[PATCH 3/3] ARM: vfp: Use cpu pm notifiers to save vfp state
From: Colin Cross <hidden>
Date: 2011-06-13 00:44:20
Also in:
lkml
Subsystem:
arm port, arm/vfp support, the rest · Maintainers:
Russell King, Linus Torvalds
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 <redacted> --- arch/arm/vfp/vfpmodule.c | 40 ++++++++++++++++++++++++++++++++++++++++ 1 files changed, 40 insertions(+), 0 deletions(-)
diff --git a/arch/arm/vfp/vfpmodule.c b/arch/arm/vfp/vfpmodule.c
index f25e7ec..6f08dbe 100644
--- a/arch/arm/vfp/vfpmodule.c
+++ b/arch/arm/vfp/vfpmodule.c@@ -21,6 +21,7 @@ #include <asm/cputype.h> #include <asm/thread_notify.h> #include <asm/vfp.h> +#include <asm/cpu_pm.h> #include "vfpinstr.h" #include "vfp.h"
@@ -169,6 +170,44 @@ static struct notifier_block vfp_notifier_block = { .notifier_call = vfp_notifier, }; +#ifdef CONFIG_CPU_PM +static int vfp_cpu_pm_notifier(struct notifier_block *self, unsigned long cmd, + void *v) +{ + u32 fpexc = fmrx(FPEXC); + unsigned int cpu = smp_processor_id(); + + switch (cmd) { + case CPU_PM_ENTER: + if (last_VFP_context[cpu]) { + fmxr(FPEXC, fpexc | FPEXC_EN); + vfp_save_state(last_VFP_context[cpu], fpexc); + /* force a reload when coming back from idle */ + last_VFP_context[cpu] = NULL; + fmxr(FPEXC, fpexc & ~FPEXC_EN); + } + break; + case CPU_PM_ENTER_FAILED: + case CPU_PM_EXIT: + /* make sure VFP is disabled when leaving idle */ + fmxr(FPEXC, fpexc & ~FPEXC_EN); + break; + } + return NOTIFY_OK; +} + +static struct notifier_block vfp_cpu_pm_notifier_block = { + .notifier_call = vfp_cpu_pm_notifier, +}; + +static void vfp_cpu_pm_init(void) +{ + cpu_pm_register_notifier(&vfp_cpu_pm_notifier_block); +} +#else +static inline void vfp_cpu_pm_init(void) { } +#endif + /* * Raise a SIGFPE for the current process. * sicode describes the signal being raised.
@@ -563,6 +602,7 @@ static int __init vfp_init(void) vfp_vector = vfp_support_entry; thread_register_notifier(&vfp_notifier_block); + vfp_cpu_pm_init(); vfp_pm_init(); /*
--
1.7.4.1