On 08/29/2014 12:54 AM, Tony Lindgren wrote:

* Sebastian Andrzej Siewior [off-list ref] [140828 12:37]:

quoted

On 08/28/2014 06:46 PM, Tony Lindgren wrote:

quoted

Sounds like there should be some way to clear that state.. I wonder
if omap-serial.c had something before it's DMA support was removed?

Its DMA was removed? Like there was DMA support?

Yeah see commit 494574304711a333386e7dd5fd3ebbc3b7024994...

Interesting. I've been browsing that file and checking other trees and
never noticed that it was there at some point. I only saw the pieces
which looked it was there.

OK thanks, I'm seeing the same issue as you. And the idlest registers
don't show any blockers. Looking at the errata docs, seems like
"Usage Note 2.7" in sprz318f.pdf says:

 Details When configured for DMA operations using smartidle mode (SYSC[4:3].IDLEMODE =
 0x2), the UART module will not acknowledge incoming idle requests. As a consequence,
 it can prevent L4 from going to idle.
 When there are additional expected transfers, the UART should be placed in force-idle
 mode.

Ehm. So I haven't found an errata document for omap3630, there is
nothing like that in that one I have for am335x or dra7. The document
you mentioned is for AM3715. Interesting?

So I've added also Paul to Cc, he may have better suggestions for the
hwmod flags to use. The experimental patch below seems to allow idling
for me, care to give it a try?

Yep, this one works. And I see DMA transfers (for RX side) after the
core hit idle so it seems to look good :)

Regards,

Tony

Sebastian