dz: clean up and improve the setup of termios settings

A set of changes to the way termios settings are propagated to the serial
port hardware.  The DZ11 only supports a selection of fixed baud settings,
so some requests may not be fulfilled.  Keep the old setting in such a case
and failing that resort to 9600bps.  Also add a missing update of the
transmit timeout.  And remove the explicit encoding of the line selected
from writes to the Line Parameters Register as it has been preencoded by
the ->set_termios() call already.  Finally, remove a duplicate macro for
the Receiver Enable bit.

Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 56 insertions, 51 deletions

diff --git a/drivers/serial/dz.c b/drivers/serial/dz.c
index ae3203b20134..765b700c019c 100644
--- a/drivers/serial/dz.c
+++ b/drivers/serial/dz.c
@@ -128,8 +128,8 @@ static void dz_stop_rx(struct uart_port *uport)
 {
         struct dz_port *dport = (struct dz_port *)uport;
 
-        dport->cflag &= ~DZ_CREAD;
-        dz_out(dport, DZ_LPR, dport->cflag | dport->port.line);
+        dport->cflag &= ~DZ_RXENAB;
+        dz_out(dport, DZ_LPR, dport->cflag);
 }
 
 static void dz_enable_ms(struct uart_port *port)
@@ -464,12 +464,51 @@ static void dz_break_ctl(struct uart_port *uport, int break_state)
         spin_unlock_irqrestore(&uport->lock, flags);
 }
 
+static int dz_encode_baud_rate(unsigned int baud)
+{
+        switch (baud) {
+        case 50:
+                return DZ_B50;
+        case 75:
+                return DZ_B75;
+        case 110:
+                return DZ_B110;
+        case 134:
+                return DZ_B134;
+        case 150:
+                return DZ_B150;
+        case 300:
+                return DZ_B300;
+        case 600:
+                return DZ_B600;
+        case 1200:
+                return DZ_B1200;
+        case 1800:
+                return DZ_B1800;
+        case 2000:
+                return DZ_B2000;
+        case 2400:
+                return DZ_B2400;
+        case 3600:
+                return DZ_B3600;
+        case 4800:
+                return DZ_B4800;
+        case 7200:
+                return DZ_B7200;
+        case 9600:
+                return DZ_B9600;
+        default:
+                return -1;
+        }
+}
+
 static void dz_set_termios(struct uart_port *uport, struct ktermios *termios,
                            struct ktermios *old_termios)
 {
         struct dz_port *dport = (struct dz_port *)uport;
         unsigned long flags;
         unsigned int cflag, baud;
+        int bflag;
 
         cflag = dport->port.line;
 
@@ -496,60 +535,26 @@ static void dz_set_termios(struct uart_port *uport, struct ktermios *termios,
                 cflag |= DZ_PARODD;
 
         baud = uart_get_baud_rate(uport, termios, old_termios, 50, 9600);
-        switch (baud) {
-        case 50:
-                cflag |= DZ_B50;
-                break;
-        case 75:
-                cflag |= DZ_B75;
-                break;
-        case 110:
-                cflag |= DZ_B110;
-                break;
-        case 134:
-                cflag |= DZ_B134;
-                break;
-        case 150:
-                cflag |= DZ_B150;
-                break;
-        case 300:
-                cflag |= DZ_B300;
-                break;
-        case 600:
-                cflag |= DZ_B600;
-                break;
-        case 1200:
-                cflag |= DZ_B1200;
-                break;
-        case 1800:
-                cflag |= DZ_B1800;
-                break;
-        case 2000:
-                cflag |= DZ_B2000;
-                break;
-        case 2400:
-                cflag |= DZ_B2400;
-                break;
-        case 3600:
-                cflag |= DZ_B3600;
-                break;
-        case 4800:
-                cflag |= DZ_B4800;
-                break;
-        case 7200:
-                cflag |= DZ_B7200;
-                break;
-        case 9600:
-        default:
-                cflag |= DZ_B9600;
+        bflag = dz_encode_baud_rate(baud);
+        if (bflag < 0)  {                       /* Try to keep unchanged.  */
+                baud = uart_get_baud_rate(uport, old_termios, NULL, 50, 9600);
+                bflag = dz_encode_baud_rate(baud);
+                if (bflag < 0)  {               /* Resort to 9600.  */
+                        baud = 9600;
+                        bflag = DZ_B9600;
+                }
+                tty_termios_encode_baud_rate(termios, baud, baud);
         }
+        cflag |= bflag;
 
         if (termios->c_cflag & CREAD)
                 cflag |= DZ_RXENAB;
 
         spin_lock_irqsave(&dport->port.lock, flags);
 
-        dz_out(dport, DZ_LPR, cflag | dport->port.line);
+        uart_update_timeout(uport, termios->c_cflag, baud);
+
+        dz_out(dport, DZ_LPR, cflag);
         dport->cflag = cflag;
 
         /* setup accept flag */
diff --git a/drivers/serial/dz.h b/drivers/serial/dz.h
index 1e836c3411d4..faf169ed27b3 100644
--- a/drivers/serial/dz.h
+++ b/drivers/serial/dz.h
@@ -109,8 +109,8 @@
 #define DZ_B7200         0x0D00
 #define DZ_B9600         0x0E00
 
-#define DZ_CREAD         0x1000               /* Enable receiver */
-#define DZ_RXENAB        0x1000               /* enable receive char */
+#define DZ_RXENAB        0x1000               /* Receiver Enable */
+
 /*
  * Addresses for the DZ registers
  */