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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: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Heikki Krogerus 2015-05-26 15:59:32 +03:00 committed by Greg Kroah-Hartman
parent 6f0c3091e7
commit 0788c39b95
1 changed files with 18 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
drivers/tty/serial/8250/8250_dw.c
View File

@ -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;