83 lines
2 KiB
C
83 lines
2 KiB
C
/*
|
|
* arch/arm/kernel/crunch.c
|
|
* Cirrus MaverickCrunch context switching and handling
|
|
*
|
|
* Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/module.h>
|
|
#include <linux/types.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/signal.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/init.h>
|
|
#include <linux/io.h>
|
|
#include <mach/ep93xx-regs.h>
|
|
#include <asm/thread_notify.h>
|
|
|
|
struct crunch_state *crunch_owner;
|
|
|
|
void crunch_task_release(struct thread_info *thread)
|
|
{
|
|
local_irq_disable();
|
|
if (crunch_owner == &thread->crunchstate)
|
|
crunch_owner = NULL;
|
|
local_irq_enable();
|
|
}
|
|
|
|
static int crunch_enabled(u32 devcfg)
|
|
{
|
|
return !!(devcfg & EP93XX_SYSCON_DEVICE_CONFIG_CRUNCH_ENABLE);
|
|
}
|
|
|
|
static int crunch_do(struct notifier_block *self, unsigned long cmd, void *t)
|
|
{
|
|
struct thread_info *thread = (struct thread_info *)t;
|
|
struct crunch_state *crunch_state;
|
|
u32 devcfg;
|
|
|
|
crunch_state = &thread->crunchstate;
|
|
|
|
switch (cmd) {
|
|
case THREAD_NOTIFY_FLUSH:
|
|
memset(crunch_state, 0, sizeof(*crunch_state));
|
|
|
|
/*
|
|
* FALLTHROUGH: Ensure we don't try to overwrite our newly
|
|
* initialised state information on the first fault.
|
|
*/
|
|
|
|
case THREAD_NOTIFY_RELEASE:
|
|
crunch_task_release(thread);
|
|
break;
|
|
|
|
case THREAD_NOTIFY_SWITCH:
|
|
devcfg = __raw_readl(EP93XX_SYSCON_DEVICE_CONFIG);
|
|
if (crunch_enabled(devcfg) || crunch_owner == crunch_state) {
|
|
devcfg ^= EP93XX_SYSCON_DEVICE_CONFIG_CRUNCH_ENABLE;
|
|
__raw_writel(0xaa, EP93XX_SYSCON_SWLOCK);
|
|
__raw_writel(devcfg, EP93XX_SYSCON_DEVICE_CONFIG);
|
|
}
|
|
break;
|
|
}
|
|
|
|
return NOTIFY_DONE;
|
|
}
|
|
|
|
static struct notifier_block crunch_notifier_block = {
|
|
.notifier_call = crunch_do,
|
|
};
|
|
|
|
static int __init crunch_init(void)
|
|
{
|
|
thread_register_notifier(&crunch_notifier_block);
|
|
elf_hwcap |= HWCAP_CRUNCH;
|
|
|
|
return 0;
|
|
}
|
|
|
|
late_initcall(crunch_init);
|