tty: Update serial core API documentation

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 39 insertions, 0 deletions

diff --git a/Documentation/serial/driver b/Documentation/serial/driver
index a6ef8dc436f1..067c47d46917 100644
--- a/Documentation/serial/driver
+++ b/Documentation/serial/driver
@@ -133,6 +133,16 @@ hardware.
         Interrupts: locally disabled.
         This call must not sleep
 
+  send_xchar(port,ch)
+        Transmit a high priority character, even if the port is stopped.
+        This is used to implement XON/XOFF flow control and tcflow().  If
+        the serial driver does not implement this function, the tty core
+        will append the character to the circular buffer and then call
+        start_tx() / stop_tx() to flush the data out.
+
+        Locking: none.
+        Interrupts: caller dependent.
+
   stop_rx(port)
         Stop receiving characters; the port is in the process of
         being closed.
@@ -254,6 +264,10 @@ hardware.
         Locking: none.
         Interrupts: caller dependent.
 
+  set_wake(port,state)
+        Enable/disable power management wakeup on serial activity.  Not
+        currently implemented.
+
   type(port)
         Return a pointer to a string constant describing the specified
         port, or return NULL, in which case the string 'unknown' is
@@ -306,6 +320,31 @@ hardware.
         Locking: none.
         Interrupts: caller dependent.
 
+  poll_init(port)
+        Called by kgdb to perform the minimal hardware initialization needed
+        to support poll_put_char() and poll_get_char().  Unlike ->startup()
+        this should not request interrupts.
+
+        Locking: tty_mutex and tty_port->mutex taken.
+        Interrupts: n/a.
+
+  poll_put_char(port,ch)
+        Called by kgdb to write a single character directly to the serial
+        port.  It can and should block until there is space in the TX FIFO.
+
+        Locking: none.
+        Interrupts: caller dependent.
+        This call must not sleep
+
+  poll_get_char(port)
+        Called by kgdb to read a single character directly from the serial
+        port.  If data is available, it should be returned; otherwise
+        the function should return NO_POLL_CHAR immediately.
+
+        Locking: none.
+        Interrupts: caller dependent.
+        This call must not sleep
+
 Other functions
 ---------------