2 * linux/arch/arm/kernel/fiq.c
4 * Copyright (C) 1998 Russell King
5 * Copyright (C) 1998, 1999 Phil Blundell
7 * FIQ support written by Philip Blundell <philb@gnu.org>, 1998.
9 * FIQ support re-written by Russell King to be more generic
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.
15 * Operation is as follows:
16 * 1. Owner A claims FIQ:
17 * - default_fiq relinquishes control.
20 * - sets any registers,
22 * 3. Owner B claims FIQ:
23 * - if owner A has a relinquish function.
25 * - saves any registers.
29 * - sets any registers,
31 * 5. Owner B releases FIQ:
32 * - Owner A is asked to reacquire FIQ:
34 * - restores saved registers.
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>
44 #include <asm/cacheflush.h>
47 #include <asm/system.h>
48 #include <asm/traps.h>
50 static unsigned long no_fiq_insn;
52 /* Default reacquire function
53 * - we always relinquish FIQ control
54 * - we always reacquire FIQ control
56 static int fiq_def_op(void *ref, int relinquish)
59 set_fiq_handler(&no_fiq_insn, sizeof(no_fiq_insn));
64 static struct fiq_handler default_owner = {
69 static struct fiq_handler *current_fiq = &default_owner;
71 int show_fiq_list(struct seq_file *p, int prec)
73 if (current_fiq != &default_owner)
74 seq_printf(p, "%*s: %s\n", prec, "FIQ",
80 void set_fiq_handler(void *start, unsigned int length)
82 #if defined(CONFIG_CPU_USE_DOMAINS)
83 memcpy((void *)0xffff001c, start, length);
85 memcpy(vectors_page + 0x1c, start, length);
87 flush_icache_range(0xffff001c, 0xffff001c + length);
89 flush_icache_range(0x1c, 0x1c + length);
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.
97 void __naked set_fiq_regs(struct pt_regs *regs)
99 register unsigned long tmp;
102 stmfd sp!, {fp, ip, lr, pc}\n\
105 msr cpsr_c, %2 @ select FIQ mode\n\
107 ldmia %1, {r8 - r14}\n\
108 msr cpsr_c, %0 @ return to SVC mode\n\
110 ldmfd sp, {fp, sp, pc}"
112 : "r" (®s->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | FIQ_MODE));
115 void __naked get_fiq_regs(struct pt_regs *regs)
117 register unsigned long tmp;
120 stmfd sp!, {fp, ip, lr, pc}\n\
123 msr cpsr_c, %2 @ select FIQ mode\n\
125 stmia %1, {r8 - r14}\n\
126 msr cpsr_c, %0 @ return to SVC mode\n\
128 ldmfd sp, {fp, sp, pc}"
130 : "r" (®s->ARM_r8), "I" (PSR_I_BIT | PSR_F_BIT | FIQ_MODE));
133 int claim_fiq(struct fiq_handler *f)
140 if (current_fiq->fiq_op != NULL)
141 ret = current_fiq->fiq_op(current_fiq->dev_id, 1);
145 f->next = current_fiq;
152 void release_fiq(struct fiq_handler *f)
154 if (current_fiq != f) {
155 printk(KERN_ERR "%s FIQ trying to release %s FIQ\n",
156 f->name, current_fiq->name);
162 current_fiq = current_fiq->next;
163 while (current_fiq->fiq_op(current_fiq->dev_id, 0));
166 void enable_fiq(int fiq)
168 enable_irq(fiq + FIQ_START);
171 void disable_fiq(int fiq)
173 disable_irq(fiq + FIQ_START);
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);
184 void __init init_FIQ(void)
186 no_fiq_insn = *(unsigned long *)0xffff001c;