stm32mp1: read auth stats and boot_partition from tamp

Obtain from TAMP backup register information about image authorization
status and partition id used for booting. Store this info in
environmental variables ("boot_auth" and "boot_part" correspondingly).

Image authorization supported values:
0x0 - No authentication done
0x1 - Authentication done and failed
0x2 - Authentication done and succeeded

These values are stored to TAMP backup register by Trusted Firmware-A [1].

Testing:
STM32MP> print boot_part
boot_part=1
STM32MP> print boot_auth
boot_auth=2

[1] https://git.trustedfirmware.org/TF-A/trusted-firmware-a.git/commit/?h=refs/heads/integration&id=ab2b325c1ab895e626d4e11a9f26b9e7c968f8d8

Signed-off-by: Igor Opaniuk <igor.opaniuk@foundries.io>
Co-developed-by: Oleksandr Suvorov <oleksandr.suvorov@foundries.io>
Signed-off-by: Oleksandr Suvorov <oleksandr.suvorov@foundries.io>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>
diff --git a/arch/arm/mach-stm32mp/include/mach/stm32.h b/arch/arm/mach-stm32mp/include/mach/stm32.h
index 1cdc5e3..ac0dece 100644
--- a/arch/arm/mach-stm32mp/include/mach/stm32.h
+++ b/arch/arm/mach-stm32mp/include/mach/stm32.h
@@ -139,8 +139,12 @@
 
 #define TAMP_BOOT_MODE_MASK		GENMASK(15, 8)
 #define TAMP_BOOT_MODE_SHIFT		8
+#define TAMP_BOOT_AUTH_MASK		GENMASK(23, 16)
+#define TAMP_BOOT_AUTH_SHIFT		16
 #define TAMP_BOOT_DEVICE_MASK		GENMASK(7, 4)
 #define TAMP_BOOT_INSTANCE_MASK		GENMASK(3, 0)
+#define TAMP_BOOT_AUTH_ST_MASK		GENMASK(7, 4)
+#define TAMP_BOOT_PARTITION_MASK	GENMASK(3, 0)
 #define TAMP_BOOT_FORCED_MASK		GENMASK(7, 0)
 
 enum forced_boot_mode {
diff --git a/arch/arm/mach-stm32mp/include/mach/sys_proto.h b/arch/arm/mach-stm32mp/include/mach/sys_proto.h
index 83fb32a..52aca1e 100644
--- a/arch/arm/mach-stm32mp/include/mach/sys_proto.h
+++ b/arch/arm/mach-stm32mp/include/mach/sys_proto.h
@@ -66,6 +66,9 @@
 /* return boot mode */
 u32 get_bootmode(void);
 
+/* return auth status and partition */
+u32 get_bootauth(void);
+
 int get_eth_nb(void);
 int setup_mac_address(void);