[PATCHv3 3/4] drivers: tee: sandbox: SCP03 control emulator

[Jorge Ramirez-Ortiz]

Adds support for a working SCP03 emulation. Input parameters are
validated however the commands (enable, provision) executed by the TEE
are assumed to always succeed.

Signed-off-by: Jorge Ramirez-Ortiz <jorge at foundries.io>
Reviewed-by: Simon Glass <sjg at chromium.org>
---
 drivers/tee/optee/Kconfig |  6 ++++
 drivers/tee/sandbox.c     | 60 +++++++++++++++++++++++++++++++++++++--
 2 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/drivers/tee/optee/Kconfig b/drivers/tee/optee/Kconfig
index d489834df9..98988c38f0 100644
--- a/drivers/tee/optee/Kconfig
+++ b/drivers/tee/optee/Kconfig
@@ -22,6 +22,12 @@ config OPTEE_TA_AVB
 	  The TA can support the "avb" subcommands "read_rb", "write"rb"
 	  and "is_unlocked".
 
+config OPTEE_TA_SCP03
+	bool "Support SCP03 TA"
+	default y
+	help
+	  Enables support for controlling (enabling, provisioning) the
+	  Secure Channel Protocol 03 operation in the OP-TEE SCP03 TA.
 endmenu
 
 endif
diff --git a/drivers/tee/sandbox.c b/drivers/tee/sandbox.c
index e1ba027fd6..273c23239a 100644
--- a/drivers/tee/sandbox.c
+++ b/drivers/tee/sandbox.c
@@ -7,6 +7,7 @@
 #include <sandboxtee.h>
 #include <tee.h>
 #include <tee/optee_ta_avb.h>
+#include <tee/optee_ta_scp03.h>
 
 /*
  * The sandbox tee driver tries to emulate a generic Trusted Exectution
@@ -32,7 +33,7 @@ struct ta_entry {
 			   struct tee_param *params);
 };
 
-#ifdef CONFIG_OPTEE_TA_AVB
+#if defined(CONFIG_OPTEE_TA_SCP03) || defined(CONFIG_OPTEE_TA_AVB)
 static u32 get_attr(uint n, uint num_params, struct tee_param *params)
 {
 	if (n >= num_params)
@@ -44,7 +45,7 @@ static u32 get_attr(uint n, uint num_params, struct tee_param *params)
 static u32 check_params(u8 p0, u8 p1, u8 p2, u8 p3, uint num_params,
 			struct tee_param *params)
 {
-	u8 p[] = { p0, p1, p2, p3};
+	u8 p[] = { p0, p1, p2, p3 };
 	uint n;
 
 	for (n = 0; n < ARRAY_SIZE(p); n++)
@@ -62,6 +63,55 @@ bad_params:
 
 	return TEE_ERROR_BAD_PARAMETERS;
 }
+#endif
+
+#ifdef CONFIG_OPTEE_TA_SCP03
+static u32 pta_scp03_open_session(struct udevice *dev, uint num_params,
+				  struct tee_param *params)
+{
+	/*
+	 * We don't expect additional parameters when opening a session to
+	 * this TA.
+	 */
+	return check_params(TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
+			    TEE_PARAM_ATTR_TYPE_NONE, TEE_PARAM_ATTR_TYPE_NONE,
+			    num_params, params);
+}
+
+static u32 pta_scp03_invoke_func(struct udevice *dev, u32 func, uint num_params,
+				 struct tee_param *params)
+{
+	u32 res;
+	static bool enabled;
+
+	switch (func) {
+	case PTA_CMD_ENABLE_SCP03:
+		res = check_params(TEE_PARAM_ATTR_TYPE_VALUE_INPUT,
+				   TEE_PARAM_ATTR_TYPE_NONE,
+				   TEE_PARAM_ATTR_TYPE_NONE,
+				   TEE_PARAM_ATTR_TYPE_NONE,
+				   num_params, params);
+		if (res)
+			return res;
+
+		if (!enabled) {
+			printf("SCP03 enabled\n");
+			enabled = true;
+		} else {
+			printf("SCP03 already enabled, no action\n");
+		}
+
+		if (params[0].u.value.a)
+			printf("SCP03 keys rotated\n");
+
+		return TEE_SUCCESS;
+	default:
+		return TEE_ERROR_NOT_SUPPORTED;
+	}
+}
+#endif
+
+#ifdef CONFIG_OPTEE_TA_AVB
 
 static u32 ta_avb_open_session(struct udevice *dev, uint num_params,
 			       struct tee_param *params)
@@ -223,6 +273,12 @@ static const struct ta_entry ta_entries[] = {
 	  .invoke_func = ta_avb_invoke_func,
 	},
 #endif
+#ifdef CONFIG_OPTEE_TA_SCP03
+	{ .uuid = PTA_SCP03_UUID,
+	  .open_session = pta_scp03_open_session,
+	  .invoke_func = pta_scp03_invoke_func,
+	},
+#endif
 };
 
 static void sandbox_tee_get_version(struct udevice *dev,
-- 
2.30.0