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authorArnd Bergmann <arnd@arndb.de>2012-03-21 18:27:34 +0400
committerArnd Bergmann <arnd@arndb.de>2012-03-21 18:27:34 +0400
commit2cbe23e3a432e3d09a849adb197c8fcc09e7391d (patch)
tree711fe5845c4c7e7eaf8c57a597d86c0f9dda5b06 /arch/arm/mach-ebsa110/core.c
parentb2f1df8d2fc14bf7e6d9d967043d4b60c2efd8dc (diff)
parented1b4acc43b0c3289faa30cf184f322ab70a5be3 (diff)
downloadlinux-2cbe23e3a432e3d09a849adb197c8fcc09e7391d.tar.xz
Merge branch 'tegra/cleanups' into next/timer
Conflicts: arch/arm/mach-tegra/Makefile arch/arm/mach-vexpress/core.h The tegra Makefile was changed in four different branches in the same line. This merge should reduce the amount of churn. Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'arch/arm/mach-ebsa110/core.c')
-rw-r--r--arch/arm/mach-ebsa110/core.c25
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/arm/mach-ebsa110/core.c b/arch/arm/mach-ebsa110/core.c
index 294aad07f7a0..804c9122b7b3 100644
--- a/arch/arm/mach-ebsa110/core.c
+++ b/arch/arm/mach-ebsa110/core.c
@@ -271,8 +271,33 @@ static struct platform_device *ebsa110_devices[] = {
&am79c961_device,
};
+/*
+ * EBSA110 idling methodology:
+ *
+ * We can not execute the "wait for interrupt" instruction since that
+ * will stop our MCLK signal (which provides the clock for the glue
+ * logic, and therefore the timer interrupt).
+ *
+ * Instead, we spin, polling the IRQ_STAT register for the occurrence
+ * of any interrupt with core clock down to the memory clock.
+ */
+static void ebsa110_idle(void)
+{
+ const char *irq_stat = (char *)0xff000000;
+
+ /* disable clock switching */
+ asm volatile ("mcr p15, 0, ip, c15, c2, 2" : : : "cc");
+
+ /* wait for an interrupt to occur */
+ while (!*irq_stat);
+
+ /* enable clock switching */
+ asm volatile ("mcr p15, 0, ip, c15, c1, 2" : : : "cc");
+}
+
static int __init ebsa110_init(void)
{
+ arm_pm_idle = ebsa110_idle;
return platform_add_devices(ebsa110_devices, ARRAY_SIZE(ebsa110_devices));
}