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