2 * allow a console to be used for early printk
3 * derived from arch/x86/kernel/early_printk.c
5 * Copyright 2007-2009 Analog Devices Inc.
7 * Licensed under the GPL-2
10 #include <linux/kernel.h>
11 #include <linux/sched/debug.h>
12 #include <linux/init.h>
13 #include <linux/serial_core.h>
14 #include <linux/console.h>
15 #include <linux/string.h>
16 #include <linux/reboot.h>
17 #include <asm/blackfin.h>
18 #include <asm/irq_handler.h>
19 #include <asm/early_printk.h>
21 #ifdef CONFIG_SERIAL_BFIN
22 extern struct console *bfin_earlyserial_init(unsigned int port,
25 #ifdef CONFIG_BFIN_JTAG_COMM
26 extern struct console *bfin_jc_early_init(void);
30 #define DEFAULT_PORT 0
31 #define DEFAULT_CFLAG CS8|B57600
33 /* Default console for early crashes */
34 #define DEFAULT_EARLY_PORT "serial,uart0,57600"
36 #ifdef CONFIG_SERIAL_CORE
37 /* What should get here is "0,57600" */
38 static struct console * __init earlyserial_init(char *buf)
42 unsigned int serial_port = DEFAULT_PORT;
43 unsigned int cflag = DEFAULT_CFLAG;
45 serial_port = simple_strtoul(buf, &buf, 10);
49 baud = simple_strtoul(buf, &buf, 10);
87 bit = simple_strtoul(buf, &buf, 10);
102 #ifdef CONFIG_SERIAL_BFIN
103 return bfin_earlyserial_init(serial_port, cflag);
111 int __init setup_early_printk(char *buf)
114 /* Crashing in here would be really bad, so check both the var
115 and the pointer before we start using it
123 if (early_console != NULL)
126 #ifdef CONFIG_SERIAL_BFIN
127 /* Check for Blackfin Serial */
128 if (!strncmp(buf, "serial,uart", 11)) {
130 early_console = earlyserial_init(buf);
134 #ifdef CONFIG_BFIN_JTAG_COMM
135 /* Check for Blackfin JTAG */
136 if (!strncmp(buf, "jtag", 4)) {
138 early_console = bfin_jc_early_init();
143 /* TODO: add framebuffer console support */
146 if (likely(early_console)) {
147 early_console->flags |= CON_BOOT;
149 register_console(early_console);
150 printk(KERN_INFO "early printk enabled on %s%d\n",
152 early_console->index);
159 * Set up a temporary Event Vector Table, so if something bad happens before
160 * the kernel is fully started, it doesn't vector off into somewhere we don't
164 asmlinkage void __init init_early_exception_vectors(void)
170 * This starts up the shadow buffer, incase anything crashes before
174 early_shadow_puts(linux_banner);
175 early_shadow_stamp();
177 if (CPUID != bfin_cpuid()) {
178 early_shadow_puts("Running on wrong machine type, expected");
179 early_shadow_reg(CPUID, 16);
180 early_shadow_puts(", but running on");
181 early_shadow_reg(bfin_cpuid(), 16);
182 early_shadow_puts("\n");
185 /* cannot program in software:
186 * evt0 - emulation (jtag)
189 for (evt = EVT2; evt <= EVT15; evt += 4)
190 bfin_write32(evt, early_trap);
193 /* Set all the return from interrupt, exception, NMI to a known place
194 * so if we do a RETI, RETX or RETN by mistake - we go somewhere known
195 * Note - don't change RETS - we are in a subroutine, or
196 * RETE - since it might screw up if emulator is attached
198 asm("\tRETI = %0; RETX = %0; RETN = %0;\n"
199 : : "p"(early_trap));
203 __attribute__((__noreturn__))
204 asmlinkage void __init early_trap_c(struct pt_regs *fp, void *retaddr)
206 /* This can happen before the uart is initialized, so initialize
207 * the UART now (but only if we are running on the processor we think
208 * we are compiled for - otherwise we write to MMRs that don't exist,
209 * and cause other problems. Nothing comes out the UART, but it does
210 * end up in the __buf_log.
212 if (likely(early_console == NULL) && CPUID == bfin_cpuid())
213 setup_early_printk(DEFAULT_EARLY_PORT);
215 if (!shadow_console_enabled()) {
216 /* crap - we crashed before setup_arch() */
217 early_shadow_puts("panic before setup_arch\n");
218 early_shadow_puts("IPEND:");
219 early_shadow_reg(fp->ipend, 16);
220 if (fp->seqstat & SEQSTAT_EXCAUSE) {
221 early_shadow_puts("\nEXCAUSE:");
222 early_shadow_reg(fp->seqstat & SEQSTAT_EXCAUSE, 8);
224 if (fp->seqstat & SEQSTAT_HWERRCAUSE) {
225 early_shadow_puts("\nHWERRCAUSE:");
227 (fp->seqstat & SEQSTAT_HWERRCAUSE) >> 14, 8);
229 early_shadow_puts("\nErr @");
230 if (fp->ipend & EVT_EVX)
231 early_shadow_reg(fp->retx, 32);
233 early_shadow_reg(fp->pc, 32);
234 #ifdef CONFIG_DEBUG_BFIN_HWTRACE_ON
235 early_shadow_puts("\nTrace:");
236 if (likely(bfin_read_TBUFSTAT() & TBUFCNT)) {
237 while (bfin_read_TBUFSTAT() & TBUFCNT) {
238 early_shadow_puts("\nT :");
239 early_shadow_reg(bfin_read_TBUF(), 32);
240 early_shadow_puts("\n S :");
241 early_shadow_reg(bfin_read_TBUF(), 32);
245 early_shadow_puts("\nUse bfin-elf-addr2line to determine "
248 * We should panic(), but we can't - since panic calls printk,
249 * and printk uses memcpy.
250 * we want to reboot, but if the machine type is different,
251 * can't due to machine specific reboot sequences
253 if (CPUID == bfin_cpuid()) {
254 early_shadow_puts("Trying to restart\n");
258 early_shadow_puts("Halting, since it is not safe to restart\n");
260 asm volatile ("EMUEXCPT; IDLE;\n");
263 printk(KERN_EMERG "Early panic\n");
265 dump_bfin_trace_buffer();
271 early_param("earlyprintk", setup_early_printk);