[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>

1 files changed, 9 insertions, 0 deletions

diff --git a/arch/arm/mach-pxa/mfp.c b/arch/arm/mach-pxa/mfp.c
index 6ce35041c7ed..f5809adce298 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 @@ static int pxa3xx_mfp_resume(struct sys_device *d)
                 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;
 }