arm: 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: Peng Fan <peng.fan@nxp.com>
Cc: Albert Aribaud <albert.u.boot@aribaud.net>
Cc: Tom Rini <trini@konsulko.com>
Cc: Stefano Babic <sbabic@denx.de>
Cc: Fabio Estevam <fabio.estevam@nxp.com>
Reviewed-by: Stefano Babic <sbabic@denx.de>
diff --git a/arch/arm/cpu/armv7/start.S b/arch/arm/cpu/armv7/start.S
index f06fd28..7b84a7a 100644
--- a/arch/arm/cpu/armv7/start.S
+++ b/arch/arm/cpu/armv7/start.S
@@ -187,6 +187,12 @@
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)
mov r3, r1, lsr #20 @ get variant field