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Subject[PATCH v2 4/5] ARM: vfp: Use cpu pm notifiers to save vfp state
Date
From: Colin Cross <ccross@android.com>

When the cpu is powered down in a low power mode, the vfp
registers may be reset.

This patch uses CPU_PM_ENTER and CPU_PM_EXIT notifiers to save
and restore the cpu's vfp registers.

Signed-off-by: Colin Cross <ccross@android.com>
[santosh.shilimkar@ti.com: Rebased against 3.1-rc4, resolved the conflicts]
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
---
arch/arm/vfp/vfpmodule.c | 29 +++++++++++++++++++++--------
1 files changed, 21 insertions(+), 8 deletions(-)
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index 79bcb43..fe4b60b 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c
@@ -11,6 +11,7 @@
#include <linux/module.h>
#include <linux/types.h>
#include <linux/cpu.h>
+#include <linux/cpu_pm.h>
#include <linux/kernel.h>
#include <linux/notifier.h>
#include <linux/signal.h>
@@ -436,9 +437,7 @@ static void vfp_enable(void *unused)
set_copro_access(access | CPACC_FULL(10) | CPACC_FULL(11));
}

-#ifdef CONFIG_PM
-#include <linux/syscore_ops.h>
-
+#ifdef CONFIG_CPU_PM
static int vfp_pm_suspend(void)
{
struct thread_info *ti = current_thread_info();
@@ -468,19 +467,33 @@ static void vfp_pm_resume(void)
fmxr(FPEXC, fmrx(FPEXC) & ~FPEXC_EN);
}

-static struct syscore_ops vfp_pm_syscore_ops = {
- .suspend = vfp_pm_suspend,
- .resume = vfp_pm_resume,
+static int vfp_cpu_pm_notifier(struct notifier_block *self, unsigned long cmd,
+ void *v)
+{
+ switch (cmd) {
+ case CPU_PM_ENTER:
+ vfp_pm_suspend();
+ break;
+ case CPU_PM_ENTER_FAILED:
+ case CPU_PM_EXIT:
+ vfp_pm_resume();
+ break;
+ }
+ return NOTIFY_OK;
+}
+
+static struct notifier_block vfp_cpu_pm_notifier_block = {
+ .notifier_call = vfp_cpu_pm_notifier,
};

static void vfp_pm_init(void)
{
- register_syscore_ops(&vfp_pm_syscore_ops);
+ cpu_pm_register_notifier(&vfp_cpu_pm_notifier_block);
}

#else
static inline void vfp_pm_init(void) { }
-#endif /* CONFIG_PM */
+#endif /* CONFIG_CPU_PM */

/*
* Ensure that the VFP state stored in 'thread->vfpstate' is up to date
--
1.7.4.1


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