diff options
Diffstat (limited to 'arch/arm/kernel/crunch.c')
-rw-r--r-- | arch/arm/kernel/crunch.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/arch/arm/kernel/crunch.c b/arch/arm/kernel/crunch.c new file mode 100644 index 000000000000..748175921f9b --- /dev/null +++ b/arch/arm/kernel/crunch.c | |||
@@ -0,0 +1,83 @@ | |||
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/config.h> | ||
14 | #include <linux/types.h> | ||
15 | #include <linux/kernel.h> | ||
16 | #include <linux/signal.h> | ||
17 | #include <linux/sched.h> | ||
18 | #include <linux/init.h> | ||
19 | #include <asm/arch/ep93xx-regs.h> | ||
20 | #include <asm/thread_notify.h> | ||
21 | #include <asm/io.h> | ||
22 | |||
23 | struct crunch_state *crunch_owner; | ||
24 | |||
25 | void crunch_task_release(struct thread_info *thread) | ||
26 | { | ||
27 | local_irq_disable(); | ||
28 | if (crunch_owner == &thread->crunchstate) | ||
29 | crunch_owner = NULL; | ||
30 | local_irq_enable(); | ||
31 | } | ||
32 | |||
33 | static int crunch_enabled(u32 devcfg) | ||
34 | { | ||
35 | return !!(devcfg & EP93XX_SYSCON_DEVICE_CONFIG_CRUNCH_ENABLE); | ||
36 | } | ||
37 | |||
38 | static int crunch_do(struct notifier_block *self, unsigned long cmd, void *t) | ||
39 | { | ||
40 | struct thread_info *thread = (struct thread_info *)t; | ||
41 | struct crunch_state *crunch_state; | ||
42 | u32 devcfg; | ||
43 | |||
44 | crunch_state = &thread->crunchstate; | ||
45 | |||
46 | switch (cmd) { | ||
47 | case THREAD_NOTIFY_FLUSH: | ||
48 | memset(crunch_state, 0, sizeof(*crunch_state)); | ||
49 | |||
50 | /* | ||
51 | * FALLTHROUGH: Ensure we don't try to overwrite our newly | ||
52 | * initialised state information on the first fault. | ||
53 | */ | ||
54 | |||
55 | case THREAD_NOTIFY_RELEASE: | ||
56 | crunch_task_release(thread); | ||
57 | break; | ||
58 | |||
59 | case THREAD_NOTIFY_SWITCH: | ||
60 | devcfg = __raw_readl(EP93XX_SYSCON_DEVICE_CONFIG); | ||
61 | if (crunch_enabled(devcfg) || crunch_owner == crunch_state) { | ||
62 | devcfg ^= EP93XX_SYSCON_DEVICE_CONFIG_CRUNCH_ENABLE; | ||
63 | __raw_writel(0xaa, EP93XX_SYSCON_SWLOCK); | ||
64 | __raw_writel(devcfg, EP93XX_SYSCON_DEVICE_CONFIG); | ||
65 | } | ||
66 | break; | ||
67 | } | ||
68 | |||
69 | return NOTIFY_DONE; | ||
70 | } | ||
71 | |||
72 | static struct notifier_block crunch_notifier_block = { | ||
73 | .notifier_call = crunch_do, | ||
74 | }; | ||
75 | |||
76 | static int __init crunch_init(void) | ||
77 | { | ||
78 | thread_register_notifier(&crunch_notifier_block); | ||
79 | |||
80 | return 0; | ||
81 | } | ||
82 | |||
83 | late_initcall(crunch_init); | ||