From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751127AbdAMBiL (ORCPT ); Thu, 12 Jan 2017 20:38:11 -0500 Received: from szxga02-in.huawei.com ([119.145.14.65]:20420 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750890AbdAMBiJ (ORCPT ); Thu, 12 Jan 2017 20:38:09 -0500 Subject: Re: [PATCH v2 1/1] serial: 8250_dw: Allow hardware flow control to be used To: Jason Uy , Greg Kroah-Hartman , Jiri Slaby References: <1484164100-9805-1-git-send-email-jason.uy@broadcom.com> <1484164100-9805-2-git-send-email-jason.uy@broadcom.com> CC: Andy Shevchenko , Noam Camus , Heikki Krogerus , "Wang Hongcheng" , , , From: Kefeng Wang Message-ID: <84277e28-d203-333f-eea0-a3d2fc4a52f3@huawei.com> Date: Fri, 13 Jan 2017 09:33:35 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <1484164100-9805-2-git-send-email-jason.uy@broadcom.com> Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.177.19.180] X-CFilter-Loop: Reflected X-Mirapoint-Virus-RAPID-Raw: score=unknown(0), refid=str=0001.0A020201.58782E76.010D,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0, ip=0.0.0.0, so=2013-06-18 04:22:30, dmn=2013-03-21 17:37:32 X-Mirapoint-Loop-Id: e4a72aed1fcfce0449d7433faab2a5f4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017/1/12 3:48, Jason Uy wrote: > In the most common use case, the Synopsys DW UART driver does not > set the set_termios callback function. This prevents UPSTAT_AUTOCTS > from being set when the UART flag CRTSCTS is set. As a result, the > driver will use software flow control as opposed to hardware flow > control. > > To fix the problem, the set_termios callback function is set to the > DW specific function. The logic to set UPSTAT_AUTOCTS is moved so > that any clock error will not affect setting the hardware flow > control. > > Reviewed-by: Scott Branden > Reviewed-by: Ray Jui > Signed-off-by: Jason Uy Reviewed-by: Kefeng Wang > --- > drivers/tty/serial/8250/8250_dw.c | 5 ++--- > 1 file changed, 2 insertions(+), 3 deletions(-) > > diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c > index c89fafc..c89ae45 100644 > --- a/drivers/tty/serial/8250/8250_dw.c > +++ b/drivers/tty/serial/8250/8250_dw.c > @@ -248,11 +248,11 @@ static void dw8250_set_termios(struct uart_port *p, struct ktermios *termios, > if (!ret) > p->uartclk = rate; > > +out: > p->status &= ~UPSTAT_AUTOCTS; > if (termios->c_cflag & CRTSCTS) > p->status |= UPSTAT_AUTOCTS; > > -out: > serial8250_do_set_termios(p, termios, old); > } > > @@ -326,13 +326,11 @@ static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data) > p->serial_in = dw8250_serial_in32; > data->uart_16550_compatible = true; > } > - p->set_termios = dw8250_set_termios; > } > > /* Platforms with iDMA */ > if (platform_get_resource_byname(to_platform_device(p->dev), > IORESOURCE_MEM, "lpss_priv")) { > - p->set_termios = dw8250_set_termios; > data->dma.rx_param = p->dev->parent; > data->dma.tx_param = p->dev->parent; > data->dma.fn = dw8250_idma_filter; > @@ -414,6 +412,7 @@ static int dw8250_probe(struct platform_device *pdev) > p->serial_in = dw8250_serial_in; > p->serial_out = dw8250_serial_out; > p->set_ldisc = dw8250_set_ldisc; > + p->set_termios = dw8250_set_termios; > > p->membase = devm_ioremap(dev, regs->start, resource_size(regs)); > if (!p->membase) >