arch/sparc/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 #include <serial.h>
  31 #include <linux/compiler.h>
  32
  33 DECLARE_GLOBAL_DATA_PTR;
  34
  35 ambapp_dev_apbuart *leon3_apbuart = NULL;
  36
  37 static int leon3_serial_init(void)
  38 {
  39         ambapp_apbdev apbdev;
  40         unsigned int tmp;
  41
  42         /* find UART */
  43         if (ambapp_apb_first(VENDOR_GAISLER, GAISLER_APBUART, &apbdev) == 1) {
  44
  45                 leon3_apbuart = (ambapp_dev_apbuart *) apbdev.address;
  46
  47                 /* found apbuart, let's init...
  48                  *
  49                  * Set scaler / baud rate
  50                  *
  51                  * Receiver & transmitter enable
  52                  */
  53                 leon3_apbuart->scaler = CONFIG_SYS_GRLIB_APBUART_SCALER;
  54
  55                 /* Let bit 11 be unchanged (debug bit for GRMON) */
  56                 tmp = READ_WORD(leon3_apbuart->ctrl);
  57
  58                 leon3_apbuart->ctrl = ((tmp & LEON_REG_UART_CTRL_DBG) |
  59                                        LEON_REG_UART_CTRL_RE |
  60                                        LEON_REG_UART_CTRL_TE);
  61
  62                 return 0;
  63         }
  64         return -1;              /* didn't find hardware */
  65 }
  66
  67 static void leon3_serial_putc_raw(const char c)
  68 {
  69         if (!leon3_apbuart)
  70                 return;
  71
  72         /* Wait for last character to go. */
  73         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_THE)) ;
  74
  75         /* Send data */
  76         leon3_apbuart->data = c;
  77
  78 #ifdef LEON_DEBUG
  79         /* Wait for data to be sent */
  80         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_TSE)) ;
  81 #endif
  82 }
  83
  84 static void leon3_serial_putc(const char c)
  85 {
  86         if (c == '\n')
  87                 leon3_serial_putc_raw('\r');
  88
  89         leon3_serial_putc_raw(c);
  90 }
  91
  92 static int leon3_serial_getc(void)
  93 {
  94         if (!leon3_apbuart)
  95                 return 0;
  96
  97         /* Wait for a character to arrive. */
  98         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_DR)) ;
  99
 100         /* read data */
 101         return READ_WORD(leon3_apbuart->data);
 102 }
 103
 104 static int leon3_serial_tstc(void)
 105 {
 106         if (leon3_apbuart)
 107                 return (READ_WORD(leon3_apbuart->status) &
 108                         LEON_REG_UART_STATUS_DR);
 109         return 0;
 110 }
 111
 112 /* set baud rate for uart */
 113 static void leon3_serial_setbrg(void)
 114 {
 115         /* update baud rate settings, read it from gd->baudrate */
 116         unsigned int scaler;
 117         if (leon3_apbuart && (gd->baudrate > 0)) {
 118                 scaler =
 119                     (((CONFIG_SYS_CLK_FREQ * 10) / (gd->baudrate * 8)) -
 120                      5) / 10;
 121                 leon3_apbuart->scaler = scaler;
 122         }
 123         return;
 124 }
 125
 126 static struct serial_device leon3_serial_drv = {
 127         .name   = "leon3_serial",
 128         .start  = leon3_serial_init,
 129         .stop   = NULL,
 130         .setbrg = leon3_serial_setbrg,
 131         .putc   = leon3_serial_putc,
 132         .puts   = default_serial_puts,
 133         .getc   = leon3_serial_getc,
 134         .tstc   = leon3_serial_tstc,
 135 };
 136
 137 void leon3_serial_initialize(void)
 138 {
 139         serial_register(&leon3_serial_drv);
 140 }
 141
 142 __weak struct serial_device *default_serial_console(void)
 143 {
 144         return &leon3_serial_drv;
 145 }