blob: cd1234c103fcdd7c85fbb7862d05a01dd1734c5e [file] [log] [blame]
Greg Kroah-Hartmanb2441312017-11-01 15:07:57 +01001// SPDX-License-Identifier: GPL-2.0
Linus Torvalds1da177e2005-04-16 15:20:36 -07002/*
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>
Thomas Gleixner4a2581a2006-07-01 22:30:09 +010042#include <linux/interrupt.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#include <linux/seq_file.h>
44
45#include <asm/cacheflush.h>
Russell King15d07dc2012-03-28 18:30:01 +010046#include <asm/cp15.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070047#include <asm/fiq.h>
48#include <asm/irq.h>
Catalin Marinas247055a2010-09-13 16:03:21 +010049#include <asm/traps.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070050
Russell Kinge39e3f32013-07-09 01:03:17 +010051#define FIQ_OFFSET ({ \
52 extern void *vector_fiq_offset; \
53 (unsigned)&vector_fiq_offset; \
54 })
55
Daniel Thompsonc0e7f7e2014-09-17 17:12:06 +010056static unsigned long dfl_fiq_insn;
57static struct pt_regs dfl_fiq_regs;
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
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{
Daniel Thompsonc0e7f7e2014-09-17 17:12:06 +010065 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 }
Linus Torvalds1da177e2005-04-16 15:20:36 -070074
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
Russell Kingf13cd412010-11-15 14:33:51 +000085int show_fiq_list(struct seq_file *p, int prec)
Linus Torvalds1da177e2005-04-16 15:20:36 -070086{
87 if (current_fiq != &default_owner)
Russell Kingf13cd412010-11-15 14:33:51 +000088 seq_printf(p, "%*s: %s\n", prec, "FIQ",
89 current_fiq->name);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090
91 return 0;
92}
93
94void set_fiq_handler(void *start, unsigned int length)
95{
Russell Kinge39e3f32013-07-09 01:03:17 +010096 void *base = vectors_page;
Russell Kinge39e3f32013-07-09 01:03:17 +010097 unsigned offset = FIQ_OFFSET;
98
99 memcpy(base + offset, start, length);
Russell King2ba85e72013-08-08 11:51:21 +0100100 if (!cache_is_vipt_nonaliasing())
Fabio Estevam7cb3be02013-08-16 12:55:56 +0100101 flush_icache_range((unsigned long)base + offset, offset +
102 length);
Russell Kinge39e3f32013-07-09 01:03:17 +0100103 flush_icache_range(0xffff0000 + offset, 0xffff0000 + offset + length);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104}
105
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106int 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) {
Russell King4ed89f22282014-10-28 11:26:42 +0000128 pr_err("%s FIQ trying to release %s FIQ\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700129 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
Shawn Guobc896632012-06-28 14:42:08 +0800139static int fiq_start;
140
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141void enable_fiq(int fiq)
142{
Shawn Guobc896632012-06-28 14:42:08 +0800143 enable_irq(fiq + fiq_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144}
145
146void disable_fiq(int fiq)
147{
Shawn Guobc896632012-06-28 14:42:08 +0800148 disable_irq(fiq + fiq_start);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700149}
150
151EXPORT_SYMBOL(set_fiq_handler);
Dave Martindc2eb922011-05-23 12:22:10 +0100152EXPORT_SYMBOL(__set_fiq_regs); /* defined in fiqasm.S */
153EXPORT_SYMBOL(__get_fiq_regs); /* defined in fiqasm.S */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154EXPORT_SYMBOL(claim_fiq);
155EXPORT_SYMBOL(release_fiq);
156EXPORT_SYMBOL(enable_fiq);
157EXPORT_SYMBOL(disable_fiq);
158
Shawn Guobc896632012-06-28 14:42:08 +0800159void __init init_FIQ(int start)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700160{
Russell Kinge39e3f32013-07-09 01:03:17 +0100161 unsigned offset = FIQ_OFFSET;
Daniel Thompsonc0e7f7e2014-09-17 17:12:06 +0100162 dfl_fiq_insn = *(unsigned long *)(0xffff0000 + offset);
163 get_fiq_regs(&dfl_fiq_regs);
Shawn Guobc896632012-06-28 14:42:08 +0800164 fiq_start = start;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700165}