[ARM] pxa: skip registers saving/restoring if entering standby mode

registers are retained during standby mode, thus it's not necessary
to save/restore and checksum

Signed-off-by: eric miao <eric.miao@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 18 insertions, 15 deletions

diff --git a/arch/arm/mach-pxa/pm.c b/arch/arm/mach-pxa/pm.c
index a941c71c7d06..039194cbe477 100644
--- a/arch/arm/mach-pxa/pm.c
+++ b/arch/arm/mach-pxa/pm.c
@@ -38,34 +38,37 @@ int pxa_pm_enter(suspend_state_t state)
                 iwmmxt_task_disable(NULL);
 #endif
 
-        pxa_cpu_pm_fns->save(sleep_save);
+        /* skip registers saving for standby */
+        if (state != PM_SUSPEND_STANDBY) {
+                pxa_cpu_pm_fns->save(sleep_save);
+                /* before sleeping, calculate and save a checksum */
+                for (i = 0; i < pxa_cpu_pm_fns->save_size - 1; i++)
+                        sleep_save_checksum += sleep_save[i];
+        }
 
         /* Clear sleep reset status */
         RCSR = RCSR_SMR;
 
-        /* before sleeping, calculate and save a checksum */
-        for (i = 0; i < pxa_cpu_pm_fns->save_size - 1; i++)
-                sleep_save_checksum += sleep_save[i];
-
         /* *** go zzz *** */
         pxa_cpu_pm_fns->enter(state);
         cpu_init();
 
-        /* after sleeping, validate the checksum */
-        for (i = 0; i < pxa_cpu_pm_fns->save_size - 1; i++)
-                checksum += sleep_save[i];
+        if (state != PM_SUSPEND_STANDBY) {
+                /* after sleeping, validate the checksum */
+                for (i = 0; i < pxa_cpu_pm_fns->save_size - 1; i++)
+                        checksum += sleep_save[i];
 
-        /* if invalid, display message and wait for a hardware reset */
-        if (checksum != sleep_save_checksum) {
+                /* if invalid, display message and wait for a hardware reset */
+                if (checksum != sleep_save_checksum) {
 #ifdef CONFIG_ARCH_LUBBOCK
-                LUB_HEXLED = 0xbadbadc5;
+                        LUB_HEXLED = 0xbadbadc5;
 #endif
-                while (1)
-                        pxa_cpu_pm_fns->enter(state);
+                        while (1)
+                                pxa_cpu_pm_fns->enter(state);
+                }
+                pxa_cpu_pm_fns->restore(sleep_save);
         }
 
-        pxa_cpu_pm_fns->restore(sleep_save);
-
         pr_debug("*** made it back from resume\n");
 
         return 0;