drop tx_fifo_size

... in favor of having what so far was called tx_empty() return the
amount of space available.

Note that in the pl011.c case, original code and comment disagreed, and
I picked the conservative value for it's ->tx_ready() handler's return
value.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>

1 files changed, 2 insertions, 4 deletions

diff --git a/xen/include/xen/serial.h b/xen/include/xen/serial.h
index 0434956c1d..f817ccd566 100644
--- a/xen/include/xen/serial.h
+++ b/xen/include/xen/serial.h
@@ -36,8 +36,6 @@ struct serial_port {
     struct uart_driver *driver;
     void               *uart;
     enum serial_port_state state;
-    /* Number of characters the port can hold for transmit. */
-    int                 tx_fifo_size;
     /* Transmit data buffer (interrupt-driven uart). */
     char               *txbuf;
     unsigned int        txbufp, txbufc;
@@ -63,8 +61,8 @@ struct uart_driver {
     /* Driver suspend/resume. */
     void (*suspend)(struct serial_port *);
     void (*resume)(struct serial_port *);
-    /* Transmit FIFO ready to receive up to @tx_fifo_size characters? */
-    int  (*tx_empty)(struct serial_port *);
+    /* Return number of characters the port can hold for transmit. */
+    unsigned int (*tx_ready)(struct serial_port *);
     /* Put a character onto the serial line. */
     void (*putc)(struct serial_port *, char);
     /* Flush accumulated characters. */