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author | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2012-05-24 01:13:01 -0700 |
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committer | Dmitry Torokhov <dmitry.torokhov@gmail.com> | 2012-05-24 01:13:01 -0700 |
commit | e644dae645e167d154c0526358940986682a72b0 (patch) | |
tree | 972993c6568085b8d407fc7e13de10f4b93c651d /arch/arm/mach-ep93xx/crunch.c | |
parent | 899c612d74d4a242158a4db20367388d6299c028 (diff) | |
parent | 86809173ce32ef03bd4d0389dfc72df0c805e9c4 (diff) |
Merge branch 'next' into for-linus
Diffstat (limited to 'arch/arm/mach-ep93xx/crunch.c')
-rw-r--r-- | arch/arm/mach-ep93xx/crunch.c | 90 |
1 files changed, 90 insertions, 0 deletions
diff --git a/arch/arm/mach-ep93xx/crunch.c b/arch/arm/mach-ep93xx/crunch.c new file mode 100644 index 00000000000..74753e2df60 --- /dev/null +++ b/arch/arm/mach-ep93xx/crunch.c @@ -0,0 +1,90 @@ +/* + * arch/arm/kernel/crunch.c + * Cirrus MaverickCrunch context switching and handling + * + * Copyright (C) 2006 Lennert Buytenhek <buytenh@wantstofly.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/kernel.h> +#include <linux/signal.h> +#include <linux/sched.h> +#include <linux/init.h> +#include <linux/io.h> + +#include <asm/thread_notify.h> + +#include "soc.h" + +struct crunch_state *crunch_owner; + +void crunch_task_release(struct thread_info *thread) +{ + local_irq_disable(); + if (crunch_owner == &thread->crunchstate) + crunch_owner = NULL; + local_irq_enable(); +} + +static int crunch_enabled(u32 devcfg) +{ + return !!(devcfg & EP93XX_SYSCON_DEVCFG_CPENA); +} + +static int crunch_do(struct notifier_block *self, unsigned long cmd, void *t) +{ + struct thread_info *thread = (struct thread_info *)t; + struct crunch_state *crunch_state; + u32 devcfg; + + crunch_state = &thread->crunchstate; + + switch (cmd) { + case THREAD_NOTIFY_FLUSH: + memset(crunch_state, 0, sizeof(*crunch_state)); + + /* + * FALLTHROUGH: Ensure we don't try to overwrite our newly + * initialised state information on the first fault. + */ + + case THREAD_NOTIFY_EXIT: + crunch_task_release(thread); + break; + + case THREAD_NOTIFY_SWITCH: + devcfg = __raw_readl(EP93XX_SYSCON_DEVCFG); + if (crunch_enabled(devcfg) || crunch_owner == crunch_state) { + /* + * We don't use ep93xx_syscon_swlocked_write() here + * because we are on the context switch path and + * preemption is already disabled. + */ + devcfg ^= EP93XX_SYSCON_DEVCFG_CPENA; + __raw_writel(0xaa, EP93XX_SYSCON_SWLOCK); + __raw_writel(devcfg, EP93XX_SYSCON_DEVCFG); + } + break; + } + + return NOTIFY_DONE; +} + +static struct notifier_block crunch_notifier_block = { + .notifier_call = crunch_do, +}; + +static int __init crunch_init(void) +{ + thread_register_notifier(&crunch_notifier_block); + elf_hwcap |= HWCAP_CRUNCH; + + return 0; +} + +late_initcall(crunch_init); |