[PATCH 5/6] soc: qcom: Introduce QMI helpers

[Bjorn Andersson]

Drivers that needs to communicate with a remote QMI service all has to
perform the operations of discovering the service, encoding and decoding
the messages and operate the socket. This introduces an abstraction for
these common operations, reducing most of the duplication in such cases.

Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxx>
---
 drivers/soc/qcom/Makefile        |   1 +
 drivers/soc/qcom/qmi_interface.c | 540 +++++++++++++++++++++++++++++++++++++++
 include/linux/soc/qcom/qmi.h     | 133 ++++++++++
 3 files changed, 674 insertions(+)
 create mode 100644 drivers/soc/qcom/qmi_interface.c

diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 27b60da7a062..812402ae9cfa 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -3,6 +3,7 @@ obj-$(CONFIG_QCOM_MDT_LOADER)	+= mdt_loader.o
 obj-$(CONFIG_QCOM_PM)	+=	spm.o
 obj-$(CONFIG_QCOM_QMI_HELPERS)	+= qmi_helpers.o
 qmi_helpers-y	+= qmi_encdec.o
+qmi_helpers-y	+= qmi_interface.o
 obj-$(CONFIG_QCOM_SMD_RPM)	+= smd-rpm.o
 obj-$(CONFIG_QCOM_SMEM) +=	smem.o
 obj-$(CONFIG_QCOM_SMEM_STATE) += smem_state.o
diff --git a/drivers/soc/qcom/qmi_interface.c b/drivers/soc/qcom/qmi_interface.c
new file mode 100644
index 000000000000..41853a9becfd
--- /dev/null
+++ b/drivers/soc/qcom/qmi_interface.c
@@ -0,0 +1,540 @@
+/*
+ * Sample QRTR client driver
+ *
+ * Copyright (C) 2017 Linaro Ltd.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/qrtr.h>
+#include <linux/net.h>
+#include <linux/completion.h>
+#include <linux/idr.h>
+#include <linux/string.h>
+#include <net/sock.h>
+#include <linux/workqueue.h>
+#include <linux/soc/qcom/qmi.h>
+
+/**
+ * qrtr_client_new_server() - handler of NEW_SERVER control message
+ * @qrtr:	qrtr handle
+ * @node:	node of the new server
+ * @port:	port of the new server
+ *
+ * Calls the new_server callback to inform the client about a newly registered
+ * server matching the currently registered service lookup.
+ */
+static void qrtr_client_new_server(struct qrtr_handle *qrtr,
+				   unsigned int node, unsigned int port)
+{
+	struct qrtr_handle_ops *ops = &qrtr->ops;
+	struct qrtr_service *service;
+	int ret;
+
+	if (!ops->new_server)
+		return;
+
+	/* Ignore EOF marker */
+	if (!node && !port)
+		return;
+
+	service = kzalloc(sizeof(*service), GFP_KERNEL);
+	if (!service)
+		return;
+
+	service->node = node;
+	service->port = port;
+
+	ret = ops->new_server(qrtr, service);
+	if (ret < 0)
+		kfree(service);
+	else
+		list_add(&service->list_node, &qrtr->services);
+}
+
+/**
+ * qrtr_client_del_server() - handler of DEL_SERVER control message
+ * @qrtr:	qrtr handle
+ * @node:	node of the dying server, a value of -1 matches all nodes
+ * @port:	port of the dying server, a value of -1 matches all ports
+ *
+ * Calls the del_server callback for each previously seen server, allowing the
+ * client to react to the disappearing server.
