[PATCH v7 08/17] firmware: qcom: scm: add a call for checking wrapped key support

[Bartosz Golaszewski <brgl@bgdev.pl>]

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Add a helper that allows users to check if wrapped key support is
available on the platform by checking if the SCM call allowing to
derive the software secret from a wrapped key is enabled.

Reviewed-by: Konrad Dybcio <konradybcio@kernel.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
 drivers/firmware/qcom/qcom_scm.c       | 7 +++++++
 include/linux/firmware/qcom/qcom_scm.h | 1 +
 2 files changed, 8 insertions(+)

diff --git a/drivers/firmware/qcom/qcom_scm.c b/drivers/firmware/qcom/qcom_scm.c
index 3a59fd2a45b5..f1f723b53e8f 100644
--- a/drivers/firmware/qcom/qcom_scm.c
+++ b/drivers/firmware/qcom/qcom_scm.c
@@ -1252,6 +1252,13 @@ int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size,
 }
 EXPORT_SYMBOL_GPL(qcom_scm_ice_set_key);
 
+bool qcom_scm_has_wrapped_key_support(void)
+{
+	return __qcom_scm_is_call_available(__scm->dev, QCOM_SCM_SVC_ES,
+					    QCOM_SCM_ES_DERIVE_SW_SECRET);
+}
+EXPORT_SYMBOL_GPL(qcom_scm_has_wrapped_key_support);
+
 /**
  * qcom_scm_derive_sw_secret() - Derive software secret from wrapped key
  * @wkey: the hardware wrapped key inaccessible to software
diff --git a/include/linux/firmware/qcom/qcom_scm.h b/include/linux/firmware/qcom/qcom_scm.h
index b5ab39b35490..94d4e3c96210 100644
--- a/include/linux/firmware/qcom/qcom_scm.h
+++ b/include/linux/firmware/qcom/qcom_scm.h
@@ -110,6 +110,7 @@ int qcom_scm_prepare_ice_key(const u8 *lt_key, size_t lt_key_size,
 			     u8 *eph_key, size_t eph_size);
 int qcom_scm_import_ice_key(const u8 *imp_key, size_t imp_size,
 			    u8 *lt_key, size_t lt_key_size);
+bool qcom_scm_has_wrapped_key_support(void);
 
 bool qcom_scm_hdcp_available(void);
 int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp);

-- 
2.43.0