From patchwork Mon Nov 14 16:29:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Ogness X-Patchwork-Id: 624718 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8D26CC43219 for ; Mon, 14 Nov 2022 16:32:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237637AbiKNQcW (ORCPT ); Mon, 14 Nov 2022 11:32:22 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35750 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237643AbiKNQaz (ORCPT ); Mon, 14 Nov 2022 11:30:55 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DBF6B2F64D; Mon, 14 Nov 2022 08:29:53 -0800 (PST) From: John Ogness DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1668443392; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lyFJ0F0+PfcRjhKzuNkMUBeWMaE9PNLLtfp/JWoaB8Q=; b=o493Ws7OLoNBwC3oJekHe/zqr8d4O1r2boZdC330Lx7sXR/IS+LlFMlQSjiYgilqi2WvYy bK6oiaWKOaMF+Ov1zkmR7m17gutu6TqbBnx+DW+0CKcPwn/WP4WoTvHeOnxG3Dcpw50L0F uCuMhIdKv8bxHZuMIY7yE5xqI87CzHeE17gRcNmlIyNpc4AunL7RVRWKjhFqzm99845QTr GU9GdrUeraNW+PFqq9HeRlvM+uQT2Bk7lgRw4l2QqcvqrMlmgfyI3VLCm+SlLEyaEy08XS 9IYpB54UDdp25QGOFuwjoXwpDVZUiUqepmIgjw9G5zSxprsVTUdFu7iZnYfhNw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1668443392; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=lyFJ0F0+PfcRjhKzuNkMUBeWMaE9PNLLtfp/JWoaB8Q=; b=3yUj92YNamRVgcCdfRvOJqzWFRVhH0VyAxXFN/+0roEsIDgaS8xom/DI+PxiHFB0NAZLYl geAOjgKKccPDeLAw== To: Petr Mladek Cc: Sergey Senozhatsky , Steven Rostedt , Thomas Gleixner , linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Jiri Slaby , linux-serial@vger.kernel.org, Linux-sh list , Linux-Renesas , Geert Uytterhoeven Subject: [PATCH printk v4 39/39] tty: serial: sh-sci: use setup() callback for early console Date: Mon, 14 Nov 2022 17:35:32 +0106 Message-Id: <20221114162932.141883-40-john.ogness@linutronix.de> In-Reply-To: <20221114162932.141883-1-john.ogness@linutronix.de> References: <20221114162932.141883-1-john.ogness@linutronix.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org When setting up the early console, the setup() callback of the regular console is used. It is called manually before registering the early console instead of providing a setup() callback for the early console. This is probably because the early setup needs a different @options during the early stage. The issue here is that the setup() callback is called without the console_list_lock held and functions such as uart_set_options() expect that. Rather than manually calling the setup() function before registering, provide an early console setup() callback that will use the different early options. This ensures that the error checking, ordering, and locking context when setting up the early console are correct. Since this early console can only be registered via the earlyprintk= parameter, the @options argument of the setup() callback will always be NULL. Rather than simply ignoring the argument, add a WARN_ON() to get our attention in case the setup() callback semantics should change in the future. Note that technically the current implementation works because it is only used in early boot. And since the early console setup is performed before registering, it cannot race with anything and thus does not need any locking. However, longterm maintenance is easier when drivers rely on the subsystem API rather than manually implementing steps that could cause breakage in the future. Signed-off-by: John Ogness Reviewed-by: Geert Uytterhoeven --- drivers/tty/serial/sh-sci.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/sh-sci.c b/drivers/tty/serial/sh-sci.c index 62f773286d44..76452fe2af86 100644 --- a/drivers/tty/serial/sh-sci.c +++ b/drivers/tty/serial/sh-sci.c @@ -3054,15 +3054,29 @@ static struct console serial_console = { }; #ifdef CONFIG_SUPERH +static char early_serial_buf[32]; + +static int early_serial_console_setup(struct console *co, char *options) +{ + /* + * This early console is always registered using the earlyprintk= + * parameter, which does not call add_preferred_console(). Thus + * @options is always NULL and the options for this early console + * are passed using a custom buffer. + */ + WARN_ON(options); + + return serial_console_setup(co, early_serial_buf); +} + static struct console early_serial_console = { .name = "early_ttySC", .write = serial_console_write, + .setup = early_serial_console_setup, .flags = CON_PRINTBUFFER, .index = -1, }; -static char early_serial_buf[32]; - static int sci_probe_earlyprintk(struct platform_device *pdev) { const struct plat_sci_port *cfg = dev_get_platdata(&pdev->dev); @@ -3074,8 +3088,6 @@ static int sci_probe_earlyprintk(struct platform_device *pdev) sci_init_single(pdev, &sci_ports[pdev->id], pdev->id, cfg, true); - serial_console_setup(&early_serial_console, early_serial_buf); - if (!strstr(early_serial_buf, "keep")) early_serial_console.flags |= CON_BOOT;