From 00e8e65870cc581a0a8496e95480ea1b39aec58b Mon Sep 17 00:00:00 2001 From: Nicolas Ferre Date: Fri, 17 Jun 2016 12:05:47 +0200 Subject: [PATCH] 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 Signed-off-by: Ludovic Desroches Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/atmel_serial.c | 53 ++++++++++++++++++++----------- 1 file changed, 34 insertions(+), 19 deletions(-) diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c index 8854ac6f383d..6c1ec7d0d497 100644 --- 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_disable(&atmel_port->tasklet); + tasklet_init(&atmel_port->tasklet_tx, atmel_tasklet_tx_func, + (unsigned long)port); + 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);