[v10 delta] tee: add OP-TEE driver

V10 delta for "tee: add OP-TEE driver"

Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>

7 files changed, 182 insertions, 50 deletions

diff --git a/drivers/tee/optee/call.c b/drivers/tee/optee/call.c
index c567f98ec4c7..8f9b12e8b915 100644
--- a/drivers/tee/optee/call.c
+++ b/drivers/tee/optee/call.c
@@ -11,14 +11,14 @@
  * GNU General Public License for more details.
  *
  */
-#include <linux/types.h>
+#include <linux/arm-smccc.h>
+#include <linux/device.h>
 #include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/slab.h>
-#include <linux/uaccess.h>
-#include <linux/device.h>
 #include <linux/tee_drv.h>
-#include <linux/arm-smccc.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
 #include "optee_private.h"
 #include "optee_smc.h"
 
@@ -29,7 +29,7 @@ struct optee_call_waiter {
 };
 
 static void optee_cq_wait_init(struct optee_call_queue *cq,
-			struct optee_call_waiter *w)
+			       struct optee_call_waiter *w)
 {
 	mutex_lock(&cq->mutex);
 	/*
@@ -45,7 +45,7 @@ static void optee_cq_wait_init(struct optee_call_queue *cq,
 }
 
 static void optee_cq_wait_for_completion(struct optee_call_queue *cq,
-			struct optee_call_waiter *w)
+					 struct optee_call_waiter *w)
 {
 	wait_for_completion(&w->c);
 
@@ -74,7 +74,7 @@ static void optee_cq_complete_one(struct optee_call_queue *cq)
 }
 
 static void optee_cq_wait_final(struct optee_call_queue *cq,
-			struct optee_call_waiter *w)
+				struct optee_call_waiter *w)
 {
 	mutex_lock(&cq->mutex);
 
@@ -94,7 +94,7 @@ static void optee_cq_wait_final(struct optee_call_queue *cq,
 
 /* Requires the filpstate mutex to be held */
 static struct optee_session *find_session(struct optee_context_data *ctxdata,
-			u32 session_id)
+					  u32 session_id)
 {
 	struct optee_session *sess;
 
@@ -104,6 +104,16 @@ static struct optee_session *find_session(struct optee_context_data *ctxdata,
 	return NULL;
 }
 
+/**
+ * optee_do_call_with_arg() - Do an SMC to OP-TEE in secure world
+ * @ctx:	calling context
+ * @parg:	physical address of message to pass to secure world
+ *
+ * Does and SMC to OP-TEE in secure world and handles eventual resulting
+ * Remote Procedure Calls (RPC) from OP-TEE.
+ *
+ * Returns return code from secure world, 0 is OK
+ */
 u32 optee_do_call_with_arg(struct tee_context *ctx, phys_addr_t parg)
 {
 	struct optee *optee = tee_get_drvdata(ctx->teedev);
@@ -148,7 +158,8 @@ u32 optee_do_call_with_arg(struct tee_context *ctx, phys_addr_t parg)
 }
 
 static struct tee_shm *get_msg_arg(struct tee_context *ctx, size_t num_params,
-			struct optee_msg_arg **msg_arg, phys_addr_t *msg_parg)
+				   struct optee_msg_arg **msg_arg,
+				   phys_addr_t *msg_parg)
 {
 	int rc;
 	struct tee_shm *shm;
@@ -179,8 +190,8 @@ out:
 }
 
 int optee_open_session(struct tee_context *ctx,
-			struct tee_ioctl_open_session_arg *arg,
-			struct tee_param *param)
+		       struct tee_ioctl_open_session_arg *arg,
+		       struct tee_param *param)
 {
 	struct optee_context_data *ctxdata = ctx->data;
 	int rc;
@@ -215,7 +226,7 @@ int optee_open_session(struct tee_context *ctx,
 	if (rc)
 		goto out;
 
-	sess = kzalloc(sizeof(struct optee_session), GFP_KERNEL);
+	sess = kzalloc(sizeof(*sess), GFP_KERNEL);
 	if (!sess) {
 		rc = -ENOMEM;
 		goto out;
@@ -282,7 +293,7 @@ int optee_close_session(struct tee_context *ctx, u32 session)
 }
 
 int optee_invoke_func(struct tee_context *ctx, struct tee_ioctl_invoke_arg *arg,
-			struct tee_param *param)
+		      struct tee_param *param)
 {
 	struct optee_context_data *ctxdata = ctx->data;
 	struct tee_shm *shm;
@@ -357,6 +368,11 @@ int optee_cancel_req(struct tee_context *ctx, u32 cancel_id, u32 session)
 	return 0;
 }
 
