[3/4] serial: 8250_lpss: Use 16B DMA burst with Elkhart Lake

Message ID 20221107110708.58223-4-ilpo.jarvinen@linux.intel.com
State New
Headers
Series 8250: DMA Fixes |

Commit Message

Ilpo Järvinen Nov. 7, 2022, 11:07 a.m. UTC
  Configure DMA to use 16B burst size with Elkhart Lake. This makes the
bus use more efficient and works around an issue which occurs with the
previously used 1B.

Fixes: 0a9410b981e9 ("serial: 8250_lpss: Enable DMA on Intel Elkhart Lake")
Cc: <stable@vger.kernel.org> # serial: 8250_lpss: Configure DMA also w/o DMA filter
Reported-by: Wentong Wu <wentong.wu@intel.com>
Co-developed-by: Srikanth Thokala <srikanth.thokala@intel.com>
Signed-off-by: Srikanth Thokala <srikanth.thokala@intel.com>
Co-developed-by: Aman Kumar <aman.kumar@intel.com>
Signed-off-by: Aman Kumar <aman.kumar@intel.com>
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>

---
I know the list of Co-dev-bys & Sob seems a bit odd for a oneliner.
The reason is that I cleaned up this from a more complex patch using
the earlier change that I authored myself so only this oneliner
remained in this patch.
---
 drivers/tty/serial/8250/8250_lpss.c | 2 ++
 1 file changed, 2 insertions(+)
  

Comments

Andy Shevchenko Nov. 7, 2022, 11:38 a.m. UTC | #1
On Mon, Nov 07, 2022 at 01:07:07PM +0200, Ilpo Järvinen wrote:
> Configure DMA to use 16B burst size with Elkhart Lake. This makes the
> bus use more efficient and works around an issue which occurs with the
> previously used 1B.
> 
> Fixes: 0a9410b981e9 ("serial: 8250_lpss: Enable DMA on Intel Elkhart Lake")
> Cc: <stable@vger.kernel.org> # serial: 8250_lpss: Configure DMA also w/o DMA filter
> Reported-by: Wentong Wu <wentong.wu@intel.com>
> Co-developed-by: Srikanth Thokala <srikanth.thokala@intel.com>
> Signed-off-by: Srikanth Thokala <srikanth.thokala@intel.com>
> Co-developed-by: Aman Kumar <aman.kumar@intel.com>
> Signed-off-by: Aman Kumar <aman.kumar@intel.com>
> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
> 
> ---
> I know the list of Co-dev-bys & Sob seems a bit odd for a oneliner.
> The reason is that I cleaned up this from a more complex patch using
> the earlier change that I authored myself so only this oneliner
> remained in this patch.

If you changed more than 70% of the code, I would suggest to drop the rest of
(Co)authors and if you want to pay a credit, just mention them in the commit
message in a free form.
  

Patch

diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c
index ed281445a97d..e0b4e1446eac 100644
--- a/drivers/tty/serial/8250/8250_lpss.c
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -174,6 +174,8 @@  static int ehl_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
 	 */
 	up->dma = dma;
 
+	lpss->dma_maxburst = 16;
+
 	port->set_termios = dw8250_do_set_termios;
 
 	return 0;