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