[PATCH 7/9] i.MX8M: HABv4: add an option to allow key revocation

[Marco Felsch <m.felsch@pengutronix.de>]

The HAB code needs an special [Unlock] instruction to keep the
SRK_REVOKE fuse bank unlocked. This is required if a key needs to be
revoked.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
---
 arch/arm/mach-imx/Kconfig            | 8 ++++++++
 include/mach/imx/habv4-imx8-gencsf.h | 6 ++++++
 2 files changed, 14 insertions(+)

diff --git a/arch/arm/mach-imx/Kconfig b/arch/arm/mach-imx/Kconfig
index 61258137736f..68f55971506b 100644
--- a/arch/arm/mach-imx/Kconfig
+++ b/arch/arm/mach-imx/Kconfig
@@ -835,6 +835,14 @@ config HABV4_QSPI
 	help
 	  Enable this option to build signed QSPI/FlexSPI images.
 
+config HABV4_CSF_UNLOCK_SRK_REVOKE
+	depends on HABV4
+	bool "Unlock SRK revocation"
+	help
+	  Enable this option to instruct the HAB code to not lock
+	  the SRK_REVOKE_LOCK sticky bit. This is required for key
+	  revocation. Don't enable this if you are unsure.
+
 config HAB_CERTS_ENV
 	depends on HAB
 	bool "Specify certificates in environment"
diff --git a/include/mach/imx/habv4-imx8-gencsf.h b/include/mach/imx/habv4-imx8-gencsf.h
index 5f92ceceab00..56d9ef2de92f 100644
--- a/include/mach/imx/habv4-imx8-gencsf.h
+++ b/include/mach/imx/habv4-imx8-gencsf.h
@@ -36,6 +36,12 @@ hab [Unlock]
 hab Engine = CAAM
 hab Features = RNG, MID
 
+#if defined(CONFIG_HABV4_CSF_UNLOCK_SRK_REVOKE)
+hab [Unlock]
+hab Engine = OCOTP
+hab Features = SRK REVOKE
+#endif
+
 hab [Install Key]
 /* verification key index in key store (0, 2...4) */
 hab Verification index = 0
-- 
2.39.2