On Sat, Aug 03, 2013 at 10:09:14AM -0400, Huang Shijie wrote:

From: Huang Shijie <redacted>

The original DMA support works only when RTS/CTS is enabled.
(see the "e800163 serial: mxs-auart: add the DMA support for mx28")
But after several patches, DMA support has lost this limit.
(see the "bcc20f9 serial: mxs-auart: move to use generic DMA helper")

So an UART without the RTS/CTS lines may also enables the DMA support,
in which case the UART may gets unpredictable results.

This patch adds an optional property for the UART DT node
which indicates the UART has RTS and CTS lines, and it also means you
enable the DMA support for this UART.

This patch also adds a macro MXS_AUART_RTSCTS, and uses it to check
RTS/CTS before we enable the DMA for the UART.

Cc: stable at vger.kernel.org
Signed-off-by: Huang Shijie <redacted>
Signed-off-by: Huang Shijie <redacted>
---
 .../bindings/tty/serial/fsl-mxs-auart.txt          |    4 ++++
 drivers/tty/serial/mxs-auart.c                     |    7 ++++++-
 2 files changed, 10 insertions(+), 1 deletions(-)

I don't see how this patch follows the stable kernel guidelines, so I'll
take the marking of it off, and queue it up for 3.12.

thanks,

greg k-h