1 files changed, 40 insertions, 0 deletions
diff --git a/arch/arm/mach-ebsa110/core.c b/arch/arm/mach-ebsa110/core.c
index 294aad07f7a0..b049edbdf152 100644
--- a/arch/arm/mach-ebsa110/core.c
+++ b/arch/arm/mach-ebsa110/core.c
@@ -119,6 +119,20 @@ static void __init ebsa110_map_io(void)
 	iotable_init(ebsa110_io_desc, ARRAY_SIZE(ebsa110_io_desc));
 }
 
+static void __iomem *ebsa110_ioremap_caller(unsigned long cookie, size_t size,
+					    unsigned int flags, void *caller)
+{
+	return (void __iomem *)cookie;
+}
+
+static void ebsa110_iounmap(volatile void __iomem *io_addr)
+{}
+
+static void __init ebsa110_init_early(void)
+{
+	arch_ioremap_caller = ebsa110_ioremap_caller;
+	arch_iounmap = ebsa110_iounmap;
+}
 
 #define PIT_CTRL		(PIT_BASE + 0x0d)
 #define PIT_T2			(PIT_BASE + 0x09)
@@ -271,8 +285,33 @@ 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));
 }
 
@@ -290,6 +329,7 @@ MACHINE_START(EBSA110, "EBSA110")
 	.reserve_lp2	= 1,
 	.restart_mode	= 's',
 	.map_io		= ebsa110_map_io,
+	.init_early	= ebsa110_init_early,
 	.init_irq	= ebsa110_init_irq,
 	.timer		= &ebsa110_timer,
 	.restart	= ebsa110_restart,