2021-07-21 21:03:21

by Andy Shevchenko

[permalink] [raw]
Subject: [PATCH v1 1/1] serial: 8250_lpss: Enable DMA on Intel Elkhart Lake

PSE UARTs on Intel Elkhart Lake support DMA mode.
Enable DMA on these ports.

Signed-off-by: Andy Shevchenko <[email protected]>
---
drivers/tty/serial/8250/8250_lpss.c | 10 ++++++++++
1 file changed, 10 insertions(+)

diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
index 4dee8a9e0c95..848d81e3838c 100644
--- a/drivers/tty/serial/8250/8250_lpss.c
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -158,6 +158,16 @@ static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)

static int ehl_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
{
+ struct uart_8250_dma *dma = &lpss->data.dma;
+ struct uart_8250_port *up = up_to_u8250p(port);
+
+ /*
+ * This simply makes the checks in the 8250_port to try the DMA
+ * channel request which in turn uses the magic of ACPI tables
+ * parsing (see drivers/dma/acpi-dma.c for the details) and
+ * matching with the registered General Purpose DMA controllers.
+ */
+ up->dma = dma;
return 0;
}

--
2.30.2