[deliverable/linux.git] / arch / arm / kernel / fiq.c

/*
 *  linux/arch/arm/kernel/fiq.c
 *
 *  Copyright (C) 1998 Russell King
 *  Copyright (C) 1998, 1999 Phil Blundell
 *
 *  FIQ support written by Philip Blundell <philb@gnu.org>, 1998.
 *
 *  FIQ support re-written by Russell King to be more generic
 *
 * We now properly support a method by which the FIQ handlers can
 * be stacked onto the vector.  We still do not support sharing
 * the FIQ vector itself.
 *
 * Operation is as follows:
 *  1. Owner A claims FIQ:
 *     - default_fiq relinquishes control.
 *  2. Owner A:
 *     - inserts code.
 *     - sets any registers,
 *     - enables FIQ.
 *  3. Owner B claims FIQ:
 *     - if owner A has a relinquish function.
 *       - disable FIQs.
 *       - saves any registers.
 *       - returns zero.
 *  4. Owner B:
 *     - inserts code.
 *     - sets any registers,
 *     - enables FIQ.
 *  5. Owner B releases FIQ:
 *     - Owner A is asked to reacquire FIQ:
 *	 - inserts code.
 *	 - restores saved registers.
 *	 - enables FIQ.
 *  6. Goto 3
 */
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/seq_file.h>

#include <asm/cacheflush.h>
#include <asm/fiq.h>
#include <asm/irq.h>
#include <asm/system.h>
#include <asm/traps.h>

static unsigned long no_fiq_insn;

/* Default reacquire function
 * - we always relinquish FIQ control
 * - we always reacquire FIQ control
 */
static int fiq_def_op(void *ref, int relinquish)
{
	if (!relinquish)
		set_fiq_handler(&no_fiq_insn, sizeof(no_fiq_insn));

	return 0;
}

static struct fiq_handler default_owner = {
	.name	= "default",
	.fiq_op = fiq_def_op,
};

static struct fiq_handler *current_fiq = &default_owner;

int show_fiq_list(struct seq_file *p, int prec)
{
	if (current_fiq != &default_owner)
		seq_printf(p, "%*s:              %s\n", prec, "FIQ",
			current_fiq->name);

	return 0;
}

void set_fiq_handler(void *start, unsigned int length)
{
#if defined(CONFIG_CPU_USE_DOMAINS)
	memcpy((void *)0xffff001c, start, length);
#else
	memcpy(vectors_page + 0x1c, start, length);
#endif
	flush_icache_range(0xffff001c, 0xffff001c + length);
	if (!vectors_high())
		flush_icache_range(0x1c, 0x1c + length);
}

/*
 * Taking an interrupt in FIQ mode is death, so both these functions
 * disable irqs for the duration.  Note - these functions are almost
 * entirely coded in assembly.
 */
void __naked set_fiq_regs(struct pt_regs *regs)
{
	register unsigned long tmp;
	asm volatile (
	"mov	ip, sp\n\
	stmfd	sp!, {fp, ip, lr, pc}\n\
	sub	fp, ip, #4\n\
	mrs	%0, cpsr\n\
	msr	cpsr_c, %2	@ select FIQ mode\n\
	mov	r0, r0\n\
	ldmia	%1, {r8 - r14}\n\
	msr	cpsr_c, %0	@ return to SVC mode\n\
	mov	r0, r0\n\
	ldmfd	sp, {fp, sp, pc}"
	: "=&r" (tmp)
	: "r" (&regs->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | FIQ_MODE));
}

void __naked get_fiq_regs(struct pt_regs *regs)
{
	register unsigned long tmp;
	asm volatile (
	"mov	ip, sp\n\
	stmfd	sp!, {fp, ip, lr, pc}\n\
	sub	fp, ip, #4\n\
	mrs	%0, cpsr\n\
	msr	cpsr_c, %2	@ select FIQ mode\n\
	mov	r0, r0\n\
	stmia	%1, {r8 - r14}\n\
	msr	cpsr_c, %0	@ return to SVC mode\n\
	mov	r0, r0\n\
	ldmfd	sp, {fp, sp, pc}"
	: "=&r" (tmp)
	: "r" (&regs->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | FIQ_MODE));
}

int claim_fiq(struct fiq_handler *f)
{
	int ret = 0;