+/**
+ * optee_enable_shm_cache() - Enables caching of some shared memory allocation
+ *			      in OP-TEE
+ * @optee:	main service struct
+ */
 void optee_enable_shm_cache(struct optee *optee)
 {
 	struct optee_call_waiter w;
@@ -375,6 +391,11 @@ void optee_enable_shm_cache(struct optee *optee)
 	optee_cq_wait_final(&optee->call_queue, &w);
 }
 
+/**
+ * optee_enable_shm_cache() - Disables caching of some shared memory allocation
+ *			      in OP-TEE
+ * @optee:	main service struct
+ */
 void optee_disable_shm_cache(struct optee *optee)
 {
 	struct optee_call_waiter w;
@@ -393,8 +414,9 @@ void optee_disable_shm_cache(struct optee *optee)
 
 			shm = reg_pair_to_ptr(res.a1, res.a2);
 			tee_shm_free(shm);
-		} else
+		} else {
 			optee_cq_wait_for_completion(&optee->call_queue, &w);
+		}
 	}
 	optee_cq_wait_final(&optee->call_queue, &w);
 }
diff --git a/drivers/tee/optee/core.c b/drivers/tee/optee/core.c
index 874550c84f30..dba3bfa7b894 100644
--- a/drivers/tee/optee/core.c
+++ b/drivers/tee/optee/core.c
@@ -11,17 +11,17 @@
  * GNU General Public License for more details.
  *
  */
-#include <linux/types.h>
-#include <linux/string.h>
 #include <linux/errno.h>
-#include <linux/module.h>
-#include <linux/platform_device.h>
-#include <linux/slab.h>
-#include <linux/uaccess.h>
 #include <linux/io.h>
+#include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/string.h>
 #include <linux/tee_drv.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
 #include "optee_private.h"
 #include "optee_smc.h"
 
@@ -29,8 +29,16 @@
 
 #define OPTEE_SHM_NUM_PRIV_PAGES	1
 
+/**
+ * optee_from_msg_param() - convert from OPTEE_MSG parameters to
+ *			    struct tee_param
+ * @params:	subsystem internal parameter representation
+ * @num_params:	number of elements in the parameter arrays
+ * @msg_params:	OPTEE_MSG parameters
+ * Returns 0 on success or <0 on failure
+ */
 int optee_from_msg_param(struct tee_param *params, size_t num_params,
-			const struct optee_msg_param *msg_params)
+			 const struct optee_msg_param *msg_params)
 {
 	int rc;
 	size_t n;
@@ -92,8 +100,15 @@ int optee_from_msg_param(struct tee_param *params, size_t num_params,
 	return 0;
 }
 
+/**
+ * optee_to_msg_param() - convert from struct tee_params to OPTEE_MSG parameters
+ * @msg_params:	OPTEE_MSG parameters
+ * @num_params:	number of elements in the parameter arrays
+ * @params:	subsystem itnernal parameter representation
+ * Returns 0 on success or <0 on failure
+ */
 int optee_to_msg_param(struct optee_msg_param *msg_params, size_t num_params,
-			const struct tee_param *params)
+		       const struct tee_param *params)
 {
 	int rc;
 	size_t n;
@@ -145,7 +160,7 @@ int optee_to_msg_param(struct optee_msg_param *msg_params, size_t num_params,
 }
 
 static void optee_get_version(struct tee_device *teedev,
-			struct tee_ioctl_version_data *vers)
+			      struct tee_ioctl_version_data *vers)
 {
 	struct tee_ioctl_version_data v = {
 		.impl_id = TEE_IMPL_ID_OPTEE,
@@ -158,11 +173,22 @@ static void optee_get_version(struct tee_device *teedev,
 static int optee_open(struct tee_context *ctx)
 {
 	struct optee_context_data *ctxdata;
+	struct tee_device *teedev = ctx->teedev;
+	struct optee *optee = tee_get_drvdata(teedev);
 
 	ctxdata = kzalloc(sizeof(*ctxdata), GFP_KERNEL);
 	if (!ctxdata)
 		return -ENOMEM;
 
