigned long flags;

	i8259A_auto_eoi = auto_eoi;

	raw_spin_lock_irqsave(&i8259A_lock, flags);

	outb(0xff, PIC_MASTER_IMR);	/* mask all of 8259A-1 */

	/*
	 * outb_pic - this has to work on a wide range of PC hardware.
	 */
	outb_pic(0x11, PIC_MASTER_CMD);	/* ICW1: select 8259A-1 init */

	/* ICW2: 8259A-1 IR0-7 mapped to ISA_IRQ_VECTOR(0) */
	outb_pic(ISA_IRQ_VECTOR(0), PIC_MASTER_IMR);

	/* 8259A-1 (the master) has a slave on IR2 */
	outb_pic(1U << PIC_CASCADE_IR, PIC_MASTER_IMR);

	if (auto_eoi)	/* master does Auto EOI */
		outb_pic(MASTER_ICW4_DEFAULT | PIC_ICW4_AEOI, PIC_MASTER_IMR);
	else		/* master expects normal EOI */
		outb_pic(MASTER_ICW4_DEFAULT, PIC_MASTER_IMR);

	outb_pic(0x11, PIC_SLAVE_CMD);	/* ICW1: select 8259A-2 init */

	/* ICW2: 8259A-2 IR0-7 mapped to ISA_IRQ_VECTOR(8) */
	outb_pic(ISA_IRQ_VECTOR(8), PIC_SLAVE_IMR);
	/* 8259A-2 is a slave on master's IR2 */
	outb_pic(PIC_CASCADE_IR, PIC_SLAVE_IMR);
	/* (slave's support for AEOI in flat mode is to be investigated) */
	outb_pic(SLAVE_ICW4_DEFAULT, PIC_SLAVE_IMR);

	if (auto_eoi)
		/*
		 * In AEOI mode we just have to mask the interrupt
		 * when acking.
		 */
		i8259A_chip.irq_mask_ack = disable_8259A_irq;
	else
		i8259A_chip.irq_mask_ack = mask_and_ack_8259A;

	udelay(100);		/* wait for 8259A to initialize */

	outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */
	outb(cached_slave_mask, PIC_SLAVE_IMR);	  /* restore slave IRQ mask */

	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
}

/*
 * make i8259 a driver so that we can select pic functions at run time. the goal
 * is to make x86 binary compatible among pc compatible and non-pc compatible
 * platforms, such as x86 MID.
 */

static void legacy_pic_noop(void) { };
static void legacy_pic_uint_noop(unsigned int unused) { };
static void legacy_pic_int_noop(int unused) { };
static int legacy_pic_irq_pending_noop(unsigned int irq)
{
	return 0;
}
static int legacy_pic_probe(void)
{
	return 0;
}

struct legacy_pic null_legacy_pic = {
	.nr_legacy_irqs = 0,
	.chip = &dummy_irq_chip,
	.mask = legacy_pic_uint_noop,
	.unmask = legacy_pic_uint_noop,
	.mask_all = legacy_pic_noop,
	.restore_mask = legacy_pic_noop,
	.init = legacy_pic_int_noop,
	.probe = legacy_pic_probe,
	.irq_pending = legacy_pic_irq_pending_noop,
	.make_irq = legacy_pic_uint_noop,
};

struct legacy_pic default_legacy_pic = {
	.nr_legacy_irqs = NR_IRQS_LEGACY,
	.chip  = &i8259A_chip,
	.mask = mask_8259A_irq,
	.unmask = unmask_8259A_irq,
	.mask_all = mask_8259A,
	.restore_mask = unmask_8259A,
	.init = init_8259A,
	.probe = probe_8259A,
	.irq_pending = i8259A_irq_pending,
	.make_irq = make_8259A_irq,
};

struct legacy_pic *legacy_pic = &default_legacy_pic;
EXPORT_SYMBOL(legacy_pic);

static int __init i8259A_init_ops(void)
{
	if (legacy_pic == &default_legacy_pic)
		register_syscore_ops(&i8259_syscore_ops);

