Arve Hjønnevåg | 8a05267 | 2010-09-27 17:50:00 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2010 Google, Inc. |
| 3 | * |
| 4 | * This software is licensed under the terms of the GNU General Public |
| 5 | * License version 2, as published by the Free Software Foundation, and |
| 6 | * may be copied, distributed, and modified under those terms. |
| 7 | * |
| 8 | * This program is distributed in the hope that it will be useful, |
| 9 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 10 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 11 | * GNU General Public License for more details. |
| 12 | */ |
| 13 | |
| 14 | #include <linux/kernel.h> |
| 15 | #include <linux/percpu.h> |
| 16 | #include <linux/slab.h> |
| 17 | #include <asm/fiq.h> |
| 18 | #include <asm/fiq_glue.h> |
| 19 | |
| 20 | extern unsigned char fiq_glue, fiq_glue_end; |
Arve Hjønnevåg | 6c0dda2 | 2013-06-24 18:02:05 -0700 | [diff] [blame] | 21 | extern void fiq_glue_setup(void *func, void *data, void *sp, |
| 22 | fiq_return_handler_t fiq_return_handler); |
Arve Hjønnevåg | 8a05267 | 2010-09-27 17:50:00 -0700 | [diff] [blame] | 23 | |
| 24 | static struct fiq_handler fiq_debbuger_fiq_handler = { |
| 25 | .name = "fiq_glue", |
| 26 | }; |
| 27 | DEFINE_PER_CPU(void *, fiq_stack); |
| 28 | static struct fiq_glue_handler *current_handler; |
Arve Hjønnevåg | 6c0dda2 | 2013-06-24 18:02:05 -0700 | [diff] [blame] | 29 | static fiq_return_handler_t fiq_return_handler; |
Arve Hjønnevåg | 8a05267 | 2010-09-27 17:50:00 -0700 | [diff] [blame] | 30 | static DEFINE_MUTEX(fiq_glue_lock); |
| 31 | |
| 32 | static void fiq_glue_setup_helper(void *info) |
| 33 | { |
| 34 | struct fiq_glue_handler *handler = info; |
| 35 | fiq_glue_setup(handler->fiq, handler, |
Arve Hjønnevåg | 6c0dda2 | 2013-06-24 18:02:05 -0700 | [diff] [blame] | 36 | __get_cpu_var(fiq_stack) + THREAD_START_SP, |
| 37 | fiq_return_handler); |
Arve Hjønnevåg | 8a05267 | 2010-09-27 17:50:00 -0700 | [diff] [blame] | 38 | } |
| 39 | |
| 40 | int fiq_glue_register_handler(struct fiq_glue_handler *handler) |
| 41 | { |
| 42 | int ret; |
| 43 | int cpu; |
| 44 | |
| 45 | if (!handler || !handler->fiq) |
| 46 | return -EINVAL; |
| 47 | |
| 48 | mutex_lock(&fiq_glue_lock); |
| 49 | if (fiq_stack) { |
| 50 | ret = -EBUSY; |
| 51 | goto err_busy; |
| 52 | } |
| 53 | |
| 54 | for_each_possible_cpu(cpu) { |
| 55 | void *stack; |
| 56 | stack = (void *)__get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER); |
| 57 | if (WARN_ON(!stack)) { |
| 58 | ret = -ENOMEM; |
| 59 | goto err_alloc_fiq_stack; |
| 60 | } |
| 61 | per_cpu(fiq_stack, cpu) = stack; |
| 62 | } |
| 63 | |
| 64 | ret = claim_fiq(&fiq_debbuger_fiq_handler); |
| 65 | if (WARN_ON(ret)) |
| 66 | goto err_claim_fiq; |
| 67 | |
| 68 | current_handler = handler; |
| 69 | on_each_cpu(fiq_glue_setup_helper, handler, true); |
| 70 | set_fiq_handler(&fiq_glue, &fiq_glue_end - &fiq_glue); |
| 71 | |
| 72 | mutex_unlock(&fiq_glue_lock); |
| 73 | return 0; |
| 74 | |
| 75 | err_claim_fiq: |
| 76 | err_alloc_fiq_stack: |
| 77 | for_each_possible_cpu(cpu) { |
| 78 | __free_pages(per_cpu(fiq_stack, cpu), THREAD_SIZE_ORDER); |
| 79 | per_cpu(fiq_stack, cpu) = NULL; |
| 80 | } |
| 81 | err_busy: |
| 82 | mutex_unlock(&fiq_glue_lock); |
| 83 | return ret; |
| 84 | } |
| 85 | |
Arve Hjønnevåg | 6c0dda2 | 2013-06-24 18:02:05 -0700 | [diff] [blame] | 86 | static void fiq_glue_update_return_handler(void (*fiq_return)(void)) |
| 87 | { |
| 88 | fiq_return_handler = fiq_return; |
| 89 | if (current_handler) |
| 90 | on_each_cpu(fiq_glue_setup_helper, current_handler, true); |
| 91 | } |
| 92 | |
| 93 | int fiq_glue_set_return_handler(void (*fiq_return)(void)) |
| 94 | { |
| 95 | int ret; |
| 96 | |
| 97 | mutex_lock(&fiq_glue_lock); |
| 98 | if (fiq_return_handler) { |
| 99 | ret = -EBUSY; |
| 100 | goto err_busy; |
| 101 | } |
| 102 | fiq_glue_update_return_handler(fiq_return); |
| 103 | ret = 0; |
| 104 | err_busy: |
| 105 | mutex_unlock(&fiq_glue_lock); |
| 106 | |
| 107 | return ret; |
| 108 | } |
| 109 | EXPORT_SYMBOL(fiq_glue_set_return_handler); |
| 110 | |
| 111 | int fiq_glue_clear_return_handler(void (*fiq_return)(void)) |
| 112 | { |
| 113 | int ret; |
| 114 | |
| 115 | mutex_lock(&fiq_glue_lock); |
| 116 | if (WARN_ON(fiq_return_handler != fiq_return)) { |
| 117 | ret = -EINVAL; |
| 118 | goto err_inval; |
| 119 | } |
| 120 | fiq_glue_update_return_handler(NULL); |
| 121 | ret = 0; |
| 122 | err_inval: |
| 123 | mutex_unlock(&fiq_glue_lock); |
| 124 | |
| 125 | return ret; |
| 126 | } |
| 127 | EXPORT_SYMBOL(fiq_glue_clear_return_handler); |
| 128 | |
Arve Hjønnevåg | 8a05267 | 2010-09-27 17:50:00 -0700 | [diff] [blame] | 129 | /** |
| 130 | * fiq_glue_resume - Restore fiqs after suspend or low power idle states |
| 131 | * |
| 132 | * This must be called before calling local_fiq_enable after returning from a |
| 133 | * power state where the fiq mode registers were lost. If a driver provided |
| 134 | * a resume hook when it registered the handler it will be called. |
| 135 | */ |
| 136 | |
| 137 | void fiq_glue_resume(void) |
| 138 | { |
| 139 | if (!current_handler) |
| 140 | return; |
| 141 | fiq_glue_setup(current_handler->fiq, current_handler, |
Arve Hjønnevåg | 6c0dda2 | 2013-06-24 18:02:05 -0700 | [diff] [blame] | 142 | __get_cpu_var(fiq_stack) + THREAD_START_SP, |
| 143 | fiq_return_handler); |
Arve Hjønnevåg | 8a05267 | 2010-09-27 17:50:00 -0700 | [diff] [blame] | 144 | if (current_handler->resume) |
| 145 | current_handler->resume(current_handler); |
| 146 | } |
| 147 | |