cpu/leon3/serial.c

   1 /* GRLIB APBUART Serial controller driver
   2  *
   3  * (C) Copyright 2007
   4  * Daniel Hellstrom, Gaisler Research, daniel@gaisler.com.
   5  *
   6  * See file CREDITS for list of people who contributed to this
   7  * project.
   8  *
   9  * This program is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU General Public License as
  11  * published by the Free Software Foundation; either version 2 of
  12  * the License, or (at your option) any later version.
  13  *
  14  * This program is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  * GNU General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  22  * MA 02111-1307 USA
  23  *
  24  */
  25
  26 #include <common.h>
  27 #include <asm/processor.h>
  28 #include <asm/leon.h>
  29 #include <ambapp.h>
  30
  31 DECLARE_GLOBAL_DATA_PTR;
  32
  33 /* Force cache miss each time a serial controller reg is read */
  34 #define CACHE_BYPASS 1
  35
  36 #ifdef CACHE_BYPASS
  37 #define READ_BYTE(var)  SPARC_NOCACHE_READ_BYTE((unsigned int)&(var))
  38 #define READ_HWORD(var) SPARC_NOCACHE_READ_HWORD((unsigned int)&(var))
  39 #define READ_WORD(var)  SPARC_NOCACHE_READ((unsigned int)&(var))
  40 #define READ_DWORD(var) SPARC_NOCACHE_READ_DWORD((unsigned int)&(var))
  41 #endif
  42
  43 ambapp_dev_apbuart *leon3_apbuart = NULL;
  44
  45 int serial_init(void)
  46 {
  47         ambapp_apbdev apbdev;
  48         unsigned int tmp;
  49
  50         /* find UART */
  51         if (ambapp_apb_first(VENDOR_GAISLER, GAISLER_APBUART, &apbdev) == 1) {
  52
  53                 leon3_apbuart = (ambapp_dev_apbuart *) apbdev.address;
  54
  55                 /* found apbuart, let's init...
  56                  *
  57                  * Set scaler / baud rate
  58                  *
  59                  * Receiver & transmitter enable
  60                  */
  61                 leon3_apbuart->scaler = CONFIG_SYS_GRLIB_APBUART_SCALER;
  62
  63                 /* Let bit 11 be unchanged (debug bit for GRMON) */
  64                 tmp = READ_WORD(leon3_apbuart->ctrl);
  65
  66                 leon3_apbuart->ctrl = ((tmp & LEON_REG_UART_CTRL_DBG) |
  67                                        LEON_REG_UART_CTRL_RE |
  68                                        LEON_REG_UART_CTRL_TE);
  69
  70                 return 0;
  71         }
  72         return -1;              /* didn't find hardware */
  73 }
  74
  75 void serial_putc(const char c)
  76 {
  77         if (c == '\n')
  78                 serial_putc_raw('\r');
  79
  80         serial_putc_raw(c);
  81 }
  82
  83 void serial_putc_raw(const char c)
  84 {
  85         if (!leon3_apbuart)
  86                 return;
  87
  88         /* Wait for last character to go. */
  89         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_THE)) ;
  90
  91         /* Send data */
  92         leon3_apbuart->data = c;
  93
  94 #ifdef LEON_DEBUG
  95         /* Wait for data to be sent */
  96         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_TSE)) ;
  97 #endif
  98 }
  99
 100 void serial_puts(const char *s)
 101 {
 102         while (*s) {
 103                 serial_putc(*s++);
 104         }
 105 }
 106
 107 int serial_getc(void)
 108 {
 109         if (!leon3_apbuart)
 110                 return 0;
 111
 112         /* Wait for a character to arrive. */
 113         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_DR)) ;
 114
 115         /* read data */
 116         return READ_WORD(leon3_apbuart->data);
 117 }
 118
 119 int serial_tstc(void)
 120 {
 121         if (leon3_apbuart)
 122                 return (READ_WORD(leon3_apbuart->status) &
 123                         LEON_REG_UART_STATUS_DR);
 124         return 0;
 125 }
 126
 127 /* set baud rate for uart */
 128 void serial_setbrg(void)
 129 {
 130         /* update baud rate settings, read it from gd->baudrate */
 131         unsigned int scaler;
 132         if (leon3_apbuart && (gd->baudrate > 0)) {
 133                 scaler =
 134                     (((CONFIG_SYS_CLK_FREQ * 10) / (gd->baudrate * 8)) -
 135                      5) / 10;
 136                 leon3_apbuart->scaler = scaler;
 137         }
 138         return;
 139 }