[PATCH v3 10/10] hab: lock GP5 on i.MX8MP socs

[Stefan Kerkmann <s.kerkmann@pengutronix.de>]

This change locks down the GP5 eFuses against modification on i.MX8MP
SoCs. To cite the i.MX8MP reference manual (Rev. 3):

  The GP5_LOCK eFuse locks the upper 64 bits of the 128-bit UNIQUE_ID
  (UID) eFuse field. The users must program the GP5_LOCK eFuse to b'11
  (WP+OP), thereby locking the upper 64-bit UID eFuse field. For devices
  shipped with date codes 2435 and later, the GP5_LOCK has been
  programmed to b'11 by NXP in production. Only devices with date codes
  prior to 2435 should be programmed to update the GP5_LOCK eFuse to
  b'11.

Signed-off-by: Stefan Kerkmann <s.kerkmann@pengutronix.de>
---
 drivers/hab/hab.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/hab/hab.c b/drivers/hab/hab.c
index 0f0c8766f069697944570290cb5796430ddae125..7fb759c152379dda2d43f139baf1aa6cf2051234 100644
--- a/drivers/hab/hab.c
+++ b/drivers/hab/hab.c
@@ -200,11 +200,15 @@ static int imx8m_hab_lockdown_device_ocotp(unsigned flags)
 	if (ret < 0)
 		return ret;
 
-	/* Only i.MX8MQ requires fusing of DIR_BT_DIS */
-	if (!cpu_is_mx8mq())
-		return ret;
+	/* Lock upper 64bit of the 128bit UNIQUE_ID eFuse field on i.MX8MP */
+	if (cpu_is_mx8mp())
+		return imx_ocotp_write_field(MX8MP_OCOTP_GP5_LOCK, 0b11);
 
-	return imx_ocotp_write_field(MX8MQ_OCOTP_DIR_BT_DIS, 1);
+	/* Only i.MX8MQ requires fusing of DIR_BT_DIS */
+	if (cpu_is_mx8mq())
+		return imx_ocotp_write_field(MX8MQ_OCOTP_DIR_BT_DIS, 1);
+
+	return 0;
 }
 
 static int imx6_hab_device_locked_down_ocotp(void)

-- 
2.39.5