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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> | |
15d07dc9 | 45 | #include <asm/cp15.h> |
1da177e4 LT |
46 | #include <asm/fiq.h> |
47 | #include <asm/irq.h> | |
247055aa | 48 | #include <asm/traps.h> |
1da177e4 | 49 | |
e39e3f3e RK |
50 | #define FIQ_OFFSET ({ \ |
51 | extern void *vector_fiq_offset; \ | |
52 | (unsigned)&vector_fiq_offset; \ | |
53 | }) | |
54 | ||
c0e7f7ee DT |
55 | static unsigned long dfl_fiq_insn; |
56 | static struct pt_regs dfl_fiq_regs; | |
1da177e4 LT |
57 | |
58 | /* Default reacquire function | |
59 | * - we always relinquish FIQ control | |
60 | * - we always reacquire FIQ control | |
61 | */ | |
62 | static int fiq_def_op(void *ref, int relinquish) | |
63 | { | |
c0e7f7ee DT |
64 | if (!relinquish) { |
65 | /* Restore default handler and registers */ | |
66 | local_fiq_disable(); | |
67 | set_fiq_regs(&dfl_fiq_regs); | |
68 | set_fiq_handler(&dfl_fiq_insn, sizeof(dfl_fiq_insn)); | |
69 | local_fiq_enable(); | |
70 | ||
71 | /* FIXME: notify irq controller to standard enable FIQs */ | |
72 | } | |
1da177e4 LT |
73 | |
74 | return 0; | |
75 | } | |
76 | ||
77 | static struct fiq_handler default_owner = { | |
78 | .name = "default", | |
79 | .fiq_op = fiq_def_op, | |
80 | }; | |
81 | ||
82 | static struct fiq_handler *current_fiq = &default_owner; | |
83 | ||
f13cd417 | 84 | int show_fiq_list(struct seq_file *p, int prec) |
1da177e4 LT |
85 | { |
86 | if (current_fiq != &default_owner) | |
f13cd417 RK |
87 | seq_printf(p, "%*s: %s\n", prec, "FIQ", |
88 | current_fiq->name); | |
1da177e4 LT |
89 | |
90 | return 0; | |
91 | } | |
92 | ||
93 | void set_fiq_handler(void *start, unsigned int length) | |
94 | { | |
e39e3f3e | 95 | void *base = vectors_page; |
e39e3f3e RK |
96 | unsigned offset = FIQ_OFFSET; |
97 | ||
98 | memcpy(base + offset, start, length); | |
2ba85e7a | 99 | if (!cache_is_vipt_nonaliasing()) |
7cb3be0a FE |
100 | flush_icache_range((unsigned long)base + offset, offset + |
101 | length); | |
e39e3f3e | 102 | flush_icache_range(0xffff0000 + offset, 0xffff0000 + offset + length); |
1da177e4 LT |
103 | } |
104 | ||
1da177e4 LT |
105 | int claim_fiq(struct fiq_handler *f) |
106 | { | |
107 | int ret = 0; | |
108 | ||
109 | if (current_fiq) { | |
110 | ret = -EBUSY; | |
111 | ||
112 | if (current_fiq->fiq_op != NULL) | |
113 | ret = current_fiq->fiq_op(current_fiq->dev_id, 1); | |
114 | } | |
115 | ||
116 | if (!ret) { | |
117 | f->next = current_fiq; | |
118 | current_fiq = f; | |
119 | } | |
120 | ||
121 | return ret; | |
122 | } | |
123 | ||
124 | void release_fiq(struct fiq_handler *f) | |
125 | { | |
126 | if (current_fiq != f) { | |
4ed89f22 | 127 | pr_err("%s FIQ trying to release %s FIQ\n", |
1da177e4 LT |
128 | f->name, current_fiq->name); |
129 | dump_stack(); | |
130 | return; | |
131 | } | |
132 | ||
133 | do | |
134 | current_fiq = current_fiq->next; | |
135 | while (current_fiq->fiq_op(current_fiq->dev_id, 0)); | |
136 | } | |
137 | ||
bc89663a SG |
138 | static int fiq_start; |
139 | ||
1da177e4 LT |
140 | void enable_fiq(int fiq) |
141 | { | |
bc89663a | 142 | enable_irq(fiq + fiq_start); |
1da177e4 LT |
143 | } |
144 | ||
145 | void disable_fiq(int fiq) | |
146 | { | |
bc89663a | 147 | disable_irq(fiq + fiq_start); |
1da177e4 LT |
148 | } |
149 | ||
150 | EXPORT_SYMBOL(set_fiq_handler); | |
dc2eb928 DM |
151 | EXPORT_SYMBOL(__set_fiq_regs); /* defined in fiqasm.S */ |
152 | EXPORT_SYMBOL(__get_fiq_regs); /* defined in fiqasm.S */ | |
1da177e4 LT |
153 | EXPORT_SYMBOL(claim_fiq); |
154 | EXPORT_SYMBOL(release_fiq); | |
155 | EXPORT_SYMBOL(enable_fiq); | |
156 | EXPORT_SYMBOL(disable_fiq); | |
157 | ||
bc89663a | 158 | void __init init_FIQ(int start) |
1da177e4 | 159 | { |
e39e3f3e | 160 | unsigned offset = FIQ_OFFSET; |
c0e7f7ee DT |
161 | dfl_fiq_insn = *(unsigned long *)(0xffff0000 + offset); |
162 | get_fiq_regs(&dfl_fiq_regs); | |
bc89663a | 163 | fiq_start = start; |
1da177e4 | 164 | } |