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Blackfin arch: Print out debug info, as early as possible

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Print out debug info, as early as possible - even before the
kernel initializes the interrupt vectors. Now we can print out debug
messages almost anytime during the boot process.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
This commit is contained in:
Robin Getz
2007-10-09 17:31:46 +08:00
committed by Bryan Wu
parent ce3afa1c04
commit 337d390b3a
7 changed files with 123 additions and 6 deletions
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61
arch/blackfin/kernel/early_printk.c
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@@ -38,13 +38,13 @@ extern struct console *bfin_earlyserial_init(unsigned int port,
static struct console *early_console;
/* Default console
* Port n == ttyBFn
* cflags == UART output modes
*/
/* Default console */
#define DEFAULT_PORT 0
#define DEFAULT_CFLAG CS8|B57600
/* Default console for early crashes */
#define DEFAULT_EARLY_PORT "serial,uart0,57600"
#ifdef CONFIG_SERIAL_CORE
/* What should get here is "0,57600" */
static struct console * __init earlyserial_init(char *buf)
@@ -158,4 +158,57 @@ int __init setup_early_printk(char *buf)
return 0;
}
/*
* Set up a temporary Event Vector Table, so if something bad happens before
* the kernel is fully started, it doesn't vector off into somewhere we don't
* know
*/
asmlinkage void __init init_early_exception_vectors(void)
{
SSYNC();
/* cannot program in software:
* evt0 - emulation (jtag)
* evt1 - reset
*/
bfin_write_EVT2(early_trap);
bfin_write_EVT3(early_trap);
bfin_write_EVT5(early_trap);
bfin_write_EVT6(early_trap);
bfin_write_EVT7(early_trap);
bfin_write_EVT8(early_trap);
bfin_write_EVT9(early_trap);
bfin_write_EVT10(early_trap);
bfin_write_EVT11(early_trap);
bfin_write_EVT12(early_trap);
bfin_write_EVT13(early_trap);
bfin_write_EVT14(early_trap);
bfin_write_EVT15(early_trap);
CSYNC();
/* Set all the return from interupt, exception, NMI to a known place
* so if we do a RETI, RETX or RETN by mistake - we go somewhere known
* Note - don't change RETS - we are in a subroutine, or
* RETE - since it might screw up if emulator is attached
*/
asm("\tRETI = %0; RETX = %0; RETN = %0;\n"
: : "p"(early_trap));
}
asmlinkage void __init early_trap_c(struct pt_regs *fp, void *retaddr)
{
/* This can happen before the uart is initialized, so initialize
* the UART now
*/
if (likely(early_console == NULL))
setup_early_printk(DEFAULT_EARLY_PORT);
dump_bfin_regs(fp, retaddr);
dump_bfin_trace_buffer();
panic("Died early");
}
early_param("earlyprintk", setup_early_printk);