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[2620:137:e000::1:20]) by mx.google.com with ESMTP id y26-20020aa79e1a000000b00639b0f72b5esi23390024pfq.55.2023.05.17.12.54.10; Wed, 17 May 2023 12:54:24 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=fail header.i=@hugovil.com header.s=x header.b=sqRxIcJ6; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229894AbjEQTpA (ORCPT + 99 others); Wed, 17 May 2023 15:45:00 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34666 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230077AbjEQTox (ORCPT ); Wed, 17 May 2023 15:44:53 -0400 Received: from mail.hugovil.com (mail.hugovil.com [162.243.120.170]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 67C9240D4; Wed, 17 May 2023 12:44:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=hugovil.com ; s=x; h=Subject:Content-Transfer-Encoding:MIME-Version:Message-Id:Date:Cc:To :From:Sender:Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Id:List-Help:List-Unsubscribe:List-Subscribe:List-Post: List-Owner:List-Archive; bh=uRn5jY22yg/grNtbC+Tg4kXWRa2p3rPCDtHdGv1KI5M=; b=s qRxIcJ6vuRm9doZ4eNPugrtGBiFVBL+9R0zAVWVFmlUvZn1wjnpcKr2QIzNufuvkAz4y4YyeBWXSf i0/cBmyy8bMp1HuTIRzOl1S8rgHuByC/W9mhE9SacLobZj1t0YZaVHc2x9jlZ3DB+l6/rvntTAfms tcQJ4zpd4lJ+/MtU=; Received: from modemcable168.174-80-70.mc.videotron.ca ([70.80.174.168]:36992 helo=pettiford.lan) by mail.hugovil.com with esmtpa (Exim 4.92) (envelope-from ) id 1pzN4l-0001n2-71; Wed, 17 May 2023 15:44:43 -0400 From: Hugo Villeneuve To: Greg Kroah-Hartman , Jiri Slaby Cc: hugo@hugovil.com, Hugo Villeneuve , linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Date: Wed, 17 May 2023 15:44:07 -0400 Message-Id: <20230517194406.4125912-1-hugo@hugovil.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-SA-Exim-Connect-IP: 70.80.174.168 X-SA-Exim-Mail-From: hugo@hugovil.com X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net X-Spam-Level: X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,SPF_HELO_PASS,SPF_PASS, T_SCC_BODY_TEXT_LINE,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 Subject: [RFC PATCH] serial: sc16is7xx: fix broken port 0 uart init X-SA-Exim-Version: 4.2.1 (built Wed, 08 May 2019 21:11:16 +0000) X-SA-Exim-Scanned: Yes (on mail.hugovil.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org X-getmail-retrieved-from-mailbox: =?utf-8?q?INBOX?= X-GMAIL-THRID: =?utf-8?q?1766172407973396507?= X-GMAIL-MSGID: =?utf-8?q?1766172407973396507?= From: Hugo Villeneuve While experimenting with rs485 configuration on a SC16IS752 dual UART, I found that the sc16is7xx_config_rs485() function was called only for the second port (index 1, channel B), causing initialization problems for the first port. For the sc16is7xx driver, port->membase and port->mapbase are not set, and their default values are 0. And we set port->iobase to the device index. This means that when the first device is registered using the uart_add_one_port() function, the following values will be in the port structure: port->membase = 0 port->mapbase = 0 port->iobase = 0 Therefore, the function uart_configure_port() in serial_core.c will exit early because of the following check: /* * If there isn't a port here, don't do anything further. */ if (!port->iobase && !port->mapbase && !port->membase) return; Typically, I2C and SPI drivers do not set port->membase and port->mapbase. But I found that the max310x driver sets port->membase to ~0 (all ones). By implementing the same change in our driver, uart_configure_port() is now correctly executed. Signed-off-by: Hugo Villeneuve --- I am not sure if this change is the best long-term solution to this problem, and maybe uart_configure_port() itself could be modified to take into account the fact that some devices have all three *base values set to zero? Also, many drivers use port->iobase as an index, is it the correct way to use it? For example, for our driver, there was commit 5da6b1c079e6 ("sc16is7xx: Set iobase to device index") with the following explanation: "Set the .iobase value to the relative index within the device to allow infering the order through sysfs." drivers/tty/serial/sc16is7xx.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index 1a3143331c1f..3e0e63498052 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -1432,6 +1432,7 @@ static int sc16is7xx_probe(struct device *dev, s->p[i].port.fifosize = SC16IS7XX_FIFO_SIZE; s->p[i].port.flags = UPF_FIXED_TYPE | UPF_LOW_LATENCY; s->p[i].port.iobase = i; + s->p[i].port.membase = (void __iomem *)~0; s->p[i].port.iotype = UPIO_PORT; s->p[i].port.uartclk = freq; s->p[i].port.rs485_config = sc16is7xx_config_rs485;