From 93726e5205daaa7475cf17c8f916a8b1842affca Mon Sep 17 00:00:00 2001
From: Sebastian Huber <sebastian.huber@embedded-brains.de>
Date: Wed, 9 Jul 2014 15:44:13 +0200
Subject: termios: Add rtems_termios_set_best_baud()

---
 cpukit/libcsupport/Makefile.am                  |  2 +-
 cpukit/libcsupport/include/rtems/termiostypes.h | 21 ++++++++++--
 cpukit/libcsupport/src/termios_setbestbaud.c    | 45 +++++++++++++++++++++++++
 3 files changed, 64 insertions(+), 4 deletions(-)
 create mode 100644 cpukit/libcsupport/src/termios_setbestbaud.c

(limited to 'cpukit/libcsupport')

diff --git a/cpukit/libcsupport/Makefile.am b/cpukit/libcsupport/Makefile.am
index 0d7597d666..41de47150e 100644
--- a/cpukit/libcsupport/Makefile.am
+++ b/cpukit/libcsupport/Makefile.am
@@ -65,7 +65,7 @@ TERMIOS_C_FILES = src/cfgetispeed.c src/cfgetospeed.c src/cfsetispeed.c \
     src/tcsetpgrp.c src/termios.c src/termiosinitialize.c \
     src/termios_baud2index.c src/termios_baud2num.c src/termios_num2baud.c \
     src/termios_setinitialbaud.c src/termios_baudtable.c src/cfsetspeed.c \
-    src/cfmakeraw.c
+    src/cfmakeraw.c src/termios_setbestbaud.c
 
 SYSTEM_CALL_C_FILES = src/open.c src/close.c src/read.c src/write.c \
     src/write_r.c \
diff --git a/cpukit/libcsupport/include/rtems/termiostypes.h b/cpukit/libcsupport/include/rtems/termiostypes.h
index df3ec0c2d7..6339456b20 100644
--- a/cpukit/libcsupport/include/rtems/termiostypes.h
+++ b/cpukit/libcsupport/include/rtems/termiostypes.h
@@ -78,7 +78,8 @@ typedef struct {
    * @retval true Successful operation.
    * @retval false Cannot open device.
    *
-   * @see rtems_termios_get_device_context() and rtems_termios_get_termios().
+   * @see rtems_termios_get_device_context(), rtems_termios_set_best_baud() and
+   *   rtems_termios_get_termios().
    */
   bool (*first_open)(
     struct rtems_termios_tty      *tty,
@@ -291,7 +292,7 @@ typedef struct rtems_termios_tty {
 } rtems_termios_tty;
 
 /**
- * @brief Installes a Termios device.
+ * @brief Installs a Termios device.
  *
  * @param[in] device_file If not @c NULL, then a device file for the specified
  * major and minor number will be created.
@@ -379,12 +380,26 @@ RTEMS_INLINE_ROUTINE void *rtems_termios_get_device_context(
  * initial attributes.
  */
 RTEMS_INLINE_ROUTINE struct termios *rtems_termios_get_termios(
-  const rtems_termios_tty *tty
+  rtems_termios_tty *tty
 )
 {
   return &tty->termios;
 }
 
+/**
+ * @brief Sets the best baud value in the Termios control.
+ *
+ * The valid Termios baud values are between 0 and 460800.  The Termios baud
+ * value is chosen which minimizes the difference to the value specified.
+ *
+ * @param[in] tty The Termios control.
+ * @param[in] baud The current baud setting of the device.
+ */
+void rtems_termios_set_best_baud(
+  rtems_termios_tty *tty,
+  uint32_t           baud
+);
+
 struct rtems_termios_linesw {
   int (*l_open) (struct rtems_termios_tty *tp);
   int (*l_close)(struct rtems_termios_tty *tp);
diff --git a/cpukit/libcsupport/src/termios_setbestbaud.c b/cpukit/libcsupport/src/termios_setbestbaud.c
new file mode 100644
index 0000000000..3d7a3a80f0
--- /dev/null
+++ b/cpukit/libcsupport/src/termios_setbestbaud.c
@@ -0,0 +1,45 @@
+/*
+ * Copyright (c) 2014 embedded brains GmbH.  All rights reserved.
+ *
+ *  embedded brains GmbH
+ *  Dornierstr. 4
+ *  82178 Puchheim
+ *  Germany
+ *  <rtems@embedded-brains.de>
+ *
+ * The license and distribution terms for this file may be
+ * found in the file LICENSE in this distribution or at
+ * http://www.rtems.org/license/LICENSE.
+ */
+
+#if HAVE_CONFIG_H
+  #include "config.h"
+#endif
+
+#include <rtems/termiostypes.h>
+
+void rtems_termios_set_best_baud(
+  rtems_termios_tty *tty,
+  uint32_t           baud
+)
+{
+  const rtems_assoc_t *current = &rtems_termios_baud_table[ 0 ];
+  const rtems_assoc_t *last = current;
+  tcflag_t cbaud_mask = CBAUD;
+  tcflag_t cbaud;
+
+  while ( current->name != NULL && current->local_value < baud ) {
+    last = current;
+    ++current;
+  }
+
+  if ( current->name != NULL ) {
+    uint32_t mid = (last->local_value + current->local_value) / UINT32_C( 2 );
+
+    cbaud = baud <= mid ? last->remote_value : current->remote_value;
+  } else {
+    cbaud = B460800;
+  }
+
+  tty->termios.c_cflag = (tty->termios.c_cflag & ~cbaud_mask) | cbaud;
+}
-- 
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