| From 1015acd59f4143b31c38d6b91e878e15c02de363 Mon Sep 17 00:00:00 2001 |
| From: Heikki Krogerus <heikki.krogerus@linux.intel.com> |
| Date: Thu, 5 Sep 2013 17:34:54 +0300 |
| Subject: serial: 8250_dw: provide a filter for DMA channel detection |
| |
| The channel IDs are set to -1 by default. It will prevent |
| dmaengine from trying to provide the first free channel if |
| it fails to allocate exclusive channel. This will fix an |
| issue with ACPI enumerated UARTs that do not support DMA |
| but still end up getting a DMA channel incorrectly. |
| |
| Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| (cherry picked from commit 7fb8c56c7fa0fa11168d3788d4591951bec27f4b) |
| Signed-off-by: Darren Hart <dvhart@linux.intel.com> |
| --- |
| drivers/tty/serial/8250/8250_dw.c | 14 ++++++++++++++ |
| 1 file changed, 14 insertions(+) |
| |
| --- a/drivers/tty/serial/8250/8250_dw.c |
| +++ b/drivers/tty/serial/8250/8250_dw.c |
| @@ -184,6 +184,14 @@ dw8250_do_pm(struct uart_port *port, uns |
| pm_runtime_put_sync_suspend(port->dev); |
| } |
| |
| +static bool dw8250_dma_filter(struct dma_chan *chan, void *param) |
| +{ |
| + struct dw8250_data *data = param; |
| + |
| + return chan->chan_id == data->dma.tx_chan_id || |
| + chan->chan_id == data->dma.rx_chan_id; |
| +} |
| + |
| static void dw8250_setup_port(struct uart_8250_port *up) |
| { |
| struct uart_port *p = &up->port; |
| @@ -344,6 +352,12 @@ static int dw8250_probe(struct platform_ |
| uart.port.uartclk = clk_get_rate(data->clk); |
| } |
| |
| + data->dma.rx_chan_id = -1; |
| + data->dma.tx_chan_id = -1; |
| + data->dma.rx_param = data; |
| + data->dma.tx_param = data; |
| + data->dma.fn = dw8250_dma_filter; |
| + |
| uart.port.iotype = UPIO_MEM; |
| uart.port.serial_in = dw8250_serial_in; |
| uart.port.serial_out = dw8250_serial_out; |
