Blackfin arch: Print out debug info, as early as possible
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>
diff --git a/arch/blackfin/kernel/early_printk.c b/arch/blackfin/kernel/early_printk.c
index 9bf6170..6ec518a 100644
--- a/arch/blackfin/kernel/early_printk.c
+++ b/arch/blackfin/kernel/early_printk.c
@@ -38,13 +38,13 @@
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 @@
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);