+	if (teedev == optee->supp_teedev) {
+		if (!atomic_dec_and_test(&optee->supp.available)) {
+			/* Supplicant device is already open */
+			atomic_inc(&optee->supp.available);
+			kfree(ctxdata);
+			return -EBUSY;
+		}
+	}
+
 	mutex_init(&ctxdata->mutex);
 	INIT_LIST_HEAD(&ctxdata->sess_list);
 
@@ -173,6 +199,8 @@ static int optee_open(struct tee_context *ctx)
 static void optee_release(struct tee_context *ctx)
 {
 	struct optee_context_data *ctxdata = ctx->data;
+	struct tee_device *teedev = ctx->teedev;
+	struct optee *optee = tee_get_drvdata(teedev);
 	struct tee_shm *shm;
 	struct optee_msg_arg *arg = NULL;
 	phys_addr_t parg;
@@ -217,6 +245,9 @@ static void optee_release(struct tee_context *ctx)
 		tee_shm_free(shm);
 
 	ctx->data = NULL;
+
+	if (teedev == optee->supp_teedev)
+		atomic_inc(&optee->supp.available);
 }
 
 static struct tee_driver_ops optee_ops = {
@@ -275,7 +306,7 @@ static bool optee_msg_api_revision_is_compatible(optee_invoke_fn *invoke_fn)
 }
 
 static bool optee_msg_exchange_capabilities(optee_invoke_fn *invoke_fn,
-			u32 *sec_caps)
+					    u32 *sec_caps)
 {
 	struct arm_smccc_res res;
 	u32 a1 = 0;
diff --git a/drivers/tee/optee/optee_msg.h b/drivers/tee/optee/optee_msg.h
index ca2f8aa54f5e..19377c77ccda 100644
--- a/drivers/tee/optee/optee_msg.h
+++ b/drivers/tee/optee/optee_msg.h
@@ -27,6 +27,7 @@
 #ifndef _OPTEE_MSG_H
 #define _OPTEE_MSG_H
 
+#include <linux/bitops.h>
 #include <linux/types.h>
 
 /*
@@ -63,14 +64,14 @@
  *
  * Currently only used with OPTEE_MSG_CMD_OPEN_SESSION.
  */
-#define OPTEE_MSG_ATTR_META			(1 << 8)
+#define OPTEE_MSG_ATTR_META			BIT(8)
 
 /*
  * The temporary shared memory object is not physically contigous and this
  * temp memref is followed by another fragment until the last temp memref
  * that doesn't have this bit set.
  */
-#define OPTEE_MSG_ATTR_FRAGMENT			(1 << 9)
+#define OPTEE_MSG_ATTR_FRAGMENT			BIT(9)
 
 /*
  * Memory attributes for caching passed with temp memrefs. The actual value
@@ -431,5 +432,4 @@ struct optee_msg_arg {
  */
 #define OPTEE_MSG_RPC_CMD_SHM_FREE	7
 
-
 #endif /* _OPTEE_MSG_H */
diff --git a/drivers/tee/optee/optee_private.h b/drivers/tee/optee/optee_private.h
index 7f13cb59da4a..2bd7dd87858d 100644
--- a/drivers/tee/optee/optee_private.h
+++ b/drivers/tee/optee/optee_private.h
@@ -15,11 +15,11 @@
 #ifndef OPTEE_PRIVATE_H
 #define OPTEE_PRIVATE_H
 
-#include <linux/types.h>
+#include <linux/arm-smccc.h>
 #include <linux/semaphore.h>
 #include <linux/tee_drv.h>
+#include <linux/types.h>
 #include "optee_msg.h"
-#include <linux/arm-smccc.h>
 
 #define OPTEE_MAX_ARG_SIZE	1024
 
@@ -37,16 +37,35 @@ typedef void (optee_invoke_fn)(unsigned long, unsigned long, unsigned long,
 				struct arm_smccc_res *);
 
 struct optee_call_queue {
+	/* Serializes access to this struct */
 	struct mutex mutex;
 	struct list_head waiters;
 };
 
 struct optee_wait_queue {
+	/* Serializes access to this struct */
 	struct mutex mu;
 	struct list_head db;
 };
 
+/**
+ * struct optee_supp - supplicant synchronization struct
+ * @available:		if 1 the supplicant device is available for use, else
+ *			busy
+ * @func:		supplicant function id to call
+ * @ret:		call return value
+ * @num_params:		number of elements in @param
+ * @param:		parameters for @func
+ * @req_posted:		if true, a request has been posted to the supplicant
+ * @supp_next_send:	if true, next step is for supplicant to send response
+ * @thrd_mutex:		held by the thread doing a request to supplicant
+ * @supp_mutex:		held by supplicant while operating on this struct
+ * @data_to_supp:	supplicant is waiting on this for next request
+ * @data_from_supp:	requesting thread is waiting on this to get the result
+ */
 struct optee_supp {
+	atomic_t available;
+
 	u32 func;
 	u32 ret;
 	size_t num_params;
@@ -54,12 +73,27 @@ struct optee_supp {
 
 	bool req_posted;
 	bool supp_next_send;
+	/* Serializes access to this struct for requesting thread */
 	struct mutex thrd_mutex;
+	/* Serializes access to this struct for supplicant threads */
 	struct mutex supp_mutex;
 	struct completion data_to_supp;
 	struct completion data_from_supp;
 };
 
+/**
+ * struct optee - main service struct
+ * @supp_teedev:	supplicant device
+ * @teedev:		client device
+ * @dev:		probed device
+ * @invoke_fn:		function to issue smc or hvc
+ * @call_queue:		queue of threads waiting to call @invoke_fn
+ * @wait_queue:		queue of threads from secure world waiting for a
+ *			secure world sync object
+ * @supp:		supplicant synchronization struct for RPC to supplicant
+ * @pool:		shared memory pool
+ * @ioremaped_shm	virtual address of memory in shared memory pool
+ */
 struct optee {
 	struct tee_device *supp_teedev;
 	struct tee_device *teedev;
@@ -78,6 +112,7 @@ struct optee_session {
 };
 
 struct optee_context_data {
+	/* Serializes access to this struct */
 	struct mutex mutex;
 	struct list_head sess_list;
 };
@@ -107,26 +142,26 @@ void optee_supp_init(struct optee_supp *supp);
 void optee_supp_uninit(struct optee_supp *supp);
 
 int optee_supp_recv(struct tee_context *ctx, u32 *func, u32 *num_params,
-			struct tee_param *param);
+		    struct tee_param *param);
 int optee_supp_send(struct tee_context *ctx, u32 ret, u32 num_params,
-			struct tee_param *param);
+		    struct tee_param *param);
 
 u32 optee_do_call_with_arg(struct tee_context *ctx, phys_addr_t parg);
 int optee_open_session(struct tee_context *ctx,
-			struct tee_ioctl_open_session_arg *arg,
-			struct tee_param *param);
+		       struct tee_ioctl_open_session_arg *arg,
+		       struct tee_param *param);
 int optee_close_session(struct tee_context *ctx, u32 session);
 int optee_invoke_func(struct tee_context *ctx, struct tee_ioctl_invoke_arg *arg,
-			struct tee_param *param);
+		      struct tee_param *param);
 int optee_cancel_req(struct tee_context *ctx, u32 cancel_id, u32 session);
 
 void optee_enable_shm_cache(struct optee *optee);
 void optee_disable_shm_cache(struct optee *optee);
 
 int optee_from_msg_param(struct tee_param *params, size_t num_params,
-			const struct optee_msg_param *msg_params);
+			 const struct optee_msg_param *msg_params);
 int optee_to_msg_param(struct optee_msg_param *msg_params, size_t num_params,
-			const struct tee_param *params);
+		       const struct tee_param *params);
 
 /*
  * Small helpers
diff --git a/drivers/tee/optee/optee_smc.h b/drivers/tee/optee/optee_smc.h
index 60d75f1791cd..2a1722984a0b 100644
--- a/drivers/tee/optee/optee_smc.h
+++ b/drivers/tee/optee/optee_smc.h
@@ -28,6 +28,7 @@
 #define OPTEE_SMC_H
 
 #include <linux/arm-smccc.h>
+#include <linux/bitops.h>
 
 #define OPTEE_SMC_STD_CALL_VAL(func_num) \
 	ARM_SMCCC_CALL_VAL(ARM_SMCCC_STD_CALL, ARM_SMCCC_SMC_32, \
@@ -202,11 +203,11 @@
  * a2-7 Preserved
  */
 /* Normal world works as a uniprocessor system */
-#define OPTEE_SMC_NSEC_CAP_UNIPROCESSOR		(1 << 0)
+#define OPTEE_SMC_NSEC_CAP_UNIPROCESSOR		BIT(0)
 /* Secure world has reserved shared memory for normal world to use */
-#define OPTEE_SMC_SEC_CAP_HAVE_RESERVERED_SHM	(1 << 0)
+#define OPTEE_SMC_SEC_CAP_HAVE_RESERVERED_SHM	BIT(0)
 /* Secure world can communicate via previously unregistered shared memory */
-#define OPTEE_SMC_SEC_CAP_UNREGISTERED_SHM	(1 << 1)
+#define OPTEE_SMC_SEC_CAP_UNREGISTERED_SHM	BIT(1)
 #define OPTEE_SMC_FUNCID_EXCHANGE_CAPABILITIES	9
 #define OPTEE_SMC_EXCHANGE_CAPABILITIES \
 	OPTEE_SMC_FAST_CALL_VAL(OPTEE_SMC_FUNCID_EXCHANGE_CAPABILITIES)
@@ -243,7 +244,6 @@
 #define OPTEE_SMC_DISABLE_SHM_CACHE \
 	OPTEE_SMC_FAST_CALL_VAL(OPTEE_SMC_FUNCID_DISABLE_SHM_CACHE)
 
-
 /*
  * Enable cache of shared memory objects
  *
diff --git a/drivers/tee/optee/rpc.c b/drivers/tee/optee/rpc.c
index 94b6ef8e00c7..ba8b5bbec203 100644
--- a/drivers/tee/optee/rpc.c
+++ b/drivers/tee/optee/rpc.c
@@ -12,8 +12,8 @@
  *
  */
 #include <linux/device.h>
-#include <linux/slab.h>
 #include <linux/sched.h>
+#include <linux/slab.h>
 #include <linux/tee_drv.h>
 #include "optee_private.h"
 #include "optee_smc.h"
@@ -67,7 +67,7 @@ static struct wq_entry *wq_entry_get(struct optee_wait_queue *wq, u32 key)
 		if (w->key == key)
 			goto out;
 
-	w = kmalloc(sizeof(struct wq_entry), GFP_KERNEL);
+	w = kmalloc(sizeof(*w), GFP_KERNEL);
 	if (w) {
 		init_completion(&w->c);
 		w->key = key;
@@ -100,7 +100,7 @@ static void wq_wakeup(struct optee_wait_queue *wq, u32 key)
 }
 
 static void handle_rpc_func_cmd_wq(struct optee *optee,
-			struct optee_msg_arg *arg)
+				   struct optee_msg_arg *arg)
 {
 	struct optee_msg_param *params;
 
@@ -157,7 +157,7 @@ bad:
 }
 
 static void handle_rpc_supp_cmd(struct tee_context *ctx,
-			struct optee_msg_arg *arg)
+				struct optee_msg_arg *arg)
 {
 	struct tee_param *params;
 	struct optee_msg_param *msg_params = OPTEE_MSG_GET_PARAMS(arg);
@@ -204,7 +204,7 @@ static struct tee_shm *cmd_alloc_suppl(struct tee_context *ctx, size_t sz)
 }
 
 static void handle_rpc_func_cmd_shm_alloc(struct tee_context *ctx,
-			struct optee_msg_arg *arg)
+					  struct optee_msg_arg *arg)
 {
 	struct tee_device *teedev = ctx->teedev;
 	struct optee_msg_param *params = OPTEE_MSG_GET_PARAMS(arg);
@@ -270,16 +270,24 @@ static void cmd_free_suppl(struct tee_context *ctx, struct tee_shm *shm)
 	param.u.value.b = tee_shm_get_id(shm);
 	param.u.value.c = 0;
 