	return 0;
}

device_initcall(i8259A_init_ops);
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
21fd5132	2	#include <linux/linkage.h>
21fd5132 PM	3	#include <linux/errno.h>
	4	#include <linux/signal.h>
	5	#include <linux/sched.h>
	6	#include <linux/ioport.h>
	7	#include <linux/interrupt.h>
21fd5132	8	#include <linux/timex.h>
21fd5132 PM	9	#include <linux/random.h>
	10	#include <linux/init.h>
	11	#include <linux/kernel_stat.h>
f3c6ea1b	12	#include <linux/syscore_ops.h>
21fd5132	13	#include <linux/bitops.h>
7bafaf30 JSR	14	#include <linux/acpi.h>
	15	#include <linux/io.h>
	16	#include <linux/delay.h>
21fd5132	17
60063497	18	#include <linux/atomic.h>
21fd5132	19	#include <asm/timer.h>
21fd5132	20	#include <asm/hw_irq.h>
21fd5132	21	#include <asm/pgtable.h>
21fd5132 PM	22	#include <asm/desc.h>
21fd5132 PM	23	#include <asm/apic.h>
21fd5132 PM	24	#include <asm/i8259.h>
	25
	26	/*
	27	* This is the 'legacy' 8259A Programmable Interrupt Controller,
	28	* present in the majority of PC/AT boxes.
	29	* plus some generic x86 specific things if generic specifics makes
	30	* any sense at all.
	31	*/
4305df94	32	static void init_8259A(int auto_eoi);
21fd5132 PM	33
21fd5132 PM	34	static int i8259A_auto_eoi;
5619c280	35	DEFINE_RAW_SPINLOCK(i8259A_lock);
21fd5132 PM	36
	37	/*
	38	* 8259A PIC functions to handle ISA devices:
	39	*/
	40
	41	/*
	42	* This contains the irq mask for both 8259A irq controllers,
	43	*/
	44	unsigned int cached_irq_mask = 0xffff;
	45
	46	/*
	47	* Not all IRQs can be routed through the IO-APIC, eg. on certain (older)
	48	* boards the timer interrupt is not really connected to any IO-APIC pin,
	49	* it's fed to the master 8259A's IR0 line only.
	50	*
	51	* Any '1' bit in this mask means the IRQ is routed through the IO-APIC.
	52	* this 'mixed mode' IRQ handling costs nothing because it's only used
	53	* at IRQ setup time.
	54	*/
	55	unsigned long io_apic_irqs;
	56
4305df94	57	static void mask_8259A_irq(unsigned int irq)
21fd5132 PM	58	{
	59	unsigned int mask = 1 << irq;
	60	unsigned long flags;
	61
5619c280	62	raw_spin_lock_irqsave(&i8259A_lock, flags);
21fd5132 PM	63	cached_irq_mask \|= mask;
	64	if (irq & 8)
	65	outb(cached_slave_mask, PIC_SLAVE_IMR);
	66	else
	67	outb(cached_master_mask, PIC_MASTER_IMR);
5619c280	68	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
21fd5132 PM	69	}
21fd5132 PM	70
4305df94 TG	71	static void disable_8259A_irq(struct irq_data *data)
	72	{
	73	mask_8259A_irq(data->irq);
	74	}
	75
	76	static void unmask_8259A_irq(unsigned int irq)
21fd5132 PM	77	{
	78	unsigned int mask = ~(1 << irq);
	79	unsigned long flags;
	80
5619c280	81	raw_spin_lock_irqsave(&i8259A_lock, flags);
21fd5132 PM	82	cached_irq_mask &= mask;
	83	if (irq & 8)
	84	outb(cached_slave_mask, PIC_SLAVE_IMR);
	85	else
	86	outb(cached_master_mask, PIC_MASTER_IMR);
5619c280	87	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
