greybus: operation: add support for initiating unidirectional operations

Add support for initiating unidirectional operations, that is, sending
requests that do not require responses.

Note that we already handle incoming unidirectional operations.

Signed-off-by: Johan Hovold <johan@hovoldconsulting.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>

diff --git a/drivers/staging/greybus/operation.c b/drivers/staging/greybus/operation.c
index bb89955..9fb7993 100644 (file)
--- a/drivers/staging/greybus/operation.c
+++ b/drivers/staging/greybus/operation.c
@@ -635,9 +635,10 @@ static void gb_operation_sync_callback(struct gb_operation *operation)
  *
  * The caller has filled in any payload so the request message is ready to go.
  * The callback function supplied will be called when the response message has
- * arrived, or the operation is cancelled, indicating that the operation is
- * complete. The callback function can fetch the result of the operation using
- * gb_operation_result() if desired.
+ * arrived, a unidirectional request has been sent, or the operation is
+ * cancelled, indicating that the operation is complete. The callback function
+ * can fetch the result of the operation using gb_operation_result() if
+ * desired.
  *
  * Return: 0 if the request was successfully queued in the host-driver queues,
  * or a negative errno.
@@ -653,6 +654,7 @@ int gb_operation_request_send(struct gb_operation *operation,
 
        if (!callback)
                return -EINVAL;
+
        /*
         * Record the callback function, which is executed in
         * non-atomic (workqueue) context when the final result
@@ -662,10 +664,15 @@ int gb_operation_request_send(struct gb_operation *operation,
 
        /*
         * Assign the operation's id, and store it in the request header.
-        * Zero is a reserved operation id.
+        * Zero is a reserved operation id for unidirectional operations.
         */
-       cycle = (unsigned int)atomic_inc_return(&connection->op_cycle);
-       operation->id = (u16)(cycle % U16_MAX + 1);
+       if (gb_operation_is_unidirectional(operation)) {
+               operation->id = 0;
+       } else {
+               cycle = (unsigned int)atomic_inc_return(&connection->op_cycle);
+               operation->id = (u16)(cycle % U16_MAX + 1);
+       }
+
        header = operation->request->header;
        header->operation_id = cpu_to_le16(operation->id);
 
@@ -799,10 +806,11 @@ void greybus_message_sent(struct gb_host_device *hd,
         * reference to the operation.  If an error occurred, report
         * it.
         *
-        * For requests, if there's no error, there's nothing more
-        * to do until the response arrives.  If an error occurred
-        * attempting to send it, record that as the result of
-        * the operation and schedule its completion.
+        * For requests, if there's no error and the operation in not
+        * unidirectional, there's nothing more to do until the response
+        * arrives. If an error occurred attempting to send it, or if the
+        * operation is unidrectional, record the result of the operation and
+        * schedule its completion.
         */
        if (message == operation->response) {
                if (status) {
@@ -810,9 +818,10 @@ void greybus_message_sent(struct gb_host_device *hd,
                                "%s: error sending response 0x%02x: %d\n",
                                connection->name, operation->type, status);
                }
+
                gb_operation_put_active(operation);
                gb_operation_put(operation);
-       } else if (status) {
+       } else if (status || gb_operation_is_unidirectional(operation)) {
                if (gb_operation_result_set(operation, status)) {
                        queue_work(gb_operation_completion_wq,
                                        &operation->work);
@@ -876,6 +885,13 @@ static void gb_connection_recv_response(struct gb_connection *connection,
        int errno = gb_operation_status_map(result);
        size_t message_size;
 
+       if (!operation_id) {
+               dev_err(&connection->hd->dev,
+                               "%s: invalid response id 0 received\n",
+                               connection->name);
+               return;
+       }
+
        operation = gb_operation_find_outgoing(connection, operation_id);
        if (!operation) {
                dev_err(&connection->hd->dev,

diff --git a/drivers/staging/greybus/operation.h b/drivers/staging/greybus/operation.h
index 38e5303..c88efe1 100644 (file)
--- a/drivers/staging/greybus/operation.h
+++ b/drivers/staging/greybus/operation.h
@@ -67,7 +67,8 @@ struct gb_message {
 #define GB_OPERATION_FLAG_UNIDIRECTIONAL       BIT(1)
 #define GB_OPERATION_FLAG_SHORT_RESPONSE       BIT(2)
 
-#define GB_OPERATION_FLAG_USER_MASK    GB_OPERATION_FLAG_SHORT_RESPONSE
+#define GB_OPERATION_FLAG_USER_MASK    (GB_OPERATION_FLAG_SHORT_RESPONSE | \
+                                        GB_OPERATION_FLAG_UNIDIRECTIONAL)
 
 /*
  * A Greybus operation is a remote procedure call performed over a