cpu/leon2/serial.c

   1 /* GRLIB APBUART Serial controller driver
   2  *
   3  * (C) Copyright 2008
   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
  30 DECLARE_GLOBAL_DATA_PTR;
  31
  32 /* Force cache miss each time a serial controller reg is read */
  33 #define CACHE_BYPASS 1
  34
  35 #ifdef CACHE_BYPASS
  36 #define READ_BYTE(var)  SPARC_NOCACHE_READ_BYTE((unsigned int)&(var))
  37 #define READ_HWORD(var) SPARC_NOCACHE_READ_HWORD((unsigned int)&(var))
  38 #define READ_WORD(var)  SPARC_NOCACHE_READ((unsigned int)&(var))
  39 #define READ_DWORD(var) SPARC_NOCACHE_READ_DWORD((unsigned int)&(var))
  40 #endif
  41
  42 int serial_init(void)
  43 {
  44         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
  45         LEON2_Uart_regs *regs;
  46         unsigned int tmp;
  47
  48         /* Init LEON2 UART
  49          *
  50          * Set scaler / baud rate
  51          *
  52          * Receiver & transmitter enable
  53          */
  54 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
  55         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
  56 #else
  57         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
  58 #endif
  59
  60         regs->UART_Scaler = CONFIG_SYS_LEON2_UART1_SCALER;
  61
  62         /* Let bit 11 be unchanged (debug bit for GRMON) */
  63         tmp = READ_WORD(regs->UART_Control);
  64
  65         regs->UART_Control = ((tmp & LEON2_UART_CTRL_DBG) |
  66                               (LEON2_UART1_LOOPBACK_ENABLE << 7) |
  67                               (LEON2_UART1_FLOWCTRL_ENABLE << 6) |
  68                               (LEON2_UART1_PARITY_ENABLE << 5) |
  69                               (LEON2_UART1_ODDPAR_ENABLE << 4) |
  70                               LEON2_UART_CTRL_RE | LEON2_UART_CTRL_TE);
  71
  72         return 0;
  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         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
  86         LEON2_Uart_regs *regs;
  87
  88 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
  89         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
  90 #else
  91         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
  92 #endif
  93
  94         /* Wait for last character to go. */
  95         while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_THE)) ;
  96
  97         /* Send data */
  98         regs->UART_Channel = c;
  99
 100 #ifdef LEON_DEBUG
 101         /* Wait for data to be sent */
 102         while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_TSE)) ;
 103 #endif
 104 }
 105
 106 void serial_puts(const char *s)
 107 {
 108         while (*s) {
 109                 serial_putc(*s++);
 110         }
 111 }
 112
 113 int serial_getc(void)
 114 {
 115         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
 116         LEON2_Uart_regs *regs;
 117
 118 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
 119         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
 120 #else
 121         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
 122 #endif
 123
 124         /* Wait for a character to arrive. */
 125         while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_DR)) ;
 126
 127         /* read data */
 128         return READ_WORD(regs->UART_Channel);
 129 }
 130
 131 int serial_tstc(void)
 132 {
 133         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
 134         LEON2_Uart_regs *regs;
 135
 136 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
 137         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
 138 #else
 139         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
 140 #endif
 141
 142         return (READ_WORD(regs->UART_Status) & LEON2_UART_STAT_DR);
 143 }
 144
 145 /* set baud rate for uart */
 146 void serial_setbrg(void)
 147 {
 148         /* update baud rate settings, read it from gd->baudrate */
 149         unsigned int scaler;
 150         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
 151         LEON2_Uart_regs *regs;
 152
 153 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
 154         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
 155 #else
 156         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
 157 #endif
 158
 159         if (gd->baudrate > 0) {
 160                 scaler =
 161                     (((CONFIG_SYS_CLK_FREQ * 10) / (gd->baudrate * 8)) -
 162                      5) / 10;
 163                 regs->UART_Scaler = scaler;
 164         }
 165 }