Implement generic support for early printf. Thought I can't find the

paper trail now, this patch is similar to one posted for one of the
preliminary versions of a new armv6 port. I took them and made them
more generic. Option not enabled by default since each board/port has
to provide its own eputc, and possibly do other things as well...

1 files changed, 22 insertions, 0 deletions

diff --git a/sys/kern/subr_prf.c b/sys/kern/subr_prf.c
index 93d8ed372f31..dac940c16382 100644
--- a/sys/kern/subr_prf.c
+++ b/sys/kern/subr_prf.c
@@ -1137,3 +1137,25 @@ hexdump(const void *ptr, int length, const char *hdr, int flags)
 	}
 }
 
+#ifdef EARLY_PRINTF
+/*
+ * Support for calling an alternate printf early in boot (like before
+ * cn_init() can be called).  Platforms need to define eputc that want
+ * to use this.
+ */
+static void
+early_putc_func(int ch, void *arg __unused)
+{
+	eputc(ch);
+}
+
+void
+eprintf(const char *fmt, ...)
+{
+	va_list ap;
+
+	va_start(ap, fmt);
+	kvprintf(fmt, early_putc_func, NULL, 10, ap);
+	va_end(ap);
+}
+#endif