From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-3607228-1519929776-2-1660357887473667309 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.249, ME_NOAUTH 0.01, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: plain='us-ascii' X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: linux-serial-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519929776; b=nTl0Qk/WY2BAgi8w2fLgQicGPSj07oCflVY8/tt1RUwEMZe ZpZxLehJa9zh0xlCa0SonCcka8ckhAmInPbfJfr3IVJ4cvEuwsIl8wsUL3HlR5so LNO1tM0wGI6y7EKH7m28JW7izDz4X6bSJyRd8aa9nhwW/08k6pdFwkfRxej8TMyq W8Lm0SENzxtiwcdYZgQ1pbIsQXbpZzKVgXUW9RVSXj/fg2QQHX0ti9QOyRS9p3yz EPQdvqsdQFhGySNtLVTxEXemd677TYBQmNh4oVgpcabzq4XkIZ11LfBavNq1Er6k jUIYZUcDRga+JwmZHSugzrflkDjOriDizJ8B+OQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=date:from:to:cc:subject:message-id :references:mime-version:content-type:in-reply-to:sender :list-id; s=arctest; t=1519929776; bh=A7/iB/FiCZv1Gk6zS3OljudbPV IzRlkYcYwyjcH7VDM=; b=XuuUn1oBgxWizpnz5+a14CIh1IZyLks0zU1mwdl3Et oqO9Ay0HcUhI0fwr/frZcYvN/r1h1hL/g2GWifakIhCRh7r2jEamsv9RUKaMl2qJ ocSozWxRehHkQ2DY0SPpzCbNcJbwel8roQxoTS1aTLiLc+nNDykfXL06RM1+2Llk p06hLU+CynPFQ/1umoFC2GuPBIXavDcyHMKSs22wi77xirIgBRVum1Ss9J1Arxdb g6nRS1aUhuCnesYQfUC7Lz7H/cExrwbzSnbcnmh/vtYRRLg5Vx0R4SoAjsFxEF/A hEXUpNQD0MyiMkbkfhwrmO8lvoVsQEStGZqcattBAP+w== ARC-Authentication-Results: i=1; mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-serial-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Authentication-Results: mx6.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=linux-serial-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linuxfoundation.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1034010AbeCASmy (ORCPT ); Thu, 1 Mar 2018 13:42:54 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:37634 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1033831AbeCASmy (ORCPT ); Thu, 1 Mar 2018 13:42:54 -0500 Date: Thu, 1 Mar 2018 19:42:52 +0100 From: Greg Kroah-Hartman To: Randy Dunlap Cc: Daniel Kurtz , adurbin@chromium.org, briannorris@chromium.org, Jiri Slaby , "open list:SERIAL DRIVERS" , open list Subject: Re: [PATCH] earlycon: Allow specifying a uartclk in options Message-ID: <20180301184252.GA29304@kroah.com> References: <20180301182028.237856-1-djkurtz@chromium.org> <57fb4f35-fd75-b2cc-75f7-8157ab1081d5@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57fb4f35-fd75-b2cc-75f7-8157ab1081d5@infradead.org> User-Agent: Mutt/1.9.3 (2018-01-21) Sender: linux-serial-owner@vger.kernel.org X-Mailing-List: linux-serial@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Thu, Mar 01, 2018 at 10:30:45AM -0800, Randy Dunlap wrote: > On 03/01/2018 10:20 AM, Daniel Kurtz wrote: > > Currently when an earlycon is registered, the uartclk is assumed to be > > BASE_BAUD * 16 = 1843200. If a baud rate is specified in the earlycon > > options, then 8250_early's init_port will program the UART clock divider > > registers based on this assumed uartclk. > > > > However, not all uarts have a UART clock of 1843200. For example, the > > 8250_dw uart in AMD's CZ/ST uses a fixed 48 MHz clock (as specified in > > cz_uart_desc in acpi_apd.c). Thus, specifying a baud when using earlycon > > on such a device will result in incorrect divider values and a wrong UART > > clock. > > > > Fix this by extending the earlycon options parameter to allow specification > > of a uartclk, like so: > > > > earlycon=uart,mmio32,0xfedc6000,115200,48000000 > > > > If none is specified, fall-back to prior behavior - 1843200. > > > > Signed-off-by: Daniel Kurtz > > Hi, > > Hopefully there will also be an update to one of > Documentation/admin-guide/kernel-parameters.txt or > Documentation/admin-guide/serial-console.rst. Well, considering I'm not taking this patch unless it comes with such an update, I'm hoping as well :) greg k-h