[PATCH 03/16] arm: stm32mp: reset to default environment when serial# change

[Patrick Delaunay]

Serial number is first checked and, in case of mismatch, all
environment variables are reset to their default value.

This patch allows to detect that environment is saved in a removable
device, as a SD card, and reused on a other board, potentially with
incompatible variables.

Signed-off-by: Patrick Delaunay <patrick.delau...@st.com>
---

 arch/arm/mach-stm32mp/cpu.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mach-stm32mp/cpu.c b/arch/arm/mach-stm32mp/cpu.c
index 9aa5794334..365c2aa4f7 100644
--- a/arch/arm/mach-stm32mp/cpu.c
+++ b/arch/arm/mach-stm32mp/cpu.c
@@ -511,8 +511,9 @@ __weak int setup_mac_address(void)
                return -EINVAL;
        }
        pr_debug("OTP MAC address = %pM\n", enetaddr);
-       ret = !eth_env_set_enetaddr("ethaddr", enetaddr);
-       if (!ret)
+
+       ret = eth_env_set_enetaddr("ethaddr", enetaddr);
+       if (ret)
                pr_err("Failed to set mac address %pM from OTP: %d\n",
                       enetaddr, ret);
 #endif
@@ -522,13 +523,13 @@ __weak int setup_mac_address(void)
 
 static int setup_serial_number(void)
 {
+       char *serial_env;
        char serial_string[25];
        u32 otp[3] = {0, 0, 0 };
        struct udevice *dev;
        int ret;
 
-       if (env_get("serial#"))
-               return 0;
+       serial_env = env_get("serial#");
 
        ret = uclass_get_device_by_driver(UCLASS_MISC,
                                          DM_GET_DRIVER(stm32mp_bsec),
@@ -542,6 +543,15 @@ static int setup_serial_number(void)
                return ret;
 
        sprintf(serial_string, "%08X%08X%08X", otp[0], otp[1], otp[2]);
+
+       if (serial_env) {
+               if (!strcmp(serial_string, serial_env))
+                       return 0;
+               /* For invalid enviromnent (serial# change), reset to default */
+               env_set_default("serial number mismatch", 0);
+       }
+
+       /* save serial number */
        env_set("serial#", serial_string);
 
        return 0;
@@ -549,9 +559,9 @@ static int setup_serial_number(void)
 
 int arch_misc_init(void)
 {
+       setup_serial_number();
        setup_boot_mode();
        setup_mac_address();
-       setup_serial_number();
 
        return 0;
 }
-- 
2.17.1