[deliverable/linux.git] / arch / arm / mach-ep93xx / crunch.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 <asm/thread_notify.h>

#include "soc.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_DEVCFG_CPENA);
}

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_EXIT:
		crunch_task_release(thread);
		break;

	case THREAD_NOTIFY_SWITCH:
		devcfg = __raw_readl(EP93XX_SYSCON_DEVCFG);
		if (crunch_enabled(devcfg) || crunch_owner == crunch_state) {
			/*
			 * We don't use ep93xx_syscon_swlocked_write() here
			 * because we are on the context switch path and
			 * preemption is already disabled.
			 */
			devcfg ^= EP93XX_SYSCON_DEVCFG_CPENA;
			__raw_writel(0xaa, EP93XX_SYSCON_SWLOCK);
			__raw_writel(devcfg, EP93XX_SYSCON_DEVCFG);
		}
		break;
	}

	return NOTIFY_DONE;
}

static struct notifier_block crunch_notifier_block = {
	.notifier_call	= crunch_do,
};

int __init crunch_init(void)
{
	thread_register_notifier(&crunch_notifier_block);
	elf_hwcap |= HWCAP_CRUNCH;

	return 0;
}
Commit	Line	Data
	1	/*
	2	* arch/arm/kernel/crunch.c
	3	* Cirrus MaverickCrunch context switching and handling
	4	*
	5	* Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
	6	*
	7	* This program is free software; you can redistribute it and/or modify
	8	* it under the terms of the GNU General Public License version 2 as
	9	* published by the Free Software Foundation.
	10	*/
	11
	12	#include <linux/module.h>
	13	#include <linux/types.h>
	14	#include <linux/kernel.h>
	15	#include <linux/signal.h>
	16	#include <linux/sched.h>
	17	#include <linux/init.h>
	18	#include <linux/io.h>
	19
	20	#include <asm/thread_notify.h>
	21
	22	#include "soc.h"
	23
	24	struct crunch_state *crunch_owner;
	25
	26	void crunch_task_release(struct thread_info *thread)
	27	{
	28	local_irq_disable();
	29	if (crunch_owner == &thread->crunchstate)
	30	crunch_owner = NULL;
	31	local_irq_enable();
	32	}
	33
	34	static int crunch_enabled(u32 devcfg)
	35	{
	36	return !!(devcfg & EP93XX_SYSCON_DEVCFG_CPENA);
	37	}
	38
	39	static int crunch_do(struct notifier_block self, unsigned long cmd, void t)
	40	{
	41	struct thread_info thread = (struct thread_info )t;
	42	struct crunch_state *crunch_state;
	43	u32 devcfg;
	44
	45	crunch_state = &thread->crunchstate;
	46
	47	switch (cmd) {
	48	case THREAD_NOTIFY_FLUSH:
	49	memset(crunch_state, 0, sizeof(*crunch_state));
	50
	51	/*
	52	* FALLTHROUGH: Ensure we don't try to overwrite our newly
	53	* initialised state information on the first fault.
	54	*/
	55
	56	case THREAD_NOTIFY_EXIT:
	57	crunch_task_release(thread);
	58	break;
	59
	60	case THREAD_NOTIFY_SWITCH:
	61	devcfg = __raw_readl(EP93XX_SYSCON_DEVCFG);
	62	if (crunch_enabled(devcfg) \|\| crunch_owner == crunch_state) {
	63	/*
	64	* We don't use ep93xx_syscon_swlocked_write() here
	65	* because we are on the context switch path and
	66	* preemption is already disabled.
	67	*/
	68	devcfg ^= EP93XX_SYSCON_DEVCFG_CPENA;
	69	__raw_writel(0xaa, EP93XX_SYSCON_SWLOCK);
	70	__raw_writel(devcfg, EP93XX_SYSCON_DEVCFG);
	71	}
	72	break;
	73	}
	74
	75	return NOTIFY_DONE;
	76	}
	77
	78	static struct notifier_block crunch_notifier_block = {
	79	.notifier_call = crunch_do,
	80	};
	81
	82	int __init crunch_init(void)
	83	{
	84	thread_register_notifier(&crunch_notifier_block);
	85	elf_hwcap \|= HWCAP_CRUNCH;
	86
	87	return 0;
	88	}