From 8aeeda822fbfe7da2d4ea391a9757e9532796598 Mon Sep 17 00:00:00 2001 From: Nicolas Ferre Date: Fri, 22 Oct 2010 17:53:39 +0200 Subject: AT91: pm: use plain cpu_do_idle() for "wait for interrupt" For power management at91_pm_enter() routine, use the cpu_do_idle() for a rock solid "wait for interrupt" implementation. For AT91SAM9 ARM 926 based chips, we can exceed the cache line length as we can access RAM even while in self-refresh mode. We keep plain access to CP15 for at91rm9200 as this feature is not available: instructions have to be in a single cache line. Signed-off-by: Nicolas Ferre --- arch/arm/mach-at91/pm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'arch/arm/mach-at91/pm.c') diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c index 615668986480..87a31baf1cb3 100644 --- a/arch/arm/mach-at91/pm.c +++ b/arch/arm/mach-at91/pm.c @@ -258,16 +258,18 @@ static int at91_pm_enter(suspend_state_t state) * NOTE: the Wait-for-Interrupt instruction needs to be * in icache so no SDRAM accesses are needed until the * wakeup IRQ occurs and self-refresh is terminated. + * For ARM 926 based chips, this requirement is weaker + * as at91sam9 can access a RAM in self-refresh mode. */ asm("b 1f; .align 5; 1:"); asm("mcr p15, 0, r0, c7, c10, 4"); /* drain write buffer */ saved_lpr = sdram_selfrefresh_enable(); - asm("mcr p15, 0, r0, c7, c0, 4"); /* wait for interrupt */ + wait_for_interrupt_enable(); sdram_selfrefresh_disable(saved_lpr); break; case PM_SUSPEND_ON: - asm("mcr p15, 0, r0, c7, c0, 4"); /* wait for interrupt */ + cpu_do_idle(); break; default: -- cgit v1.2.2 From a2a571b74a3881963d8d09deb272d13afe5b49e3 Mon Sep 17 00:00:00 2001 From: Nicolas Ferre Date: Fri, 22 Oct 2010 18:55:39 +0200 Subject: AT91: pm: make sure that r0 is 0 when dealing with cache operations When using CP15 cache operations (c7), we make sure that Rd (r0) is actually 0 as ARM 926 TRM is saying. Signed-off-by: Nicolas Ferre --- arch/arm/mach-at91/pm.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'arch/arm/mach-at91/pm.c') diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c index 87a31baf1cb3..dafbacc25eb1 100644 --- a/arch/arm/mach-at91/pm.c +++ b/arch/arm/mach-at91/pm.c @@ -261,8 +261,13 @@ static int at91_pm_enter(suspend_state_t state) * For ARM 926 based chips, this requirement is weaker * as at91sam9 can access a RAM in self-refresh mode. */ - asm("b 1f; .align 5; 1:"); - asm("mcr p15, 0, r0, c7, c10, 4"); /* drain write buffer */ + asm volatile ( "mov r0, #0\n\t" + "b 1f\n\t" + ".align 5\n\t" + "1: mcr p15, 0, r0, c7, c10, 4\n\t" + : /* no output */ + : /* no input */ + : "r0"); saved_lpr = sdram_selfrefresh_enable(); wait_for_interrupt_enable(); sdram_selfrefresh_disable(saved_lpr); -- cgit v1.2.2