projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 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> |
| a09e64fb | 19 | #include <mach/ep93xx-regs.h> |
| c17fad11 | 20 | #include <asm/thread_notify.h> |
| c17fad11 LB |
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 | { | |
| 02239f0a | 34 | return !!(devcfg & EP93XX_SYSCON_DEVCFG_CPENA); |
| c17fad11 LB |
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 | ||
| 797245f5 | 54 | case THREAD_NOTIFY_EXIT: |
| c17fad11 LB |
55 | crunch_task_release(thread); |
| 56 | break; | |
| 57 | ||
| 58 | case THREAD_NOTIFY_SWITCH: | |
| 02239f0a | 59 | devcfg = __raw_readl(EP93XX_SYSCON_DEVCFG); |
| c17fad11 | 60 | if (crunch_enabled(devcfg) || crunch_owner == crunch_state) { |
| 02239f0a HS |
61 | /* |
| 62 | * We don't use ep93xx_syscon_swlocked_write() here | |
| 63 | * because we are on the context switch path and | |
| 64 | * preemption is already disabled. | |
| 65 | */ | |
| 66 | devcfg ^= EP93XX_SYSCON_DEVCFG_CPENA; | |
| c17fad11 | 67 | __raw_writel(0xaa, EP93XX_SYSCON_SWLOCK); |
| 02239f0a | 68 | __raw_writel(devcfg, EP93XX_SYSCON_DEVCFG); |
| c17fad11 LB |
69 | } |
| 70 | break; | |
| 71 | } | |
| 72 | ||
| 73 | return NOTIFY_DONE; | |
| 74 | } | |
| 75 | ||
| 76 | static struct notifier_block crunch_notifier_block = { | |
| 77 | .notifier_call = crunch_do, | |
| 78 | }; | |
| 79 | ||
| 80 | static int __init crunch_init(void) | |
| 81 | { | |
| 82 | thread_register_notifier(&crunch_notifier_block); | |
| fac105d0 | 83 | elf_hwcap |= HWCAP_CRUNCH; |
| c17fad11 LB |
84 | |
| 85 | return 0; | |
| 86 | } | |
| 87 | ||
| 88 | late_initcall(crunch_init); |