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Merge branch 'next-spi' of git://git.secretlab.ca/git/linux-2.6
[mv-sheeva.git] / arch / blackfin / kernel / early_printk.c
1 /*
2  * allow a console to be used for early printk
3  * derived from arch/x86/kernel/early_printk.c
4  *
5  * Copyright 2007-2009 Analog Devices Inc.
6  *
7  * Licensed under the GPL-2
8  */
9
10 #include <linux/kernel.h>
11 #include <linux/init.h>
12 #include <linux/serial_core.h>
13 #include <linux/console.h>
14 #include <linux/string.h>
15 #include <linux/reboot.h>
16 #include <asm/blackfin.h>
17 #include <asm/irq_handler.h>
18 #include <asm/early_printk.h>
19
20 #ifdef CONFIG_SERIAL_BFIN
21 extern struct console *bfin_earlyserial_init(unsigned int port,
22                                                 unsigned int cflag);
23 #endif
24 #ifdef CONFIG_BFIN_JTAG_COMM
25 extern struct console *bfin_jc_early_init(void);
26 #endif
27
28 static struct console *early_console;
29
30 /* Default console */
31 #define DEFAULT_PORT 0
32 #define DEFAULT_CFLAG CS8|B57600
33
34 /* Default console for early crashes */
35 #define DEFAULT_EARLY_PORT "serial,uart0,57600"
36
37 #ifdef CONFIG_SERIAL_CORE
38 /* What should get here is "0,57600" */
39 static struct console * __init earlyserial_init(char *buf)
40 {
41         int baud, bit;
42         char parity;
43         unsigned int serial_port = DEFAULT_PORT;
44         unsigned int cflag = DEFAULT_CFLAG;
45
46         serial_port = simple_strtoul(buf, &buf, 10);
47         buf++;
48
49         cflag = 0;
50         baud = simple_strtoul(buf, &buf, 10);
51         switch (baud) {
52         case 1200:
53                 cflag |= B1200;
54                 break;
55         case 2400:
56                 cflag |= B2400;
57                 break;
58         case 4800:
59                 cflag |= B4800;
60                 break;
61         case 9600:
62                 cflag |= B9600;
63                 break;
64         case 19200:
65                 cflag |= B19200;
66                 break;
67         case 38400:
68                 cflag |= B38400;
69                 break;
70         case 115200:
71                 cflag |= B115200;
72                 break;
73         default:
74                 cflag |= B57600;
75         }
76
77         parity = buf[0];
78         buf++;
79         switch (parity) {
80         case 'e':
81                 cflag |= PARENB;
82                 break;
83         case 'o':
84                 cflag |= PARODD;
85                 break;
86         }
87
88         bit = simple_strtoul(buf, &buf, 10);
89         switch (bit) {
90         case 5:
91                 cflag |= CS5;
92                 break;
93         case 6:
94                 cflag |= CS6;
95                 break;
96         case 7:
97                 cflag |= CS7;
98                 break;
99         default:
100                 cflag |= CS8;
101         }
102
103 #ifdef CONFIG_SERIAL_BFIN
104         return bfin_earlyserial_init(serial_port, cflag);
105 #else
106         return NULL;
107 #endif
108
109 }
110 #endif
111
112 int __init setup_early_printk(char *buf)
113 {
114
115         /* Crashing in here would be really bad, so check both the var
116            and the pointer before we start using it
117          */
118         if (!buf)
119                 return 0;
120
121         if (!*buf)
122                 return 0;
123
124         if (early_console != NULL)
125                 return 0;
126
127 #ifdef CONFIG_SERIAL_BFIN
128         /* Check for Blackfin Serial */
129         if (!strncmp(buf, "serial,uart", 11)) {
130                 buf += 11;
131                 early_console = earlyserial_init(buf);
132         }
133 #endif
134
135 #ifdef CONFIG_BFIN_JTAG_COMM
136         /* Check for Blackfin JTAG */
137         if (!strncmp(buf, "jtag", 4)) {
138                 buf += 4;
139                 early_console = bfin_jc_early_init();
140         }
141 #endif
142
143 #ifdef CONFIG_FB
144                 /* TODO: add framebuffer console support */
145 #endif
146
147         if (likely(early_console)) {
148                 early_console->flags |= CON_BOOT;
149
150                 register_console(early_console);
151                 printk(KERN_INFO "early printk enabled on %s%d\n",
152                         early_console->name,
153                         early_console->index);
154         }
155
156         return 0;
157 }
158
159 /*
160  * Set up a temporary Event Vector Table, so if something bad happens before
161  * the kernel is fully started, it doesn't vector off into somewhere we don't
162  * know
163  */
164
165 asmlinkage void __init init_early_exception_vectors(void)
