This fixes an issue when setting the baud rate. The baud rate is set
using the cfsetospeed and cfsetispeed system calls. The code is using
speed_t for clarity. The non-blocking status is only reset when Block is
True. And serial blocking mode is now properly set according to termios
manual.
Add documentation about a way to debug and test a serial port on
GNU/Linux without the need for a physical serial port.
Tested on x86_64-pc-linux-gnu, committed on trunk
gcc/ada/
* libgnat/g-sercom__linux.adb (Set): Use cfsetospeed and
cfsetispeed to set the baud rate. Clear non-blocking serial port
status when blocking is requested.diff --git a/gcc/ada/libgnat/g-sercom__linux.adb b/gcc/ada/libgnat/g-sercom__linux.adb
--- a/gcc/ada/libgnat/g-sercom__linux.adb
+++ b/gcc/ada/libgnat/g-sercom__linux.adb
@@ -30,6 +30,33 @@
------------------------------------------------------------------------------
-- This is the GNU/Linux implementation of this package
+--
+-- Testing on GNU/Linux can be done with socat & stty tools.
+--
+-- First in a terminal create a virtual serial port:
+--
+-- * First solution, the terminal is one of the side of the channel
+-- characters written with Write into the port will be displayed
+-- there and characters typed into the terminal will be send to the
+-- channel and will be received by a Read call.
+--
+-- $ socat PTY,link=/tmp/virtual-tty,raw,echo=1 -
+--
+-- * Second solution, the virtual channel contains two side and the
+-- program can Read and Write date to it.
+--
+-- $ socat PTY,link=/tmp/virtual-tty,raw,echo=1 \
+-- PTY,link=/tmp/virtual-tty,raw,echo=1
+--
+-- Connect to this virtual serial port with:
+--
+-- Open (Port => P, Name => "/tmp/virtual-tty");
+--
+-- Do any settings using the Set routine below, then you can check
+-- the serial port configuration with:
+--
+-- $ stty --file /tmp/virtual-tty
+--
with Ada.Streams; use Ada.Streams;
@@ -52,6 +79,34 @@ package body GNAT.Serial_Communications is
function fcntl (fd : int; cmd : int; value : int) return int;
pragma Import (C, fcntl, "fcntl");
+ C_Data_Rate : constant array (Data_Rate) of unsigned :=
+ (B75 => OSC.B75,
+ B110 => OSC.B110,
+ B150 => OSC.B150,
+ B300 => OSC.B300,
+ B600 => OSC.B600,
+ B1200 => OSC.B1200,
+ B2400 => OSC.B2400,
+ B4800 => OSC.B4800,
+ B9600 => OSC.B9600,
+ B19200 => OSC.B19200,
+ B38400 => OSC.B38400,
+ B57600 => OSC.B57600,
+ B115200 => OSC.B115200,
+ B230400 => OSC.B230400,
+ B460800 => OSC.B460800,
+ B500000 => OSC.B500000,
+ B576000 => OSC.B576000,
+ B921600 => OSC.B921600,
+ B1000000 => OSC.B1000000,
+ B1152000 => OSC.B1152000,
+ B1500000 => OSC.B1500000,
+ B2000000 => OSC.B2000000,
+ B2500000 => OSC.B2500000,
+ B3000000 => OSC.B3000000,
+ B3500000 => OSC.B3500000,
+ B4000000 => OSC.B4000000);
+
C_Bits : constant array (Data_Bits) of unsigned :=
(CS7 => OSC.CS7, CS8 => OSC.CS8);
@@ -162,6 +217,8 @@ package body GNAT.Serial_Communications is
is
use OSC;
+ subtype speed_t is unsigned;
+
type termios is record
c_iflag : unsigned;
c_oflag : unsigned;
@@ -169,8 +226,8 @@ package body GNAT.Serial_Communications is
c_lflag : unsigned;
c_line : unsigned_char;
c_cc : Interfaces.C.char_array (0 .. 31);
- c_ispeed : unsigned;
- c_ospeed : unsigned;
+ c_ispeed : speed_t;
+ c_ospeed : speed_t;
end record;
pragma Convention (C, termios);
@@ -184,9 +241,15 @@ package body GNAT.Serial_Communications is
function tcflush (fd : int; queue_selector : int) return int;
pragma Import (C, tcflush, "tcflush");
+ function cfsetospeed (termios_p : Address; speed : speed_t) return int;
+ pragma Import (C, cfsetospeed, "cfsetospeed");
+
+ function cfsetispeed (termios_p : Address; speed : speed_t) return int;
+ pragma Import (C, cfsetispeed, "cfsetispeed");
+
Current : termios;
- Res : int;
+ Res : int := 0;
pragma Warnings (Off, Res);
-- Warnings off, since we don't always test the result
@@ -205,6 +268,7 @@ package body GNAT.Serial_Communications is
or C_Stop_Bits (Stop_Bits)
or C_Parity (Parity)
or CREAD;
+
Current.c_iflag := 0;
Current.c_lflag := 0;
Current.c_oflag := 0;
@@ -224,10 +288,36 @@ package body GNAT.Serial_Communications is
Current.c_iflag := Current.c_iflag or IXON;
end case;
- Current.c_ispeed := Data_Rate_Value (Rate);
- Current.c_ospeed := Data_Rate_Value (Rate);
- Current.c_cc (VMIN) := char'Val (0);
- Current.c_cc (VTIME) := char'Val (Natural (Timeout * 10));
+ Current.c_ispeed := Data_Rate_Value (Rate);
+ Current.c_ospeed := Data_Rate_Value (Rate);
+
+ -- See man termios for descriptions about the different modes
+
+ if Block and then Timeout = 0.0 then
+ -- MIN > 0, TIME == 0 (blocking read)
+ Current.c_cc (VMIN) := char'Val (1);
+ Current.c_cc (VTIME) := char'Val (0);
+
+ else
+ -- MIN == 0, TIME > 0 (read with timeout)
+ -- MIN == 0, TIME == 0 (polling read)
+ Current.c_cc (VMIN) := char'Val (0);
+ Current.c_cc (VTIME) := char'Val (Natural (Timeout * 10));
+
+ Current.c_lflag := Current.c_lflag or (not ICANON);
+ end if;
+
+ Res := cfsetispeed (Current'Address, C_Data_Rate (Rate));
+
+ if Res = -1 then
+ Raise_Error ("set: cfsetispeed failed");
+ end if;
+
+ Res := cfsetospeed (Current'Address, C_Data_Rate (Rate));
+
+ if Res = -1 then
+ Raise_Error ("set: cfsetospeed failed");
+ end if;
-- Set port settings
@@ -236,7 +326,11 @@ package body GNAT.Serial_Communications is
-- Block
- Res := fcntl (int (Port.H), F_SETFL, (if Block then 0 else FNDELAY));
+ if Block then
+ -- In blocking mode, remove the non-blocking flags set while
+ -- opening the serial port (see Open).
+ Res := fcntl (int (Port.H), F_SETFL, 0);
+ end if;
if Res = -1 then
Raise_Error ("set: fcntl failed");
