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: 1557441 Return-Path: X-Original-To: patchwork-linux-arm@patchwork.kernel.org Delivered-To: patchwork-process-083081@patchwork1.kernel.org Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) by patchwork1.kernel.org (Postfix) with ESMTP id 543753FD56 for ; Sat, 6 Oct 2012 12:44:17 +0000 (UTC) Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.76 #1 (Red Hat Linux)) id 1TKTiG-0002cW-0E; Sat, 06 Oct 2012 12:42:36 +0000 Received: from [2002:4e20:1eda::1] (helo=caramon.arm.linux.org.uk) by merlin.infradead.org with esmtps (Exim 4.76 #1 (Red Hat Linux)) id 1TKTiB-0002b9-1T for linux-arm-kernel@lists.infradead.org; Sat, 06 Oct 2012 12:42:31 +0000 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 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 X-Spam-Note: CRM114 invocation failed X-Spam-Score: -1.2 (-) X-Spam-Report: SpamAssassin version 3.3.2 on merlin.infradead.org summary: Content analysis details: (-1.2 points) pts rule name description ---- ---------------------- -------------------------------------------------- -1.9 BAYES_00 BODY: Bayes spam probability is 0 to 1% [score: 0.0000] -0.1 DKIM_VALID_AU Message has a valid DKIM or DK signature from author's domain 0.1 DKIM_SIGNED Message has a DKIM or DK signature, not necessarily valid -0.1 DKIM_VALID Message has at least one valid DKIM or DK signature 0.8 RDNS_NONE Delivered to internal network by a host with no rDNS Cc: linux-omap@vger.kernel.org, linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Sender: linux-arm-kernel-bounces@lists.infradead.org Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.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))