From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lf1-f65.google.com ([209.85.167.65]:33876 "EHLO mail-lf1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725741AbeIXEeL (ORCPT ); Mon, 24 Sep 2018 00:34:11 -0400 Received: by mail-lf1-f65.google.com with SMTP id y10-v6so870337lfj.1 for ; Sun, 23 Sep 2018 15:34:57 -0700 (PDT) From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= To: stable@vger.kernel.org Cc: Michal Simek , Greg Kroah-Hartman , Jiri Slaby , Russell King , Hauke Mehrtens , bcm-kernel-feedback-list , =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= Subject: [PATCH 4.14-4.17 1/2] earlycon: Initialize port->uartclk based on clock-frequency property Date: Mon, 24 Sep 2018 00:34:45 +0200 Message-Id: <20180923223446.3773-1-zajec5@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: From: Michal Simek commit 814453adea7d081ad8917aa0f32d6a14165a3563 upstream. On DT based platforms when current-speed property is present baudrate is setup. Also port->uartclk is initialized to bogus BASE_BAUD * 16 value. Drivers like uartps/ns16550 contain logic when baudrate and uartclk is used for baudrate calculation. The patch is reading optional clock-frequency property to replace bogus BASE_BAUD * 16 calculation to have proper baudrate calculation. [-stable comment: commit 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") has changed 8250_early.c behavior which now tries to setup UART speed. Ignoring clock-frequency results in wrong value of calculated divisor & malformed early console output.] Fixes: 31cb9a8575ca ("earlycon: initialise baud field of earlycon device structure") Signed-off-by: Michal Simek Signed-off-by: Greg Kroah-Hartman [rmilecki: add -stable comment and Fixes tag] Signed-off-by: Rafał Miłecki --- drivers/tty/serial/earlycon.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c index ac667b47f199..05ba1875bb3e 100644 --- a/drivers/tty/serial/earlycon.c +++ b/drivers/tty/serial/earlycon.c @@ -289,6 +289,10 @@ int __init of_setup_earlycon(const struct earlycon_id *match, if (val) early_console_dev.baud = be32_to_cpu(*val); + val = of_get_flat_dt_prop(node, "clock-frequency", NULL); + if (val) + port->uartclk = be32_to_cpu(*val); + if (options) { early_console_dev.baud = simple_strtoul(options, NULL, 0); strlcpy(early_console_dev.options, options, -- 2.13.7