diff options
Diffstat (limited to 'arch/arm/common/fiq_glue_setup.c')
-rw-r--r-- | arch/arm/common/fiq_glue_setup.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/arch/arm/common/fiq_glue_setup.c b/arch/arm/common/fiq_glue_setup.c new file mode 100644 index 000000000000..8cb1b611c6d5 --- /dev/null +++ b/arch/arm/common/fiq_glue_setup.c @@ -0,0 +1,147 @@ +/* + * Copyright (C) 2010 Google, Inc. + * + * This software is licensed under the terms of the GNU General Public + * License version 2, as published by the Free Software Foundation, and + * may be copied, distributed, and modified under those terms. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/kernel.h> +#include <linux/percpu.h> +#include <linux/slab.h> +#include <asm/fiq.h> +#include <asm/fiq_glue.h> + +extern unsigned char fiq_glue, fiq_glue_end; +extern void fiq_glue_setup(void *func, void *data, void *sp, + fiq_return_handler_t fiq_return_handler); + +static struct fiq_handler fiq_debbuger_fiq_handler = { + .name = "fiq_glue", +}; +DEFINE_PER_CPU(void *, fiq_stack); +static struct fiq_glue_handler *current_handler; +static fiq_return_handler_t fiq_return_handler; +static DEFINE_MUTEX(fiq_glue_lock); + +static void fiq_glue_setup_helper(void *info) +{ + struct fiq_glue_handler *handler = info; + fiq_glue_setup(handler->fiq, handler, + __get_cpu_var(fiq_stack) + THREAD_START_SP, + fiq_return_handler); +} + +int fiq_glue_register_handler(struct fiq_glue_handler *handler) +{ + int ret; + int cpu; + + if (!handler || !handler->fiq) + return -EINVAL; + + mutex_lock(&fiq_glue_lock); + if (fiq_stack) { + ret = -EBUSY; + goto err_busy; + } + + for_each_possible_cpu(cpu) { + void *stack; + stack = (void *)__get_free_pages(GFP_KERNEL, THREAD_SIZE_ORDER); + if (WARN_ON(!stack)) { + ret = -ENOMEM; + goto err_alloc_fiq_stack; + } + per_cpu(fiq_stack, cpu) = stack; + } + + ret = claim_fiq(&fiq_debbuger_fiq_handler); + if (WARN_ON(ret)) + goto err_claim_fiq; + + current_handler = handler; + on_each_cpu(fiq_glue_setup_helper, handler, true); + set_fiq_handler(&fiq_glue, &fiq_glue_end - &fiq_glue); + + mutex_unlock(&fiq_glue_lock); + return 0; + +err_claim_fiq: +err_alloc_fiq_stack: + for_each_possible_cpu(cpu) { + __free_pages(per_cpu(fiq_stack, cpu), THREAD_SIZE_ORDER); + per_cpu(fiq_stack, cpu) = NULL; + } +err_busy: + mutex_unlock(&fiq_glue_lock); + return ret; +} + +static void fiq_glue_update_return_handler(void (*fiq_return)(void)) +{ + fiq_return_handler = fiq_return; + if (current_handler) + on_each_cpu(fiq_glue_setup_helper, current_handler, true); +} + +int fiq_glue_set_return_handler(void (*fiq_return)(void)) +{ + int ret; + + mutex_lock(&fiq_glue_lock); + if (fiq_return_handler) { + ret = -EBUSY; + goto err_busy; + } + fiq_glue_update_return_handler(fiq_return); + ret = 0; +err_busy: + mutex_unlock(&fiq_glue_lock); + + return ret; +} +EXPORT_SYMBOL(fiq_glue_set_return_handler); + +int fiq_glue_clear_return_handler(void (*fiq_return)(void)) +{ + int ret; + + mutex_lock(&fiq_glue_lock); + if (WARN_ON(fiq_return_handler != fiq_return)) { + ret = -EINVAL; + goto err_inval; + } + fiq_glue_update_return_handler(NULL); + ret = 0; +err_inval: + mutex_unlock(&fiq_glue_lock); + + return ret; +} +EXPORT_SYMBOL(fiq_glue_clear_return_handler); + +/** + * fiq_glue_resume - Restore fiqs after suspend or low power idle states + * + * This must be called before calling local_fiq_enable after returning from a + * power state where the fiq mode registers were lost. If a driver provided + * a resume hook when it registered the handler it will be called. + */ + +void fiq_glue_resume(void) +{ + if (!current_handler) + return; + fiq_glue_setup(current_handler->fiq, current_handler, + __get_cpu_var(fiq_stack) + THREAD_START_SP, + fiq_return_handler); + if (current_handler->resume) + current_handler->resume(current_handler); +} + |