cpu/s3c44b0/serial.c

   1 /*
   2  * (C) Copyright 2004
   3  * DAVE Srl
   4  * http://www.dave-tech.it
   5  * http://www.wawnet.biz
   6  * mailto:info@wawnet.biz
   7  *
   8  * (C) Copyright 2002-2004
   9  * Wolfgang Denk, DENX Software Engineering, <wd@denx.de>
  10  *
  11  * (C) Copyright 2002
  12  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  13  * Marius Groeger <mgroeger@sysgo.de>
  14  *
  15  * (C) Copyright 2002
  16  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  17  * Alex Zuepke <azu@sysgo.de>
  18  *
  19  * Copyright (C) 1999 2000 2001 Erik Mouw (J.A.K.Mouw@its.tudelft.nl)
  20  *
  21  * This program is free software; you can redistribute it and/or modify
  22  * it under the terms of the GNU General Public License as published by
  23  * the Free Software Foundation; either version 2 of the License, or
  24  * (at your option) any later version.
  25  *
  26  * This program is distributed in the hope that it will be useful,
  27  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  28  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  29  * GNU General Public License for more details.
  30  *
  31  * You should have received a copy of the GNU General Public License
  32  * along with this program; if not, write to the Free Software
  33  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  34  *
  35  */
  36
  37 #include <common.h>
  38 #include <asm/hardware.h>
  39
  40 DECLARE_GLOBAL_DATA_PTR;
  41
  42 /* flush serial input queue. returns 0 on success or negative error
  43  * number otherwise
  44  */
  45 static int serial_flush_input(void)
  46 {
  47         volatile u32 tmp;
  48
  49         /* keep on reading as long as the receiver is not empty */
  50         while(UTRSTAT0&0x01) {
  51                 tmp = REGB(URXH0);
  52         }
  53
  54         return 0;
  55 }
  56
  57
  58 /* flush output queue. returns 0 on success or negative error number
  59  * otherwise
  60  */
  61 static int serial_flush_output(void)
  62 {
  63         /* wait until the transmitter is no longer busy */
  64         while(!(UTRSTAT0 & 0x02)) {
  65         }
  66
  67         return 0;
  68 }
  69
  70
  71 void serial_setbrg (void)
  72 {
  73         u32 divisor = 0;
  74
  75         /* get correct divisor */
  76         switch(gd->baudrate) {
  77
  78         case 1200:
  79 #if CONFIG_S3C44B0_CLOCK_SPEED==66
  80                 divisor = 3124;
  81 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
  82                 divisor = 3905;
  83 #else
  84 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
  85 #endif
  86                 break;
  87
  88         case 9600:
  89 #if CONFIG_S3C44B0_CLOCK_SPEED==66
  90                 divisor = 390;
  91 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
  92                 divisor = 487;
  93 #else
  94 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
  95 #endif
  96                 break;
  97
  98         case 19200:
  99 #if CONFIG_S3C44B0_CLOCK_SPEED==66
 100                 divisor = 194;
 101 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
 102                 divisor = 243;
 103 #else
 104 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
 105 #endif
 106                 break;
 107
 108         case 38400:
 109 #if CONFIG_S3C44B0_CLOCK_SPEED==66
 110                 divisor = 97;
 111 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
 112                 divisor = 121;
 113 #else
 114 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
 115 #endif  /* break; */
 116
 117         case 57600:
 118 #if CONFIG_S3C44B0_CLOCK_SPEED==66
 119                 divisor = 64;
 120 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
 121                 divisor = 80;
 122 #else
 123 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
 124 #endif  /* break; */
 125
 126         case 115200:
 127 #if CONFIG_S3C44B0_CLOCK_SPEED==66
 128                 divisor = 32;
 129 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
 130                 divisor = 40;
 131 #else
 132 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
 133 #endif  /* break; */
 134         }
 135
 136         serial_flush_output();
 137         serial_flush_input();
 138         UFCON0 = 0x0;
 139         ULCON0 = 0x03;
 140         UCON0 = 0x05;
 141         UBRDIV0 = divisor;
 142
 143         UFCON1 = 0x0;
 144         ULCON1 = 0x03;
 145         UCON1 = 0x05;
 146         UBRDIV1 = divisor;
 147
 148         for(divisor=0; divisor<100; divisor++) {
 149                 /* NOP */
 150         }
 151 }
 152
 153
 154 /*
 155  * Initialise the serial port with the given baudrate. The settings
 156  * are always 8 data bits, no parity, 1 stop bit, no start bits.
 157  *
 158  */
 159 int serial_init (void)
 160 {
 161         serial_setbrg ();
 162
 163         return (0);
 164 }
 165
 166
 167 /*
 168  * Output a single byte to the serial port.
 169  */
 170 void serial_putc (const char c)
 171 {
 172         /* wait for room in the transmit FIFO */
 173         while(!(UTRSTAT0 & 0x02));
 174
 175         UTXH0 = (unsigned char)c;
 176
 177         /*
 178                 to be polite with serial console add a line feed
 179                 to the carriage return character
 180         */
 181         if (c=='\n')
 182                 serial_putc('\r');
 183 }
 184
 185 /*
 186  * Read a single byte from the serial port. Returns 1 on success, 0
 187  * otherwise. When the function is succesfull, the character read is
 188  * written into its argument c.
 189  */
 190 int serial_tstc (void)
 191 {
 192         return (UTRSTAT0 & 0x01);
 193 }
 194
 195 /*
 196  * Read a single byte from the serial port. Returns 1 on success, 0
 197  * otherwise. When the function is succesfull, the character read is
 198  * written into its argument c.
 199  */
 200 int serial_getc (void)
 201 {
 202         int rv;
 203
 204         for(;;) {
 205                 rv = serial_tstc();
 206
 207                 if(rv > 0)
 208                         return URXH0;
 209         }
 210 }
 211
 212 void
 213 serial_puts (const char *s)
 214 {
 215         while (*s) {
 216                 serial_putc (*s++);
 217         }
 218 }