drivers/serial_pl011.c

   1 /*
   2  * (C) Copyright 2000
   3  * Rob Taylor, Flying Pig Systems. robt@flyingpig.com.
   4  *
   5  * (C) Copyright 2004
   6  * ARM Ltd.
   7  * Philippe Robin, <philippe.robin@arm.com>
   8  *
   9  * See file CREDITS for list of people who contributed to this
  10  * project.
  11  *
  12  * This program is free software; you can redistribute it and/or
  13  * modify it under the terms of the GNU General Public License as
  14  * published by the Free Software Foundation; either version 2 of
  15  * the License, or (at your option) any later version.
  16  *
  17  * This program is distributed in the hope that it will be useful,
  18  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  19  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  20  * GNU General Public License for more details.
  21  *
  22  * You should have received a copy of the GNU General Public License
  23  * along with this program; if not, write to the Free Software
  24  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  25  * MA 02111-1307 USA
  26  */
  27
  28 /* Simple U-Boot driver for the PrimeCell PL011 UARTs on the IntegratorCP */
  29 /* Should be fairly simple to make it work with the PL010 as well */
  30
  31 #include <common.h>
  32
  33 #ifdef CFG_PL011_SERIAL
  34
  35 #include "serial_pl011.h"
  36
  37 #define IO_WRITE(addr, val) (*(volatile unsigned int *)(addr) = (val))
  38 #define IO_READ(addr) (*(volatile unsigned int *)(addr))
  39
  40 /*
  41  * IntegratorCP has two UARTs, use the first one, at 38400-8-N-1
  42  * Versatile PB has four UARTs.
  43  */
  44 #define NUM_PORTS 2
  45 #define CONSOLE_PORT CONFIG_CONS_INDEX
  46 #define baudRate CONFIG_BAUDRATE
  47 static volatile unsigned char * const port[NUM_PORTS] = {(void*)(CFG_SERIAL0),
  48                                                          (void*)(CFG_SERIAL1)};
  49
  50
  51 static void pl011_putc(int portnum, char c);
  52 static int pl011_getc(int portnum);
  53 static int pl011_tstc(int portnum);
  54
  55
  56 int serial_init (void)
  57 {
  58     unsigned int temp;
  59     unsigned int divider;
  60     unsigned int remainder;
  61     unsigned int fraction;
  62
  63     /*
  64     ** First, disable everything.
  65     */
  66     IO_WRITE(port[CONSOLE_PORT] + UART_PL011_CR, 0x0);
  67
  68     /*
  69     ** Set baud rate
  70     **
  71     ** IBRD = UART_CLK / (16 * BAUD_RATE)
  72     ** FBRD = ROUND((64 * MOD(UART_CLK,(16 * BAUD_RATE))) / (16 * BAUD_RATE))
  73     */
  74 #ifdef CONFIG_VERSATILE
  75     temp      = 16 * baudRate;
  76     divider   = 24000000 / temp;
  77     remainder = 24000000 % temp;
  78     temp      = (8 * remainder) / baudRate;
  79     fraction  = (temp >> 1) + (temp & 1);
  80 #endif
  81 #ifdef CONFIG_INTEGRATOR
  82     temp      = 16 * baudRate;
  83     divider   = 14745600 / temp;
  84     remainder = 14745600 % temp;
  85     temp      = (8 * remainder) / baudRate;
  86     fraction  = (temp >> 1) + (temp & 1);
  87 #endif
  88
  89     IO_WRITE(port[CONSOLE_PORT] + UART_PL011_IBRD, divider);
  90     IO_WRITE(port[CONSOLE_PORT] + UART_PL011_FBRD, fraction);
  91
  92     /*
  93     ** Set the UART to be 8 bits, 1 stop bit, no parity, fifo enabled.
  94     */
  95     IO_WRITE(port[CONSOLE_PORT] + UART_PL011_LCRH,
  96         (UART_PL011_LCRH_WLEN_8 | UART_PL011_LCRH_FEN));
  97
  98     /*
  99     ** Finally, enable the UART
 100     */
 101     IO_WRITE(port[CONSOLE_PORT] + UART_PL011_CR,
 102         (UART_PL011_CR_UARTEN | UART_PL011_CR_TXE | UART_PL011_CR_RXE));
 103
 104     return (0);
 105 }
 106
 107 void
 108 serial_putc(const char c)
 109 {
 110         if (c == '\n')
 111                 pl011_putc(CONSOLE_PORT, '\r');
 112
 113         pl011_putc(CONSOLE_PORT, c);
 114 }
 115
 116 void
 117 serial_puts (const char *s)
 118 {
 119         while (*s) {
 120                 serial_putc (*s++);
 121         }
 122 }
 123
 124 int
 125 serial_getc(void)
 126 {
 127         return pl011_getc(CONSOLE_PORT);
 128 }
 129
 130 int
 131 serial_tstc(void)
 132 {
 133         return pl011_tstc(CONSOLE_PORT);
 134 }
 135
 136 void
 137 serial_setbrg (void)
 138 {
 139 }
 140
 141 static void pl011_putc(int portnum, char c)
 142 {
 143     /* Wait until there is space in the FIFO */
 144     while (IO_READ(port[portnum] + UART_PL01x_FR) & UART_PL01x_FR_TXFF);
 145
 146     /* Send the character */
 147     IO_WRITE(port[portnum] + UART_PL01x_DR, c);
 148 }
 149
 150 static int pl011_getc(int portnum)
 151 {
 152     unsigned int data;
 153
 154     /* Wait until there is data in the FIFO */
 155     while (IO_READ(port[portnum] + UART_PL01x_FR) & UART_PL01x_FR_RXFE);
 156
 157     data = IO_READ(port[portnum] + UART_PL01x_DR);
 158
 159     /* Check for an error flag */
 160     if (data & 0xFFFFFF00)
 161     {
 162         /* Clear the error */
 163         IO_WRITE(port[portnum] + UART_PL01x_ECR, 0xFFFFFFFF);
 164         return -1;
 165     }
 166
 167     return (int)data;
 168 }
 169
 170 static int pl011_tstc(int portnum)
 171 {
 172     return !(IO_READ(port[portnum] + UART_PL01x_FR) & UART_PL01x_FR_RXFE);
 173 }
 174
 175 #endif