Merge remote-tracking branch 'remotes/mst/tags/for_upstream' into staging

[qemu.git] / include / hw / stream.h

diff --git a/include/hw/stream.h b/include/hw/stream.h
index f6137d6e258d89a2821c622ac314e9b3b6cf86b9..15774f07abc6b0f01bf7c619d47f28bb24845fe7 100644 (file)
--- a/include/hw/stream.h
+++ b/include/hw/stream.h
@@ -1,5 +1,5 @@
 #ifndef STREAM_H
-#define STREAM_H 1
+#define STREAM_H
 
 #include "qemu-common.h"
 #include "qom/object.h"
@@ -14,18 +14,42 @@
 #define STREAM_SLAVE(obj) \
      INTERFACE_CHECK(StreamSlave, (obj), TYPE_STREAM_SLAVE)
 
-typedef struct StreamSlave {
-    Object Parent;
-} StreamSlave;
+typedef struct StreamSlave StreamSlave;
+
+typedef void (*StreamCanPushNotifyFn)(void *opaque);
 
 typedef struct StreamSlaveClass {
     InterfaceClass parent;
-
-    void (*push)(StreamSlave *obj, unsigned char *buf, size_t len,
-                                                    uint32_t *app);
+    /**
+     * can push - determine if a stream slave is capable of accepting at least
+     * one byte of data. Returns false if cannot accept. If not implemented, the
+     * slave is assumed to always be capable of receiving.
+     * @notify: Optional callback that the slave will call when the slave is
+     * capable of receiving again. Only called if false is returned.
+     * @notify_opaque: opaque data to pass to notify call.
+     */
+    bool (*can_push)(StreamSlave *obj, StreamCanPushNotifyFn notify,
+                     void *notify_opaque);
+    /**
+     * push - push data to a Stream slave. The number of bytes pushed is
+     * returned. If the slave short returns, the master must wait before trying
+     * again, the slave may continue to just return 0 waiting for the vm time to
+     * advance. The can_push() function can be used to trap the point in time
+     * where the slave is ready to receive again, otherwise polling on a QEMU
+     * timer will work.
+     * @obj: Stream slave to push to
+     * @buf: Data to write
+     * @len: Maximum number of bytes to write
+     */
+    size_t (*push)(StreamSlave *obj, unsigned char *buf, size_t len);
 } StreamSlaveClass;
 
-void
-stream_push(StreamSlave *sink, uint8_t *buf, size_t len, uint32_t *app);
+size_t
+stream_push(StreamSlave *sink, uint8_t *buf, size_t len);
+
+bool
+stream_can_push(StreamSlave *sink, StreamCanPushNotifyFn notify,
+                void *notify_opaque);
+
 
 #endif /* STREAM_H */