Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755439AbZCFGml (ORCPT ); Fri, 6 Mar 2009 01:42:41 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754558AbZCFGk6 (ORCPT ); Fri, 6 Mar 2009 01:40:58 -0500 Received: from nwd2mail10.analog.com ([137.71.25.55]:50912 "EHLO nwd2mail10.analog.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754520AbZCFGk4 (ORCPT ); Fri, 6 Mar 2009 01:40:56 -0500 X-IronPort-AV: E=Sophos;i="4.38,312,1233550800"; d="scan'208";a="83883649" From: Bryan Wu To: alan@lxorguk.ukuu.org.uk Cc: linux-kernel@vger.kernel.org, Mike Frysinger , Bryan Wu Subject: [PATCH 06/18] Blackfin Serial Driver: explain why we cannot cpu_relax() in early serial code Date: Fri, 6 Mar 2009 14:42:48 +0800 Message-Id: <1236321780-28718-7-git-send-email-cooloney@kernel.org> X-Mailer: git-send-email 1.5.6.3 In-Reply-To: <1236321780-28718-1-git-send-email-cooloney@kernel.org> References: <1236321780-28718-1-git-send-email-cooloney@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1097 Lines: 30 From: Mike Frysinger Signed-off-by: Mike Frysinger Signed-off-by: Bryan Wu --- drivers/serial/bfin_5xx.c | 4 ++++ 1 files changed, 4 insertions(+), 0 deletions(-) diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c index 5a163f6..de8709d 100644 --- a/drivers/serial/bfin_5xx.c +++ b/drivers/serial/bfin_5xx.c @@ -1190,6 +1190,10 @@ static __init void early_serial_putc(struct uart_port *port, int ch) unsigned timeout = 0xffff; struct bfin_serial_port *uart = (struct bfin_serial_port *)port; + /* We cannot cpu_relax() here as doing so on the BF561 relies + * on the per-cpu region being setup, and since this is early + * serial code, it may not yet be usable ... + */ while ((!(UART_GET_LSR(uart) & THRE)) && --timeout) barrier(); -- 1.5.6.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/