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Viewing changes to arch/arm/kernel/crunch.c

  • Committer: Package Import Robot
  • Author(s): Alessio Igor Bogani
  • Date: 2011-10-26 11:13:05 UTC
  • Revision ID: package-import@ubuntu.com-20111026111305-tz023xykf0i6eosh
Tags: upstream-3.2.0
Import upstream version 3.2.0

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arch/arm/kernel/crunch.c
 
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/*
 
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 * arch/arm/kernel/crunch.c
 
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 * Cirrus MaverickCrunch context switching and handling
 
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 *
 
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 * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
 
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 *
 
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 * This program is free software; you can redistribute it and/or modify
 
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 * it under the terms of the GNU General Public License version 2 as
 
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 * published by the Free Software Foundation.
 
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 */
 
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#include <linux/module.h>
 
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#include <linux/types.h>
 
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#include <linux/kernel.h>
 
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#include <linux/signal.h>
 
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#include <linux/sched.h>
 
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#include <linux/init.h>
 
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#include <linux/io.h>
 
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#include <mach/ep93xx-regs.h>
 
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#include <asm/thread_notify.h>
 
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struct crunch_state *crunch_owner;
 
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void crunch_task_release(struct thread_info *thread)
 
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{
 
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        local_irq_disable();
 
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        if (crunch_owner == &thread->crunchstate)
 
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                crunch_owner = NULL;
 
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        local_irq_enable();
 
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}
 
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static int crunch_enabled(u32 devcfg)
 
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{
 
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        return !!(devcfg & EP93XX_SYSCON_DEVCFG_CPENA);
 
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}
 
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static int crunch_do(struct notifier_block *self, unsigned long cmd, void *t)
 
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{
 
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        struct thread_info *thread = (struct thread_info *)t;
 
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        struct crunch_state *crunch_state;
 
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        u32 devcfg;
 
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        crunch_state = &thread->crunchstate;
 
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        switch (cmd) {
 
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        case THREAD_NOTIFY_FLUSH:
 
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                memset(crunch_state, 0, sizeof(*crunch_state));
 
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                /*
 
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                 * FALLTHROUGH: Ensure we don't try to overwrite our newly
 
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                 * initialised state information on the first fault.
 
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                 */
 
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        case THREAD_NOTIFY_EXIT:
 
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                crunch_task_release(thread);
 
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                break;
 
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        case THREAD_NOTIFY_SWITCH:
 
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                devcfg = __raw_readl(EP93XX_SYSCON_DEVCFG);
 
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                if (crunch_enabled(devcfg) || crunch_owner == crunch_state) {
 
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                        /*
 
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                         * We don't use ep93xx_syscon_swlocked_write() here
 
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                         * because we are on the context switch path and
 
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                         * preemption is already disabled.
 
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                         */
 
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                        devcfg ^= EP93XX_SYSCON_DEVCFG_CPENA;
 
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                        __raw_writel(0xaa, EP93XX_SYSCON_SWLOCK);
 
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                        __raw_writel(devcfg, EP93XX_SYSCON_DEVCFG);
 
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                }
 
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                break;
 
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        }
 
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        return NOTIFY_DONE;
 
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}
 
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static struct notifier_block crunch_notifier_block = {
 
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        .notifier_call  = crunch_do,
 
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};
 
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static int __init crunch_init(void)
 
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{
 
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        thread_register_notifier(&crunch_notifier_block);
 
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        elf_hwcap |= HWCAP_CRUNCH;
 
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        return 0;
 
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}
 
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late_initcall(crunch_init);