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authorHeikki Krogerus <heikki.krogerus@linux.intel.com>2015-05-26 15:59:32 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-06-01 06:55:12 +0900
commit0788c39b955151d92711800ce14f41154095bfa6 (patch)
treecab103edc82aa9bc47b2d62c90af56f27c90fe47 /drivers/tty
parent6f0c3091e73df7ad1393c3400d168b9777b4a63c (diff)
downloadlinux-0788c39b955151d92711800ce14f41154095bfa6.tar.bz2
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>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/8250/8250_dw.c19
1 files changed, 18 insertions, 1 deletions
diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index 176f18f2e3ab..d48b50641e9a 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;