Greg Kroah-Hartman | b244131 | 2017-11-01 15:07:57 +0100 | [diff] [blame] | 1 | // SPDX-License-Identifier: GPL-2.0 |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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> |
Thomas Gleixner | 4a2581a | 2006-07-01 22:30:09 +0100 | [diff] [blame] | 42 | #include <linux/interrupt.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 43 | #include <linux/seq_file.h> |
| 44 | |
| 45 | #include <asm/cacheflush.h> |
Russell King | 15d07dc | 2012-03-28 18:30:01 +0100 | [diff] [blame] | 46 | #include <asm/cp15.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 47 | #include <asm/fiq.h> |
| 48 | #include <asm/irq.h> |
Catalin Marinas | 247055a | 2010-09-13 16:03:21 +0100 | [diff] [blame] | 49 | #include <asm/traps.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 50 | |
Russell King | e39e3f3 | 2013-07-09 01:03:17 +0100 | [diff] [blame] | 51 | #define FIQ_OFFSET ({ \ |
| 52 | extern void *vector_fiq_offset; \ |
| 53 | (unsigned)&vector_fiq_offset; \ |
| 54 | }) |
| 55 | |
Daniel Thompson | c0e7f7e | 2014-09-17 17:12:06 +0100 | [diff] [blame] | 56 | static unsigned long dfl_fiq_insn; |
| 57 | static struct pt_regs dfl_fiq_regs; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 58 | |
| 59 | /* Default reacquire function |
| 60 | * - we always relinquish FIQ control |
| 61 | * - we always reacquire FIQ control |
| 62 | */ |
| 63 | static int fiq_def_op(void *ref, int relinquish) |
| 64 | { |
Daniel Thompson | c0e7f7e | 2014-09-17 17:12:06 +0100 | [diff] [blame] | 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 | } |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 74 | |
| 75 | return 0; |
| 76 | } |
| 77 | |
| 78 | static struct fiq_handler default_owner = { |
| 79 | .name = "default", |
| 80 | .fiq_op = fiq_def_op, |
| 81 | }; |
| 82 | |
| 83 | static struct fiq_handler *current_fiq = &default_owner; |
| 84 | |
Russell King | f13cd41 | 2010-11-15 14:33:51 +0000 | [diff] [blame] | 85 | int show_fiq_list(struct seq_file *p, int prec) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 86 | { |
| 87 | if (current_fiq != &default_owner) |
Russell King | f13cd41 | 2010-11-15 14:33:51 +0000 | [diff] [blame] | 88 | seq_printf(p, "%*s: %s\n", prec, "FIQ", |
| 89 | current_fiq->name); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 90 | |
| 91 | return 0; |
| 92 | } |
| 93 | |
| 94 | void set_fiq_handler(void *start, unsigned int length) |
| 95 | { |
Russell King | e39e3f3 | 2013-07-09 01:03:17 +0100 | [diff] [blame] | 96 | void *base = vectors_page; |
Russell King | e39e3f3 | 2013-07-09 01:03:17 +0100 | [diff] [blame] | 97 | unsigned offset = FIQ_OFFSET; |
| 98 | |
| 99 | memcpy(base + offset, start, length); |
Russell King | 2ba85e7 | 2013-08-08 11:51:21 +0100 | [diff] [blame] | 100 | if (!cache_is_vipt_nonaliasing()) |
Fabio Estevam | 7cb3be0 | 2013-08-16 12:55:56 +0100 | [diff] [blame] | 101 | flush_icache_range((unsigned long)base + offset, offset + |
| 102 | length); |
Russell King | e39e3f3 | 2013-07-09 01:03:17 +0100 | [diff] [blame] | 103 | flush_icache_range(0xffff0000 + offset, 0xffff0000 + offset + length); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 104 | } |
| 105 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 106 | int 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 | |
| 125 | void release_fiq(struct fiq_handler *f) |
| 126 | { |
| 127 | if (current_fiq != f) { |
Russell King | 4ed89f2228 | 2014-10-28 11:26:42 +0000 | [diff] [blame] | 128 | pr_err("%s FIQ trying to release %s FIQ\n", |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 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 | |
Shawn Guo | bc89663 | 2012-06-28 14:42:08 +0800 | [diff] [blame] | 139 | static int fiq_start; |
| 140 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 141 | void enable_fiq(int fiq) |
| 142 | { |
Shawn Guo | bc89663 | 2012-06-28 14:42:08 +0800 | [diff] [blame] | 143 | enable_irq(fiq + fiq_start); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 144 | } |
| 145 | |
| 146 | void disable_fiq(int fiq) |
| 147 | { |
Shawn Guo | bc89663 | 2012-06-28 14:42:08 +0800 | [diff] [blame] | 148 | disable_irq(fiq + fiq_start); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | } |
| 150 | |
| 151 | EXPORT_SYMBOL(set_fiq_handler); |
Dave Martin | dc2eb92 | 2011-05-23 12:22:10 +0100 | [diff] [blame] | 152 | EXPORT_SYMBOL(__set_fiq_regs); /* defined in fiqasm.S */ |
| 153 | EXPORT_SYMBOL(__get_fiq_regs); /* defined in fiqasm.S */ |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 154 | EXPORT_SYMBOL(claim_fiq); |
| 155 | EXPORT_SYMBOL(release_fiq); |
| 156 | EXPORT_SYMBOL(enable_fiq); |
| 157 | EXPORT_SYMBOL(disable_fiq); |
| 158 | |
Shawn Guo | bc89663 | 2012-06-28 14:42:08 +0800 | [diff] [blame] | 159 | void __init init_FIQ(int start) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 160 | { |
Russell King | e39e3f3 | 2013-07-09 01:03:17 +0100 | [diff] [blame] | 161 | unsigned offset = FIQ_OFFSET; |
Daniel Thompson | c0e7f7e | 2014-09-17 17:12:06 +0100 | [diff] [blame] | 162 | dfl_fiq_insn = *(unsigned long *)(0xffff0000 + offset); |
| 163 | get_fiq_regs(&dfl_fiq_regs); |
Shawn Guo | bc89663 | 2012-06-28 14:42:08 +0800 | [diff] [blame] | 164 | fiq_start = start; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 165 | } |