Blackfin: fix jtag console tstc

The jtag tstc operation was checking the hardware to see if data is
available from it (which is fine for the jtag getc operation), but the
higher layers need to know whether any data is available.  Since we have
to read up to 4 bytes at a time from the hardware, the higher layers need
to know they can consume the cached bytes as well.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>

cpu/blackfin/jtag-console.c

@@ -54,16 +54,23 @@ static void jtag_puts(const char *s)
 	jtag_send(s, strlen(s));
 }
 
-static int jtag_tstc(void)
+static size_t inbound_len, leftovers_len;
+
+/* Lower layers want to know when jtag has data */
+static int jtag_tstc_dbg(void)
 {
 	return (bfin_read_DBGSTAT() & 0x2);
 }
 
+/* Higher layers want to know when any data is available */
+static int jtag_tstc(void)
+{
+	return jtag_tstc_dbg() || leftovers_len;
+}
+
 /* Receive a buffer.  The format is:
  * [32bit length][actual data]
  */
-static size_t inbound_len;
-static int leftovers_len;
 static uint32_t leftovers;
 static int jtag_getc(void)
 {
@@ -79,7 +86,7 @@ static int jtag_getc(void)
 	}
 
 	/* wait for new data ! */
-	while (!jtag_tstc())
+	while (!jtag_tstc_dbg())
 		continue;
 	__asm__("%0 = emudat;" : "=d"(emudat));