2016-04-24 19:00:25

by Ramon Fried

[permalink] [raw]
Subject: dmatest - scatter gather mode

I'm looking of a way to validate a DMA engine driver I've written.
I came across dmatest module and while reading the code I've noticed that scatter-gather DMA mode is not implemented.
I wonder if anyone one knows the reason, and if such enhancement will be welcome as a patch.

Thanks.
Ramon


2016-04-26 14:37:11

by Andy Shevchenko

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Subject: Re: dmatest - scatter gather mode

On Sun, Apr 24, 2016 at 9:44 PM, Ramon Fried <[email protected]> wrote:
> I'm looking of a way to validate a DMA engine driver I've written.
> I came across dmatest module and while reading the code I've noticed that scatter-gather DMA mode is not implemented.
> I wonder if anyone one knows the reason, and if such enhancement will be welcome as a patch.

You meant the actual slave interaction? How can you implement this in
a generic way?
For example we are using an SPI controller in loopback mode to check DMA driver.
In your case it might be something really specific.

Otherwise you may try mem copy functionality if your DMA engine supports such.

--
With Best Regards,
Andy Shevchenko

2016-04-26 16:22:17

by Vinod Koul

[permalink] [raw]
Subject: Re: dmatest - scatter gather mode

On Tue, Apr 26, 2016 at 05:37:04PM +0300, Andy Shevchenko wrote:
> On Sun, Apr 24, 2016 at 9:44 PM, Ramon Fried <[email protected]> wrote:
> > I'm looking of a way to validate a DMA engine driver I've written.
> > I came across dmatest module and while reading the code I've noticed that scatter-gather DMA mode is not implemented.
> > I wonder if anyone one knows the reason, and if such enhancement will be welcome as a patch.
>
> You meant the actual slave interaction? How can you implement this in
> a generic way?
> For example we are using an SPI controller in loopback mode to check DMA driver.
> In your case it might be something really specific.
>
> Otherwise you may try mem copy functionality if your DMA engine supports such.

I think he means dma copy using sg lists, see the patch posted today for
that


--
~Vinod