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authorAnders Larsen <al@alarsen.net>2010-04-13 07:05:32 -0400
committerRussell King <rmk+kernel@arm.linux.org.uk>2010-05-02 18:13:13 -0400
commitaec9562f3db8ece218125042e0b2b7ac5b7091e7 (patch)
tree047bd61d5794b40dd2283f1925af0bdb00f3f0bc /arch/arm/mach-at91/include
parente2941054ed596dd67a6094b7aca165af1b1f9926 (diff)
ARM: 6053/1: AT91: Save power by disabling the processor clock when CPU is idle
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 <al@alarsen.net> Acked-by: Andrew Victor <avictor.za@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-at91/include')
-rw-r--r--arch/arm/mach-at91/include/mach/system.h7
1 files changed, 5 insertions, 2 deletions
diff --git a/arch/arm/mach-at91/include/mach/system.h b/arch/arm/mach-at91/include/mach/system.h
index 5268af3933c2..c80e090b3670 100644
--- a/arch/arm/mach-at91/include/mach/system.h
+++ b/arch/arm/mach-at91/include/mach/system.h
@@ -24,21 +24,24 @@
24#include <mach/hardware.h> 24#include <mach/hardware.h>
25#include <mach/at91_st.h> 25#include <mach/at91_st.h>
26#include <mach/at91_dbgu.h> 26#include <mach/at91_dbgu.h>
27#include <mach/at91_pmc.h>
27 28
28static inline void arch_idle(void) 29static inline void arch_idle(void)
29{ 30{
31#ifndef CONFIG_DEBUG_KERNEL
30 /* 32 /*
31 * Disable the processor clock. The processor will be automatically 33 * Disable the processor clock. The processor will be automatically
32 * re-enabled by an interrupt or by a reset. 34 * re-enabled by an interrupt or by a reset.
33 */ 35 */
34// at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK); 36 at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK);
35 37#else
36 /* 38 /*
37 * Set the processor (CP15) into 'Wait for Interrupt' mode. 39 * Set the processor (CP15) into 'Wait for Interrupt' mode.
38 * Unlike disabling the processor clock via the PMC (above) 40 * Unlike disabling the processor clock via the PMC (above)
39 * this allows the processor to be woken via JTAG. 41 * this allows the processor to be woken via JTAG.
40 */ 42 */
41 cpu_do_idle(); 43 cpu_do_idle();
44#endif
42} 45}
43 46
44void (*at91_arch_reset)(void); 47void (*at91_arch_reset)(void);