char: document the functions that will be the public interface

Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

qemu-char.h

@@ -76,33 +76,156 @@ struct CharDriverState {
     QTAILQ_ENTRY(CharDriverState) next;
 };
 
-QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename);
+/**
+ * @qemu_chr_new_from_opts:
+ *
+ * Create a new character backend from a QemuOpts list.
+ *
+ * @opts see qemu-config.c for a list of valid options
+ * @init not sure..
+ *
+ * Returns: a new character backend
+ */
 CharDriverState *qemu_chr_new_from_opts(QemuOpts *opts,
                                     void (*init)(struct CharDriverState *s));
-CharDriverState *qemu_chr_new(const char *label, const char *filename, void (*init)(struct CharDriverState *s));
+
+/**
+ * @qemu_chr_new:
+ *
+ * Create a new character backend from a URI.
+ *
+ * @label the name of the backend
+ * @filename the URI
+ * @init not sure..
+ *
+ * Returns: a new character backend
+ */
+CharDriverState *qemu_chr_new(const char *label, const char *filename,
+                              void (*init)(struct CharDriverState *s));
+
+/**
+ * @qemu_chr_delete:
+ *
+ * Destroy a character backend.
+ */
+void qemu_chr_delete(CharDriverState *chr);
+
+/**
+ * @qemu_chr_fe_set_echo:
+ *
+ * Ask the backend to override its normal echo setting.  This only really
+ * applies to the stdio backend and is used by the QMP server such that you
+ * can see what you type if you try to type QMP commands.
+ *
+ * @echo true to enable echo, false to disable echo
+ */
 void qemu_chr_fe_set_echo(struct CharDriverState *chr, bool echo);
+
+/**
+ * @qemu_chr_fe_open:
+ *
+ * Open a character backend.  This function call is an indication that the
+ * front end is ready to begin doing I/O.
+ */
 void qemu_chr_fe_open(struct CharDriverState *chr);
+
+/**
+ * @qemu_chr_fe_close:
+ *
+ * Close a character backend.  This function call indicates that the front end
+ * no longer is able to process I/O.  To process I/O again, the front end will
+ * call @qemu_chr_fe_open.
+ */
 void qemu_chr_fe_close(struct CharDriverState *chr);
-void qemu_chr_delete(CharDriverState *chr);
+
+/**
+ * @qemu_chr_fe_printf:
+ *
+ * Write to a character backend using a printf style interface.
+ *
+ * @fmt see #printf
+ */
 void qemu_chr_fe_printf(CharDriverState *s, const char *fmt, ...)
     GCC_FMT_ATTR(2, 3);
+
+/**
+ * @qemu_chr_fe_write:
+ *
+ * Write data to a character backend from the front end.  This function will
+ * send data from the front end to the back end.
+ *
+ * @buf the data
+ * @len the number of bytes to send
+ *
+ * Returns: the number of bytes consumed
+ */
 int qemu_chr_fe_write(CharDriverState *s, const uint8_t *buf, int len);
+
+/**
+ * @qemu_chr_fe_ioctl:
+ *
+ * Issue a device specific ioctl to a backend.
+ *
+ * @cmd see CHR_IOCTL_*
+ * @arg the data associated with @cmd
+ *
+ * Returns: if @cmd is not supported by the backend, -ENOTSUP, otherwise the
+ *          return value depends on the semantics of @cmd
+ */
+int qemu_chr_fe_ioctl(CharDriverState *s, int cmd, void *arg);
+
+/**
+ * @qemu_chr_fe_get_msgfd:
+ *
+ * For backends capable of fd passing, return the latest file descriptor passed
+ * by a client.
+ *
+ * Returns: -1 if fd passing isn't supported or there is no pending file
+ *          descriptor.  If a file descriptor is returned, subsequent calls to
+ *          this function will return -1 until a client sends a new file
+ *          descriptor.
+ */
+int qemu_chr_fe_get_msgfd(CharDriverState *s);
+
+/**
+ * @qemu_chr_be_can_write:
+ *
+ * Determine how much data the front end can currently accept.  This function
+ * returns the number of bytes the front end can accept.  If it returns 0, the
+ * front end cannot receive data at the moment.  The function must be polled
+ * to determine when data can be received.
+ *
+ * Returns: the number of bytes the front end can receive via @qemu_chr_be_write
+ */
+int qemu_chr_be_can_write(CharDriverState *s);
+
+/**
+ * @qemu_chr_be_write:
+ *
+ * Write data from the back end to the front end.  Before issuing this call,
+ * the caller should call @qemu_chr_be_can_write to determine how much data
+ * the front end can currently accept.
+ *
+ * @buf a buffer to receive data from the front end
+ * @len the number of bytes to receive from the front end
+ */
+void qemu_chr_be_write(CharDriverState *s, uint8_t *buf, int len);
+
 void qemu_chr_add_handlers(CharDriverState *s,
                            IOCanReadHandler *fd_can_read,
                            IOReadHandler *fd_read,
                            IOEventHandler *fd_event,
                            void *opaque);
-int qemu_chr_fe_ioctl(CharDriverState *s, int cmd, void *arg);
+
 void qemu_chr_generic_open(CharDriverState *s);
-int qemu_chr_be_can_write(CharDriverState *s);
-void qemu_chr_be_write(CharDriverState *s, uint8_t *buf, int len);
-int qemu_chr_fe_get_msgfd(CharDriverState *s);
 void qemu_chr_accept_input(CharDriverState *s);
 int qemu_chr_add_client(CharDriverState *s, int fd);
 void qemu_chr_info_print(Monitor *mon, const QObject *ret_data);
 void qemu_chr_info(Monitor *mon, QObject **ret_data);
 CharDriverState *qemu_chr_find(const char *name);
 
+QemuOpts *qemu_chr_parse_compat(const char *label, const char *filename);
+
 /* add an eventfd to the qemu devices that are polled */
 CharDriverState *qemu_chr_open_eventfd(int eventfd);