drivers/serial/serial_pl01x.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 PL010/PL011 UARTs */
  29
  30 #include <common.h>
  31 #include <watchdog.h>
  32 #include <asm/io.h>
  33 #include "serial_pl01x.h"
  34
  35 /*
  36  * Integrator AP has two UARTs, we use the first one, at 38400-8-N-1
  37  * Integrator CP has two UARTs, use the first one, at 38400-8-N-1
  38  * Versatile PB has four UARTs.
  39  */
  40 #define CONSOLE_PORT CONFIG_CONS_INDEX
  41 static volatile unsigned char *const port[] = CONFIG_PL01x_PORTS;
  42 #define NUM_PORTS (sizeof(port)/sizeof(port[0]))
  43
  44 static void pl01x_putc (int portnum, char c);
  45 static int pl01x_getc (int portnum);
  46 static int pl01x_tstc (int portnum);
  47 unsigned int baudrate = CONFIG_BAUDRATE;
  48 DECLARE_GLOBAL_DATA_PTR;
  49
  50 static struct pl01x_regs *pl01x_get_regs(int portnum)
  51 {
  52         return (struct pl01x_regs *) port[portnum];
  53 }
  54
  55 #ifdef CONFIG_PL010_SERIAL
  56
  57 int serial_init (void)
  58 {
  59         struct pl01x_regs *regs = pl01x_get_regs(CONSOLE_PORT);
  60         unsigned int divisor;
  61
  62         /* First, disable everything */
  63         writel(0, &regs->pl010_cr);
  64
  65         /* Set baud rate */
  66         switch (baudrate) {
  67         case 9600:
  68                 divisor = UART_PL010_BAUD_9600;
  69                 break;
  70
  71         case 19200:
  72                 divisor = UART_PL010_BAUD_9600;
  73                 break;
  74
  75         case 38400:
  76                 divisor = UART_PL010_BAUD_38400;
  77                 break;
  78
  79         case 57600:
  80                 divisor = UART_PL010_BAUD_57600;
  81                 break;
  82
  83         case 115200:
  84                 divisor = UART_PL010_BAUD_115200;
  85                 break;
  86
  87         default:
  88                 divisor = UART_PL010_BAUD_38400;
  89         }
  90
  91         writel((divisor & 0xf00) >> 8, &regs->pl010_lcrm);
  92         writel(divisor & 0xff, &regs->pl010_lcrl);
  93
  94         /* Set the UART to be 8 bits, 1 stop bit, no parity, fifo enabled */
  95         writel(UART_PL010_LCRH_WLEN_8 | UART_PL010_LCRH_FEN, &regs->pl010_lcrh);
  96
  97         /* Finally, enable the UART */
  98         writel(UART_PL010_CR_UARTEN, &regs->pl010_cr);
  99
 100         return 0;
 101 }
 102
 103 #endif /* CONFIG_PL010_SERIAL */
 104
 105 #ifdef CONFIG_PL011_SERIAL
 106
 107 int serial_init (void)
 108 {
 109         struct pl01x_regs *regs = pl01x_get_regs(CONSOLE_PORT);
 110         unsigned int temp;
 111         unsigned int divider;
 112         unsigned int remainder;
 113         unsigned int fraction;
 114         unsigned int lcr;
 115
 116 #ifdef CONFIG_PL011_SERIAL_FLUSH_ON_INIT
 117         /* Empty RX fifo if necessary */
 118         if (readl(&regs->pl011_cr) & UART_PL011_CR_UARTEN) {
 119                 while (!(readl(&regs->fr) & UART_PL01x_FR_RXFE))
 120                         readl(&regs->dr);
 121         }
 122 #endif
 123
 124         /* First, disable everything */
 125         writel(0, &regs->pl011_cr);
 126
 127         /*
 128          * Set baud rate
 129          *
 130          * IBRD = UART_CLK / (16 * BAUD_RATE)
 131          * FBRD = RND((64 * MOD(UART_CLK,(16 * BAUD_RATE))) / (16 * BAUD_RATE))
 132          */
 133         temp = 16 * baudrate;
 134         divider = CONFIG_PL011_CLOCK / temp;
 135         remainder = CONFIG_PL011_CLOCK % temp;
 136         temp = (8 * remainder) / baudrate;
