ARM: at91: implement the standby function for pm/cpuidle

This patch groups the self-refresh on/cpu_do_idle/self-refresh off into
a single 'standby' function.

The standby routine for rm9200 has been turned into an asm routine to have
a better control of the self refresh and to prevent a memory access when
running this code.

Draining the write buffer is done automatically when switching for the self
refresh on sam9, so the instruction is added to the rm9200 only.

Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

1 files changed, 30 insertions, 23 deletions

diff --git a/arch/arm/mach-at91/pm.h b/arch/arm/mach-at91/pm.h
index 38f9a13ee794..bba9ce1aaaec 100644
--- a/arch/arm/mach-at91/pm.h
+++ b/arch/arm/mach-at91/pm.h
@@ -24,17 +24,25 @@
  * still in self-refresh is "not recommended", but seems to work.
  */
 
-static inline u32 sdram_selfrefresh_enable(void)
+static inline void at91rm9200_standby(void)
 {
-	u32 saved_lpr = at91_sys_read(AT91_SDRAMC_LPR);
-
-	at91_sys_write(AT91_SDRAMC_LPR, 0);
-	at91_sys_write(AT91_SDRAMC_SRR, 1);
-	return saved_lpr;
+	u32 lpr = at91_sys_read(AT91_SDRAMC_LPR);
+
+	asm volatile(
+		"b    1f\n\t"
+		".align    5\n\t"
+		"1:  mcr    p15, 0, %0, c7, c10, 4\n\t"
+		"    str    %0, [%1, %2]\n\t"
+		"    str    %3, [%1, %4]\n\t"
+		"    mcr    p15, 0, %0, c7, c0, 4\n\t"
+		"    str    %5, [%1, %2]"
+		:
+		: "r" (0), "r" (AT91_BASE_SYS), "r" (AT91_SDRAMC_LPR),
+		  "r" (1), "r" (AT91_SDRAMC_SRR),
+		  "r" (lpr));
 }
 
-#define sdram_selfrefresh_disable(saved_lpr) \
-	at91_sys_write(AT91_SDRAMC_LPR, saved_lpr)
+#define at91_standby at91rm9200_standby
 
 #elif defined(CONFIG_ARCH_AT91SAM9G45)
 #include <mach/at91sam9_ddrsdr.h>
@@ -42,14 +50,12 @@ static inline u32 sdram_selfrefresh_enable(void)
 /* We manage both DDRAM/SDRAM controllers, we need more than one value to
  * remember.
  */
-static u32 saved_lpr1;
-
-static inline u32 sdram_selfrefresh_enable(void)
+static inline void at91sam9g45_standby(void)
 {
-	/* Those tow values allow us to delay self-refresh activation
+	/* Those two values allow us to delay self-refresh activation
 	 * to the maximum. */
 	u32 lpr0, lpr1;
-	u32 saved_lpr0;
+	u32 saved_lpr0, saved_lpr1;
 
 	saved_lpr1 = at91_ramc_read(1, AT91_DDRSDRC_LPR);
 	lpr1 = saved_lpr1 & ~AT91_DDRSDRC_LPCB;
@@ -63,14 +69,13 @@ static inline u32 sdram_selfrefresh_enable(void)
 	at91_ramc_write(0, AT91_DDRSDRC_LPR, lpr0);
 	at91_ramc_write(1, AT91_DDRSDRC_LPR, lpr1);
 
-	return saved_lpr0;
+	cpu_do_idle();
+
+	at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0);
+	at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1);
 }
 
-#define sdram_selfrefresh_disable(saved_lpr0)	\
-	do { \
-		at91_ramc_write(0, AT91_DDRSDRC_LPR, saved_lpr0); \
-		at91_ramc_write(1, AT91_DDRSDRC_LPR, saved_lpr1); \
-	} while (0)
+#define at91_standby at91sam9g45_standby
 
 #else
 #include <mach/at91sam9_sdramc.h>
@@ -83,7 +88,7 @@ static inline u32 sdram_selfrefresh_enable(void)
 #warning Assuming EB1 SDRAM controller is *NOT* used
 #endif
 
-static inline u32 sdram_selfrefresh_enable(void)
+static inline void at91sam9_standby(void)
 {
 	u32 saved_lpr, lpr;
 
@@ -92,11 +97,13 @@ static inline u32 sdram_selfrefresh_enable(void)
 	lpr = saved_lpr & ~AT91_SDRAMC_LPCB;
 	at91_ramc_write(0, AT91_SDRAMC_LPR, lpr |
 			AT91_SDRAMC_LPCB_SELF_REFRESH);
-	return saved_lpr;
+
+	cpu_do_idle();
+
+	at91_ramc_write(0, AT91_SDRAMC_LPR, saved_lpr);
 }
 
-#define sdram_selfrefresh_disable(saved_lpr) \
-	at91_ramc_write(0, AT91_SDRAMC_LPR, saved_lpr)
+#define at91_standby at91sam9_standby
 
 #endif