Subject: Re: [PATCH v19 00/14] crypto/dmaengine: qce: introduce BAM locking and use DMA for register I/O

From: Vinod Koul <[email-masked]>
Date: Thu, 4 Jun 2026 15:54:48 +0530

On 02-06-26, 18:38, Stephan Gerhold wrote:
> On Tue, May 26, 2026 at 03:10:48PM +0200, Bartosz Golaszewski wrote:
> > I feel like I fell into the trap of trying to address pre-existing
> > issues reported by sashiko and in the process provoking more reports so
> > let this be the last iteration where I do this. Vinod can we get this
> > queued for v7.2 now and iron out any previously existing problems in
> > tree?
> 
> Thanks a lot for working on fixing all these issues!
> 
> I agree there is no point addressing all the "pre-existing issues"
> pointed out by Sashiko, but have you looked through the other comments
> for new issues pointed out for your patches?

I hope Bart and Qualcomm can fix these driver issues as well
> 
> Out of curiosity, I was looking a bit at the comments for [PATCH v19
> 06/14] dmaengine: qcom: bam_dma: add support for BAM locking [1]. There
> are 8 open comments there (Critical: 1, High: 6 and Medium: 1). From a
> quick look I would say most of these could be valid. The critical one
> about the usage of dma_cookie_assign() sounds a bit concerning to me, if
> it is true we would be basically breaking parts of the dmaengine API for
> consumers by inserting the lock descriptor in front of everything else.

Yes this seems to be a valid one. Attaching another descriptor for lock
does not sound right to me, as in this case causes descriptor to be
marked 'done' prematurely.

Honestly, I am not quite happy with the way lock is being handled here.
I would hope we can have some better suggestions. Adding a descriptor
for lock does not look right to me. We are adding odd hardware/firmware
behaviour on engine apis.

I had earlier suggested to lock always or lock only for hw/sw versions
supported inside the driver, that might be simplist solution without the
complexity added here

-- 
~Vinod