[PATCH] Update v850 nb85e_uart serial driver to set baud min/max

diff --git a/drivers/serial/nb85e_uart.c b/drivers/serial/nb85e_uart.c
index 03c6b15e89cb660a759d75a9e057b8bd88b4ef26..873aba4fc8fa01809672f9686cb4c639505b80f0 100644 (file)
--- a/drivers/serial/nb85e_uart.c
+++ b/drivers/serial/nb85e_uart.c
@@ -1,8 +1,8 @@
 /*
  * drivers/serial/nb85e_uart.c -- Serial I/O using V850E/NB85E on-chip UART
  *
- *  Copyright (C) 2001,02  NEC Corporation
- *  Copyright (C) 2001,02  Miles Bader <miles@gnu.org>
+ *  Copyright (C) 2001,02,03  NEC Corporation
+ *  Copyright (C) 2001,02,03  Miles Bader <miles@gnu.org>
  *
  * This file is subject to the terms and conditions of the GNU General
  * Public License.  See the file COPYING in the main directory of this
@@ -31,6 +31,9 @@
 #define NB85E_UART_INIT_CFLAGS (B115200 | CS8 | CREAD)
 #endif
 
+/* XXX This should be in a header file.  */
+#define NB85E_UART_BRGC_MIN    8
+
 /* A string used for prefixing printed descriptions; since the same UART
    macro is actually used on other chips than the V850E/NB85E.  This must
    be a constant string.  */
@@ -38,6 +41,29 @@
 #define NB85E_UART_CHIP_NAME "V850E/NB85E"
 #endif
 
+\f
+/* Helper functions for doing baud-rate/frequency calculations.  */
+
+/* Calculate the minimum value for CKSR on this processor.  */
+static inline unsigned cksr_min (void)
+{
+       int min = 0;
+       unsigned freq = NB85E_UART_BASE_FREQ;
+       while (freq > NB85E_UART_CKSR_MAX_FREQ) {
+               freq >>= 1;
+               min++;
+       }
+       return min;
+}
+
+/* Minimum baud rate possible.  */
+#define min_baud() \
+   ((NB85E_UART_BASE_FREQ >> NB85E_UART_CKSR_MAX) / (2 * 255) + 1)
+
+/* Maximum baud rate possible.  The error is quite high at max, though.  */
+#define max_baud() \
+   ((NB85E_UART_BASE_FREQ >> cksr_min()) / (2 * NB85E_UART_BRGC_MIN))
+
 \f
 /* Low-level UART functions.  */
 
@@ -60,7 +86,7 @@ static inline void nb85e_uart_delay (unsigned cycles)
    modes' bits in CFLAGS, and a baud-rate of BAUD.  */
 void nb85e_uart_configure (unsigned chan, unsigned cflags, unsigned baud)
 {
-       int cksr_min, flags;
+       int flags;
        unsigned new_config = 0; /* What we'll write to the control reg. */
        unsigned new_clk_divlog2; /* New baud-rate generate clock divider. */
        unsigned new_brgen_count; /* New counter max for baud-rate generator.*/
@@ -68,14 +94,12 @@ void nb85e_uart_configure (unsigned chan, unsigned cflags, unsigned baud)
        unsigned old_config, old_clk_divlog2, old_brgen_count;
 
        /* Calculate new baud-rate generator config values.  */
-       cksr_min = 0;
-       while ((NB85E_UART_BASE_FREQ >> cksr_min) > NB85E_UART_CKSR_MAX_FREQ)
-               cksr_min++;
+
        /* Calculate the log2 clock divider and baud-rate counter values
           (note that the UART divides the resulting clock by 2, so
           multiply BAUD by 2 here to compensate).  */
        calc_counter_params (NB85E_UART_BASE_FREQ, baud * 2,
-                            cksr_min, NB85E_UART_CKSR_MAX, 8/*bits*/,
+                            cksr_min(), NB85E_UART_CKSR_MAX, 8/*bits*/,
                             &new_clk_divlog2, &new_brgen_count);
 
        /* Figure out new configuration of control register.  */
@@ -443,10 +467,18 @@ static void
 nb85e_uart_set_termios (struct uart_port *port, struct termios *termios,
                        struct termios *old)
 {
-       /* FIXME: Which termios flags does this driver support? --rmk */
+       unsigned cflags = termios->c_cflag;
 
-       nb85e_uart_configure (port->line, termios->c_cflags,
-                       uart_get_baud_rate(port, termios));
+       /* Restrict flags to legal values.  */
+       if ((cflags & CSIZE) != CS7 && (cflags & CSIZE) != CS8)
+               /* The new value of CSIZE is invalid, use the old value.  */
+               cflags = (cflags & ~CSIZE) | (old->c_cflag & CSIZE);
+
+       termios->c_cflag = cflags;
+
+       nb85e_uart_configure (port->line, cflags,
+                             uart_get_baud_rate (port, termios, old,
+                                                 min_baud(), max_baud()));
 }
 
 static const char *nb85e_uart_type (struct uart_port *port)
@@ -519,7 +551,6 @@ static int __init nb85e_uart_init (void)
                unsigned chan;
 
                for (chan = 0; chan < NB85E_UART_NUM_CHANNELS; chan++) {
-                       int cksr_min;
                        struct uart_port *port = &nb85e_uart_ports[chan];
                        
                        memset (port, 0, sizeof *port);
@@ -550,15 +581,13 @@ static int __init nb85e_uart_init (void)
                           the framework will puke during its internal
                           calculations, and force the baud rate to be 9600.
                           To be accurate though, just repeat the calculation
-                          we use when actually setting the speed.  */
-                       cksr_min = 0;
-                       while ((NB85E_UART_BASE_FREQ >> cksr_min)
-                              > NB85E_UART_CKSR_MAX_FREQ)
-                               cksr_min++;
-                       /* The `* 8' means `* 16 / 2':  16 to account for for
+                          we use when actually setting the speed.
+
+                          The `* 8' means `* 16 / 2':  16 to account for for
                           the serial framework's built-in bias, and 2 because
                           there's an additional / 2 in the hardware.  */
-                       port->uartclk = (NB85E_UART_BASE_FREQ >> cksr_min) * 8;
+                       port->uartclk =
+                               (NB85E_UART_BASE_FREQ >> cksr_min()) * 8;
 
                        uart_add_one_port (&nb85e_uart_driver, port);
                }