Re: Synopsys Ethernet QoS Driver

[Giuseppe CAVALLARO]

On 11/21/2016 4:00 PM, Joao Pinto wrote:
> On 21-11-2016 14:36, Giuseppe CAVALLARO wrote:
> > Hello Joao
> >
> > On 11/21/2016 2:48 PM, Joao Pinto wrote:
> > > Synopsys QoS IP is a separated hardware component, so it should be reusable by
> > > all implementations using it and so have its own "core driver" and platform +
> > > pci glue drivers. This is necessary for example in hardware validation, where
> > > you prototype an IP and instantiate its drivers and test it.
> > >
> > > Was there a strong reason to integrate QoS features directly in stmmac and not
> > > in synopsys/dwc_eth_qos.*?
> >
> > We decided to enhance the stmmac on supporting the QoS for several
> > reasons; for example the common APIs that the driver already exposed and
> > actually suitable for other SYNP chips. Then, PTP, EEE,
> > S/RGMII, MMC could be shared among different chips with a minimal
> > effort.  This meant a lot of code already ready.
> >
> > For sure, the net-core, Ethtool, mdio parts were reused. Same for the
> > glue logic files.
> > For the latter, this helped to easily bring-up new platforms also
> > because the stmmac uses the HW cap register to auto-configure many
> > parts of the MAC core, DMA and modules. This helped many users, AFAIK.
> >
> > For validation purpose, this is my experience, the stmmac helped
> > a lot because people used the same code to validate different HW
> > and it was easy to switch to a platform to another one in order to
> > verify / check if the support was ok or if a regression was introduced.
> > This is important for complex supports like PTP or EEE.
> >
> > Hoping this can help.
> >
> > Do not hesitate to contact me for further details
>
> Thanks for the highly detailed info.
> My target application is to prototype the Ethernet QoS IP in a FPGA, with a PHY
> attached and make hardware validation.
>
> In your opinion a refactored stmmac with the missing QoS features would be
> suitable for it?

I think so; somebody also added code for FPGA.

In any case, step-by-step we can explore and understand
how to proceed. I wonder if you could start looking at the internal
of the stmmac. Then welcome doubts and open question...

> Thanks.

welcome

peppe

> > peppe