arch/blackfin/kernel/early_printk.c

   1 /*
   2  * File:         arch/blackfin/kernel/early_printk.c
   3  * Based on:     arch/x86_64/kernel/early_printk.c
   4  * Author:       Robin Getz <rgetz@blackfin.uclinux.org
   5  *
   6  * Created:      14Aug2007
   7  * Description:  allow a console to be used for early printk
   8  *
   9  * Modified:
  10  *               Copyright 2004-2007 Analog Devices Inc.
  11  *
  12  * Bugs:         Enter bugs at http://blackfin.uclinux.org/
  13  *
  14  * This program is free software; you can redistribute it and/or modify
  15  * it under the terms of the GNU General Public License as published by
  16  * the Free Software Foundation; either version 2 of the License, or
  17  * (at your option) any later version.
  18  *
  19  * This program is distributed in the hope that it will be useful,
  20  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  21  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  22  * GNU General Public License for more details.
  23  */
  24
  25 #include <linux/kernel.h>
  26 #include <linux/init.h>
  27 #include <linux/serial_core.h>
  28 #include <linux/console.h>
  29 #include <linux/string.h>
  30 #include <asm/blackfin.h>
  31 #include <asm/irq_handler.h>
  32 #include <asm/early_printk.h>
  33
  34 #ifdef CONFIG_SERIAL_BFIN
  35 extern struct console *bfin_earlyserial_init(unsigned int port,
  36                                                 unsigned int cflag);
  37 #endif
  38
  39 static struct console *early_console;
  40
  41 /* Default console */
  42 #define DEFAULT_PORT 0
  43 #define DEFAULT_CFLAG CS8|B57600
  44
  45 /* Default console for early crashes */
  46 #define DEFAULT_EARLY_PORT "serial,uart0,57600"
  47
  48 #ifdef CONFIG_SERIAL_CORE
  49 /* What should get here is "0,57600" */
  50 static struct console * __init earlyserial_init(char *buf)
  51 {
  52         int baud, bit;
  53         char parity;
  54         unsigned int serial_port = DEFAULT_PORT;
  55         unsigned int cflag = DEFAULT_CFLAG;
  56
  57         serial_port = simple_strtoul(buf, &buf, 10);
  58         buf++;
  59
  60         cflag = 0;
  61         baud = simple_strtoul(buf, &buf, 10);
  62         switch (baud) {
  63         case 1200:
  64                 cflag |= B1200;
  65                 break;
  66         case 2400:
  67                 cflag |= B2400;
  68                 break;
  69         case 4800:
  70                 cflag |= B4800;
  71                 break;
  72         case 9600:
  73                 cflag |= B9600;
  74                 break;
  75         case 19200:
  76                 cflag |= B19200;
  77                 break;
  78         case 38400:
  79                 cflag |= B38400;
  80                 break;
  81         case 115200:
  82                 cflag |= B115200;
  83                 break;
  84         default:
  85                 cflag |= B57600;
  86         }
  87
  88         parity = buf[0];
  89         buf++;
  90         switch (parity) {
  91         case 'e':
  92                 cflag |= PARENB;
  93                 break;
  94         case 'o':
  95                 cflag |= PARODD;
  96                 break;
  97         }
  98
  99         bit = simple_strtoul(buf, &buf, 10);
 100         switch (bit) {
 101         case 5:
 102                 cflag |= CS5;
 103                 break;
 104         case 6:
 105                 cflag |= CS5;
 106                 break;
 107         case 7:
 108                 cflag |= CS5;
 109                 break;
 110         default:
 111                 cflag |= CS8;
 112         }
 113
 114 #ifdef CONFIG_SERIAL_BFIN
 115         return bfin_earlyserial_init(serial_port, cflag);
 116 #else
 117         return NULL;
 118 #endif
 119
 120 }
 121 #endif
 122
 123 int __init setup_early_printk(char *buf)
 124 {
 125
 126         /* Crashing in here would be really bad, so check both the var
 127            and the pointer before we start using it
 128          */
 129         if (!buf)
 130                 return 0;
 131
 132         if (!*buf)
 133                 return 0;
 134
 135         if (early_console != NULL)
 136                 return 0;
 137
 138 #ifdef CONFIG_SERIAL_BFIN
 139         /* Check for Blackfin Serial */
 140         if (!strncmp(buf, "serial,uart", 11)) {
 141                 buf += 11;
 142                 early_console = earlyserial_init(buf);
 143         }
 144 #endif
 145 #ifdef CONFIG_FB
 146                 /* TODO: add framebuffer console support */
 147 #endif
 148
 149         if (likely(early_console)) {
 150                 early_console->flags |= CON_BOOT;
 151
 152                 register_console(early_console);
 153                 printk(KERN_INFO "early printk enabled on %s%d\n",
 154                         early_console->name,
 155                         early_console->index);
 156         }
 157
 158         return 0;
 159 }
 160
 161 /*
 162  * Set up a temporary Event Vector Table, so if something bad happens before
 163  * the kernel is fully started, it doesn't vector off into somewhere we don't
 164  * know
 165  */
 166
 167 asmlinkage void __init init_early_exception_vectors(void)
 168 {
 169         SSYNC();
 170
 171         /* cannot program in software:
 172          * evt0 - emulation (jtag)
 173          * evt1 - reset
 174          */
 175         bfin_write_EVT2(early_trap);
 176         bfin_write_EVT3(early_trap);
 177         bfin_write_EVT5(early_trap);
 178         bfin_write_EVT6(early_trap);
 179         bfin_write_EVT7(early_trap);
 180         bfin_write_EVT8(early_trap);
 181         bfin_write_EVT9(early_trap);
 182         bfin_write_EVT10(early_trap);
 183         bfin_write_EVT11(early_trap);
 184         bfin_write_EVT12(early_trap);
 185         bfin_write_EVT13(early_trap);
 186         bfin_write_EVT14(early_trap);
 187         bfin_write_EVT15(early_trap);
 188         CSYNC();
 189
 190         /* Set all the return from interupt, exception, NMI to a known place
 191          * so if we do a RETI, RETX or RETN by mistake - we go somewhere known
 192          * Note - don't change RETS - we are in a subroutine, or
 193          * RETE - since it might screw up if emulator is attached
 194          */
 195         asm("\tRETI = %0; RETX = %0; RETN = %0;\n"
 196                 : : "p"(early_trap));
 197
 198 }
 199
 200 asmlinkage void __init early_trap_c(struct pt_regs *fp, void *retaddr)
 201 {
 202         /* This can happen before the uart is initialized, so initialize
 203          * the UART now
 204          */
 205         if (likely(early_console == NULL))
 206                 setup_early_printk(DEFAULT_EARLY_PORT);
 207
 208         dump_bfin_regs(fp, retaddr);
 209         dump_bfin_trace_buffer();
 210
 211         panic("Died early");
 212 }
 213
 214 early_param("earlyprintk", setup_early_printk);