+ */
+static void qrtr_client_del_server(struct qrtr_handle *qrtr,
+				   unsigned int node, unsigned int port)
+{
+	struct qrtr_handle_ops *ops = &qrtr->ops;
+	struct qrtr_service *service;
+	struct qrtr_service *tmp;
+
+	list_for_each_entry_safe(service, tmp, &qrtr->services, list_node) {
+		if (node != -1 && service->node != node)
+			continue;
+		if (port != -1 && service->port != port)
+			continue;
+
+		if (ops->del_server)
+			ops->del_server(qrtr, service);
+
+		list_del(&service->list_node);
+		kfree(service);
+	}
+}
+
+static void qrtr_client_ctrl_pkt(struct qrtr_handle *qrtr,
+				 const void *buf, size_t len)
+{
+	const struct qrtr_ctrl_pkt *pkt = buf;
+
+	if (len < sizeof(struct qrtr_ctrl_pkt)) {
+		pr_debug("ignoring short control packet\n");
+		return;
+	}
+
+	switch (le32_to_cpu(pkt->cmd)) {
+	case QRTR_TYPE_NEW_SERVER:
+		qrtr_client_new_server(qrtr,
+				       le32_to_cpu(pkt->server.node),
+				       le32_to_cpu(pkt->server.port));
+		break;
+	case QRTR_TYPE_DEL_SERVER:
+		qrtr_client_del_server(qrtr,
+				       le32_to_cpu(pkt->server.node),
+				       le32_to_cpu(pkt->server.port));
+		break;
+	}
+}
+
+static void qrtr_client_data_ready_work(struct work_struct *work)
+{
+	struct qrtr_handle *qrtr = container_of(work, struct qrtr_handle, work);
+	struct qrtr_handle_ops *ops = &qrtr->ops;
+	struct sockaddr_qrtr sq;
+	struct msghdr msg = { .msg_name = &sq, .msg_namelen = sizeof(sq) };
+	struct kvec iv;
+	ssize_t msglen;
+
+	for (;;) {
+		iv.iov_base = qrtr->recv_buf;
+		iv.iov_len = qrtr->recv_buf_size;
+
+		msglen = kernel_recvmsg(qrtr->sock, &msg, &iv, 1, iv.iov_len,
+					MSG_DONTWAIT);
+		if (msglen == -EAGAIN)
+			break;
+
+		if (msglen == -ENETRESET) {
+			if (ops->net_reset)
+				ops->net_reset(qrtr);
+			break;
+		}
+
+		if (msglen < 0) {
+			pr_err("qrtr_handle recvmsg failed: %zd\n", msglen);
+			break;
+		}
+
+		if (sq.sq_node == qrtr->sq.sq_node &&
+		    sq.sq_port == QRTR_PORT_CTRL) {
+			qrtr_client_ctrl_pkt(qrtr, qrtr->recv_buf, msglen);
+		} else {
+			if (!ops->msg_handler)
+				continue;
+
+			ops->msg_handler(qrtr, &sq, qrtr->recv_buf, msglen);
+		}
+	}
+}
+
+static void qrtr_client_schedule_worker(struct sock *sk)
+{
+	struct qrtr_handle *qrtr = sk->sk_user_data;
+
+	/*
+	 * This will be NULL if we receive data while being in
+	 * qrtr_client_release()
+	 */
+	if (!qrtr)
+		return;
+
+	queue_work(qrtr->wq, &qrtr->work);
+}
+
+/**
+ * qrtr_client_init() - initialize a qrtr_handle
+ * @qrtr:		reference to qrtr handle
+ * @recv_buf_size:	maximum size of received messages
+ * @ops:		qrtr_handle_ops struct with callbacks
+ *
+ * Returns 0 on success, negative errno on failure.
+ *
+ * This function initializes @qrtr to allow sending, receiving and handling
+ * QRTR control messages and data packets.
+ */
+int qrtr_client_init(struct qrtr_handle *qrtr, size_t recv_buf_size,
+		     struct qrtr_handle_ops *ops)
+{
+	struct sockaddr_qrtr sq;
+	struct socket *sock;
+	int ret;
+	int sl = sizeof(sq);
+
+	if (recv_buf_size < sizeof(struct qrtr_ctrl_pkt))
+		recv_buf_size = sizeof(struct qrtr_ctrl_pkt);
+
+	INIT_LIST_HEAD(&qrtr->services);
+	INIT_WORK(&qrtr->work, qrtr_client_data_ready_work);
+
+	qrtr->wq = alloc_workqueue("qrtr_handle", WQ_UNBOUND, 1);
+	if (!qrtr->wq)
+		return -ENOMEM;
+
+	qrtr->ops = *ops;
+	qrtr->recv_buf_size = recv_buf_size;
+	qrtr->recv_buf = kzalloc(recv_buf_size, GFP_KERNEL);
+	if (!qrtr->recv_buf)
+		return -ENOMEM;
+
+	ret = sock_create_kern(&init_net, AF_QIPCRTR, SOCK_DGRAM,
+			       PF_QIPCRTR, &sock);
+	if (ret < 0)
+		goto err_free_recv_buf;
+
+	ret = kernel_getsockname(sock, (struct sockaddr *)&sq, &sl);
+	if (ret < 0)
+		goto err_release_sock;
+
+	qrtr->sock = sock;
+	qrtr->sq = sq;
+
+	sock->sk->sk_user_data = qrtr;
+	sock->sk->sk_data_ready = qrtr_client_schedule_worker;
+	sock->sk->sk_error_report = qrtr_client_schedule_worker;
+
+	return 0;
+err_release_sock:
+	sock_release(sock);
+
+err_free_recv_buf:
+	kfree(qrtr->recv_buf);
+
+	return ret;
+}
+EXPORT_SYMBOL(qrtr_client_init);
+
+/**
+ * qrtr_client_release() - tear down a qrtr_handle
+ * @qrtr:	qrtr handle
+ *
+ * This will tear down the qrtr handle, stop handling of any incoming messages
+ * and release the underlying socket.
