firmware: qcom: scm: add calls for wrapped key support

Add helper functions for the SCM calls required to support
hardware-wrapped inline storage encryption keys.  These SCM calls manage
wrapped keys via Qualcomm's Hardware Key Manager (HWKM), which can only
be accessed from TrustZone.

QCOM_SCM_ES_GENERATE_ICE_KEY and QCOM_SCM_ES_IMPORT_ICE_KEY create a new
long-term wrapped key, with the former making the hardware generate the
key and the latter importing a raw key.  QCOM_SCM_ES_PREPARE_ICE_KEY
converts the key to ephemerally-wrapped form so that it can be used for
inline storage encryption.  These are planned to be wired up to new
ioctls via the blk-crypto framework; see the proposed documentation for
the hardware-wrapped keys feature for more information.

Similarly there's also QCOM_SCM_ES_DERIVE_SW_SECRET which derives a
"software secret" from an ephemerally-wrapped key and will be wired up
to the corresponding operation in the blk_crypto_profile.

These will all be used by the ICE driver in drivers/soc/qcom/ice.c.

[EB: merged related patches, fixed error handling, fixed naming, fixed
     docs for size parameters, fixed qcom_scm_has_wrapped_key_support(),
     improved comments, improved commit message.]

Signed-off-by: Gaurav Kashyap <quic_gaurkash@quicinc.com>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20241213041958.202565-9-ebiggers@kernel.org
Signed-off-by: Bjorn Andersson <andersson@kernel.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/linux/firmware/qcom/qcom_scm.h b/include/linux/firmware/qcom/qcom_scm.h
index 4621aec0328c..983e1591bbba 100644
--- a/include/linux/firmware/qcom/qcom_scm.h
+++ b/include/linux/firmware/qcom/qcom_scm.h
@@ -105,6 +105,14 @@ bool qcom_scm_ice_available(void);
 int qcom_scm_ice_invalidate_key(u32 index);
 int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size,
 			 enum qcom_scm_ice_cipher cipher, u32 data_unit_size);
+bool qcom_scm_has_wrapped_key_support(void);
+int qcom_scm_derive_sw_secret(const u8 *eph_key, size_t eph_key_size,
+			      u8 *sw_secret, size_t sw_secret_size);
+int qcom_scm_generate_ice_key(u8 *lt_key, size_t lt_key_size);
+int qcom_scm_prepare_ice_key(const u8 *lt_key, size_t lt_key_size,
+			     u8 *eph_key, size_t eph_key_size);
+int qcom_scm_import_ice_key(const u8 *raw_key, size_t raw_key_size,
+			    u8 *lt_key, size_t lt_key_size);
 
 bool qcom_scm_hdcp_available(void);
 int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp);