[ARM] 3370/2: ep93xx: add crunch support
Patch from Lennert Buytenhek
Add the necessary kernel bits for crunch task switching.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/crunch.c b/arch/arm/kernel/crunch.c
new file mode 100644
index 0000000..7481759
--- /dev/null
+++ b/arch/arm/kernel/crunch.c
@@ -0,0 +1,83 @@
+/*
+ * 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/config.h>
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/signal.h>
+#include <linux/sched.h>
+#include <linux/init.h>
+#include <asm/arch/ep93xx-regs.h>
+#include <asm/thread_notify.h>
+#include <asm/io.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_DEVICE_CONFIG_CRUNCH_ENABLE);
+}
+
+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_RELEASE:
+ crunch_task_release(thread);
+ break;
+
+ case THREAD_NOTIFY_SWITCH:
+ devcfg = __raw_readl(EP93XX_SYSCON_DEVICE_CONFIG);
+ if (crunch_enabled(devcfg) || crunch_owner == crunch_state) {
+ devcfg ^= EP93XX_SYSCON_DEVICE_CONFIG_CRUNCH_ENABLE;
+ __raw_writel(0xaa, EP93XX_SYSCON_SWLOCK);
+ __raw_writel(devcfg, EP93XX_SYSCON_DEVICE_CONFIG);
+ }
+ 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);
+
+ return 0;
+}
+
+late_initcall(crunch_init);