+ */
+void qrtr_client_release(struct qrtr_handle *qrtr)
+{
+	struct socket *sock = qrtr->sock;
+
+	sock->sk->sk_user_data = NULL;
+	cancel_work_sync(&qrtr->work);
+
+	kfree(qrtr->recv_buf);
+
+	qrtr_client_del_server(qrtr, -1, -1);
+
+	sock_release(sock);
+	qrtr->sock = NULL;
+
+	destroy_workqueue(qrtr->wq);
+}
+EXPORT_SYMBOL(qrtr_client_release);
+
+/**
+ * qrtr_client_new_lookup() - register a new lookup with the name service
+ * @qrtr:	qrtr handle
+ * @service:	service id of the request
+ * @instance:	instance id of the request
+ *
+ * Returns 0 on success, negative errno on failure.
+ *
+ * Registering a lookup query with the name server will cause the name server
+ * to send NEW_SERVER and DEL_SERVER control messages to this socket as
+ * matching services are registered.
+ */
+int qrtr_client_new_lookup(struct qrtr_handle *qrtr,
+			   unsigned int service, unsigned int instance)
+{
+	struct qrtr_ctrl_pkt pkt;
+	struct sockaddr_qrtr sq;
+	struct msghdr msg = {0};
+	struct kvec iv = { &pkt, sizeof(pkt) };
+	int ret;
+
+	memset(&pkt, 0, sizeof(pkt));
+	pkt.cmd = cpu_to_le32(QRTR_TYPE_NEW_LOOKUP);
+	pkt.server.service = cpu_to_le32(service);
+	pkt.server.instance = cpu_to_le32(instance);
+
+	sq.sq_family = qrtr->sq.sq_family;
+	sq.sq_node = qrtr->sq.sq_node;
+	sq.sq_port = QRTR_PORT_CTRL;
+
+	msg.msg_name = &sq;
+	msg.msg_namelen = sizeof(sq);
+
+	ret = kernel_sendmsg(qrtr->sock, &msg, &iv, 1, sizeof(pkt));
+	if (ret < 0)
+		pr_err("failed to send lookup registration: %d\n", ret);
+
+	return ret < 0 ? ret : 0;
+}
+EXPORT_SYMBOL(qrtr_client_new_lookup);
+
+/**
+ * qmi_txn_init() - allocate transaction id within the given QMI handle
+ * @qmi:	QMI handle
+ * @txn:	transaction context
+ * @ei:		description of how to decode a matching response (optional)
+ * @c_struct:	pointer to the object to decode the response into (optional)
+ *
+ * Returns transaction id on success, negative errno on failure.
+ *
+ * This allocates a transaction id within the QMI handle. If @ei and @c_struct
+ * are specified any responses to this transaction will be decoded as described
+ * by @ei into @c_struct.
