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>
 41#include <linux/interrupt.h>
 42#include <linux/seq_file.h>
 43
 44#include <asm/cacheflush.h>
 45#include <asm/cp15.h>
 46#include <asm/fiq.h>
 47#include <asm/irq.h>
 48#include <asm/traps.h>
 49
 50static unsigned long no_fiq_insn;
 
 
 
 
 
 
 51
 52/* Default reacquire function
 53 * - we always relinquish FIQ control
 54 * - we always reacquire FIQ control
 55 */
 56static 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
 64static struct fiq_handler default_owner = {
 65	.name	= "default",
 66	.fiq_op = fiq_def_op,
 67};
 68
 69static struct fiq_handler *current_fiq = &default_owner;
 70
 71int show_fiq_list(struct seq_file *p, int prec)
 72{
 73	if (current_fiq != &default_owner)
 74		seq_printf(p, "%*s:              %s\n", prec, "FIQ",
 75			current_fiq->name);
 76
 77	return 0;
 78}
 79
 80void set_fiq_handler(void *start, unsigned int length)
 81{
 82#if defined(CONFIG_CPU_USE_DOMAINS)
 83	memcpy((void *)0xffff001c, start, length);
 84#else
 85	memcpy(vectors_page + 0x1c, start, length);
 86#endif
 87	flush_icache_range(0xffff001c, 0xffff001c + length);
 88	if (!vectors_high())
 89		flush_icache_range(0x1c, 0x1c + length);
 90}
 91
 92int claim_fiq(struct fiq_handler *f)
 93{
 94	int ret = 0;
 95
 96	if (current_fiq) {
 97		ret = -EBUSY;
 98
 99		if (current_fiq->fiq_op != NULL)
100			ret = current_fiq->fiq_op(current_fiq->dev_id, 1);
101	}
102
103	if (!ret) {
104		f->next = current_fiq;
105		current_fiq = f;
106	}
107
108	return ret;
109}
110
111void release_fiq(struct fiq_handler *f)
112{
113	if (current_fiq != f) {
114		printk(KERN_ERR "%s FIQ trying to release %s FIQ\n",
115		       f->name, current_fiq->name);
116		dump_stack();
117		return;
118	}
119
120	do
121		current_fiq = current_fiq->next;
122	while (current_fiq->fiq_op(current_fiq->dev_id, 0));
123}
124
 
 
125void enable_fiq(int fiq)
126{
127	enable_irq(fiq + FIQ_START);
128}
129
130void disable_fiq(int fiq)
131{
132	disable_irq(fiq + FIQ_START);
133}
134
135EXPORT_SYMBOL(set_fiq_handler);
136EXPORT_SYMBOL(__set_fiq_regs);	/* defined in fiqasm.S */
137EXPORT_SYMBOL(__get_fiq_regs);	/* defined in fiqasm.S */
138EXPORT_SYMBOL(claim_fiq);
139EXPORT_SYMBOL(release_fiq);
140EXPORT_SYMBOL(enable_fiq);
141EXPORT_SYMBOL(disable_fiq);
142
143void __init init_FIQ(void)
144{
145	no_fiq_insn = *(unsigned long *)0xffff001c;
 
 
 
