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 /* Force cache miss each time a serial controller reg is read */
  36 #define CACHE_BYPASS 1
  37
  38 #ifdef CACHE_BYPASS
  39 #define READ_BYTE(var)  SPARC_NOCACHE_READ_BYTE((unsigned int)&(var))
  40 #define READ_HWORD(var) SPARC_NOCACHE_READ_HWORD((unsigned int)&(var))
  41 #define READ_WORD(var)  SPARC_NOCACHE_READ((unsigned int)&(var))
  42 #define READ_DWORD(var) SPARC_NOCACHE_READ_DWORD((unsigned int)&(var))
  43 #endif
  44
  45 ambapp_dev_apbuart *leon3_apbuart = NULL;
  46
  47 static int leon3_serial_init(void)
  48 {
  49         ambapp_apbdev apbdev;
  50         unsigned int tmp;
  51
  52         /* find UART */
  53         if (ambapp_apb_first(VENDOR_GAISLER, GAISLER_APBUART, &apbdev) == 1) {
  54
  55                 leon3_apbuart = (ambapp_dev_apbuart *) apbdev.address;
  56
  57                 /* found apbuart, let's init...
  58                  *
  59                  * Set scaler / baud rate
  60                  *
  61                  * Receiver & transmitter enable
  62                  */
  63                 leon3_apbuart->scaler = CONFIG_SYS_GRLIB_APBUART_SCALER;
  64
  65                 /* Let bit 11 be unchanged (debug bit for GRMON) */
  66                 tmp = READ_WORD(leon3_apbuart->ctrl);
  67
  68                 leon3_apbuart->ctrl = ((tmp & LEON_REG_UART_CTRL_DBG) |
  69                                        LEON_REG_UART_CTRL_RE |
  70                                        LEON_REG_UART_CTRL_TE);
  71
  72                 return 0;
  73         }
  74         return -1;              /* didn't find hardware */
  75 }
  76
  77 static void leon3_serial_putc_raw(const char c)
  78 {
  79         if (!leon3_apbuart)
  80                 return;
  81
  82         /* Wait for last character to go. */
  83         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_THE)) ;
  84
  85         /* Send data */
  86         leon3_apbuart->data = c;
  87
  88 #ifdef LEON_DEBUG
  89         /* Wait for data to be sent */
  90         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_TSE)) ;
  91 #endif
  92 }
  93
  94 static void leon3_serial_putc(const char c)
  95 {
  96         if (c == '\n')
  97                 leon3_serial_putc_raw('\r');
  98
  99         leon3_serial_putc_raw(c);
 100 }
 101
 102 static int leon3_serial_getc(void)
 103 {
 104         if (!leon3_apbuart)
 105                 return 0;
 106
 107         /* Wait for a character to arrive. */
 108         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_DR)) ;
 109
 110         /* read data */
 111         return READ_WORD(leon3_apbuart->data);
 112 }
 113
 114 static int leon3_serial_tstc(void)
 115 {
 116         if (leon3_apbuart)
 117                 return (READ_WORD(leon3_apbuart->status) &
 118                         LEON_REG_UART_STATUS_DR);
 119         return 0;
 120 }
 121
 122 /* set baud rate for uart */
 123 static void leon3_serial_setbrg(void)
 124 {
 125         /* update baud rate settings, read it from gd->baudrate */
 126         unsigned int scaler;
 127         if (leon3_apbuart && (gd->baudrate > 0)) {
 128                 scaler =
 129                     (((CONFIG_SYS_CLK_FREQ * 10) / (gd->baudrate * 8)) -
 130                      5) / 10;
 131                 leon3_apbuart->scaler = scaler;
 132         }
 133         return;
 134 }
 135
 136 static struct serial_device leon3_serial_drv = {
 137         .name   = "leon3_serial",
 138         .start  = leon3_serial_init,
 139         .stop   = NULL,
 140         .setbrg = leon3_serial_setbrg,
 141         .putc   = leon3_serial_putc,
 142         .puts   = default_serial_puts,
 143         .getc   = leon3_serial_getc,
 144         .tstc   = leon3_serial_tstc,
 145 };
 146
 147 void leon3_serial_initialize(void)
 148 {
 149         serial_register(&leon3_serial_drv);
 150 }
 151
 152 __weak struct serial_device *default_serial_console(void)
 153 {
 154         return &leon3_serial_drv;
 155 }