21fd5132 PM	88	}
21fd5132 PM	89
4305df94 TG	90	static void enable_8259A_irq(struct irq_data *data)
	91	{
	92	unmask_8259A_irq(data->irq);
	93	}
	94
b81bb373	95	static int i8259A_irq_pending(unsigned int irq)
21fd5132 PM	96	{
	97	unsigned int mask = 1<<irq;
	98	unsigned long flags;
	99	int ret;
	100
5619c280	101	raw_spin_lock_irqsave(&i8259A_lock, flags);
21fd5132 PM	102	if (irq < 8)
	103	ret = inb(PIC_MASTER_CMD) & mask;
	104	else
	105	ret = inb(PIC_SLAVE_CMD) & (mask >> 8);
5619c280	106	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
21fd5132 PM	107
	108	return ret;
	109	}
	110
b81bb373	111	static void make_8259A_irq(unsigned int irq)
21fd5132 PM	112	{
	113	disable_irq_nosync(irq);
	114	io_apic_irqs &= ~(1<<irq);
60e684f0	115	irq_set_chip_and_handler(irq, &i8259A_chip, handle_level_irq);
21fd5132 PM	116	enable_irq(irq);
	117	}
	118
	119	/*
	120	* This function assumes to be called rarely. Switching between
	121	* 8259A registers is slow.
	122	* This has to be protected by the irq controller spinlock
	123	* before being called.
	124	*/
	125	static inline int i8259A_irq_real(unsigned int irq)
	126	{
	127	int value;
	128	int irqmask = 1<<irq;
	129
	130	if (irq < 8) {
680afbf9	131	outb(0x0B, PIC_MASTER_CMD); /* ISR register */
21fd5132	132	value = inb(PIC_MASTER_CMD) & irqmask;
680afbf9	133	outb(0x0A, PIC_MASTER_CMD); /* back to the IRR register */
21fd5132 PM	134	return value;
21fd5132 PM	135	}
680afbf9	136	outb(0x0B, PIC_SLAVE_CMD); /* ISR register */
21fd5132	137	value = inb(PIC_SLAVE_CMD) & (irqmask >> 8);
680afbf9	138	outb(0x0A, PIC_SLAVE_CMD); /* back to the IRR register */
21fd5132 PM	139	return value;
	140	}
	141
	142	/*
	143	* Careful! The 8259A is a fragile beast, it pretty
	144	* much _has_ to be done exactly like this (mask it
	145	* first, _then_ send the EOI, and the order of EOI
	146	* to the two 8259s is important!
	147	*/
4305df94	148	static void mask_and_ack_8259A(struct irq_data *data)
21fd5132	149	{
4305df94	150	unsigned int irq = data->irq;
21fd5132 PM	151	unsigned int irqmask = 1 << irq;
	152	unsigned long flags;
	153
5619c280	154	raw_spin_lock_irqsave(&i8259A_lock, flags);
21fd5132 PM	155	/*
	156	* Lightweight spurious IRQ detection. We do not want
	157	* to overdo spurious IRQ handling - it's usually a sign
	158	* of hardware problems, so we only do the checks we can
	159	* do without slowing down good hardware unnecessarily.
	160	*
	161	* Note that IRQ7 and IRQ15 (the two spurious IRQs
	162	* usually resulting from the 8259A-1\|2 PICs) occur
	163	* even if the IRQ is masked in the 8259A. Thus we
	164	* can check spurious 8259A IRQs without doing the
	165	* quite slow i8259A_irq_real() call for every IRQ.
	166	* This does not cover 100% of spurious interrupts,
	167	* but should be enough to warn the user that there
	168	* is something bad going on ...
	169	*/
	170	if (cached_irq_mask & irqmask)