+ */
+int qmi_txn_init(struct qmi_handle *qmi, struct qmi_txn *txn,
+		 struct qmi_elem_info *ei, void *c_struct)
+{
+	int ret;
+
+	memset(txn, 0, sizeof(*txn));
+
+	init_completion(&txn->completion);
+	txn->qmi = qmi;
+	txn->ei = ei;
+	txn->dest = c_struct;
+
+	mutex_lock(&qmi->txn_lock);
+	ret = idr_alloc_cyclic(&qmi->txns, txn, 0, INT_MAX, GFP_KERNEL);
+	if (ret < 0)
+		pr_err("failed to allocate transaction id\n");
+
+	txn->id = ret;
+	mutex_unlock(&qmi->txn_lock);
+
+	return ret;
+}
+EXPORT_SYMBOL(qmi_txn_init);
+
+/**
+ * qmi_txn_wait() - wait for a response on a transaction
+ * @txn:	transaction handle
+ * @timeout:	timeout, in jiffies
+ *
+ * Returns the transaction response on success, negative errno on failure.
+ *
+ * If the transaction is decoded by the means of @ei and @c_struct the return
+ * value will be the returned value of qmi_decode_message(), otherwise it's up
+ * to the specified message handler to fill out the result.
+ */
+int qmi_txn_wait(struct qmi_txn *txn, unsigned long timeout)
+{
+	struct qmi_handle *qmi = txn->qmi;
+	int ret;
+
+	ret = wait_for_completion_interruptible_timeout(&txn->completion,
+							timeout);
+
+	mutex_lock(&qmi->txn_lock);
+	idr_remove(&qmi->txns, txn->id);
+	mutex_unlock(&qmi->txn_lock);
+
+	if (ret < 0)
+		return ret;
+	else if (ret == 0)
+		return -ETIMEDOUT;
+	else
+		return txn->result;
+}
+EXPORT_SYMBOL(qmi_txn_wait);
+
+/**
+ * qmi_txn_cancel() - cancel an ongoing transaction
+ * @txn:	transaction id
+ */
+void qmi_txn_cancel(struct qmi_txn *txn)
+{
+	struct qmi_handle *qmi = txn->qmi;
+
+	mutex_lock(&qmi->txn_lock);
+	idr_remove(&qmi->txns, txn->id);
+	mutex_unlock(&qmi->txn_lock);
+}
+EXPORT_SYMBOL(qmi_txn_cancel);
+
+static void qmi_client_handle_data(struct qrtr_handle *qrtr,
+				   struct sockaddr_qrtr *sq,
+				   const void *buf, size_t len)
+{
+	const struct qmi_header *hdr = buf;
+	struct qmi_handle *qmi = container_of(qrtr, struct qmi_handle, qrtr);
+	struct qmi_msg_handler *handler;
+	struct qmi_txn *txn = NULL;
+	void *dest;
+	int ret;
+
+	if (len < sizeof(*hdr)) {
+		pr_err("ignoring short QMI packet\n");
+		return;
+	}
+
+	mutex_lock(&qmi->txn_lock);
+
+	/* If this is a response, find the matching transaction handle */
+	if (hdr->type == QMI_RESPONSE)
+		txn = idr_find(&qmi->txns, hdr->txn_id);
+
+	if (txn && txn->dest && txn->ei) {
+		ret = qmi_decode_message(buf, len, txn->ei, txn->dest);
+		if (ret < 0)
+			pr_err("failed to decode incoming message\n");
+
+		txn->result = ret;
+		complete(&txn->completion);
+	} else if (qmi->handlers) {
+		for (handler = qmi->handlers; handler->fn; handler++) {
+			if (handler->type == hdr->type &&
+			    handler->msg_id == hdr->msg_id)
+				break;
+		}
+
+		if (!handler->fn)
+			goto out;
+
+		dest = kzalloc(handler->decoded_size, GFP_KERNEL);
+		if (!dest)
+			goto out;
+
+		ret = qmi_decode_message(buf, len, handler->ei, dest);
+		if (ret < 0)
+			pr_err("failed to decode incoming message\n");
+		else
+			handler->fn(qmi, sq, txn, dest);
+
+		kfree(dest);
+	}
+
+out:
+	mutex_unlock(&qmi->txn_lock);
+}
+
+/**
+ * qmi_client_init() - initialize a QMI client handle
+ * @qmi:	QMI handle to initialize
+ * @max_msg_len: maximum size of incoming message
+ * @handlers:	NULL-terminated list of QMI message handlers
+ *
+ * Returns 0 on success, negative errno on failure.
+ *
+ * This initializes the QMI client handle to allow sending and receiving QMI
+ * messages. As messages are received the appropriate handler will be invoked.
