Extend hab command with an additional parameter to burn the field return
fuse.
Since there is now a convenient way to burn the field return fuse, give
a hint at the Kconfig option about this, as it already describes what to
do in order to burn the fuse to make it complete.

Reviewed-by: Marco Felsch <[email protected]>
Signed-off-by: Fabian Pflug <[email protected]>
---
 arch/arm/mach-imx/Kconfig |  6 +++++-
 commands/hab.c            | 24 ++++++++++++++++++++----
 2 files changed, 25 insertions(+), 5 deletions(-)

diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index 5f50d1a823..5fea0bbbca 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -926,13 +926,17 @@ config HABV4_CSF_UNLOCK_UID
           feature. This value must match the per device UNIQUE_ID fuses.
 
          The below example shows the expected format. The UNIQUE_ID is
-         queried by Linux via:
+         printed during boot by barebox:
+           i.MX___ unique ID: 7766554433221100
+         or it can be queried by Linux via:
             - cat /sys/devices/soc0/serial_number
              7766554433221100
 
          So this value have to be set:
            - 0x00, 0x11, 0x22, 0x33, 0x44, 0x55, 0x66, 0x77
 
+         Afterwards, the `hab -p -r` command can be used to burn the fuse.
+
 config HABV4_IMG_CRT_PEM
        string "Path to IMG certificate"
        default "../crts/IMG1_1_sha256_4096_65537_v3_usr_crt.pem"
diff --git a/commands/hab.c b/commands/hab.c
index 8ae943a4c8..df045df470 100644
--- a/commands/hab.c
+++ b/commands/hab.c
@@ -16,9 +16,9 @@ static int do_hab(int argc, char *argv[])
        char *srkhashfile = NULL, *srkhash = NULL;
        unsigned flags = 0;
        u8 srk[SRK_HASH_SIZE];
-       int lockdown = 0, info = 0;
+       int lockdown = 0, info = 0, field_return = 0;
 
-       while ((opt = getopt(argc, argv, "s:fpx:li")) > 0) {
+       while ((opt = getopt(argc, argv, "s:fpx:lir")) > 0) {
                switch (opt) {
                case 's':
                        srkhashfile = optarg;
@@ -38,12 +38,15 @@ static int do_hab(int argc, char *argv[])
                case 'i':
                        info = 1;
                        break;
+               case 'r':
+                       field_return = 1;
+                       break;
                default:
                        return COMMAND_ERROR_USAGE;
                }
        }
 
-       if (!info && !lockdown && !srkhashfile && !srkhash) {
+       if (!info && !lockdown && !srkhashfile && !srkhash && !field_return) {
                printf("Nothing to do\n");
                return COMMAND_ERROR_USAGE;
        }
@@ -94,7 +97,19 @@ static int do_hab(int argc, char *argv[])
                printf("Device successfully locked down\n");
        }
 
-       return 0;
+       if (field_return) {
+               ret = imx_hab_field_return(flags & 
IMX_SRK_HASH_WRITE_PERMANENT);
+               if (ret == -EINVAL && 
IS_ENABLED(CONFIG_HABV4_CSF_UNLOCK_FIELD_RETURN))
+                       printf("Field-return burn failed, check 
HABV4_CSF_UNLOCK_UID!\n");
+               else if (ret == -EINVAL && 
!IS_ENABLED(CONFIG_HABV4_CSF_UNLOCK_FIELD_RETURN))
+                       printf("Field-return burn failed because 
CONFIG_HABV4_CSF_UNLOCK_FIELD_RETURN=n\n");
+               else if (ret)
+                       printf("Field-return burn failed\n");
+               else
+                       printf("Field return fuse successfully burnt\n");
+       }
+
+       return ret;
 }
 
 BAREBOX_CMD_HELP_START(hab)
@@ -105,6 +120,7 @@ BAREBOX_CMD_HELP_OPT ("-x <sha256>",  "Burn Super Root Key 
hash from hex string"
 BAREBOX_CMD_HELP_OPT ("-i",  "Print HAB info")
 BAREBOX_CMD_HELP_OPT ("-f",  "Force. Write even when a key is already written")
 BAREBOX_CMD_HELP_OPT ("-l",  "Lockdown device. Dangerous! After executing only 
signed images can be booted")
+BAREBOX_CMD_HELP_OPT ("-r",  "Field Return. Dangerous! Access to device keys 
will be disabled forever")
 BAREBOX_CMD_HELP_OPT ("-p",  "Permanent. Really burn fuses. Be careful!")
 BAREBOX_CMD_HELP_END
 

-- 
2.47.3


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