	171	goto spurious_8259A_irq;
	172	cached_irq_mask \|= irqmask;
	173
	174	handle_real_irq:
	175	if (irq & 8) {
	176	inb(PIC_SLAVE_IMR); /* DUMMY - (do we need this?) */
	177	outb(cached_slave_mask, PIC_SLAVE_IMR);
21fd5132	178	/* 'Specific EOI' to slave */
3e8631d2	179	outb(0x60+(irq&7), PIC_SLAVE_CMD);
21fd5132	180	/* 'Specific EOI' to master-IRQ2 */
3e8631d2	181	outb(0x60+PIC_CASCADE_IR, PIC_MASTER_CMD);
21fd5132 PM	182	} else {
	183	inb(PIC_MASTER_IMR); /* DUMMY - (do we need this?) */
	184	outb(cached_master_mask, PIC_MASTER_IMR);
3e8631d2	185	outb(0x60+irq, PIC_MASTER_CMD); /* 'Specific EOI to master */
21fd5132	186	}
5619c280	187	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
21fd5132 PM	188	return;
	189
	190	spurious_8259A_irq:
	191	/*
	192	* this is the slow path - should happen rarely.
	193	*/
	194	if (i8259A_irq_real(irq))
	195	/*
	196	* oops, the IRQ _is_ in service according to the
	197	* 8259A - not spurious, go handle it.
	198	*/
	199	goto handle_real_irq;
	200
	201	{
	202	static int spurious_irq_mask;
	203	/*
	204	* At this point we can be sure the IRQ is spurious,
	205	* lets ACK and report it. [once per IRQ]
	206	*/
	207	if (!(spurious_irq_mask & irqmask)) {
21fd5132 PM	208	printk(KERN_DEBUG
21fd5132 PM	209	"spurious 8259A interrupt: IRQ%d.\n", irq);
21fd5132 PM	210	spurious_irq_mask \|= irqmask;
	211	}
	212	atomic_inc(&irq_err_count);
	213	/*
	214	* Theoretically we do not have to handle this IRQ,
	215	* but in Linux this does not cause problems and is
	216	* simpler for us.
	217	*/
	218	goto handle_real_irq;
	219	}
	220	}
	221
4305df94 TG	222	struct irq_chip i8259A_chip = {
	223	.name = "XT-PIC",
	224	.irq_mask = disable_8259A_irq,
	225	.irq_disable = disable_8259A_irq,
	226	.irq_unmask = enable_8259A_irq,
	227	.irq_mask_ack = mask_and_ack_8259A,
	228	};
	229
21fd5132 PM	230	static char irq_trigger[2];
	231	/**
	232	* ELCR registers (0x4d0, 0x4d1) control edge/level of IRQ
	233	*/
	234	static void restore_ELCR(char *trigger)
	235	{
	236	outb(trigger[0], 0x4d0);
	237	outb(trigger[1], 0x4d1);
	238	}
	239
	240	static void save_ELCR(char *trigger)
	241	{
	242	/* IRQ 0,1,2,8,13 are marked as reserved */
	243	trigger[0] = inb(0x4d0) & 0xF8;
	244	trigger[1] = inb(0x4d1) & 0xDE;
	245	}
	246
f3c6ea1b	247	static void i8259A_resume(void)
21fd5132 PM	248	{
	249	init_8259A(i8259A_auto_eoi);
	250	restore_ELCR(irq_trigger);
21fd5132 PM	251	}
21fd5132 PM	252
f3c6ea1b	253	static int i8259A_suspend(void)
21fd5132 PM	254	{
	255	save_ELCR(irq_trigger);
	256	return 0;
	257	}
	258
f3c6ea1b	259	static void i8259A_shutdown(void)
21fd5132 PM	260	{
	261	/* Put the i8259A into a quiescent state that
	262	* the kernel initialization code can get it
	263	* out of.
	264	*/
	265	outb(0xff, PIC_MASTER_IMR); /* mask all of 8259A-1 */
d3a8009b	266	outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */
21fd5132 PM	267	}
21fd5132 PM	268
