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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> | |
fced80c7 | 18 | #include <linux/io.h> |
a6de3df4 | 19 | |
c17fad11 | 20 | #include <asm/thread_notify.h> |
c17fad11 | 21 | |
9aeec63e RM |
22 | #include "soc.h" |
23 | ||
c17fad11 LB |
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 | { | |
02239f0a | 36 | return !!(devcfg & EP93XX_SYSCON_DEVCFG_CPENA); |
c17fad11 LB |
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 | ||
797245f5 | 56 | case THREAD_NOTIFY_EXIT: |
c17fad11 LB |
57 | crunch_task_release(thread); |
58 | break; | |
59 | ||
60 | case THREAD_NOTIFY_SWITCH: | |
02239f0a | 61 | devcfg = __raw_readl(EP93XX_SYSCON_DEVCFG); |
c17fad11 | 62 | if (crunch_enabled(devcfg) || crunch_owner == crunch_state) { |
02239f0a HS |
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; | |
c17fad11 | 69 | __raw_writel(0xaa, EP93XX_SYSCON_SWLOCK); |
02239f0a | 70 | __raw_writel(devcfg, EP93XX_SYSCON_DEVCFG); |
c17fad11 LB |
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 | ||
c914283f | 82 | int __init crunch_init(void) |
c17fad11 LB |
83 | { |
84 | thread_register_notifier(&crunch_notifier_block); | |
fac105d0 | 85 | elf_hwcap |= HWCAP_CRUNCH; |
c17fad11 LB |
86 | |
87 | return 0; | |
88 | } |