Re: Synopsys Ethernet QoS Driver

[Giuseppe CAVALLARO]

On 11/21/2016 2:28 PM, Lars Persson wrote:
> > 21 nov. 2016 kl. 13:53 skrev Giuseppe CAVALLARO <peppe.cavallaro@xxxxxx>:
> >
> > Hello Joao
> >
> > > On 11/21/2016 1:32 PM, Joao Pinto wrote:
> > > Hello,
> > >
> > > > On 21-11-2016 05:29, Rayagond Kokatanur wrote:
> > > > > On Sat, Nov 19, 2016 at 7:26 PM, Rabin Vincent <rabin@xxxxxx> wrote:
> > > > > > On Fri, Nov 18, 2016 at 02:20:27PM +0000, Joao Pinto wrote:
> > > > > > For now we are interesting in improving the synopsys QoS driver under
> > > > > > /nect/ethernet/synopsys. For now the driver structure consists of a single file
> > > > > > called dwc_eth_qos.c, containing synopsys ethernet qos common ops and platform
> > > > > > related stuff.
> > > > > >
> > > > > > Our strategy would be:
> > > > > >
> > > > > > a) Implement a platform glue driver (dwc_eth_qos_pltfm.c)
> > > > > > b) Implement a pci glue driver (dwc_eth_qos_pci.c)
> > > > > > c) Implement a "core driver" (dwc_eth_qos.c) that would only have Ethernet QoS
> > > > > > related stuff to be reused by the platform / pci drivers
> > > > > > d) Add a set of features to the "core driver" that we have available internally
> > > > >
> > > > > Note that there are actually two drivers in mainline for this hardware:
> > > > >
> > > > > drivers/net/ethernet/synopsis/
> > > > > drivers/net/ethernet/stmicro/stmmac/
> > > >
> > > > Yes the later driver (drivers/net/ethernet/stmicro/stmmac/) supports
> > > > both 3.x and 4.x. It has glue layer for pci, platform, core etc,
> > > > please refer this driver once before you start.
> > > >
> > > > You can start adding missing feature of 4.x in stmmac driver.
> > >
> > > Thanks you all for all the info.
> > > Well, I think we are in a good position to organize the ethernet drivers
> > > concerning Synopsys IPs.
> > >
> > > First of all, in my opinion, it does not make sense to have a ethernet/synopsis
> > > (typo :)) when ethernet/stmicro is also for a synopsys IP. If we have another
> > > vendor using the same IP it should be able to reuse the commonn operations. But
> > > I would put that discussion for later :)
> > >
> > > For now I suggest that for we create ethernet/qos and create there a folder
> > > called dwc (designware controller) where all the synopsys qos IP specific code
> > > in order to be reused for example by ethernet/stmicro/stmmac/. We just have to
> > > figure out a clean interface for "client drivers" like stmmac to interact with
> > > the new qos driver.
> > >
> > > What do you think about this approach?
> >
> > The stmmac drivers run since many years on several platforms
> > (sh4, stm32, arm, x86, mips ...) and it supports an huge of amount of
> > configurations starting from 3.1x to 3.7x databooks.
> >
> > It also supports QoS hardware; for example, 4.00a, 4.10a and 4.20a
> > are fully working.
> >
> > Also the stmmac has platform, device-tree and pcie supports and
> > a lot of maintained glue-logic files.
> >
> > It is fully documented inside the kernel tree.
> >
> > I am happy to have new enhancements from other developers.
> > So, on my side, if you want to spend your time on improving it on your
> > platforms please feel free to do it!
> >
> > Concerning the stmicro/stmmac naming, these come from a really old
> > story and have no issue to adopt new folder/file names.
> >
> > I am also open to merge fixes and changes from ethernet/synopsis.
> > I want to point you on some benchmarks made by Alex some months ago
> > (IIRC) that showed an stmmac winner (due to the several optimizations
> > analyzed and reviewed in this mailing list).
> >
> > Peppe
>
> Hello Joao and others,
>
> As the maintainer of dwc_eth_qos.c I prefer also that we put efforts on the most mature driver, the stmmac.
>
> I hope that the code can migrate into an ethernet/synopsys folder to keep the convention of naming the folder after the vendor. This makes it easy for others to find the driver.
>
> The dwc_eth_qos.c will eventually be removed and its DT binding interface can then be implemented in the stmmac driver.

Thanks Lars, I will be happy to support all you on this transition
and I agree on renaming all.

peppe


> - Lars
>
> > > > > (See http://lists.openwall.net/netdev/2016/02/29/127)
> > > > >
> > > > > The former only supports 4.x of the hardware.
> > > > >
> > > > > The later supports 4.x and 3.x and already has a platform glue driver
> > > > > with support for several platforms, a PCI glue driver, and a core driver
> > > > > with several features not present in the former (for example: TX/RX
> > > > > interrupt coalescing, EEE, PTP).
> > > > >
> > > > > Have you evaluated both drivers?  Why have you decided to work on the
> > > > > former rather than the latter?
> > >
> > > Thanks.