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c17fad11 LB |
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> | |
c17fad11 LB |
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 <asm/arch/ep93xx-regs.h> | |
19 | #include <asm/thread_notify.h> | |
20 | #include <asm/io.h> | |
21 | ||
22 | struct crunch_state *crunch_owner; | |
23 | ||
24 | void 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 | ||
32 | static int crunch_enabled(u32 devcfg) | |
33 | { | |
34 | return !!(devcfg & EP93XX_SYSCON_DEVICE_CONFIG_CRUNCH_ENABLE); | |
35 | } | |
36 | ||
37 | static 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 | ||
71 | static struct notifier_block crunch_notifier_block = { | |
72 | .notifier_call = crunch_do, | |
73 | }; | |
74 | ||
75 | static int __init crunch_init(void) | |
76 | { | |
77 | thread_register_notifier(&crunch_notifier_block); | |
fac105d0 | 78 | elf_hwcap |= HWCAP_CRUNCH; |
c17fad11 LB |
79 | |
80 | return 0; | |
81 | } | |
82 | ||
83 | late_initcall(crunch_init); |