drivers/serial/serial_s3c44b0.c

   1 pyright 2002
   2  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
   3  * Marius Groeger <mgroeger@sysgo.de>
   4  *
   5  * (C) Copyright 2002
   6  * ght 2002-2004
   7  * Wolfgang Denk, DENX Software Engineering, <wd@denx.de>
   8  *
   9  * (C) Copyright 2002
  10  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  11  * Marius Groeger <mgroeger@sysgo.de>
  12  *
  13  * (C) Copyright 2002
  14  * Sysgo Real-Time Solutions, GmbH <www.elinos.com>
  15  * Alex Zuepke <azu@sysgo.de>
  16  *
  17  * Copyright (C) 1999 2000 2001 Erik Mouw (J.A.K.Mouw@its.tudelft.nl)
  18  *
  19  * SPDX-License-Identifier:     GPL-2.0+
  20  */
  21
  22 #include <common.h>
  23 #include <asm/hardware.h>
  24
  25 DECLARE_GLOBAL_DATA_PTR;
  26
  27 /* flush serial input queue. returns 0 on success or negative error
  28  * number otherwise
  29  */
  30 static int serial_flush_input(void)
  31 {
  32         volatile u32 tmp;
  33
  34         /* keep on reading as long as the receiver is not empty */
  35         while(UTRSTAT0&0x01) {
  36                 tmp = REGB(URXH0);
  37         }
  38
  39         return 0;
  40 }
  41
  42
  43 /* flush output queue. returns 0 on success or negative error number
  44  * otherwise
  45  */
  46 static int serial_flush_output(void)
  47 {
  48         /* wait until the transmitter is no longer busy */
  49         while(!(UTRSTAT0 & 0x02)) {
  50         }
  51
  52         return 0;
  53 }
  54
  55
  56 static void s3c44b0_serial_setbrg(void)
  57 {
  58         u32 divisor = 0;
  59
  60         /* get correct divisor */
  61         switch(gd->baudrate) {
  62
  63         case 1200:
  64 #if CONFIG_S3C44B0_CLOCK_SPEED==66
  65                 divisor = 3124;
  66 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
  67                 divisor = 3905;
  68 #else
  69 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
  70 #endif
  71                 break;
  72
  73         case 9600:
  74 #if CONFIG_S3C44B0_CLOCK_SPEED==66
  75                 divisor = 390;
  76 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
  77                 divisor = 487;
  78 #else
  79 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
  80 #endif
  81                 break;
  82
  83         case 19200:
  84 #if CONFIG_S3C44B0_CLOCK_SPEED==66
  85                 divisor = 194;
  86 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
  87                 divisor = 243;
  88 #else
  89 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
  90 #endif
  91                 break;
  92
  93         case 38400:
  94 #if CONFIG_S3C44B0_CLOCK_SPEED==66
  95                 divisor = 97;
  96 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
  97                 divisor = 121;
  98 #else
  99 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
 100 #endif  /* break; */
 101
 102         case 57600:
 103 #if CONFIG_S3C44B0_CLOCK_SPEED==66
 104                 divisor = 64;
 105 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
 106                 divisor = 80;
 107 #else
 108 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
 109 #endif  /* break; */
 110
 111         case 115200:
 112 #if CONFIG_S3C44B0_CLOCK_SPEED==66
 113                 divisor = 32;
 114 #elif CONFIG_S3C44B0_CLOCK_SPEED==75
 115                 divisor = 40;
 116 #else
 117 # error CONFIG_S3C44B0_CLOCK_SPEED undefined
 118 #endif  /* break; */
 119         }
 120
 121         serial_flush_output();
 122         serial_flush_input();
 123         UFCON0 = 0x0;
 124         ULCON0 = 0x03;
 125         UCON0 = 0x05;
 126         UBRDIV0 = divisor;
 127
 128         UFCON1 = 0x0;
 129         ULCON1 = 0x03;
 130         UCON1 = 0x05;
 131         UBRDIV1 = divisor;
 132
 133         for(divisor=0; divisor<100; divisor++) {
 134                 /* NOP */
 135         }
 136 }
 137
 138
 139 /*
 140  * Initialise the serial port with the given baudrate. The settings
 141  * are always 8 data bits, no parity, 1 stop bit, no start bits.
 142  *
 143  */
 144 static int s3c44b0_serial_init(void)
 145 {
 146         serial_setbrg ();
 147
 148         return (0);
 149 }
 150
 151
 152 /*
 153  * Output a single byte to the serial port.
 154  */
 155 static void s3c44b0_serial_putc(const char c)
 156 {
 157         /* wait for room in the transmit FIFO */
 158         while(!(UTRSTAT0 & 0x02));
 159
 160         UTXH0 = (unsigned char)c;
 161
 162         /*
 163                 to be polite with serial console add a line feed
 164                 to the carriage return character
 165         */
 166         if (c=='\n')
 167                 serial_putc('\r');
 168 }
 169
 170 /*
 171  * Read a single byte from the serial port. Returns 1 on success, 0
 172  * otherwise. When the function is succesfull, the character read is
 173  * written into its argument c.
 174  */
 175 static int s3c44b0_serial_tstc(void)
 176 {
 177         return (UTRSTAT0 & 0x01);
 178 }
 179
 180 /*
 181  * Read a single byte from the serial port. Returns 1 on success, 0
 182  * otherwise. When the function is succesfull, the character read is
 183  * written into its argument c.
 184  */
 185 static int s3c44b0_serial_getc(void)
 186 {
 187         int rv;
 188
 189         for(;;) {
 190                 rv = s3c44b0_serial_tstc();
 191
 192                 if(rv > 0)
 193                         return URXH0;
 194         }
 195 }
 196
 197 static struct serial_device s3c44b0_serial_drv = {
 198         .name   = "s3c44b0_serial",
 199         .start  = s3c44b0_serial_init,
 200         .stop   = NULL,
 201         .setbrg = s3c44b0_serial_setbrg,
 202         .putc   = s3c44b0_serial_putc,
 203         .puts   = default_serial_puts,
 204         .getc   = s3c44b0_serial_getc,
 205         .tstc   = s3c44b0_serial_tstc,
 206 };
 207
 208 void s3c44b0_serial_initialize(void)
 209 {
 210         serial_register(&s3c44b0_serial_drv);
 211 }
 212
 213 __weak struct serial_device *default_serial_console(void)
 214 {
 215         return &s3c44b0_serial_drv;
 216 }