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