MLK-10524: iMX6x: Implement workaround for Cortex-A9 errata 845369

Under very rare timing circumstances, transitioning into streaming
mode might create a data corruption. Present on Two or more processors
or 1 core with ACP, all revisions. This erratum can be worked round
by setting bit[22] of the undocumented Diagnostic Control Register to 1.

Signed-off-by: Nitin Garg <nitin.garg@freescale.com>
(cherry picked from commit 70ad44e523680de67dd8b7a7505d7f27799980ee)

README

@@ -683,6 +683,7 @@ The following options need to be configured:
 		CONFIG_ARM_ERRATA_751472
 		CONFIG_ARM_ERRATA_794072
 		CONFIG_ARM_ERRATA_761320
+		CONFIG_ARM_ERRATA_845369
 
 		If set, the workarounds for these ARM errata are applied early
 		during U-Boot startup. Note that these options force the

arch/arm/cpu/armv7/start.S

@@ -164,6 +164,11 @@ ENTRY(cpu_init_cp15)
 	orr	r0, r0, #1 << 21	@ set bit #21
 	mcr	p15, 0, r0, c15, c0, 1	@ write diagnostic register
 #endif
+#ifdef CONFIG_ARM_ERRATA_845369
+	mrc	p15, 0, r0, c15, c0, 1	@ read diagnostic register
+	orr	r0, r0, #1 << 22	@ set bit #22
+	mcr	p15, 0, r0, c15, c0, 1	@ write diagnostic register
+#endif
 
 	mov	r5, lr			@ Store my Caller
 	mrc	p15, 0, r1, c0, c0, 0	@ r1 has Read Main ID Register (MIDR)

include/configs/mx6_common.h

@@ -21,6 +21,7 @@
 #define CONFIG_ARM_ERRATA_751472
 #define CONFIG_ARM_ERRATA_794072
 #define CONFIG_ARM_ERRATA_761320
+#define CONFIG_ARM_ERRATA_845369
 #define CONFIG_BOARD_POSTCLK_INIT
 #define CONFIG_LDO_BYPASS_CHECK