blob: 627d79414c9d68212382eaefe64af6f896035509 [file] [log] [blame]
Lennert Buytenhekc17fad12006-06-27 23:03:03 +01001/*
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>
Lennert Buytenhekc17fad12006-06-27 23:03:03 +010013#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 <asm/arch/ep93xx-regs.h>
19#include <asm/thread_notify.h>
20#include <asm/io.h>
21
22struct crunch_state *crunch_owner;
23
24void crunch_task_release(struct thread_info *thread)
25{
26 local_irq_disable();
27 if (crunch_owner == &thread->crunchstate)
28 crunch_owner = NULL;
29 local_irq_enable();
30}
31
32static int crunch_enabled(u32 devcfg)
33{
34 return !!(devcfg & EP93XX_SYSCON_DEVICE_CONFIG_CRUNCH_ENABLE);
35}
36
37static int crunch_do(struct notifier_block *self, unsigned long cmd, void *t)
38{
39 struct thread_info *thread = (struct thread_info *)t;
40 struct crunch_state *crunch_state;
41 u32 devcfg;
42
43 crunch_state = &thread->crunchstate;
44
45 switch (cmd) {
46 case THREAD_NOTIFY_FLUSH:
47 memset(crunch_state, 0, sizeof(*crunch_state));
48
49 /*
50 * FALLTHROUGH: Ensure we don't try to overwrite our newly
51 * initialised state information on the first fault.
52 */
53
54 case THREAD_NOTIFY_RELEASE:
55 crunch_task_release(thread);
56 break;
57
58 case THREAD_NOTIFY_SWITCH:
59 devcfg = __raw_readl(EP93XX_SYSCON_DEVICE_CONFIG);
60 if (crunch_enabled(devcfg) || crunch_owner == crunch_state) {
61 devcfg ^= EP93XX_SYSCON_DEVICE_CONFIG_CRUNCH_ENABLE;
62 __raw_writel(0xaa, EP93XX_SYSCON_SWLOCK);
63 __raw_writel(devcfg, EP93XX_SYSCON_DEVICE_CONFIG);
64 }
65 break;
66 }
67
68 return NOTIFY_DONE;
69}
70
71static struct notifier_block crunch_notifier_block = {
72 .notifier_call = crunch_do,
73};
74
75static int __init crunch_init(void)
76{
77 thread_register_notifier(&crunch_notifier_block);
Lennert Buytenhekfac105d2007-02-05 00:35:37 +010078 elf_hwcap |= HWCAP_CRUNCH;
Lennert Buytenhekc17fad12006-06-27 23:03:03 +010079
80 return 0;
81}
82
83late_initcall(crunch_init);