Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752671AbdGCHI2 (ORCPT ); Mon, 3 Jul 2017 03:08:28 -0400 Received: from metis.ext.4.pengutronix.de ([92.198.50.35]:52009 "EHLO metis.ext.4.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752590AbdGCHI0 (ORCPT ); Mon, 3 Jul 2017 03:08:26 -0400 Date: Mon, 3 Jul 2017 09:08:21 +0200 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: Romain Perier Cc: Greg Kroah-Hartman , linux-serial@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Nandor Han , kernel@pengutronix.de Subject: Re: [PATCH 7/7] serial: imx: Fix imx_shutdown procedure Message-ID: <20170703070821.jnyyylwszz2bqprh@pengutronix.de> References: <20170630120446.13994-1-romain.perier@collabora.com> <20170630120446.13994-8-romain.perier@collabora.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20170630120446.13994-8-romain.perier@collabora.com> User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:5054:ff:fe2a:3aa X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3591 Lines: 110 On Fri, Jun 30, 2017 at 02:04:46PM +0200, Romain Perier wrote: > From: Nandor Han > > In some cases, It looks that interrupts can happen after the dma was s/It/it/ > disabled and port was not yet shutdown. This will result in interrupts > handled by imx_rxint. > > This commits updates the shutdown function to ensure that underlying > components are disabled in the right order. This disables RX and TX > blocks, then it disabled interrupts. In case DMA is enabled, it disables > DMA and free corresponding resources. It disables UART port and stop > clocks. > > Signed-off-by: Nandor Han > Signed-off-by: Romain Perier > --- > drivers/tty/serial/imx.c | 38 +++++++++++++++++++------------------- > 1 file changed, 19 insertions(+), 19 deletions(-) > > diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c > index d5b6e09..7dc6f0c 100644 > --- a/drivers/tty/serial/imx.c > +++ b/drivers/tty/serial/imx.c > @@ -1404,44 +1404,44 @@ static void imx_shutdown(struct uart_port *port) > unsigned long temp; > unsigned long flags; > > - if (sport->dma_is_enabled) { > - sport->dma_is_rxing = 0; > - sport->dma_is_txing = 0; > - dmaengine_terminate_sync(sport->dma_chan_tx); > - dmaengine_terminate_sync(sport->dma_chan_rx); > - > + if (!sport->port.suspended) { > spin_lock_irqsave(&sport->port.lock, flags); > imx_stop_tx(port); > imx_stop_rx(port); > - imx_disable_dma(sport); > spin_unlock_irqrestore(&sport->port.lock, flags); > - imx_uart_dma_exit(sport); > } > > - mctrl_gpio_disable_ms(sport->gpios); > + if (sport->dma_is_inited) { > + if (sport->dma_is_enabled) { > + spin_lock_irqsave(&sport->port.lock, flags); > + imx_disable_dma(sport); > + spin_unlock_irqrestore(&sport->port.lock, flags); > + } > + imx_uart_dma_exit(sport); > + } > > spin_lock_irqsave(&sport->port.lock, flags); > temp = readl(sport->port.membase + UCR2); > - temp &= ~(UCR2_TXEN); > + temp &= ~(UCR2_TXEN | UCR2_RXEN); > writel(temp, sport->port.membase + UCR2); > + temp = readl(sport->port.membase + UCR4); > + temp &= ~UCR4_OREN; > + writel(temp, sport->port.membase + UCR4); > spin_unlock_irqrestore(&sport->port.lock, flags); The function already had two critical blocks protected by spin_lock_irqsave on sport->port.lock. With your patch there are three. Is it possible to grab the lock only once? > > - /* > - * Stop our timer. > - */ > - del_timer_sync(&sport->timer); > + mctrl_gpio_disable_ms(sport->gpios); > > - /* > - * Disable all interrupts, port and break condition. > - */ > + /* Stop our timer. */ Updating the comment style in such a commit makes the diff unnecessarily hard to read. > + del_timer_sync(&sport->timer); > > + /* Disable port. */ > spin_lock_irqsave(&sport->port.lock, flags); > temp = readl(sport->port.membase + UCR1); > - temp &= ~(UCR1_TXMPTYEN | UCR1_RRDYEN | UCR1_RTSDEN | UCR1_UARTEN); > - > + temp &= ~UCR1_UARTEN; > writel(temp, sport->port.membase + UCR1); > spin_unlock_irqrestore(&sport->port.lock, flags); > > + /* Disable clocks. */ > clk_disable_unprepare(sport->clk_per); > clk_disable_unprepare(sport->clk_ipg); > } > -- > 1.8.3.1 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-serial" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- Pengutronix e.K. | Uwe Kleine-K?nig | Industrial Linux Solutions | http://www.pengutronix.de/ |