2 * arch/arm/kernel/crunch.c
3 * Cirrus MaverickCrunch context switching and handling
5 * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org>
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.
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>
23 struct crunch_state
*crunch_owner
;
25 void crunch_task_release(struct thread_info
*thread
)
28 if (crunch_owner
== &thread
->crunchstate
)
33 static int crunch_enabled(u32 devcfg
)
35 return !!(devcfg
& EP93XX_SYSCON_DEVICE_CONFIG_CRUNCH_ENABLE
);
38 static int crunch_do(struct notifier_block
*self
, unsigned long cmd
, void *t
)
40 struct thread_info
*thread
= (struct thread_info
*)t
;
41 struct crunch_state
*crunch_state
;
44 crunch_state
= &thread
->crunchstate
;
47 case THREAD_NOTIFY_FLUSH
:
48 memset(crunch_state
, 0, sizeof(*crunch_state
));
51 * FALLTHROUGH: Ensure we don't try to overwrite our newly
52 * initialised state information on the first fault.
55 case THREAD_NOTIFY_RELEASE
:
56 crunch_task_release(thread
);
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
);
72 static struct notifier_block crunch_notifier_block
= {
73 .notifier_call
= crunch_do
,
76 static int __init
crunch_init(void)
78 thread_register_notifier(&crunch_notifier_block
);
83 late_initcall(crunch_init
);