+ */
+int qmi_client_init(struct qmi_handle *qmi, size_t max_msg_len,
+		    struct qmi_msg_handler *handlers)
+{
+	struct qrtr_handle_ops ops = { 0 };
+	int ret;
+
+	mutex_init(&qmi->txn_lock);
+	idr_init(&qmi->txns);
+
+	ops.msg_handler = qmi_client_handle_data;
+
+	ret = qrtr_client_init(&qmi->qrtr, max_msg_len, &ops);
+	if (ret < 0)
+		return ret;
+
+	qmi->handlers = handlers;
+
+	return 0;
+}
+EXPORT_SYMBOL(qmi_client_init);
+
+/**
+ * qrtr_client_release() - release the QMI client handle
+ * @qmi:	QMI client handle
+ *
+ * This closes the underlying socket and stops any handling of QMI messages.
+ */
+void qmi_client_release(struct qmi_handle *qmi)
+{
+	qrtr_client_release(&qmi->qrtr);
+
+	idr_destroy(&qmi->txns);
+
+}
+EXPORT_SYMBOL(qmi_client_release);
+
+/**
+ * qmi_send_message() - send a QMI message
+ * @qmi:	QMI client handle
+ * @sq:		destination sockaddr
+ * @txn:	transaction object to use for the message
+ * @type:	type of message to send
+ * @msg_id:	message id
+ * @len:	max length of the QMI message
+ * @ei:		QMI message description
+ * @c_struct:	object to be encoded
+ *
+ * Returns 0 on success, negative errno on failure.
+ *
+ * This function encodes @c_struct using @ei into a message of type @type,
+ * with @msg_id and @txn into a buffer of maximum size @len, and sends this to
+ * @sq.
+ */
+ssize_t qmi_send_message(struct qmi_handle *qmi,
+			 struct sockaddr_qrtr *sq, struct qmi_txn *txn,
+			 int type, int msg_id, size_t len,
+			 struct qmi_elem_info *ei, const void *c_struct)
+{
+	struct qrtr_handle *qrtr = &qmi->qrtr;
+	struct msghdr msghdr = {0};
+	struct kvec iv;
+	void *msg;
+	int ret;
+
+	msg = qmi_encode_message(type,
+				 msg_id, &len,
+				 txn->id, ei,
+				 c_struct);
+	if (IS_ERR(msg))
+		return PTR_ERR(msg);
+
+	iv.iov_base = msg;
+	iv.iov_len = len;
+
+	if (sq) {
+		msghdr.msg_name = sq;
+		msghdr.msg_namelen = sizeof(*sq);
+	}
+
+	ret = kernel_sendmsg(qrtr->sock, &msghdr, &iv, 1, len);
+	if (ret < 0)
+		pr_err("failed to send QMI message\n");
+
+	kfree(msg);
+
+	return ret < 0 ? ret : 0;
+}
+EXPORT_SYMBOL(qmi_send_message);
diff --git a/include/linux/soc/qcom/qmi.h b/include/linux/soc/qcom/qmi.h
index c012a1e9e24b..add7570fa14b 100644
--- a/include/linux/soc/qcom/qmi.h
+++ b/include/linux/soc/qcom/qmi.h
@@ -105,6 +105,135 @@ struct qmi_response_type_v01 {
 
 extern struct qmi_elem_info qmi_response_type_v01_ei[];
 
+/**
+ * struct qrtr_service - context to track lookup-results
+ * @node:	node of the service
+ * @port:	port of the service
+ * @cookie:	handle for client's use
+ * @list_node:	list_head for house keeping
+ */
+struct qrtr_service {
+	unsigned int node;
+	unsigned int port;
+
+	void *cookie;
+	struct list_head list_node;
+};
+
+struct qrtr_handle;
+
+/**
+ * struct qrtr_handle_ops - callbacks from qrtr_handle
+ * @new_server:		invoked as a new_server message arrives
+ * @del_server:		invoked as a del_server message arrives
+ * @net_reset:		invoked as the name server is restarted
+ * @msg_handler:	invoked as a non-control message arrives
+ */
+struct qrtr_handle_ops {
+	int (*new_server)(struct qrtr_handle *, struct qrtr_service *);
+	void (*del_server)(struct qrtr_handle *, struct qrtr_service *);
+	void (*net_reset)(struct qrtr_handle *);
+	void (*msg_handler)(struct qrtr_handle *, struct sockaddr_qrtr *,
