tty/serial: atmel: split tx and rx paths

Split TX and RX paths to not schedule RX tasklet on TX events and vice versa.

Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Ludovic Desroches <ludovic.desroches@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
index 8854ac6f383d848a13719efbaa61f022539697f2..6c1ec7d0d497c880fe68438bbebe4a95e384c447 100644 (file)
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -145,7 +145,8 @@ struct atmel_uart_port {
        dma_cookie_t                    cookie_rx;
        struct scatterlist              sg_tx;
        struct scatterlist              sg_rx;
-       struct tasklet_struct   tasklet;
+       struct tasklet_struct   tasklet_rx;
+       struct tasklet_struct   tasklet_tx;
        unsigned int            irq_status_prev;
        unsigned int            tx_len;
 
@@ -708,7 +709,7 @@ static void atmel_rx_chars(struct uart_port *port)
                status = atmel_uart_readl(port, ATMEL_US_CSR);
        }
 
-       tasklet_schedule(&atmel_port->tasklet);
+       tasklet_schedule(&atmel_port->tasklet_rx);
 }
 
 /*
@@ -779,7 +780,7 @@ static void atmel_complete_tx_dma(void *arg)
         * remaining data from the beginning of xmit->buf to xmit->head.
         */
        if (!uart_circ_empty(xmit))
-               tasklet_schedule(&atmel_port->tasklet);
+               tasklet_schedule(&atmel_port->tasklet_tx);
 
        spin_unlock_irqrestore(&port->lock, flags);
 }
@@ -964,7 +965,7 @@ static void atmel_complete_rx_dma(void *arg)
        struct uart_port *port = arg;
        struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-       tasklet_schedule(&atmel_port->tasklet);
+       tasklet_schedule(&atmel_port->tasklet_rx);
 }
 
 static void atmel_release_rx_dma(struct uart_port *port)
@@ -1004,7 +1005,7 @@ static void atmel_rx_from_dma(struct uart_port *port)
        if (dmastat == DMA_ERROR) {
                dev_dbg(port->dev, "Get residue error, restart tasklet\n");
                atmel_uart_writel(port, ATMEL_US_IER, ATMEL_US_TIMEOUT);
-               tasklet_schedule(&atmel_port->tasklet);
+               tasklet_schedule(&atmel_port->tasklet_rx);
                return;
        }
 
@@ -1158,7 +1159,7 @@ static void atmel_uart_timer_callback(unsigned long data)
        struct uart_port *port = (void *)data;
        struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
-       tasklet_schedule(&atmel_port->tasklet);
+       tasklet_schedule(&atmel_port->tasklet_rx);
        mod_timer(&atmel_port->uart_timer, jiffies + uart_poll_timeout(port));
 }
 
@@ -1181,7 +1182,7 @@ atmel_handle_receive(struct uart_port *port, unsigned int pending)
                if (pending & (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT)) {
                        atmel_uart_writel(port, ATMEL_US_IDR,
                                          (ATMEL_US_ENDRX | ATMEL_US_TIMEOUT));
-                       tasklet_schedule(&atmel_port->tasklet);
+                       tasklet_schedule(&atmel_port->tasklet_rx);
                }
 
                if (pending & (ATMEL_US_RXBRK | ATMEL_US_OVRE |
@@ -1193,7 +1194,7 @@ atmel_handle_receive(struct uart_port *port, unsigned int pending)
                if (pending & ATMEL_US_TIMEOUT) {
                        atmel_uart_writel(port, ATMEL_US_IDR,
                                          ATMEL_US_TIMEOUT);
-                       tasklet_schedule(&atmel_port->tasklet);
+                       tasklet_schedule(&atmel_port->tasklet_rx);
                }
        }
 
@@ -1223,7 +1224,7 @@ atmel_handle_transmit(struct uart_port *port, unsigned int pending)
                /* Either PDC or interrupt transmission */
                atmel_uart_writel(port, ATMEL_US_IDR,
                                  atmel_port->tx_done_mask);
-               tasklet_schedule(&atmel_port->tasklet);
+               tasklet_schedule(&atmel_port->tasklet_tx);
        }
 }
 
@@ -1582,18 +1583,25 @@ static int atmel_prepare_rx_pdc(struct uart_port *port)
 /*
  * tasklet handling tty stuff outside the interrupt handler.
  */
-static void atmel_tasklet_func(unsigned long data)
+static void atmel_tasklet_rx_func(unsigned long data)
 {
        struct uart_port *port = (struct uart_port *)data;
        struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
 
        /* The interrupt handler does not take the lock */
        spin_lock(&port->lock);
-
-       atmel_port->schedule_tx(port);
-
        atmel_port->schedule_rx(port);
+       spin_unlock(&port->lock);
+}
 
+static void atmel_tasklet_tx_func(unsigned long data)
+{
+       struct uart_port *port = (struct uart_port *)data;
+       struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
+
+       /* The interrupt handler does not take the lock */
+       spin_lock(&port->lock);
+       atmel_port->schedule_tx(port);
        spin_unlock(&port->lock);
 }
 
@@ -1777,7 +1785,8 @@ static int atmel_startup(struct uart_port *port)
                return retval;
        }
 
-       tasklet_enable(&atmel_port->tasklet);
+       tasklet_enable(&atmel_port->tasklet_rx);
+       tasklet_enable(&atmel_port->tasklet_tx);
 
        /*
         * Initialize DMA (if necessary)
@@ -1906,8 +1915,10 @@ static void atmel_shutdown(struct uart_port *port)
         * Clear out any scheduled tasklets before
         * we destroy the buffers
         */
-       tasklet_disable(&atmel_port->tasklet);
-       tasklet_kill(&atmel_port->tasklet);
+       tasklet_disable(&atmel_port->tasklet_rx);
+       tasklet_disable(&atmel_port->tasklet_tx);
+       tasklet_kill(&atmel_port->tasklet_rx);
+       tasklet_kill(&atmel_port->tasklet_tx);
 
        /*
         * Ensure everything is stopped and
@@ -2302,9 +2313,12 @@ static int atmel_init_port(struct atmel_uart_port *atmel_port,
        port->irq       = pdev->resource[1].start;
        port->rs485_config      = atmel_config_rs485;
 
-       tasklet_init(&atmel_port->tasklet, atmel_tasklet_func,
+       tasklet_init(&atmel_port->tasklet_rx, atmel_tasklet_rx_func,
+                       (unsigned long)port);
+       tasklet_init(&atmel_port->tasklet_tx, atmel_tasklet_tx_func,
                        (unsigned long)port);
-       tasklet_disable(&atmel_port->tasklet);
+       tasklet_disable(&atmel_port->tasklet_rx);
+       tasklet_disable(&atmel_port->tasklet_tx);
 
        memset(&atmel_port->rx_ring, 0, sizeof(atmel_port->rx_ring));
 
@@ -2786,7 +2800,8 @@ static int atmel_serial_remove(struct platform_device *pdev)
        struct atmel_uart_port *atmel_port = to_atmel_uart_port(port);
        int ret = 0;
 
-       tasklet_kill(&atmel_port->tasklet);
+       tasklet_kill(&atmel_port->tasklet_rx);
+       tasklet_kill(&atmel_port->tasklet_tx);
 
        device_init_wakeup(&pdev->dev, 0);