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Defer the wakeup to a per-port work item and coalesce multiple TX events using a pending flag, so only one wakeup is scheduled while a previous one is still outstanding. Signed-off-by: Crescent Hsieh --- drivers/tty/serial/8250/8250_mxpcie.c | 34 +++++++++++++++++++++++---- 1 file changed, 29 insertions(+), 5 deletions(-) diff --git a/drivers/tty/serial/8250/8250_mxpcie.c b/drivers/tty/serial/8250/8250_mxpcie.c index 63885348c14c..f8b7abd7871b 100644 --- a/drivers/tty/serial/8250/8250_mxpcie.c +++ b/drivers/tty/serial/8250/8250_mxpcie.c @@ -15,6 +15,7 @@ #include #include #include +#include #include #include @@ -104,7 +105,12 @@ #define MOXA_EVEN_RS_MASK GENMASK(3, 0) #define MOXA_ODD_RS_MASK GENMASK(7, 4) +#define MOXA_EVENT_TXLOW BIT(0) + struct mxpcie8250_port { + struct uart_port *port; + struct work_struct work; + unsigned long event_flags; int line; }; @@ -328,6 +334,8 @@ static void mxpcie8250_tx_chars(struct uart_8250_port *up) { struct uart_port *port = &up->port; struct tty_port *tport = &port->state->port; + struct device *dev = port->dev; + struct mxpcie8250 *priv = dev_get_drvdata(dev); unsigned int i, count, txsize; unsigned char c; @@ -348,9 +356,10 @@ static void mxpcie8250_tx_chars(struct uart_8250_port *up) serial_out(up, MOXA_PUART_TX_FIFO_MEM + i, c); } - if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) - uart_write_wakeup(port); - + if (kfifo_len(&tport->xmit_fifo) < WAKEUP_CHARS) { + if (!test_and_set_bit(MOXA_EVENT_TXLOW, &priv->port[port->port_id].event_flags)) + schedule_work(&priv->port[port->port_id].work); + } if (kfifo_is_empty(&tport->xmit_fifo) && !(up->capabilities & UART_CAP_RPM)) port->ops->stop_tx(port); } @@ -382,6 +391,14 @@ static int mxpcie8250_handle_irq(struct uart_port *port) return 1; } +static void mxpcie8250_work_handler(struct work_struct *work) +{ + struct mxpcie8250_port *priv_port = container_of(work, struct mxpcie8250_port, work); + + if (test_and_clear_bit(MOXA_EVENT_TXLOW, &priv_port->event_flags)) + uart_write_wakeup(priv_port->port); +} + static void mxpcie8250_init_board(struct pci_dev *pdev, struct mxpcie8250 *priv) { void __iomem *bar2_base = priv->bar2_base; @@ -437,7 +454,7 @@ static void mxpcie8250_setup_port(struct pci_dev *pdev, static int mxpcie8250_probe(struct pci_dev *pdev, const struct pci_device_id *id) { struct device *dev = &pdev->dev; - struct uart_8250_port up = {}; + struct uart_8250_port up = {}, *new_port; struct mxpcie8250 *priv; unsigned short device = pdev->device; unsigned int num_ports; @@ -497,6 +514,11 @@ static int mxpcie8250_probe(struct pci_dev *pdev, const struct pci_device_id *id up.port.iotype, priv->port[i].line); break; } + new_port = serial8250_get_port(priv->port[i].line); + + priv->port[i].port = &new_port->port; + + INIT_WORK(&priv->port[i].work, mxpcie8250_work_handler); } pci_set_drvdata(pdev, priv); @@ -507,8 +529,10 @@ static void mxpcie8250_remove(struct pci_dev *pdev) { struct mxpcie8250 *priv = pci_get_drvdata(pdev); - for (unsigned int i = 0; i < priv->num_ports; i++) + for (unsigned int i = 0; i < priv->num_ports; i++) { + cancel_work_sync(&priv->port[i].work); serial8250_unregister_port(priv->port[i].line); + } } static const struct pci_device_id mxpcie8250_pci_ids[] = { -- 2.45.2