include/hw/stream.h

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