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>

1 files changed, 23 insertions, 0 deletions

diff --git a/arch/arm/mach-stm32mp/cpu.c b/arch/arm/mach-stm32mp/cpu.c
index bab318875c..55574fd4be 100644
--- a/arch/arm/mach-stm32mp/cpu.c
+++ b/arch/arm/mach-stm32mp/cpu.c
@@ -40,6 +40,13 @@ u32 get_bootmode(void)
 		    TAMP_BOOT_MODE_SHIFT;
 }
 
+u32 get_bootauth(void)
+{
+	/* read boot auth status and partition from TAMP backup register */
+	return (readl(TAMP_BOOT_CONTEXT) & TAMP_BOOT_AUTH_MASK) >>
+		    TAMP_BOOT_AUTH_SHIFT;
+}
+
 /*
  * weak function overidde: set the DDR/SYSRAM executable before to enable the
  * MMU and configure DACR, for early early_enable_caches (SPL or pre-reloc)
@@ -371,8 +378,24 @@ __weak void stm32mp_misc_init(void)
 {
 }
 
+static int setup_boot_auth_info(void)
+{
+	char buf[10];
+	u32 bootauth = get_bootauth();
+
+	snprintf(buf, sizeof(buf), "%d", bootauth >> 4);
+	env_set("boot_auth", buf);
+
+	snprintf(buf, sizeof(buf), "%d", bootauth &
+		 (u32)TAMP_BOOT_PARTITION_MASK);
+	env_set("boot_part", buf);
+
+	return 0;
+}
+
 int arch_misc_init(void)
 {
+	setup_boot_auth_info();
 	setup_boot_mode();
 	setup_mac_address();
 	setup_serial_number();