f3c6ea1b	269	static struct syscore_ops i8259_syscore_ops = {
21fd5132 PM	270	.suspend = i8259A_suspend,
	271	.resume = i8259A_resume,
	272	.shutdown = i8259A_shutdown,
	273	};
	274
b81bb373	275	static void mask_8259A(void)
d94d93ca SS	276	{
	277	unsigned long flags;
	278
5619c280	279	raw_spin_lock_irqsave(&i8259A_lock, flags);
d94d93ca SS	280
	281	outb(0xff, PIC_MASTER_IMR); /* mask all of 8259A-1 */
	282	outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */
	283
5619c280	284	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
d94d93ca SS	285	}
d94d93ca SS	286
b81bb373	287	static void unmask_8259A(void)
d94d93ca SS	288	{
	289	unsigned long flags;
	290
5619c280	291	raw_spin_lock_irqsave(&i8259A_lock, flags);
d94d93ca SS	292
	293	outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */
	294	outb(cached_slave_mask, PIC_SLAVE_IMR); /* restore slave IRQ mask */
	295
5619c280	296	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
d94d93ca SS	297	}
d94d93ca SS	298
8c058b0b	299	static int probe_8259A(void)
21fd5132 PM	300	{
21fd5132 PM	301	unsigned long flags;
e179f691 S	302	unsigned char probe_val = ~(1 << PIC_CASCADE_IR);
e179f691 S	303	unsigned char new_val;
e179f691 S	304	/*
	305	* Check to see if we have a PIC.
	306	* Mask all except the cascade and read
	307	* back the value we just wrote. If we don't
	308	* have a PIC, we will read 0xff as opposed to the
	309	* value we wrote.
	310	*/
8c058b0b VK	311	raw_spin_lock_irqsave(&i8259A_lock, flags);
8c058b0b VK	312
21fd5132	313	outb(0xff, PIC_SLAVE_IMR); /* mask all of 8259A-2 */
e179f691 S	314	outb(probe_val, PIC_MASTER_IMR);
	315	new_val = inb(PIC_MASTER_IMR);
	316	if (new_val != probe_val) {
	317	printk(KERN_INFO "Using NULL legacy PIC\n");
	318	legacy_pic = &null_legacy_pic;
e179f691 S	319	}
e179f691 S	320
8c058b0b VK	321	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
	322	return nr_legacy_irqs();
	323	}
	324
	325	static void init_8259A(int auto_eoi)
	326	{
	327	unsigned long flags;
	328
	329	i8259A_auto_eoi = auto_eoi;
	330
	331	raw_spin_lock_irqsave(&i8259A_lock, flags);
	332
e179f691	333	outb(0xff, PIC_MASTER_IMR); /* mask all of 8259A-1 */
21fd5132 PM	334
	335	/*
	336	* outb_pic - this has to work on a wide range of PC hardware.
	337	*/
	338	outb_pic(0x11, PIC_MASTER_CMD); /* ICW1: select 8259A-1 init */
c46e62f7	339
8b455e65 BG	340	/* ICW2: 8259A-1 IR0-7 mapped to ISA_IRQ_VECTOR(0) */
8b455e65 BG	341	outb_pic(ISA_IRQ_VECTOR(0), PIC_MASTER_IMR);
c46e62f7	342
21fd5132	343	/* 8259A-1 (the master) has a slave on IR2 */
c46e62f7 PM	344	outb_pic(1U << PIC_CASCADE_IR, PIC_MASTER_IMR);
c46e62f7 PM	345
21fd5132 PM	346	if (auto_eoi) /* master does Auto EOI */
	347	outb_pic(MASTER_ICW4_DEFAULT \| PIC_ICW4_AEOI, PIC_MASTER_IMR);
	348	else /* master expects normal EOI */
	349	outb_pic(MASTER_ICW4_DEFAULT, PIC_MASTER_IMR);
	350
