serial: earlycon: prefer EARLYCON_DECLARE() variant

If a driver exposes early consoles with EARLYCON_DECLARE() and OF_EARLYCON_DECLARE(), pefer the non-OF variant if the user specifies it by earlycon=<driver>,<options> The rationale behind this is that some drivers register multiple setup functions under the same driver name. Eg. OF_EARLYCON_DECLARE(lpuart, "fsl,vf610-lpuart", lpuart_early_console_setup); OF_EARLYCON_DECLARE(lpuart32, "fsl,ls1021a-lpuart", lpuart32_early_console_setup); OF_EARLYCON_DECLARE(lpuart32, "fsl,imx7ulp-lpuart", lpuart32_imx_early_console_setup); EARLYCON_DECLARE(lpuart, lpuart_early_console_setup); EARLYCON_DECLARE(lpuart32, lpuart32_early_console_setup); It depends on the order of the entries which console_setup() actually gets called. To make things worse, I guess it also depends on the compiler how these are ordered. Thus always prefer the EARLYCON_DECLARE() ones. Signed-off-by: Michael Walle <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]>
ambv · Mar 7, 2020 · f8c3686 · f8c3686
1 parent 4f5f588
commit f8c3686
Showing 1 changed file with 11 additions and 0 deletions.
diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c
@@ -170,13 +170,15 @@ static int __init register_earlycon(char *buf, const struct earlycon_id *match)
 int __init setup_earlycon(char *buf)
 {
 	const struct earlycon_id **p_match;
+	bool empty_compatible = true;
 
 	if (!buf || !buf[0])
 		return -EINVAL;
 
 	if (early_con.flags & CON_ENABLED)
 		return -EALREADY;
 
+again:
 	for (p_match = __earlycon_table; p_match < __earlycon_table_end;
 	     p_match++) {
 		const struct earlycon_id *match = *p_match;
@@ -185,6 +187,10 @@ int __init setup_earlycon(char *buf)
 		if (strncmp(buf, match->name, len))
 			continue;
 
+		/* prefer entries with empty compatible */
+		if (empty_compatible && *match->compatible)
+			continue;
+
 		if (buf[len]) {
 			if (buf[len] != ',')
 				continue;
@@ -195,6 +201,11 @@ int __init setup_earlycon(char *buf)
 		return register_earlycon(buf, match);
 	}
 
+	if (empty_compatible) {
+		empty_compatible = false;
+		goto again;
+	}
+
 	return -ENOENT;
 }