| From df7dc8aaa5188f63b1c3e3a0368226c5330a7772 Mon Sep 17 00:00:00 2001 |
| From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= <u.kleine-koenig@pengutronix.de> |
| Date: Mon, 11 Apr 2011 10:59:09 +0200 |
| Subject: [PATCH] serial/imx: read cts state only after acking cts change irq |
| MIME-Version: 1.0 |
| Content-Type: text/plain; charset=UTF-8 |
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| |
| commit 5680e94148a86e8c31fdc5cb0ea0d5c6810c05b0 upstream. |
| |
| If cts changes between reading the level at the cts input (USR1_RTSS) |
| and acking the irq (USR1_RTSD) the last edge doesn't generate an irq and |
| uart_handle_cts_change is called with a outdated value for cts. |
| |
| The race was introduced by commit |
| |
| ceca629 ([ARM] 2971/1: i.MX uart handle rts irq) |
| |
| [PG: file in drivers/serial not drivers/tty/serial in .34] |
| |
| Reported-by: Arwed Springer <Arwed.Springer@de.trumpf.com> |
| Tested-by: Arwed Springer <Arwed.Springer@de.trumpf.com> |
| Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
| Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> |
| |
| diff --git a/drivers/serial/imx.c b/drivers/serial/imx.c |
| index eacb588..6d2028e 100644 |
| --- a/drivers/serial/imx.c |
| +++ b/drivers/serial/imx.c |
| @@ -383,12 +383,13 @@ static void imx_start_tx(struct uart_port *port) |
| static irqreturn_t imx_rtsint(int irq, void *dev_id) |
| { |
| struct imx_port *sport = dev_id; |
| - unsigned int val = readl(sport->port.membase + USR1) & USR1_RTSS; |
| + unsigned int val; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&sport->port.lock, flags); |
| |
| writel(USR1_RTSD, sport->port.membase + USR1); |
| + val = readl(sport->port.membase + USR1) & USR1_RTSS; |
| uart_handle_cts_change(&sport->port, !!val); |
| wake_up_interruptible(&sport->port.state->port.delta_msr_wait); |
| |
| -- |
| 1.7.7 |
| |
