arch/sparc/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 #include <serial.h>
  30 #include <linux/compiler.h>
  31
  32 DECLARE_GLOBAL_DATA_PTR;
  33
  34 /* Force cache miss each time a serial controller reg is read */
  35 #define CACHE_BYPASS 1
  36
  37 #ifdef CACHE_BYPASS
  38 #define READ_BYTE(var)  SPARC_NOCACHE_READ_BYTE((unsigned int)&(var))
  39 #define READ_HWORD(var) SPARC_NOCACHE_READ_HWORD((unsigned int)&(var))
  40 #define READ_WORD(var)  SPARC_NOCACHE_READ((unsigned int)&(var))
  41 #define READ_DWORD(var) SPARC_NOCACHE_READ_DWORD((unsigned int)&(var))
  42 #endif
  43
  44 static int leon2_serial_init(void)
  45 {
  46         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
  47         LEON2_Uart_regs *regs;
  48         unsigned int tmp;
  49
  50         /* Init LEON2 UART
  51          *
  52          * Set scaler / baud rate
  53          *
  54          * Receiver & transmitter enable
  55          */
  56 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
  57         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
  58 #else
  59         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
  60 #endif
  61
  62         regs->UART_Scaler = CONFIG_SYS_LEON2_UART1_SCALER;
  63
  64         /* Let bit 11 be unchanged (debug bit for GRMON) */
  65         tmp = READ_WORD(regs->UART_Control);
  66
  67         regs->UART_Control = ((tmp & LEON2_UART_CTRL_DBG) |
  68                               (LEON2_UART1_LOOPBACK_ENABLE << 7) |
  69                               (LEON2_UART1_FLOWCTRL_ENABLE << 6) |
  70                               (LEON2_UART1_PARITY_ENABLE << 5) |
  71                               (LEON2_UART1_ODDPAR_ENABLE << 4) |
  72                               LEON2_UART_CTRL_RE | LEON2_UART_CTRL_TE);
  73
  74         return 0;
  75 }
  76
  77 static void leon2_serial_putc_raw(const char c)
  78 {
  79         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
  80         LEON2_Uart_regs *regs;
  81
  82 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
  83         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
  84 #else
  85         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
  86 #endif
  87
  88         /* Wait for last character to go. */
  89         while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_THE)) ;
  90
  91         /* Send data */
  92         regs->UART_Channel = c;
  93
  94 #ifdef LEON_DEBUG
  95         /* Wait for data to be sent */
  96         while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_TSE)) ;
  97 #endif
  98 }
  99
 100 static void leon2_serial_putc(const char c)
 101 {
 102         if (c == '\n')
 103                 leon2_serial_putc_raw('\r');
 104
 105         leon2_serial_putc_raw(c);
 106 }
 107
 108 static int leon2_serial_getc(void)
 109 {
 110         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
 111         LEON2_Uart_regs *regs;
 112
 113 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
 114         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
 115 #else
 116         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
 117 #endif
 118
 119         /* Wait for a character to arrive. */
 120         while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_DR)) ;
 121
 122         /* read data */
 123         return READ_WORD(regs->UART_Channel);
 124 }
 125
 126 static int leon2_serial_tstc(void)
 127 {
 128         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
 129         LEON2_Uart_regs *regs;
 130
 131 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
 132         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
 133 #else
 134         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
 135 #endif
 136
 137         return (READ_WORD(regs->UART_Status) & LEON2_UART_STAT_DR);
 138 }
 139
 140 /* set baud rate for uart */
 141 static void leon2_serial_setbrg(void)
 142 {
 143         /* update baud rate settings, read it from gd->baudrate */
 144         unsigned int scaler;
 145         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
 146         LEON2_Uart_regs *regs;
 147
 148 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
 149         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
 150 #else
 151         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
 152 #endif
 153
 154         if (gd->baudrate > 0) {
 155                 scaler =
 156                     (((CONFIG_SYS_CLK_FREQ * 10) / (gd->baudrate * 8)) -
 157                      5) / 10;
 158                 regs->UART_Scaler = scaler;
 159         }
 160 }
 161
 162 static struct serial_device leon2_serial_drv = {
 163         .name   = "leon2_serial",
 164         .start  = leon2_serial_init,
 165         .stop   = NULL,
 166         .setbrg = leon2_serial_setbrg,
 167         .putc   = leon2_serial_putc,
 168         .puts   = default_serial_puts,
 169         .getc   = leon2_serial_getc,
 170         .tstc   = leon2_serial_tstc,
 171 };
 172
 173 void leon2_serial_initialize(void)
 174 {
 175         serial_register(&leon2_serial_drv);
 176 }
 177
 178 __weak struct serial_device *default_serial_console(void)
 179 {
 180         return &leon2_serial_drv;
 181 }