From patchwork Sat Oct 6 12:42:24 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Russell King X-Patchwork-Id: 1557361 Return-Path: X-Original-To: patchwork-linux-omap@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by patchwork1.kernel.org (Postfix) with ESMTP id 5D9F33FD56 for ; Sat, 6 Oct 2012 12:42:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756231Ab2JFMmd (ORCPT ); Sat, 6 Oct 2012 08:42:33 -0400 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:47262 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756146Ab2JFMmd (ORCPT ); Sat, 6 Oct 2012 08:42:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=arm.linux.org.uk; s=caramon; h=Date:Sender:Message-Id:Subject:Cc:To:From:References:In-Reply-To; bh=q2YrX4S9WykWk26+9G4LRyoOeqx4skEHbvPhaGgIF9s=; b=Gi2aXyXRKzGQhFQRz4IAQfjuGWTNF6iuU10eHazsWqAbPJbz9M1jC3XMTBbj5xSsrVZr6yMH06CNAwHSgBaGMsuxwx39hd9NNzXDqX8/e3/KHKK8RSUDt7Vednabz2gu7gKKXsKn/NcVs6S/qlKAPBK5Yda7JGtGXMBGlGxF63c=; Received: from e0022681537dd.dyn.arm.linux.org.uk ([2002:4e20:1eda:1:222:68ff:fe15:37dd]:39601 helo=rmk-PC.arm.linux.org.uk) by caramon.arm.linux.org.uk with esmtpsa (TLSv1:AES256-SHA:256) (Exim 4.76) (envelope-from ) id 1TKTi4-00087u-SO; Sat, 06 Oct 2012 13:42:24 +0100 Received: from rmk by rmk-PC.arm.linux.org.uk with local (Exim 4.76) (envelope-from ) id 1TKTi4-0002n2-0b; Sat, 06 Oct 2012 13:42:24 +0100 In-Reply-To: <20121006123803.GD15246@n2100.arm.linux.org.uk> References: <20121006123803.GD15246@n2100.arm.linux.org.uk> From: Russell King To: Tony Lindgren , Alan Cox , Greg Kroah-Hartman Cc: linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org, linux-serial@vger.kernel.org Subject: [RFC 10/24] SERIAL: core: add hardware assisted h/w flow control support Message-Id: Date: Sat, 06 Oct 2012 13:42:24 +0100 Sender: linux-omap-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org Ports which are handling h/w flow control in hardware must not have their RTS state altered depending on the tty's hardware-stopped state. Avoid this additional logic when setting the termios state. Signed-off-by: Russell King --- drivers/tty/serial/serial_core.c | 7 +++++++ include/linux/serial_core.h | 2 ++ 2 files changed, 9 insertions(+), 0 deletions(-) diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index ec6d029..02b10bc 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1239,6 +1239,13 @@ static void uart_set_termios(struct tty_struct *tty, uart_set_mctrl(uport, mask); } + /* + * If the port is doing h/w assisted flow control, do nothing. + * We assume that tty->hw_stopped has never been set. + */ + if (uport->flags & UPF_HARD_FLOW) + return; + /* Handle turning off CRTSCTS */ if ((old_termios->c_cflag & CRTSCTS) && !(cflag & CRTSCTS)) { spin_lock_irqsave(&uport->lock, flags); diff --git a/include/linux/serial_core.h b/include/linux/serial_core.h index be3f8d9..8e8500e 100644 --- a/include/linux/serial_core.h +++ b/include/linux/serial_core.h @@ -356,6 +356,8 @@ struct uart_port { #define UPF_BUGGY_UART ((__force upf_t) (1 << 14)) #define UPF_NO_TXEN_TEST ((__force upf_t) (1 << 15)) #define UPF_MAGIC_MULTIPLIER ((__force upf_t) (1 << 16)) +/* Port has hardware-assisted h/w flow control (iow, auto-RTS *not* auto-CTS) */ +#define UPF_HARD_FLOW ((__force upf_t) (1 << 21)) /* Port has hardware-assisted s/w flow control */ #define UPF_SOFT_FLOW ((__force upf_t) (1 << 22)) #define UPF_CONS_FLOW ((__force upf_t) (1 << 23))