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Commit 0788c39b authored by Heikki Krogerus's avatar Heikki Krogerus Committed by Greg Kroah-Hartman
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serial: 8250_dw: support ACPI platforms with integrated DMA engine 



On many new Intel SoCs the UART has an integrated DMA engine
(iDMA). In order to use it a special filter function is needed.

Signed-off-by: default avatarHeikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 6f0c3091

drivers/tty/serial/8250/8250_dw.c

+18 −1
Original line number Diff line number Diff line
@@ -377,6 +377,16 @@ static int dw8250_probe_of(struct uart_port *p, 
	return 0;

}



static bool dw8250_idma_filter(struct dma_chan *chan, void *param)

{

	struct device *dev = param;



	if (dev != chan->device->dev->parent)

		return false;



	return true;

}



static int dw8250_probe_acpi(struct uart_8250_port *up,

			     struct dw8250_data *data)

{
@@ -389,8 +399,15 @@ static int dw8250_probe_acpi(struct uart_8250_port *up, 
	p->serial_out = dw8250_serial_out32;

	p->regshift = 2;



	up->dma = &data->dma;

	/* Platforms with iDMA */

	if (platform_get_resource_byname(to_platform_device(up->port.dev),

					 IORESOURCE_MEM, "lpss_priv")) {

		data->dma.rx_param = up->port.dev->parent;

		data->dma.tx_param = up->port.dev->parent;

		data->dma.fn = dw8250_idma_filter;

	}



	up->dma = &data->dma;

	up->dma->rxconf.src_maxburst = p->fifosize / 4;

	up->dma->txconf.dst_maxburst = p->fifosize / 4;