Disable the processor clock when the CPU is idle.
This saves much more power than merely entering 'Wait for Interrupt' mode.
Since JTAG-debugging doesn't work when the processor clock is switched off,
make it conditional on CONFIG_DEBUG_KERNEL.
Signed-off-by: Anders Larsen <[email protected]>
Cc: Andrew Victor <[email protected]>
---
KernelVersion: 2.6.33
arch/arm/mach-at91/include/mach/system.h | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
Index: b/arch/arm/mach-at91/include/mach/system.h
===================================================================
--- a/arch/arm/mach-at91/include/mach/system.h
+++ b/arch/arm/mach-at91/include/mach/system.h
@@ -24,21 +24,24 @@
#include <mach/hardware.h>
#include <mach/at91_st.h>
#include <mach/at91_dbgu.h>
+#include <mach/at91_pmc.h>
static inline void arch_idle(void)
{
+#ifndef CONFIG_DEBUG_KERNEL
/*
* Disable the processor clock. The processor will be automatically
* re-enabled by an interrupt or by a reset.
*/
-// at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK);
-
+ at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK);
+#else
/*
* Set the processor (CP15) into 'Wait for Interrupt' mode.
* Unlike disabling the processor clock via the PMC (above)
* this allows the processor to be woken via JTAG.
*/
cpu_do_idle();
+#endif
}
void (*at91_arch_reset)(void);