From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Tue, 07 Mar 2017 00:39:03 +0100 (CET) Received: from mail-oi0-x22d.google.com ([IPv6:2607:f8b0:4003:c06::22d]:36511 "EHLO mail-oi0-x22d.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S23993887AbdCFXi5D0UEi (ORCPT ); Tue, 7 Mar 2017 00:38:57 +0100 Received: by mail-oi0-x22d.google.com with SMTP id 126so42273397oig.3 for ; Mon, 06 Mar 2017 15:38:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; h=from:references:in-reply-to:mime-version:thread-index:date :message-id:subject:to:cc; bh=nHQts+SkyPXx3/UuaGXVUUcs8tv6ALsZua2vAcTNmog=; b=f7dgnoOuUsKMhRa//zM1CuAdBvt6ADN4krBCnHZJ3x9yA29gcsXHWSkt+FhcxS1+oF /oZ4C+jFIijV7DpRqmPvZSj8V83ljIMN/L5tgynZWi1KkZV5qY7cCvTDaVuVGuZqrgoY lWuqarhN/aKvLrPvy/b6UUQ+agpOuvZyNCp3I= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:references:in-reply-to:mime-version :thread-index:date:message-id:subject:to:cc; bh=nHQts+SkyPXx3/UuaGXVUUcs8tv6ALsZua2vAcTNmog=; b=qPtMd3dfLH/Ib0AlduLEMpyjwVo3YyiqQdMXhflbw9gm21W39hqk7nNvql1QTc5AbN lItrn4WUsa5PYL1mpSYNUAko0GUBmTjADICW2Aw8hxFKzBKA9QXwdGZqKx8p8upmgLsp o3MejPs9p8XQWxx5jHbuq+Bwb6LkVhC4/FGN6Koo2ewIYQ7ucxwjDI8IW0oglfgBkgYq rxKZlKQb0vNHsehNKPYT9fxwgRbvAVSMQPuD4fm8oEs9XzppO3kg77QW3NiB+OAzDBMo rVUiF8GizDfxBOhUvH8W0hmKXCMSfYdUJXMWwd11clpXDBSXnC67KUdMPe6Qk+uKGgyl o1og== X-Gm-Message-State: AMke39lMNZZGNEuGQbCUj1Ccvt/rZd1NBEZ0+mlYte3AYWh/83vO5W4vfOjDaRLNuBLCp3XgXJKsi7diFPX59OmF X-Received: by 10.202.74.213 with SMTP id x204mr2825809oia.159.1488843529462; Mon, 06 Mar 2017 15:38:49 -0800 (PST) From: Jason Uy References: <20170304130958.23655-1-james.hogan@imgtec.com> <20170306101603.GW996@jhogan-linux.le.imgtec.org> In-Reply-To: <20170306101603.GW996@jhogan-linux.le.imgtec.org> MIME-Version: 1.0 X-Mailer: Microsoft Outlook 15.0 Thread-Index: AQLIZbgW9Bvy6eKawokZdQ+hem2wcAHBgSYUAtxZ/WwBGOEh459vJBGw Date: Mon, 6 Mar 2017 15:38:47 -0800 Message-ID: <18720dd546d32a1455fb17ad46ee73e4@mail.gmail.com> Subject: RE: [PATCH] serial: 8250_dw: Fix breakage when HAVE_CLK=n To: James Hogan , Andy Shevchenko Cc: linux-kernel@vger.kernel.org, Greg Kroah-Hartman , Andy Shevchenko , Kefeng Wang , Heiko Stuebner , David Daney , Russell King , linux-serial@vger.kernel.org, linux-clk@vger.kernel.org, linux-mips@linux-mips.org, bcm-kernel-feedback-list Content-Type: text/plain; charset=UTF-8 Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 57062 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: jason.uy@broadcom.com Precedence: bulk List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: linux-mips X-List-ID: linux-mips List-subscribe: List-owner: List-post: List-archive: X-list: linux-mips Looks good Reviewed-by: Jason Uy -----Original Message----- From: James Hogan [mailto:james.hogan@imgtec.com] Sent: March-06-17 2:16 AM To: Andy Shevchenko Cc: linux-kernel@vger.kernel.org; Greg Kroah-Hartman ; Andy Shevchenko ; Jason Uy ; Kefeng Wang ; Heiko Stuebner ; David Daney ; Russell King ; linux-serial@vger.kernel.org; linux-clk@vger.kernel.org; linux-mips@linux-mips.org; bcm-kernel-feedback-list Subject: Re: [PATCH] serial: 8250_dw: Fix breakage when HAVE_CLK=n On Sat, Mar 04, 2017 at 04:37:17PM +0200, Andy Shevchenko wrote: > On Sat, Mar 4, 2017 at 3:09 PM, James Hogan > wrote: > > Commit 6a171b299379 ("serial: 8250_dw: Allow hardware flow control > > to be > > used") recently broke the 8250_dw driver on platforms which don't > > select HAVE_CLK, as dw8250_set_termios() gets confused by the > > behaviour of the fallback HAVE_CLK=n clock API in linux/clk.h which > > pretends everything is fine but returns (valid) NULL clocks and 0 HZ > > clock rates. > > > > That 0 rate is written into the uartclk resulting in a crash at > > boot, e.g. on Cavium Octeon III based UTM-8 we get something like this: > > > > 1180000000800.serial: ttyS0 at MMIO 0x1180000000800 (irq = 41, > > base_baud = 25000000) is a OCTEON ------------[ cut here > > ]------------ > > WARNING: CPU: 2 PID: 1 at drivers/tty/serial/serial_core.c:441 > > uart_get_baud_rate+0xfc/0x1f0 ... > > Call Trace: > > ... > > [] uart_get_baud_rate+0xfc/0x1f0 > > [] serial8250_do_set_termios+0xb0/0x440 > > [] uart_set_options+0xe8/0x190 > > [] serial8250_console_setup+0x84/0x158 > > [] univ8250_console_setup+0x54/0x70 > > [] register_console+0x1c8/0x418 > > [] uart_add_one_port+0x434/0x4b0 > > [] serial8250_register_8250_port+0x2d8/0x440 > > [] dw8250_probe+0x388/0x5e8 ... > > > > The clock API is defined such that NULL is a valid clock handle so > > it wouldn't be right to check explicitly for NULL. Instead treat a > > clk_round_rate() return value of 0 as an error which prevents > > uartclk being overwritten. > > > > You forgot to add that it is dependent to Heiko's patch > http://www.spinics.net/lists/linux-serial/msg25314.html Indeed I did. Sorry about that. > > Patch looks good to me and shouldn't bring any regression to Intel > hardware (x86 is using clock framework). > > Reviewed-by: Andy Shevchenko Thanks James