+			    const void *, size_t);
+};
+
+/**
+ * struct qrtr_handle - qrtr client context
+ * @sock:	socket handle
+ * @sq:		sockaddr of @sock
+ * @work:	work for handling incoming messages
+ * @wq:		workqueue to post @work on
+ * @recv_buf:	scratch buffer for handling incoming messages
+ * @recv_buf_size:	size of @recv_buf
+ * @services:	list of services advertised to the client
+ * @ops:	reference to callbacks
+ */
+struct qrtr_handle {
+	struct socket *sock;
+	struct sockaddr_qrtr sq;
+
+	struct work_struct work;
+	struct workqueue_struct *wq;
+
+	void *recv_buf;
+	size_t recv_buf_size;
+
+	struct list_head services;
+
+	struct qrtr_handle_ops ops;
+};
+
+/**
+ * struct qmi_txn - transaction context
+ * @qmi:	QMI handle this transaction is associated with
+ * @id:		transaction id
+ * @completion:	completion object as the transaction receives a response
+ * @result:	result code for the completed transaction
+ * @ei:		description of the QMI encoded response (optional)
+ * @dest:	destination buffer to decode message into (optional)
+ */
+struct qmi_txn {
+	struct qmi_handle *qmi;
+
+	int id;
+
+	struct completion completion;
+	int result;
+
+	struct qmi_elem_info *ei;
+	void *dest;
+};
+
+/**
+ * struct qmi_msg_handler - description of QMI message handler
+ * @type:	type of message
+ * @msg_id:	message id
+ * @ei:		description of the QMI encoded message
+ * @decoded_size:	size of the decoded object
+ * @fn:		function to invoke as the message is decoded
+ */
+struct qmi_msg_handler {
+	unsigned int type;
+	unsigned int msg_id;
+
+	struct qmi_elem_info *ei;
+
+	size_t decoded_size;
+	void (*fn)(struct qmi_handle *qmi, struct sockaddr_qrtr *sq,
+		   struct qmi_txn *txn, const void *decoded);
+};
+
+/**
+ * struct qmi_handle - QMI client handle
+ * @qrtr:	qrtr handle backing the QMI client
+ * @txns:	outstanding transactions
+ * @txn_lock:	lock for modifications of @txns
+ * @handlers:	list of handlers for incoming messages
+ */
+struct qmi_handle {
+	struct qrtr_handle qrtr;
+
+	struct idr txns;
+	struct mutex txn_lock;
+
+	struct qmi_msg_handler *handlers;
+};
+
+int qrtr_client_init(struct qrtr_handle *qrtr, size_t recv_buf_size,
+		     struct qrtr_handle_ops *ops);
+void qrtr_client_release(struct qrtr_handle *qrtr);
+int qrtr_client_new_lookup(struct qrtr_handle *qrtr,
+			   unsigned int service, unsigned int instance);
+
+int qmi_client_init(struct qmi_handle *qmi, size_t max_msg_len,
+		    struct qmi_msg_handler *handlers);
+void qmi_client_release(struct qmi_handle *qmi);
+
+ssize_t qmi_send_message(struct qmi_handle *qmi,
+			 struct sockaddr_qrtr *sq, struct qmi_txn *txn,
+			 int type, int msg_id, size_t len,
+			 struct qmi_elem_info *ei, const void *c_struct);
+
 void *qmi_encode_message(int type, unsigned int msg_id, size_t *len,
 			 unsigned int txn_id, struct qmi_elem_info *ei,
 			 const void *c_struct);
@@ -112,5 +241,9 @@ void *qmi_encode_message(int type, unsigned int msg_id, size_t *len,
 int qmi_decode_message(const void *buf, size_t len,
 		       struct qmi_elem_info *ei, void *c_struct);
 
+int qmi_txn_init(struct qmi_handle *qmi, struct qmi_txn *txn,
+		 struct qmi_elem_info *ei, void *c_struct);
+int qmi_txn_wait(struct qmi_txn *txn, unsigned long timeout);
+void qmi_txn_cancel(struct qmi_txn *txn);
 
 #endif
-- 
2.12.0