From: Heikki Krogerus Date: Wed, 16 Jan 2013 12:08:16 +0000 (+0200) Subject: serial: 8250_dw: Set maxburst size X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=f5836a55dee705d47a16c32139c02721763ff699;p=linux-beck.git serial: 8250_dw: Set maxburst size The default burst is often 1 byte which is not very optimal. The ideal burst size when using 16550A type port would be 1/2 of fifosize, but this does not work with all Designware implementations. Setting it to 1/4 fifosize. Signed-off-by: Heikki Krogerus Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c index bfdaf8b2680b..117bb8b03598 100644 --- a/drivers/tty/serial/8250/8250_dw.c +++ b/drivers/tty/serial/8250/8250_dw.c @@ -178,6 +178,7 @@ dw8250_acpi_walk_resource(struct acpi_resource *res, void *data) slave->direction = DMA_MEM_TO_DEV; slave->dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; slave->slave_id = fixed_dma->request_lines; + slave->dst_maxburst = port->tx_loadsz / 4; dma->tx_chan_id = fixed_dma->channels; dma->tx_param = &dma->tx_chan_id; @@ -189,6 +190,7 @@ dw8250_acpi_walk_resource(struct acpi_resource *res, void *data) slave->direction = DMA_DEV_TO_MEM; slave->src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE; slave->slave_id = fixed_dma->request_lines; + slave->src_maxburst = p->fifosize / 4; dma->rx_chan_id = fixed_dma->channels; dma->rx_param = &dma->rx_chan_id; @@ -296,6 +298,8 @@ static int dw8250_probe(struct platform_device *pdev) uart.port.serial_in = dw8250_serial_in; uart.port.serial_out = dw8250_serial_out; + dw8250_setup_port(&uart); + if (pdev->dev.of_node) { err = dw8250_probe_of(&uart.port); if (err) @@ -308,8 +312,6 @@ static int dw8250_probe(struct platform_device *pdev) return -ENODEV; } - dw8250_setup_port(&uart); - data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM;