2 files changed, 75 insertions, 10 deletions

diff --git a/drivers/char/tty_ioctl.c b/drivers/char/tty_ioctl.c
index 3ee73cf64bd2..745d552620bf 100644
--- a/drivers/char/tty_ioctl.c
+++ b/drivers/char/tty_ioctl.c
@@ -206,8 +206,6 @@ speed_t tty_termios_input_baud_rate(struct ktermios *termios)
 
 EXPORT_SYMBOL(tty_termios_input_baud_rate);
 
-#ifdef BOTHER
-
 /**
  *      tty_termios_encode_baud_rate
  *      @termios: ktermios structure holding user requested state
@@ -225,6 +223,9 @@ EXPORT_SYMBOL(tty_termios_input_baud_rate);
  *
  *      Locking: Caller should hold termios lock. This is already held
  *      when calling this function from the driver termios handler.
+ *
+ *      The ifdefs deal with platforms whose owners have yet to update them
+ *      and will all go away once this is done.
  */
 
 void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud, speed_t obaud)
@@ -234,9 +235,13 @@ void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud, speed
         int iclose = ibaud/50, oclose = obaud/50;
         int ibinput = 0;
 
+        if (obaud == 0)                 /* CD dropped             */
+                ibaud = 0;              /* Clear ibaud to be sure */
+
         termios->c_ispeed = ibaud;
         termios->c_ospeed = obaud;
 
+#ifdef BOTHER
         /* If the user asked for a precise weird speed give a precise weird
            answer. If they asked for a Bfoo speed they many have problems
            digesting non-exact replies so fuzz a bit */
@@ -247,32 +252,60 @@ void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud, speed
                 iclose = 0;
         if ((termios->c_cflag >> IBSHIFT) & CBAUD)
                 ibinput = 1;    /* An input speed was specified */
-
+#endif
         termios->c_cflag &= ~CBAUD;
 
+        /*
+         *      Our goal is to find a close match to the standard baud rate
+         *      returned. Walk the baud rate table and if we get a very close
+         *      match then report back the speed as a POSIX Bxxxx value by
+         *      preference
+         */
+
         do {
                 if (obaud - oclose >= baud_table[i] && obaud + oclose <= baud_table[i]) {
                         termios->c_cflag |= baud_bits[i];
                         ofound = i;
                 }
                 if (ibaud - iclose >= baud_table[i] && ibaud + iclose <= baud_table[i]) {
-                        /* For the case input == output don't set IBAUD bits if the user didn't do so */
-                        if (ofound != i || ibinput)
+                        if (ofound == i && !ibinput)
+                                ifound  = i;
+#ifdef IBSHIFT
+                        else {
+                                ifound = i;
                                 termios->c_cflag |= (baud_bits[i] << IBSHIFT);
-                        ifound = i;
+                        }
+#endif
                 }
         } while (++i < n_baud_table);
+
+        /*
+         *      If we found no match then use BOTHER if provided or warn
+         *      the user their platform maintainer needs to wake up if not.
+         */
+#ifdef BOTHER
         if (ofound == -1)
                 termios->c_cflag |= BOTHER;
         /* Set exact input bits only if the input and output differ or the
            user already did */
         if (ifound == -1 && (ibaud != obaud || ibinput))
                 termios->c_cflag |= (BOTHER << IBSHIFT);
+#else
+        if (ifound == -1 || ofound == -1) {
+                static int warned;
+                if (!warned++)
+                        printk(KERN_WARNING "tty: Unable to return correct "
+                          "speed data as your architecture needs updating.\n");
+        }
+#endif
 }
-
 EXPORT_SYMBOL_GPL(tty_termios_encode_baud_rate);
 
-#endif
+void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud, speed_t obaud)
+{
+        tty_termios_encode_baud_rate(tty->termios, ibaud, obaud);
+}
+EXPORT_SYMBOL_GPL(tty_encode_baud_rate);
 
 /**
  *      tty_get_baud_rate       -       get tty bit rates
@@ -304,6 +337,29 @@ speed_t tty_get_baud_rate(struct tty_struct *tty)
 EXPORT_SYMBOL(tty_get_baud_rate);
 
 /**
+ *      tty_termios_copy_hw     -       copy hardware settings
+ *      @new: New termios
+ *      @old: Old termios
+ *
+ *      Propogate the hardware specific terminal setting bits from
+ *      the old termios structure to the new one. This is used in cases
+ *      where the hardware does not support reconfiguration or as a helper
+ *      in some cases where only minimal reconfiguration is supported
+ */
+
+void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old)
+{
+        /* The bits a dumb device handles in software. Smart devices need
+           to always provide a set_termios method */
+        new->c_cflag &= HUPCL | CREAD | CLOCAL;
+        new->c_cflag |= old->c_cflag & ~(HUPCL | CREAD | CLOCAL);
+        new->c_ispeed = old->c_ispeed;
+        new->c_ospeed = old->c_ospeed;
+}
+
+EXPORT_SYMBOL(tty_termios_copy_hw);
+
+/**
  *      change_termios          -       update termios values
  *      @tty: tty to update
  *      @new_termios: desired new value
@@ -340,13 +396,12 @@ static void change_termios(struct tty_struct * tty, struct ktermios * new_termio
                 tty->erasing = 0;
         }
         
-        
+        /* This bit should be in the ldisc code */
         if (canon_change && !L_ICANON(tty) && tty->read_cnt)
                 /* Get characters left over from canonical mode. */
                 wake_up_interruptible(&tty->read_wait);
 
         /* See if packet mode change of state. */
-
         if (tty->link && tty->link->packet) {
                 int old_flow = ((old_termios.c_iflag & IXON) &&
                                 (old_termios.c_cc[VSTOP] == '\023') &&
@@ -366,6 +421,8 @@ static void change_termios(struct tty_struct * tty, struct ktermios * new_termio
            
         if (tty->driver->set_termios)
                 (*tty->driver->set_termios)(tty, &old_termios);
+        else
+                tty_termios_copy_hw(tty->termios, &old_termios);
 
         ld = tty_ldisc_ref(tty);
         if (ld != NULL) {
@@ -440,6 +497,11 @@ static int set_termios(struct tty_struct * tty, void __user *arg, int opt)
         }
 
         change_termios(tty, &tmp_termios);
+
+        /* FIXME: Arguably if tmp_termios == tty->termios AND the
+           actual requested termios was not tmp_termios then we may
+           want to return an error as no user requested change has
+           succeeded */
         return 0;
 }
 
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 274b40ff0cd8..56164d7ba0ad 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -316,6 +316,9 @@ extern void tty_flip_buffer_push(struct tty_struct *tty);
 extern speed_t tty_get_baud_rate(struct tty_struct *tty);
 extern speed_t tty_termios_baud_rate(struct ktermios *termios);
 extern speed_t tty_termios_input_baud_rate(struct ktermios *termios);
+extern void tty_termios_encode_baud_rate(struct ktermios *termios, speed_t ibaud, speed_t obaud);
+extern void tty_encode_baud_rate(struct tty_struct *tty, speed_t ibaud, speed_t obaud);
+extern void tty_termios_copy_hw(struct ktermios *new, struct ktermios *old);
 
 extern struct tty_ldisc *tty_ldisc_ref(struct tty_struct *);
 extern void tty_ldisc_deref(struct tty_ldisc *);