drivers/s3c4510b_uart.c

   1 /*
   2  * Copyright (c) 2004   Cucy Systems (http://www.cucy.com)
   3  * Curt Brune <curt@cucy.com>
   4  *
   5  * (C) Copyright 2004
   6  * DAVE Srl
   7  * http://www.dave-tech.it
   8  * http://www.wawnet.biz
   9  * mailto:info@wawnet.biz
  10  *
  11  * (C) Copyright 2002-2004
  12  * Wolfgang Denk, DENX Software Engineering, <wd@denx.de>
  13  *
  14  * (C) Copyright 2002
  15  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  16  * Marius Groeger <mgroeger@sysgo.de>
  17  *
  18  * (C) Copyright 2002
  19  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  20  * Alex Zuepke <azu@sysgo.de>
  21  *
  22  * Copyright (C) 1999 2000 2001 Erik Mouw (J.A.K.Mouw@its.tudelft.nl)
  23  *
  24  * This program is free software; you can redistribute it and/or modify
  25  * it under the terms of the GNU General Public License as published by
  26  * the Free Software Foundation; either version 2 of the License, or
  27  * (at your option) any later version.
  28  *
  29  * This program is distributed in the hope that it will be useful,
  30  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  31  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  32  * GNU General Public License for more details.
  33  *
  34  * You should have received a copy of the GNU General Public License
  35  * along with this program; if not, write to the Free Software
  36  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  37  *
  38  * MODULE:        $Id:$
  39  * Description:   UART/Serial interface for Samsung S3C4510B SoC
  40  * Runtime Env:   ARM7TDMI
  41  * Change History:
  42  *     03-02-04    Create (Curt Brune) curt@cucy.com
  43  *
  44  */
  45
  46 #include <common.h>
  47
  48 #ifdef CONFIG_DRIVER_S3C4510_UART
  49
  50 #include <asm/hardware.h>
  51 #include "s3c4510b_uart.h"
  52
  53 static UART    *uart;
  54
  55 /* flush serial input queue. returns 0 on success or negative error
  56  * number otherwise
  57  */
  58 static int serial_flush_input(void)
  59 {
  60         volatile u32 tmp;
  61
  62         /* keep on reading as long as the receiver is not empty */
  63         while( uart->m_stat.bf.rxReady) {
  64                 tmp = uart->m_rx;
  65         }
  66
  67         return 0;
  68 }
  69
  70
  71 /* flush output queue. returns 0 on success or negative error number
  72  * otherwise
  73  */
  74 static int serial_flush_output(void)
  75 {
  76         /* wait until the transmitter is no longer busy */
  77         while( !uart->m_stat.bf.txBufEmpty);
  78
  79         return 0;
  80 }
  81
  82
  83 void serial_setbrg (void)
  84 {
  85         DECLARE_GLOBAL_DATA_PTR;
  86
  87         UART_LINE_CTRL ulctrl;
  88         UART_CTRL      uctrl;
  89         UART_BAUD_DIV  ubd;
  90
  91         serial_flush_output();
  92         serial_flush_input();
  93
  94         /* control register */
  95         uctrl.ui = 0x0;
  96         uctrl.bf.rxMode = 0x1;
  97         uctrl.bf.rxIrq = 0x0;
  98         uctrl.bf.txMode = 0x1;
  99         uctrl.bf.DSR = 0x0;
 100         uctrl.bf.sendBreak = 0x0;
 101         uctrl.bf.loopBack = 0x0;
 102         uart->m_ctrl.ui = uctrl.ui;
 103
 104         /* line control register */
 105         ulctrl.ui  = 0x0;
 106         ulctrl.bf.wordLen   = 0x3; /* 8 bit data */
 107         ulctrl.bf.nStop     = 0x0; /* 1 stop bit */
 108         ulctrl.bf.parity    = 0x0; /* no parity */
 109         ulctrl.bf.clk       = 0x0; /* internal clock */
 110         ulctrl.bf.infra_red = 0x0; /* no infra_red */
 111         uart->m_lineCtrl.ui = ulctrl.ui;
 112
 113         ubd.ui = 0x0;
 114
 115         /* see table on page 10-15 in SAMSUNG S3C4510B manual */
 116         /* get correct divisor */
 117         switch(gd->baudrate) {
 118         case   1200:    ubd.bf.cnt0 = 1301;     break;
 119         case   2400:    ubd.bf.cnt0 =  650;     break;
 120         case   4800:    ubd.bf.cnt0 =  324;     break;
 121         case   9600:    ubd.bf.cnt0 =  162;     break;
 122         case  19200:    ubd.bf.cnt0 =   80;     break;
 123         case  38400:    ubd.bf.cnt0 =   40;     break;
 124         case  57600:    ubd.bf.cnt0 =   26;     break;
 125         case 115200:    ubd.bf.cnt0 =   13;     break;
 126         }
 127
 128         uart->m_baudDiv.ui = ubd.ui;
 129         uart->m_baudCnt = 0x0;
 130         uart->m_baudClk = 0x0;
 131
 132 }
 133
 134
 135 /*
 136  * Initialise the serial port with the given baudrate. The settings
 137  * are always 8 data bits, no parity, 1 stop bit, no start bits.
 138  *
 139  */
 140 int serial_init (void)
 141 {
 142
 143 #if   CONFIG_SERIAL1 == 1
 144         uart = (UART *)UART0_BASE;
 145 #elif CONFIG_SERIAL1 == 2
 146         uart = (UART *)UART1_BASE;
 147 #else
 148 #error CONFIG_SERIAL1 not equal to 1 or 2
 149 #endif
 150
 151         serial_setbrg ();
 152
 153         return (0);
 154 }
 155
 156
 157 /*
 158  * Output a single byte to the serial port.
 159  */
 160 void serial_putc (const char c)
 161 {
 162         /* wait for room in the transmit FIFO */
 163         while( !uart->m_stat.bf.txBufEmpty);
 164
 165         uart->m_tx = c;
 166
 167         /*
 168                 to be polite with serial console add a line feed
 169                 to the carriage return character
 170         */
 171         if (c=='\n')
 172                 serial_putc('\r');
 173 }
 174
 175 /*
 176  * Test if an input byte is ready from the serial port. Returns non-zero on
 177  * success, 0 otherwise.
 178  */
 179 int serial_tstc (void)
 180 {
 181         return uart->m_stat.bf.rxReady;
 182 }
 183
 184 /*
 185  * Read a single byte from the serial port. Returns 1 on success, 0
 186  * otherwise. When the function is succesfull, the character read is
 187  * written into its argument c.
 188  */
 189 int serial_getc (void)
 190 {
 191         int rv;
 192
 193         for(;;) {
 194                 rv = serial_tstc();
 195
 196                 if (rv) {
 197                         return uart->m_rx & 0xFF;
 198                 }
 199         }
 200 }
 201
 202 void serial_puts (const char *s)
 203 {
 204         while (*s) {
 205                 serial_putc (*s++);
 206         }
 207
 208         /* busy wait for tx complete */
 209         while ( !uart->m_stat.bf.txComplete);
 210
 211         /* clear break */
 212         uart->m_ctrl.bf.sendBreak = 0;
 213
 214 }
 215
 216 #endif