6ec518a81113c2571df593dd6fe6f2e08c7a24ec
[linux-2.6.git] / 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);