	351	outb_pic(0x11, PIC_SLAVE_CMD); /* ICW1: select 8259A-2 init */
c46e62f7	352
8b455e65 BG	353	/* ICW2: 8259A-2 IR0-7 mapped to ISA_IRQ_VECTOR(8) */
8b455e65 BG	354	outb_pic(ISA_IRQ_VECTOR(8), PIC_SLAVE_IMR);
21fd5132 PM	355	/* 8259A-2 is a slave on master's IR2 */
	356	outb_pic(PIC_CASCADE_IR, PIC_SLAVE_IMR);
	357	/* (slave's support for AEOI in flat mode is to be investigated) */
	358	outb_pic(SLAVE_ICW4_DEFAULT, PIC_SLAVE_IMR);
	359
21fd5132 PM	360	if (auto_eoi)
	361	/*
	362	* In AEOI mode we just have to mask the interrupt
	363	* when acking.
	364	*/
4305df94	365	i8259A_chip.irq_mask_ack = disable_8259A_irq;
21fd5132	366	else
4305df94	367	i8259A_chip.irq_mask_ack = mask_and_ack_8259A;
21fd5132 PM	368
	369	udelay(100); /* wait for 8259A to initialize */
	370
	371	outb(cached_master_mask, PIC_MASTER_IMR); /* restore master IRQ mask */
	372	outb(cached_slave_mask, PIC_SLAVE_IMR); /* restore slave IRQ mask */
	373
5619c280	374	raw_spin_unlock_irqrestore(&i8259A_lock, flags);
21fd5132	375	}
b81bb373	376
ef354866 JP	377	/*
	378	* make i8259 a driver so that we can select pic functions at run time. the goal
	379	* is to make x86 binary compatible among pc compatible and non-pc compatible
	380	* platforms, such as x86 MID.
	381	*/
	382
28a3c93d JP	383	static void legacy_pic_noop(void) { };
	384	static void legacy_pic_uint_noop(unsigned int unused) { };
	385	static void legacy_pic_int_noop(int unused) { };
ef354866 JP	386	static int legacy_pic_irq_pending_noop(unsigned int irq)
	387	{
	388	return 0;
	389	}
8c058b0b VK	390	static int legacy_pic_probe(void)
	391	{
	392	return 0;
	393	}
ef354866 JP	394
	395	struct legacy_pic null_legacy_pic = {
	396	.nr_legacy_irqs = 0,
4305df94 TG	397	.chip = &dummy_irq_chip,
	398	.mask = legacy_pic_uint_noop,
	399	.unmask = legacy_pic_uint_noop,
ef354866 JP	400	.mask_all = legacy_pic_noop,
	401	.restore_mask = legacy_pic_noop,
	402	.init = legacy_pic_int_noop,
8c058b0b	403	.probe = legacy_pic_probe,
ef354866 JP	404	.irq_pending = legacy_pic_irq_pending_noop,
	405	.make_irq = legacy_pic_uint_noop,
	406	};
	407
	408	struct legacy_pic default_legacy_pic = {
	409	.nr_legacy_irqs = NR_IRQS_LEGACY,
	410	.chip = &i8259A_chip,
4305df94 TG	411	.mask = mask_8259A_irq,
	412	.unmask = unmask_8259A_irq,
	413	.mask_all = mask_8259A,
ef354866 JP	414	.restore_mask = unmask_8259A,
ef354866 JP	415	.init = init_8259A,
8c058b0b	416	.probe = probe_8259A,
ef354866 JP	417	.irq_pending = i8259A_irq_pending,
	418	.make_irq = make_8259A_irq,
	419	};
	420
	421	struct legacy_pic *legacy_pic = &default_legacy_pic;
7ee06cb2	422	EXPORT_SYMBOL(legacy_pic);
087b255a	423
f3c6ea1b	424	static int __init i8259A_init_ops(void)
087b255a	425	{
f3c6ea1b RW	426	if (legacy_pic == &default_legacy_pic)
f3c6ea1b RW	427	register_syscore_ops(&i8259_syscore_ops);
087b255a	428
f3c6ea1b	429	return 0;
087b255a AL	430	}
087b255a AL	431
f3c6ea1b	432	device_initcall(i8259A_init_ops);