include/hw/stream.h

   1 #ifndef STREAM_H
   2 #define STREAM_H
   3
   4 #include "qemu-common.h"
   5 #include "qom/object.h"
   6
   7 /* stream slave. Used until qdev provides a generic way.  */
   8 #define TYPE_STREAM_SLAVE "stream-slave"
   9
  10 #define STREAM_SLAVE_CLASS(klass) \
  11      OBJECT_CLASS_CHECK(StreamSlaveClass, (klass), TYPE_STREAM_SLAVE)
  12 #define STREAM_SLAVE_GET_CLASS(obj) \
  13     OBJECT_GET_CLASS(StreamSlaveClass, (obj), TYPE_STREAM_SLAVE)
  14 #define STREAM_SLAVE(obj) \
  15      INTERFACE_CHECK(StreamSlave, (obj), TYPE_STREAM_SLAVE)
  16
  17 typedef struct StreamSlave {
  18     Object Parent;
  19 } StreamSlave;
  20
  21 typedef void (*StreamCanPushNotifyFn)(void *opaque);
  22
  23 typedef struct StreamSlaveClass {
  24     InterfaceClass parent;
  25     /**
  26      * can push - determine if a stream slave is capable of accepting at least
  27      * one byte of data. Returns false if cannot accept. If not implemented, the
  28      * slave is assumed to always be capable of receiving.
  29      * @notify: Optional callback that the slave will call when the slave is
  30      * capable of receiving again. Only called if false is returned.
  31      * @notify_opaque: opaque data to pass to notify call.
  32      */
  33     bool (*can_push)(StreamSlave *obj, StreamCanPushNotifyFn notify,
  34                      void *notify_opaque);
  35     /**
  36      * push - push data to a Stream slave. The number of bytes pushed is
  37      * returned. If the slave short returns, the master must wait before trying
  38      * again, the slave may continue to just return 0 waiting for the vm time to
  39      * advance. The can_push() function can be used to trap the point in time
  40      * where the slave is ready to receive again, otherwise polling on a QEMU
  41      * timer will work.
  42      * @obj: Stream slave to push to
  43      * @buf: Data to write
  44      * @len: Maximum number of bytes to write
  45      */
  46     size_t (*push)(StreamSlave *obj, unsigned char *buf, size_t len);
  47 } StreamSlaveClass;
  48
  49 size_t
  50 stream_push(StreamSlave *sink, uint8_t *buf, size_t len);
  51
  52 bool
  53 stream_can_push(StreamSlave *sink, StreamCanPushNotifyFn notify,
  54                 void *notify_opaque);
  55
  56
  57 #endif /* STREAM_H */