ARM: rockchip: enable ARM_ERRATA_821420 for RK3288

Signed-off-by: Huang, Tao <huangtao@rock-chips.com>

arch/arm/mach-rockchip/Kconfig

@@ -21,6 +21,7 @@ config ARCH_ROCKCHIP
 	select PL330_DMA
 	select FIQ_GLUE
 	select ARM_ERRATA_818325
+	select ARM_ERRATA_821420
 
 if ARCH_ROCKCHIP
 

arch/arm/mach-rockchip/pm-rk3288.c

@@ -1290,6 +1290,14 @@ static void rkpm_save_setting(u32 ctrbits)
 }
 static void rkpm_save_setting_resume(void)
 {
+#ifdef CONFIG_ARM_ERRATA_821420
+	u32 v;
+
+	asm volatile("mrc p15, 0, %0, c15, c0, 2" : "=r" (v));
+	v |= 1 << 1;
+	asm volatile("mcr p15, 0, %0, c15, c0, 2" : : "r" (v));
+	isb();
+#endif
 
         #if 0
         rkpm_ddr_printascii("l2&arm_errata--");