pm: sometimes wake up from suspend to RAM would fail

Sometimes it fails to wake up from suspend to RAM, this is because
we would flush the data cache by assemble command FLUSHINV before
suspend to RAM, and there is a delay between this command execution
and cache flush completion. Add a 1uS delay to works around this.

Signed-off-by: Aaron Wu <Aaron.wu@analog.com>

diff --git a/arch/blackfin/mach-common/pm.c b/arch/blackfin/mach-common/pm.c
index 1387a94bcfd5a30e68fb00d9e293eea7db710d98..a66d979ec6512b24857f98227e01412a3ea83a75 100644 (file)
--- a/arch/blackfin/mach-common/pm.c
+++ b/arch/blackfin/mach-common/pm.c
@@ -14,6 +14,7 @@
 #include <linux/slab.h>
 #include <linux/io.h>
 #include <linux/irq.h>
+#include <linux/delay.h>
 
 #include <asm/cplb.h>
 #include <asm/gpio.h>
@@ -180,6 +181,7 @@ int bfin_pm_suspend_mem_enter(void)
 
 #if defined(CONFIG_BFIN_EXTMEM_WRITEBACK) || defined(CONFIG_BFIN_L2_WRITEBACK)
        flushinv_all_dcache();
+       udelay(1);
 #endif
        _disable_dcplb();
        _disable_icplb();