166 {
167         u32 evt;
168         SSYNC();
169
170         /*
171          * This starts up the shadow buffer, incase anything crashes before
172          * setup arch
173          */
174         mark_shadow_error();
175         early_shadow_puts(linux_banner);
176         early_shadow_stamp();
177
178         if (CPUID != bfin_cpuid()) {
179                 early_shadow_puts("Running on wrong machine type, expected");
180                 early_shadow_reg(CPUID, 16);
181                 early_shadow_puts(", but running on");
182                 early_shadow_reg(bfin_cpuid(), 16);
183                 early_shadow_puts("\n");
184         }
185
186         /* cannot program in software:
187          * evt0 - emulation (jtag)
188          * evt1 - reset
189          */
190         for (evt = EVT2; evt <= EVT15; evt += 4)
191                 bfin_write32(evt, early_trap);
192         CSYNC();
193
194         /* Set all the return from interrupt, exception, NMI to a known place
195          * so if we do a RETI, RETX or RETN by mistake - we go somewhere known
196          * Note - don't change RETS - we are in a subroutine, or
197          * RETE - since it might screw up if emulator is attached
198          */
199         asm("\tRETI = %0; RETX = %0; RETN = %0;\n"
200                 : : "p"(early_trap));
201
202 }
203
204 __attribute__((__noreturn__))
205 asmlinkage void __init early_trap_c(struct pt_regs *fp, void *retaddr)
206 {
207         /* This can happen before the uart is initialized, so initialize
208          * the UART now (but only if we are running on the processor we think
209          * we are compiled for - otherwise we write to MMRs that don't exist,
210          * and cause other problems. Nothing comes out the UART, but it does
211          * end up in the __buf_log.
212          */
213         if (likely(early_console == NULL) && CPUID == bfin_cpuid())
214                 setup_early_printk(DEFAULT_EARLY_PORT);
215
216         if (!shadow_console_enabled()) {
217                 /* crap - we crashed before setup_arch() */
218                 early_shadow_puts("panic before setup_arch\n");
219                 early_shadow_puts("IPEND:");
220                 early_shadow_reg(fp->ipend, 16);
221                 if (fp->seqstat & SEQSTAT_EXCAUSE) {
222                         early_shadow_puts("\nEXCAUSE:");
223                         early_shadow_reg(fp->seqstat & SEQSTAT_EXCAUSE, 8);
224                 }
225                 if (fp->seqstat & SEQSTAT_HWERRCAUSE) {
226                         early_shadow_puts("\nHWERRCAUSE:");
227                         early_shadow_reg(
228                                 (fp->seqstat & SEQSTAT_HWERRCAUSE) >> 14, 8);
229                 }
230                 early_shadow_puts("\nErr @");
231                 if (fp->ipend & EVT_EVX)
232                         early_shadow_reg(fp->retx, 32);
233                 else
234                         early_shadow_reg(fp->pc, 32);
235 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
236                 early_shadow_puts("\nTrace:");
237                 if (likely(bfin_read_TBUFSTAT() & TBUFCNT)) {
238                         while (bfin_read_TBUFSTAT() & TBUFCNT) {
239                                 early_shadow_puts("\nT  :");
240                                 early_shadow_reg(bfin_read_TBUF(), 32);
241                                 early_shadow_puts("\n S :");
242                                 early_shadow_reg(bfin_read_TBUF(), 32);
243                         }
244                 }
245 #endif
246                 early_shadow_puts("\nUse bfin-elf-addr2line to determine "
247                         "function names\n");
248                 /*
249                  * We should panic(), but we can't - since panic calls printk,
250                  * and printk uses memcpy.
251                  * we want to reboot, but if the machine type is different,
252                  * can't due to machine specific reboot sequences
253                  */
254                 if (CPUID == bfin_cpuid()) {
255                         early_shadow_puts("Trying to restart\n");
256                         machine_restart("");
257                 }
258
259                 early_shadow_puts("Halting, since it is not safe to restart\n");
260                 while (1)
261                         asm volatile ("EMUEXCPT; IDLE;\n");
262
263         } else {
264                 printk(KERN_EMERG "Early panic\n");
265                 show_regs(fp);
266                 dump_bfin_trace_buffer();
267         }
268
269         panic("Died early");
270 }
271
272 early_param("earlyprintk", setup_early_printk);