cpu/arm920t/serial.c

   1         /*
   2          * (C) Copyright 2002
   3          * Gary Jennejohn, DENX Software Engineering, <gj@denx.de>
   4          *
   5          * This program is free software; you can redistribute it and/or modify
   6          * it under the terms of the GNU General Public License as published by
   7          * the Free Software Foundation; either version 2 of the License, or
   8          * (at your option) any later version.
   9          *
  10          * This program is distributed in the hope that it will be useful,
  11          * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12          * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13          * GNU General Public License for more details.
  14          *
  15          * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  *
  19  */
  20
  21 #include <common.h>
  22 #if defined(CONFIG_S3C2400) || defined(CONFIG_TRAB)
  23 #include <s3c2400.h>
  24 #elif defined(CONFIG_S3C2410)
  25 #include <s3c2410.h>
  26 #endif
  27
  28 #ifdef CONFIG_SERIAL1
  29 #define UART_NR S3C24X0_UART0
  30
  31 #elif defined(CONFIG_SERIAL2)
  32 # if defined(CONFIG_TRAB)
  33 #  error "TRAB supports only CONFIG_SERIAL1"
  34 # endif
  35 #define UART_NR S3C24X0_UART1
  36
  37 #elif defined(CONFIG_SERIAL3)
  38 # if defined(CONFIG_TRAB)
  39 #  #error "TRAB supports only CONFIG_SERIAL1"
  40 # endif
  41 #define UART_NR S3C24X0_UART2
  42
  43 #else
  44 #error "Bad: you didn't configure serial ..."
  45 #endif
  46
  47 void serial_setbrg (void)
  48 {
  49         DECLARE_GLOBAL_DATA_PTR;
  50         S3C24X0_UART * const uart = S3C24X0_GetBase_UART(UART_NR);
  51         int i;
  52         unsigned int reg = 0;
  53
  54         /* value is calculated so : (int)(PCLK/16./baudrate) -1 */
  55         reg = get_PCLK() / (16 * gd->baudrate) - 1;
  56
  57         /* FIFO enable, Tx/Rx FIFO clear */
  58         uart->UFCON = 0x07;
  59         uart->UMCON = 0x0;
  60         /* Normal,No parity,1 stop,8 bit */
  61         uart->ULCON = 0x3;
  62         /*
  63          * tx=level,rx=edge,disable timeout int.,enable rx error int.,
  64          * normal,interrupt or polling
  65          */
  66         uart->UCON = 0x245;
  67         uart->UBRDIV = reg;
  68
  69 #ifdef CONFIG_HWFLOW
  70         uart->UMCON = 0x1; /* RTS up */
  71 #endif
  72         for (i = 0; i < 100; i++);
  73 }
  74
  75 /*
  76  * Initialise the serial port with the given baudrate. The settings
  77  * are always 8 data bits, no parity, 1 stop bit, no start bits.
  78  *
  79  */
  80 int serial_init (void)
  81 {
  82         serial_setbrg ();
  83
  84         return (0);
  85 }
  86
  87 /*
  88  * Read a single byte from the serial port. Returns 1 on success, 0
  89  * otherwise. When the function is succesfull, the character read is
  90  * written into its argument c.
  91  */
  92 int serial_getc (void)
  93 {
  94         S3C24X0_UART * const uart = S3C24X0_GetBase_UART(UART_NR);
  95
  96         /* wait for character to arrive */
  97         while (!(uart->UTRSTAT & 0x1));
  98
  99         return uart->URXH & 0xff;
 100 }
 101
 102 #ifdef CONFIG_HWFLOW
 103 static int hwflow = 0; /* turned off by default */
 104 int hwflow_onoff(int on)
 105 {
 106         switch(on) {
 107         case 0:
 108         default:
 109                 break; /* return current */
 110         case 1:
 111                 hwflow = 1; /* turn on */
 112                 break;
 113         case -1:
 114                 hwflow = 0; /* turn off */
 115                 break;
 116         }
 117         return hwflow;
 118 }
 119 #endif
 120
 121 #ifdef CONFIG_MODEM_SUPPORT
 122 static int be_quiet = 0;
 123 void disable_putc(void)
 124 {
 125         be_quiet = 1;
 126 }
 127
 128 void enable_putc(void)
 129 {
 130         be_quiet = 0;
 131 }
 132 #endif
 133
 134
 135 /*
 136  * Output a single byte to the serial port.
 137  */
 138 void serial_putc (const char c)
 139 {
 140         S3C24X0_UART * const uart = S3C24X0_GetBase_UART(UART_NR);
 141 #ifdef CONFIG_MODEM_SUPPORT
 142         if (be_quiet)
 143                 return;
 144 #endif
 145
 146         /* wait for room in the tx FIFO */
 147         while (!(uart->UTRSTAT & 0x2));
 148
 149 #ifdef CONFIG_HWFLOW
 150         /* Wait for CTS up */
 151         while(hwflow && !(uart->UMSTAT & 0x1))
 152                 ;
 153 #endif
 154
 155         uart->UTXH = c;
 156
 157         /* If \n, also do \r */
 158         if (c == '\n')
 159                 serial_putc ('\r');
 160 }
 161
 162 /*
 163  * Test whether a character is in the RX buffer
 164  */
 165 int serial_tstc (void)
 166 {
 167         S3C24X0_UART * const uart = S3C24X0_GetBase_UART(UART_NR);
 168
 169         return uart->UTRSTAT & 0x1;
 170 }
 171
 172 void
 173 serial_puts (const char *s)
 174 {
 175         while (*s) {
 176                 serial_putc (*s++);
 177         }
 178 }