-	optee_supp_thrd_req(ctx, OPTEE_MSG_RPC_CMD_SHM_FREE, 1, &param);
 	/*
 	 * Match the tee_shm_get_from_id() in cmd_alloc_suppl() as secure
 	 * world has released its reference.
+	 *
+	 * It's better to do this before sending the request to supplicant
+	 * as we'd like to let the process doing the initial allocation to
+	 * do release the last reference too in order to avoid stacking
+	 * many pending fput() on the client process. This could otherwise
+	 * happen if secure world does many allocate and free in a single
+	 * invoke.
 	 */
 	tee_shm_put(shm);
+
+	optee_supp_thrd_req(ctx, OPTEE_MSG_RPC_CMD_SHM_FREE, 1, &param);
 }
 
 static void handle_rpc_func_cmd_shm_free(struct tee_context *ctx,
-			struct optee_msg_arg *arg)
+					 struct optee_msg_arg *arg)
 {
 	struct optee_msg_param *params = OPTEE_MSG_GET_PARAMS(arg);
 	struct tee_shm *shm;
@@ -307,7 +315,7 @@ static void handle_rpc_func_cmd_shm_free(struct tee_context *ctx,
 }
 
 static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
-			struct tee_shm *shm)
+				struct tee_shm *shm)
 {
 	struct optee_msg_arg *arg;
 
@@ -339,6 +347,13 @@ static void handle_rpc_func_cmd(struct tee_context *ctx, struct optee *optee,
 	}
 }
 
+/**
+ * optee_handle_rpc() - handle RPC from secure world
+ * @ctx:	context doing the RPC
+ * @param:	value of registers for the RPC
+ *
+ * Result of RPC is written back into @param.
+ */
 void optee_handle_rpc(struct tee_context *ctx, struct optee_rpc_param *param)
 {
 	struct tee_device *teedev = ctx->teedev;
diff --git a/drivers/tee/optee/supp.c b/drivers/tee/optee/supp.c
index b6478b63d379..c64650aadcf7 100644
--- a/drivers/tee/optee/supp.c
+++ b/drivers/tee/optee/supp.c
@@ -23,6 +23,7 @@ void optee_supp_init(struct optee_supp *supp)
 	mutex_init(&supp->supp_mutex);
 	init_completion(&supp->data_to_supp);
 	init_completion(&supp->data_from_supp);
+	atomic_set(&supp->available, 1);
 }
 
 void optee_supp_uninit(struct optee_supp *supp)
@@ -31,6 +32,15 @@ void optee_supp_uninit(struct optee_supp *supp)
 	mutex_destroy(&supp->supp_mutex);
 }
 
+/**
+ * optee_supp_thrd_req() - request service from supplicant
+ * @ctx:	context doing the request
+ * @func:	function requested
+ * @num_params:	number of elements in @param array
+ * @param:	parameters for function
+ *
+ * Returns result of operation to be passed to secure world
+ */
 u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
 			struct tee_param *param)
 {
@@ -77,8 +87,18 @@ u32 optee_supp_thrd_req(struct tee_context *ctx, u32 func, size_t num_params,
 	return ret;
 }
 
+/**
+ * optee_supp_recv() - receive request for supplicant
+ * @ctx:	context receiving the request
+ * @func:	requested function in supplicant
+ * @num_params:	number of elements allocated in @param, updated with number
+ *		used elements
+ * @param:	space for parameters for @func
+ *
+ * Returns 0 on success or <0 on failure
+ */
 int optee_supp_recv(struct tee_context *ctx, u32 *func, u32 *num_params,
-		struct tee_param *param)
+		    struct tee_param *param)
 {
 	struct tee_device *teedev = ctx->teedev;
 	struct optee *optee = tee_get_drvdata(teedev);
@@ -144,8 +164,17 @@ out:
 	return rc;
 }
 
+/**
+ * optee_supp_send() - send result of request from supplicant
+ * @ctx:	context sending result
+ * @ret:	return value of request
+ * @num_params:	number of parameters returned
+ * @param:	returned parameters
+ *
+ * Returns 0 on success or <0 on failure.
+ */
 int optee_supp_send(struct tee_context *ctx, u32 ret, u32 num_params,
-			struct tee_param *param)
+		    struct tee_param *param)
 {
 	struct tee_device *teedev = ctx->teedev;
 	struct optee *optee = tee_get_drvdata(teedev);