From mboxrd@z Thu Jan 1 00:00:00 1970 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 DFC7BC43334 for ; Mon, 13 Jun 2022 12:25:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354755AbiFMMZP (ORCPT ); Mon, 13 Jun 2022 08:25:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34324 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355465AbiFMMX4 (ORCPT ); Mon, 13 Jun 2022 08:23:56 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E68BC27B07; Mon, 13 Jun 2022 04:05:01 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 8359261435; Mon, 13 Jun 2022 11:05:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 97F18C3411E; Mon, 13 Jun 2022 11:05:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655118301; bh=QI3AuAZvr75V5aJQHl56NIamTjjLOnw/1y4LERXWWoI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ILqZDHDqUJ2zd3qKT824WgWe4bxzPMqOeHGZPwnVA/CGOSuJCWSrDe5QJZkz1rcse cLriIpqaJI4FJAd+SZClJDPVVadYIdAwWgsQkM8oLULGYJlh1WWOc4MdQ07uYjyTPY pqUMVytzF2jiRpnlxLVSPZqbz78dEd4gd1yHQR0A= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, "Maciej W. Rozycki" , Sasha Levin Subject: [PATCH 5.10 026/172] serial: sifive: Report actual baud base rather than fixed 115200 Date: Mon, 13 Jun 2022 12:09:46 +0200 Message-Id: <20220613094856.690320361@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094850.166931805@linuxfoundation.org> References: <20220613094850.166931805@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Maciej W. Rozycki [ Upstream commit 0a7ff843d507ce2cca2c3b7e169ee56e28133530 ] The base baud value reported is supposed to be the highest baud rate that can be set for a serial port. The SiFive FU740-C000 SOC's on-chip UART supports baud rates of up to 1/16 of the input clock rate, which is the bus clock `tlclk'[1], often at 130MHz in the case of the HiFive Unmatched board. However the sifive UART driver reports a fixed value of 115200 instead: 10010000.serial: ttySIF0 at MMIO 0x10010000 (irq = 1, base_baud = 115200) is a SiFive UART v0 10011000.serial: ttySIF1 at MMIO 0x10011000 (irq = 2, base_baud = 115200) is a SiFive UART v0 even though we already support setting higher baud rates, e.g.: $ tty /dev/ttySIF1 $ stty speed 230400 The baud base value is computed by the serial core by dividing the UART clock recorded in `struct uart_port' by 16, which is also the minimum value of the clock divider supported, so correct the baud base value reported by setting the UART clock recorded to the input clock rate rather than 115200: 10010000.serial: ttySIF0 at MMIO 0x10010000 (irq = 1, base_baud = 8125000) is a SiFive UART v0 10011000.serial: ttySIF1 at MMIO 0x10011000 (irq = 2, base_baud = 8125000) is a SiFive UART v0 [1] "SiFive FU740-C000 Manual", v1p3, SiFive, Inc., August 13, 2021, Section 16.9 "Baud Rate Divisor Register (div)", pp.143-144 Signed-off-by: Maciej W. Rozycki Fixes: 1f1496a923b6 ("riscv: Fix sifive serial driver") Link: https://lore.kernel.org/r/alpine.DEB.2.21.2204291656280.9383@angie.orcam.me.uk Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/sifive.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/sifive.c b/drivers/tty/serial/sifive.c index 214bf3086c68..24036a02a424 100644 --- a/drivers/tty/serial/sifive.c +++ b/drivers/tty/serial/sifive.c @@ -999,7 +999,7 @@ static int sifive_serial_probe(struct platform_device *pdev) /* Set up clock divider */ ssp->clkin_rate = clk_get_rate(ssp->clk); ssp->baud_rate = SIFIVE_DEFAULT_BAUD_RATE; - ssp->port.uartclk = ssp->baud_rate * 16; + ssp->port.uartclk = ssp->clkin_rate; __ssp_update_div(ssp); platform_set_drvdata(pdev, ssp); -- 2.35.1