Re: Synopsys Ethernet QoS Driver

On 11/21/2016 4:00 PM, Joao Pinto wrote:

On 21-11-2016 14:36, Giuseppe CAVALLARO wrote:

quoted

Hello Joao

On 11/21/2016 2:48 PM, Joao Pinto wrote:

quoted

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

quoted

peppe