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