serial: imx: fix a race condition in receive path

[linux-2.6-microblaze.git] / drivers / tty / serial / imx.c

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
index 83c6e2a..0c6c631 100644 (file)
--- a/drivers/tty/serial/imx.c
+++ b/drivers/tty/serial/imx.c
@@ -696,22 +696,33 @@ static void imx_uart_start_tx(struct uart_port *port)
        }
 }
 
-static irqreturn_t imx_uart_rtsint(int irq, void *dev_id)
+static irqreturn_t __imx_uart_rtsint(int irq, void *dev_id)
 {
        struct imx_port *sport = dev_id;
        u32 usr1;
 
-       spin_lock(&sport->port.lock);
-
        imx_uart_writel(sport, USR1_RTSD, USR1);
        usr1 = imx_uart_readl(sport, USR1) & USR1_RTSS;
        uart_handle_cts_change(&sport->port, !!usr1);
        wake_up_interruptible(&sport->port.state->port.delta_msr_wait);
 
-       spin_unlock(&sport->port.lock);
        return IRQ_HANDLED;
 }
 
+static irqreturn_t imx_uart_rtsint(int irq, void *dev_id)
+{
+       struct imx_port *sport = dev_id;
+       irqreturn_t ret;
+
+       spin_lock(&sport->port.lock);
+
+       ret = __imx_uart_rtsint(irq, dev_id);
+
+       spin_unlock(&sport->port.lock);
+
+       return ret;
+}
+
 static irqreturn_t imx_uart_txint(int irq, void *dev_id)
 {
        struct imx_port *sport = dev_id;
@@ -722,14 +733,12 @@ static irqreturn_t imx_uart_txint(int irq, void *dev_id)
        return IRQ_HANDLED;
 }
 
-static irqreturn_t imx_uart_rxint(int irq, void *dev_id)
+static irqreturn_t __imx_uart_rxint(int irq, void *dev_id)
 {
        struct imx_port *sport = dev_id;
        unsigned int rx, flg, ignored = 0;
        struct tty_port *port = &sport->port.state->port;
 
-       spin_lock(&sport->port.lock);
-
        while (imx_uart_readl(sport, USR2) & USR2_RDR) {
                u32 usr2;
 
@@ -786,11 +795,25 @@ static irqreturn_t imx_uart_rxint(int irq, void *dev_id)
        }
 
 out:
-       spin_unlock(&sport->port.lock);
        tty_flip_buffer_push(port);
+
        return IRQ_HANDLED;
 }
 
+static irqreturn_t imx_uart_rxint(int irq, void *dev_id)
+{
+       struct imx_port *sport = dev_id;
+       irqreturn_t ret;
+
+       spin_lock(&sport->port.lock);
+
+       ret = __imx_uart_rxint(irq, dev_id);
+
+       spin_unlock(&sport->port.lock);
+
+       return ret;
+}
+
 static void imx_uart_clear_rx_errors(struct imx_port *sport);
 
 /*
@@ -849,6 +872,8 @@ static irqreturn_t imx_uart_int(int irq, void *dev_id)
        unsigned int usr1, usr2, ucr1, ucr2, ucr3, ucr4;
        irqreturn_t ret = IRQ_NONE;
 
+       spin_lock(&sport->port.lock);
+
        usr1 = imx_uart_readl(sport, USR1);
        usr2 = imx_uart_readl(sport, USR2);
        ucr1 = imx_uart_readl(sport, UCR1);
@@ -882,27 +907,25 @@ static irqreturn_t imx_uart_int(int irq, void *dev_id)
                usr2 &= ~USR2_ORE;
 
        if (usr1 & (USR1_RRDY | USR1_AGTIM)) {
-               imx_uart_rxint(irq, dev_id);
+               __imx_uart_rxint(irq, dev_id);
                ret = IRQ_HANDLED;
        }
 
        if ((usr1 & USR1_TRDY) || (usr2 & USR2_TXDC)) {
-               imx_uart_txint(irq, dev_id);
+               imx_uart_transmit_buffer(sport);
                ret = IRQ_HANDLED;
        }
 
        if (usr1 & USR1_DTRD) {
                imx_uart_writel(sport, USR1_DTRD, USR1);
 
-               spin_lock(&sport->port.lock);
                imx_uart_mctrl_check(sport);
-               spin_unlock(&sport->port.lock);
 
                ret = IRQ_HANDLED;
        }
 
        if (usr1 & USR1_RTSD) {
-               imx_uart_rtsint(irq, dev_id);
+               __imx_uart_rtsint(irq, dev_id);
                ret = IRQ_HANDLED;
        }
 
@@ -917,6 +940,8 @@ static irqreturn_t imx_uart_int(int irq, void *dev_id)
                ret = IRQ_HANDLED;
        }
 
+       spin_unlock(&sport->port.lock);
+
        return ret;
 }