From cb809b1a5ebffca8cf0314b788919989e8e4ab5f Mon Sep 17 00:00:00 2001 From: Greg Ungerer Date: Tue, 21 Sep 2010 20:39:40 +1000 Subject: AT91: fix use of clock disable on idle for AT91x40 devices The simpler AT91x40 processors do not have the same power management controller as the new AT91 devices. They do have a simpler power controller module that we can use to disable the CPU clock at idle time. Add code to support that. Signed-off-by: Greg Ungerer Acked-by: Jean-Christophe PLAGNIOL-VILLARD Acked-by: Nicolas Ferre --- arch/arm/mach-at91/include/mach/system.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/arm/mach-at91/include/mach/system.h') diff --git a/arch/arm/mach-at91/include/mach/system.h b/arch/arm/mach-at91/include/mach/system.h index c80e090b3670..bfbb612265d6 100644 --- a/arch/arm/mach-at91/include/mach/system.h +++ b/arch/arm/mach-at91/include/mach/system.h @@ -33,7 +33,11 @@ static inline void arch_idle(void) * Disable the processor clock. The processor will be automatically * re-enabled by an interrupt or by a reset. */ +#ifdef AT91_PS + at91_sys_write(AT91_PS_CR, AT91_PS_CR_CPU); +#else at91_sys_write(AT91_PMC_SCDR, AT91_PMC_PCK); +#endif #else /* * Set the processor (CP15) into 'Wait for Interrupt' mode. -- cgit v1.2.3 From 5c189208b606a85b4e97109af70d59f10a42fdfd Mon Sep 17 00:00:00 2001 From: Anders Larsen Date: Thu, 7 Oct 2010 20:44:15 +0100 Subject: ARM: 6436/1: AT91: Fix power-saving in idle-mode on 926T processors According to Atmel, their 926T processors (AT91 post RM9200) requires 'Wait for Interrupt' mode be entered right after disabling the processor clock in order to minimise current consumption when idle, so do both provided we're not running on a 920T (an RM9200). Furthermore, get rid of the #ifndef CONFIG_DEBUG_KERNEL, since arch_idle() can be turned off completely with the kernel parameter 'nohlt'. Cc: Andrew Victor Signed-off-by: Anders Larsen Signed-off-by: Russell King --- arch/arm/mach-at91/include/mach/system.h | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) (limited to 'arch/arm/mach-at91/include/mach/system.h') diff --git a/arch/arm/mach-at91/include/mach/system.h b/arch/arm/mach-at91/include/mach/system.h index c80e090b3670..ee8db152592e 100644 --- a/arch/arm/mach-at91/include/mach/system.h +++ b/arch/arm/mach-at91/include/mach/system.h @@ -28,17 +28,16 @@ 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); -#else +#ifndef CONFIG_CPU_ARM920T /* * 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. + * Post-RM9200 processors need this in conjunction with the above + * to save power when idle. */ cpu_do_idle(); #endif -- cgit v1.2.3