146}

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 *  linux/arch/arm/kernel/fiq.c
  4 *
  5 *  Copyright (C) 1998 Russell King
  6 *  Copyright (C) 1998, 1999 Phil Blundell
  7 *
  8 *  FIQ support written by Philip Blundell <philb@gnu.org>, 1998.
  9 *
 10 *  FIQ support re-written by Russell King to be more generic
 11 *
 12 * We now properly support a method by which the FIQ handlers can
 13 * be stacked onto the vector.  We still do not support sharing
 14 * the FIQ vector itself.
 15 *
 16 * Operation is as follows:
 17 *  1. Owner A claims FIQ:
 18 *     - default_fiq relinquishes control.
 19 *  2. Owner A:
 20 *     - inserts code.
 21 *     - sets any registers,
 22 *     - enables FIQ.
 23 *  3. Owner B claims FIQ:
 24 *     - if owner A has a relinquish function.
 25 *       - disable FIQs.
 26 *       - saves any registers.
 27 *       - returns zero.
 28 *  4. Owner B:
 29 *     - inserts code.
 30 *     - sets any registers,
 31 *     - enables FIQ.
 32 *  5. Owner B releases FIQ:
 33 *     - Owner A is asked to reacquire FIQ:
 34 *	 - inserts code.
 35 *	 - restores saved registers.
 36 *	 - enables FIQ.
 37 *  6. Goto 3
 38 */
 39#include <linux/module.h>
 40#include <linux/kernel.h>
 41#include <linux/init.h>
 42#include <linux/interrupt.h>
 43#include <linux/seq_file.h>
 44
 45#include <asm/cacheflush.h>
 46#include <asm/cp15.h>
 47#include <asm/fiq.h>
 48#include <asm/irq.h>
 49#include <asm/traps.h>
 50
 51#define FIQ_OFFSET ({					\
 52		extern void *vector_fiq_offset;		\
 53		(unsigned)&vector_fiq_offset;		\
 54	})
 55
 56static unsigned long dfl_fiq_insn;
 57static struct pt_regs dfl_fiq_regs;
 58
 59/* Default reacquire function
 60 * - we always relinquish FIQ control
 61 * - we always reacquire FIQ control
 62 */
 63static int fiq_def_op(void *ref, int relinquish)
 64{
 65	if (!relinquish) {
 66		/* Restore default handler and registers */
 67		local_fiq_disable();
 68		set_fiq_regs(&dfl_fiq_regs);
 69		set_fiq_handler(&dfl_fiq_insn, sizeof(dfl_fiq_insn));
 70		local_fiq_enable();
 71
 72		/* FIXME: notify irq controller to standard enable FIQs */
 73	}
 74
 75	return 0;
 76}
 77
 78static struct fiq_handler default_owner = {
 79	.name	= "default",
 80	.fiq_op = fiq_def_op,
 81};
 82
 83static struct fiq_handler *current_fiq = &default_owner;
 84
 85int show_fiq_list(struct seq_file *p, int prec)
 86{
 87	if (current_fiq != &default_owner)
 88		seq_printf(p, "%*s:              %s\n", prec, "FIQ",
 89			current_fiq->name);
 90
 91	return 0;
 92}
 93
 94void set_fiq_handler(void *start, unsigned int length)
 95{
 96	void *base = vectors_page;
 97	unsigned offset = FIQ_OFFSET;
 98
 99	memcpy(base + offset, start, length);
100	if (!cache_is_vipt_nonaliasing())
101		flush_icache_range((unsigned long)base + offset,
102				   (unsigned long)base + offset + length);
103	flush_icache_range(0xffff0000 + offset, 0xffff0000 + offset + length);
104}
105
106int claim_fiq(struct fiq_handler *f)
107{
108	int ret = 0;
109
110	if (current_fiq) {
111		ret = -EBUSY;
112
113		if (current_fiq->fiq_op != NULL)
114			ret = current_fiq->fiq_op(current_fiq->dev_id, 1);
115	}
116
117	if (!ret) {
118		f->next = current_fiq;
119		current_fiq = f;
120	}
121
122	return ret;
123}
124
125void release_fiq(struct fiq_handler *f)
126{
127	if (current_fiq != f) {
128		pr_err("%s FIQ trying to release %s FIQ\n",
129		       f->name, current_fiq->name);
130		dump_stack();
131		return;
132	}
133
134	do
135		current_fiq = current_fiq->next;
136	while (current_fiq->fiq_op(current_fiq->dev_id, 0));
137}
138
139static int fiq_start;
140
141void enable_fiq(int fiq)
142{
143	enable_irq(fiq + fiq_start);
144}
145
146void disable_fiq(int fiq)
147{
148	disable_irq(fiq + fiq_start);
149}
150
151EXPORT_SYMBOL(set_fiq_handler);
152EXPORT_SYMBOL(__set_fiq_regs);	/* defined in fiqasm.S */
153EXPORT_SYMBOL(__get_fiq_regs);	/* defined in fiqasm.S */
154EXPORT_SYMBOL(claim_fiq);
155EXPORT_SYMBOL(release_fiq);
156EXPORT_SYMBOL(enable_fiq);
157EXPORT_SYMBOL(disable_fiq);
158
159void __init init_FIQ(int start)
160{
161	unsigned offset = FIQ_OFFSET;
162	dfl_fiq_insn = *(unsigned long *)(0xffff0000 + offset);
163	get_fiq_regs(&dfl_fiq_regs);
164	fiq_start = start;
165}