Re: [PATCH V2 2/3] dmaselftest: add memcpy selftest support functions

[Sinan Kaya]

On 11/3/2015 2:44 AM, Dan Williams wrote:
> On Mon, Nov 2, 2015 at 10:30 PM, Vinod Koul <vinod.koul@xxxxxxxxx> wrote:
> > On Mon, Nov 02, 2015 at 11:18:37PM -0500, Sinan Kaya wrote:
> > > On 11/2/2015 11:15 PM, Vinod Koul wrote:
> > > > On Mon, Nov 02, 2015 at 01:07:38AM -0500, Sinan Kaya wrote:
> > > > > This patch adds supporting utility functions
> > > > > for selftest. The intention is to share the self
> > > > > test code between different drivers.
> > > > >
> > > > > Supported test cases include:
> > > > > 1. dma_map_single
> > > > > 2. streaming DMA
> > > > > 3. coherent DMA
> > > > > 4. scatter-gather DMA
> > > >
> > > > This seems quite similar to dmatest, any reason why you cannot use/enhance
> > > > that?
> > > Dmatest is a standalone kernel module intended for stress testing
> > > DMA engines from userspace with N number of threads and M size
> > > combinations etc.
> > >
> > > This one; on the other hand, is selftest to verify hardware is
> > > working as expected during power up.
> > >
> > > Almost all DMA engine drivers come with some sort of selftest code
> > > called from probe. I followed the same design pattern.
> >
> > which ones ?
> >
> > >


> > > I think the goal is to remove the duplicate self test code in all
> > > drivers over time.
> >
> > and what prevents us from having common selftest plus dmatest code. Most of
> > the code here to do selftest is _same_ dmaengine routine code used in
> > dmatest
> >
> > We can have common code which is used for dmatest as well as selftest. I do
> > not want to see same code duplicated..
>
> Originally ioatdma and iop-adma had local self tests before Haavard
> created dmatest.  I agree having the drivers also do a test each boot
> is redundant, but then again dmatest is not automatic and I saw the
> local self test catch an interrupt setup regression.

I see the following files still have some sort of self test code in them.

ioat\dma.c
ioat\dma_v2.c
ioat\dma_v3.c
iop-adma.c
mv_xor.c


> Maybe you could arrange for drivers to do a quick autorun through
> dmatest on load if dmatest is enabled, but otherwise load without
> testing?  Just my 2 cents from a dmaengine spectator.

I'm on the same boat. Almost all kernel configurations that I have seen 
do not have dmatest enabled. Dmatest is considered debug only and is not 
included into the kernel binaries.

I have no problem for moving the code from one location to the other but 
I still want to be able to run self-test code in mission mode before 
enabling DMA as today.

I'm open to suggestions.

--
Sinan Kaya
Qualcomm Technologies, Inc. on behalf of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a 
Linux Foundation Collaborative Project
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/