[ARM] pxa: add preliminary suspend/resume code for pxa3xx
1. clear RDH bit after resuming back from D3, otherwise, the multi function
pins will retain the low power state
2. save/restore essential system registers
Signed-off-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mach-pxa/mfp.c b/arch/arm/mach-pxa/mfp.c
index 6ce3504..f5809ad 100644
--- a/arch/arm/mach-pxa/mfp.c
+++ b/arch/arm/mach-pxa/mfp.c
@@ -22,6 +22,7 @@
#include <asm/hardware.h>
#include <asm/arch/mfp.h>
#include <asm/arch/mfp-pxa3xx.h>
+#include <asm/arch/pxa3xx-regs.h>
/* mfp_spin_lock is used to ensure that MFP register configuration
* (most likely a read-modify-write operation) is atomic, and that
@@ -223,6 +224,14 @@
struct pxa3xx_mfp_pin *p = &mfp_table[pin];
__mfp_config_run(p);
}
+
+ /* clear RDH bit when MFP settings are restored
+ *
+ * NOTE: the last 3 bits DxS are write-1-to-clear so carefully
+ * preserve them here in case they will be referenced later
+ */
+ ASCR &= ~(ASCR_RDH | ASCR_D1S | ASCR_D2S | ASCR_D3S);
+
return 0;
}