	if (current_fiq) {
		ret = -EBUSY;

		if (current_fiq->fiq_op != NULL)
			ret = current_fiq->fiq_op(current_fiq->dev_id, 1);
	}

	if (!ret) {
		f->next = current_fiq;
		current_fiq = f;
	}

	return ret;
}

void release_fiq(struct fiq_handler *f)
{
	if (current_fiq != f) {
		printk(KERN_ERR "%s FIQ trying to release %s FIQ\n",
		       f->name, current_fiq->name);
		dump_stack();
		return;
	}

	do
		current_fiq = current_fiq->next;
	while (current_fiq->fiq_op(current_fiq->dev_id, 0));
}

void enable_fiq(int fiq)
{
	enable_irq(fiq + FIQ_START);
}

void disable_fiq(int fiq)
{
	disable_irq(fiq + FIQ_START);
}

EXPORT_SYMBOL(set_fiq_handler);
EXPORT_SYMBOL(set_fiq_regs);
EXPORT_SYMBOL(get_fiq_regs);
EXPORT_SYMBOL(claim_fiq);
EXPORT_SYMBOL(release_fiq);
EXPORT_SYMBOL(enable_fiq);
EXPORT_SYMBOL(disable_fiq);

void __init init_FIQ(void)
{
	no_fiq_insn = *(unsigned long *)0xffff001c;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/arch/arm/kernel/fiq.c
	3	*
	4	* Copyright (C) 1998 Russell King
	5	* Copyright (C) 1998, 1999 Phil Blundell
	6	*
	7	* FIQ support written by Philip Blundell <philb@gnu.org>, 1998.
	8	*
	9	* FIQ support re-written by Russell King to be more generic
	10	*
	11	* We now properly support a method by which the FIQ handlers can
	12	* be stacked onto the vector. We still do not support sharing
	13	* the FIQ vector itself.
	14	*
	15	* Operation is as follows:
	16	* 1. Owner A claims FIQ:
	17	* - default_fiq relinquishes control.
	18	* 2. Owner A:
	19	* - inserts code.
	20	* - sets any registers,
	21	* - enables FIQ.
	22	* 3. Owner B claims FIQ:
	23	* - if owner A has a relinquish function.
	24	* - disable FIQs.
	25	* - saves any registers.
	26	* - returns zero.
	27	* 4. Owner B:
	28	* - inserts code.
	29	* - sets any registers,
	30	* - enables FIQ.
	31	* 5. Owner B releases FIQ:
	32	* - Owner A is asked to reacquire FIQ:
	33	* - inserts code.
	34	* - restores saved registers.
	35	* - enables FIQ.
	36	* 6. Goto 3
	37	*/
	38	#include <linux/module.h>
	39	#include <linux/kernel.h>
	40	#include <linux/init.h>
4a2581a0	41	#include <linux/interrupt.h>
1da177e4 LT	42	#include <linux/seq_file.h>
	43
	44	#include <asm/cacheflush.h>
	45	#include <asm/fiq.h>
	46	#include <asm/irq.h>
	47	#include <asm/system.h>
247055aa	48	#include <asm/traps.h>
1da177e4 LT	49
	50	static unsigned long no_fiq_insn;
	51
	52	/* Default reacquire function
	53	* - we always relinquish FIQ control
	54	* - we always reacquire FIQ control
	55	*/
	56	static int fiq_def_op(void *ref, int relinquish)
	57	{
	58	if (!relinquish)
	59	set_fiq_handler(&no_fiq_insn, sizeof(no_fiq_insn));
	60
	61	return 0;
	62	}
	63
	64	static struct fiq_handler default_owner = {
	65	.name = "default",
	66	.fiq_op = fiq_def_op,
	67	};
	68
	69	static struct fiq_handler *current_fiq = &default_owner;
	70
f13cd417	71	int show_fiq_list(struct seq_file *p, int prec)
1da177e4 LT	72	{
1da177e4 LT	73	if (current_fiq != &default_owner)
