sunxi: Enable non-secure access to RTC on sun6i (A31s)

On the A31s the RTC is by default secured. Thus when u-boot
loads the kernel in non-secure world, the RTC is unavailable. The
SoC has a TrustZone Protection Controller, which can be used to
enable non-secure access to the RTC.

On the A31 the TZPC doesn't seem to do anything, i.e. changes to
its register contents do not affect access to the RTC.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/sunxi/tzpc.c b/arch/arm/cpu/armv7/sunxi/tzpc.c
new file mode 100644
index 0000000..5c9c69b
--- /dev/null
+++ b/arch/arm/cpu/armv7/sunxi/tzpc.c
@@ -0,0 +1,18 @@
+/*
+ * (C) Copyright 2015 Chen-Yu Tsai <wens@csie.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <asm/io.h>
+#include <asm/arch/cpu.h>
+#include <asm/arch/tzpc.h>
+
+/* Configure Trust Zone Protection Controller */
+void tzpc_init(void)
+{
+	struct sunxi_tzpc *tzpc = (struct sunxi_tzpc *)SUNXI_TZPC_BASE;
+
+	/* Enable non-secure access to the RTC */
+	writel(SUNXI_TZPC_DECPORT0_RTC, &tzpc->decport0_set);
+}