From: "Uwe Kleine-König" <u.kleine-koenig@pengutronix.de>
To: Romain Perier <romain.perier@collabora.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-serial@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, Nandor Han <nandor.han@ge.com>,
kernel@pengutronix.de
Subject: Re: [PATCH 7/7] serial: imx: Fix imx_shutdown procedure
Date: Mon, 3 Jul 2017 09:08:21 +0200 [thread overview]
Message-ID: <20170703070821.jnyyylwszz2bqprh@pengutronix.de> (raw)
In-Reply-To: <20170630120446.13994-8-romain.perier@collabora.com>
On Fri, Jun 30, 2017 at 02:04:46PM +0200, Romain Perier wrote:
> From: Nandor Han <nandor.han@ge.com>
>
> 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 <nandor.han@ge.com>
> Signed-off-by: Romain Perier <romain.perier@collabora.com>
> ---
> 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
>
> --
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>
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | http://www.pengutronix.de/ |
prev parent reply other threads:[~2017-07-03 7:08 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-30 12:04 [PATCH 0/7] serial: imx: various improvements Romain Perier
2017-06-30 12:04 ` [PATCH 1/7] serial: imx: only set DMA rx-ing when DMA starts Romain Perier
2017-07-03 6:48 ` Uwe Kleine-König
2017-07-04 8:55 ` Romain Perier
2017-06-30 12:04 ` [PATCH 2/7] serial: imx: move log from error to debug type Romain Perier
2017-07-03 6:50 ` Uwe Kleine-König
2017-06-30 12:04 ` [PATCH 3/7] serial: imx: init dma_is_{rx|tx}ing variables Romain Perier
2017-06-30 12:13 ` Lothar Waßmann
2017-07-03 6:52 ` Uwe Kleine-König
2017-07-05 10:14 ` Romain Perier
2017-07-05 11:58 ` Uwe Kleine-König
2017-06-30 12:04 ` [PATCH 4/7] serial: imx: Simplify DMA disablement Romain Perier
2017-07-03 6:58 ` Uwe Kleine-König
2017-06-30 12:04 ` [PATCH 5/7] serial: imx: umap sg buffers when DMA channel is released Romain Perier
2017-07-03 7:01 ` Uwe Kleine-König
2017-06-30 12:04 ` [PATCH 6/7] serial: imx: update the stop rx,tx procedures Romain Perier
2017-07-03 7:03 ` Uwe Kleine-König
2017-06-30 12:04 ` [PATCH 7/7] serial: imx: Fix imx_shutdown procedure Romain Perier
2017-07-03 7:08 ` Uwe Kleine-König [this message]
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