f13cd417 RK	74	seq_printf(p, "%*s: %s\n", prec, "FIQ",
f13cd417 RK	75	current_fiq->name);
1da177e4 LT	76
	77	return 0;
	78	}
	79
	80	void set_fiq_handler(void *start, unsigned int length)
	81	{
247055aa	82	#if defined(CONFIG_CPU_USE_DOMAINS)
1da177e4	83	memcpy((void *)0xffff001c, start, length);
247055aa CM	84	#else
	85	memcpy(vectors_page + 0x1c, start, length);
	86	#endif
1da177e4 LT	87	flush_icache_range(0xffff001c, 0xffff001c + length);
	88	if (!vectors_high())
	89	flush_icache_range(0x1c, 0x1c + length);
	90	}
	91
	92	/*
	93	* Taking an interrupt in FIQ mode is death, so both these functions
	94	* disable irqs for the duration. Note - these functions are almost
	95	* entirely coded in assembly.
	96	*/
446c92b2	97	void __naked set_fiq_regs(struct pt_regs *regs)
1da177e4 LT	98	{
	99	register unsigned long tmp;
	100	asm volatile (
	101	"mov ip, sp\n\
	102	stmfd sp!, {fp, ip, lr, pc}\n\
	103	sub fp, ip, #4\n\
	104	mrs %0, cpsr\n\
	105	msr cpsr_c, %2 @ select FIQ mode\n\
	106	mov r0, r0\n\
	107	ldmia %1, {r8 - r14}\n\
	108	msr cpsr_c, %0 @ return to SVC mode\n\
	109	mov r0, r0\n\
90303b10	110	ldmfd sp, {fp, sp, pc}"
1da177e4 LT	111	: "=&r" (tmp)
	112	: "r" (&regs->ARM_r8), "I" (PSR_I_BIT \| PSR_F_BIT \| FIQ_MODE));
	113	}
	114
446c92b2	115	void __naked get_fiq_regs(struct pt_regs *regs)
1da177e4 LT	116	{
	117	register unsigned long tmp;
	118	asm volatile (
	119	"mov ip, sp\n\
	120	stmfd sp!, {fp, ip, lr, pc}\n\
	121	sub fp, ip, #4\n\
	122	mrs %0, cpsr\n\
	123	msr cpsr_c, %2 @ select FIQ mode\n\
	124	mov r0, r0\n\
	125	stmia %1, {r8 - r14}\n\
	126	msr cpsr_c, %0 @ return to SVC mode\n\
	127	mov r0, r0\n\
90303b10	128	ldmfd sp, {fp, sp, pc}"
1da177e4 LT	129	: "=&r" (tmp)
	130	: "r" (&regs->ARM_r8), "I" (PSR_I_BIT \| PSR_F_BIT \| FIQ_MODE));
	131	}
	132
	133	int claim_fiq(struct fiq_handler *f)
	134	{
	135	int ret = 0;
	136
	137	if (current_fiq) {
	138	ret = -EBUSY;
	139
	140	if (current_fiq->fiq_op != NULL)
	141	ret = current_fiq->fiq_op(current_fiq->dev_id, 1);
	142	}
	143
	144	if (!ret) {
	145	f->next = current_fiq;
	146	current_fiq = f;
	147	}
	148
	149	return ret;
	150	}
	151
	152	void release_fiq(struct fiq_handler *f)
	153	{
	154	if (current_fiq != f) {
	155	printk(KERN_ERR "%s FIQ trying to release %s FIQ\n",
	156	f->name, current_fiq->name);
	157	dump_stack();
	158	return;
	159	}
	160
	161	do
	162	current_fiq = current_fiq->next;
	163	while (current_fiq->fiq_op(current_fiq->dev_id, 0));
	164	}
	165
	166	void enable_fiq(int fiq)
	167	{
	168	enable_irq(fiq + FIQ_START);
	169	}
	170
	171	void disable_fiq(int fiq)
	172	{
	173	disable_irq(fiq + FIQ_START);
	174	}
	175
	176	EXPORT_SYMBOL(set_fiq_handler);
	177	EXPORT_SYMBOL(set_fiq_regs);
	178	EXPORT_SYMBOL(get_fiq_regs);
	179	EXPORT_SYMBOL(claim_fiq);
	180	EXPORT_SYMBOL(release_fiq);
	181	EXPORT_SYMBOL(enable_fiq);
	182	EXPORT_SYMBOL(disable_fiq);
	183
	184	void __init init_FIQ(void)
	185	{
	186	no_fiq_insn = (unsigned long )0xffff001c;
	187	}