 137         fraction = (temp >> 1) + (temp & 1);
 138
 139         writel(divider, &regs->pl011_ibrd);
 140         writel(fraction, &regs->pl011_fbrd);
 141
 142         /* Set the UART to be 8 bits, 1 stop bit, no parity, fifo enabled */
 143         lcr = UART_PL011_LCRH_WLEN_8 | UART_PL011_LCRH_FEN;
 144         writel(lcr, &regs->pl011_lcrh);
 145
 146 #ifdef CONFIG_PL011_SERIAL_RLCR
 147         {
 148                 int i;
 149
 150                 /*
 151                  * Program receive line control register after waiting
 152                  * 10 bus cycles.  Delay be writing to readonly register
 153                  * 10 times
 154                  */
 155                 for (i = 0; i < 10; i++)
 156                         writel(lcr, &regs->fr);
 157
 158                 writel(lcr, &regs->pl011_rlcr);
 159                 /* lcrh needs to be set again for change to be effective */
 160                 writel(lcr, &regs->pl011_lcrh);
 161         }
 162 #endif
 163         /* Finally, enable the UART */
 164         writel(UART_PL011_CR_UARTEN | UART_PL011_CR_TXE | UART_PL011_CR_RXE,
 165                &regs->pl011_cr);
 166
 167         return 0;
 168 }
 169
 170 #endif /* CONFIG_PL011_SERIAL */
 171
 172 void serial_putc (const char c)
 173 {
 174         if (c == '\n')
 175                 pl01x_putc (CONSOLE_PORT, '\r');
 176
 177         pl01x_putc (CONSOLE_PORT, c);
 178 }
 179
 180 void serial_puts (const char *s)
 181 {
 182         while (*s) {
 183                 serial_putc (*s++);
 184         }
 185 }
 186
 187 int serial_getc (void)
 188 {
 189         return pl01x_getc (CONSOLE_PORT);
 190 }
 191
 192 int serial_tstc (void)
 193 {
 194         return pl01x_tstc (CONSOLE_PORT);
 195 }
 196
 197 void serial_setbrg (void)
 198 {
 199         struct pl01x_regs *regs = pl01x_get_regs(CONSOLE_PORT);
 200
 201         baudrate = gd->baudrate;
 202         /*
 203          * Flush FIFO and wait for non-busy before changing baudrate to avoid
 204          * crap in console
 205          */
 206         while (!(readl(&regs->fr) & UART_PL01x_FR_TXFE))
 207                 WATCHDOG_RESET();
 208         while (readl(&regs->fr) & UART_PL01x_FR_BUSY)
 209                 WATCHDOG_RESET();
 210         serial_init();
 211 }
 212
 213 static void pl01x_putc (int portnum, char c)
 214 {
 215         struct pl01x_regs *regs = pl01x_get_regs(portnum);
 216
 217         /* Wait until there is space in the FIFO */
 218         while (readl(&regs->fr) & UART_PL01x_FR_TXFF)
 219                 WATCHDOG_RESET();
 220
 221         /* Send the character */
 222         writel(c, &regs->dr);
 223 }
 224
 225 static int pl01x_getc (int portnum)
 226 {
 227         struct pl01x_regs *regs = pl01x_get_regs(portnum);
 228         unsigned int data;
 229
 230         /* Wait until there is data in the FIFO */
 231         while (readl(&regs->fr) & UART_PL01x_FR_RXFE)
 232                 WATCHDOG_RESET();
 233
 234         data = readl(&regs->dr);
 235
 236         /* Check for an error flag */
 237         if (data & 0xFFFFFF00) {
 238                 /* Clear the error */
 239                 writel(0xFFFFFFFF, &regs->ecr);
 240                 return -1;
 241         }
 242
 243         return (int) data;
 244 }
 245
 246 static int pl01x_tstc (int portnum)
 247 {
 248         struct pl01x_regs *regs = pl01x_get_regs(portnum);
 249
 250         WATCHDOG_RESET();
 251         return !(readl(&regs->fr) & UART_PL01x_FR_RXFE);
 252 }