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@xxxxxxxxxxxxxxx>
---
drivers/tty/serial/8250/8250_dw.c | 19 ++++++++++++++++++-
1 file changed, 18 insertions(+), 1 deletion(-)
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 1e2b3f4..3b8b542 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -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;
--
2.1.4
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