optee: add FF-A support

Adds support for using FF-A [1] as transport to the OP-TEE driver.

Introduces struct optee_msg_param_fmem which carries all information
needed when OP-TEE is calling FFA_MEM_RETRIEVE_REQ to get the shared
memory reference mapped by the hypervisor in S-EL2. Register usage is
also updated to include the information needed.

The FF-A part of this driver is enabled if CONFIG_ARM_FFA_TRANSPORT is
enabled.

[1] https://developer.arm.com/documentation/den0077/latest
Acked-by: Sumit Garg <[email protected]>
Signed-off-by: Jens Wiklander <[email protected]>

Author: jenswi-linaro

drivers/tee/optee/Makefile

@@ -6,6 +6,7 @@ optee-objs += rpc.o
 optee-objs += supp.o
 optee-objs += device.o
 optee-objs += smc_abi.o
+optee-objs += ffa_abi.o
 
 # for tracing framework to find optee_trace.h
 CFLAGS_smc_abi.o := -I$(src)

drivers/tee/optee/call.c

@@ -107,11 +107,20 @@ static struct optee_session *find_session(struct optee_context_data *ctxdata,
 struct tee_shm *optee_get_msg_arg(struct tee_context *ctx, size_t num_params,
 				  struct optee_msg_arg **msg_arg)
 {
+	struct optee *optee = tee_get_drvdata(ctx->teedev);
+	size_t sz = OPTEE_MSG_GET_ARG_SIZE(num_params);
 	struct tee_shm *shm;
 	struct optee_msg_arg *ma;
 
-	shm = tee_shm_alloc(ctx, OPTEE_MSG_GET_ARG_SIZE(num_params),
-			    TEE_SHM_MAPPED | TEE_SHM_PRIV);
+	/*
+	 * rpc_arg_count is set to the number of allocated parameters in
+	 * the RPC argument struct if a second MSG arg struct is expected.
+	 * The second arg struct will then be used for RPC.
+	 */
+	if (optee->rpc_arg_count)
+		sz += OPTEE_MSG_GET_ARG_SIZE(optee->rpc_arg_count);
+
+	shm = tee_shm_alloc(ctx, sz, TEE_SHM_MAPPED | TEE_SHM_PRIV);
 	if (IS_ERR(shm))
 		return shm;
 

drivers/tee/optee/core.c

@@ -172,6 +172,9 @@ void optee_remove_common(struct optee *optee)
 	mutex_destroy(&optee->call_queue.mutex);
 }
 
+static int smc_abi_rc;
+static int ffa_abi_rc;
+
 static int optee_core_init(void)
 {
 	/*
@@ -184,13 +187,22 @@ static int optee_core_init(void)
 	if (is_kdump_kernel())
 		return -ENODEV;
 
-	return optee_smc_abi_register();
+	smc_abi_rc = optee_smc_abi_register();
+	ffa_abi_rc = optee_ffa_abi_register();
+
+	/* If both failed there's no point with this module */
+	if (smc_abi_rc && ffa_abi_rc)
+		return smc_abi_rc;
+	return 0;
 }
 module_init(optee_core_init);
 
 static void optee_core_exit(void)
 {
-	optee_smc_abi_unregister();
+	if (!smc_abi_rc)
+		optee_smc_abi_unregister();
+	if (!ffa_abi_rc)
+		optee_ffa_abi_unregister();
 }
 module_exit(optee_core_exit);