Re: [RFC PATCH v2 3/8] net: sparx5: add hostmode with phylink support

On Wed, Dec 23, 2020 at 09:58:52PM +0100, Alexandre Belloni wrote:

On 22/12/2020 15:41:41+0100, Andrew Lunn wrote:

quoted

quoted

Yes the register based injection/extration is not going to be fast, but
the FDMA and its driver is being sent later as separate series to keep
the size of this review down.

FDMA?

I need a bit more background here, just to make use this should be a
pure switchdev driver and not a DSA driver.

I don't think this should be a DSA driver. As for Ocelot, the CPU
port is not a MAC and in that use case, this would be like a top of the
rack switch with traffic going to the CPU port being mostly used for
managmement (dhcp, stp, etc...) as opposed to being used to forward
traffic to another interface, like WAN or wifi.

However, I would think there will be cases where the internal CPU is not
use and instead use ths switch in a DSA setting, very much like what is
done for Felix with regards to Ocelot.

From what i have heard so far, it does seem like a pure switchdev
driver is correct. So long as FDMA is not a standalone Ethernet
driver, but just a DMA engine incorporated into this driver, the
architecture looks correct.

I was asking because from the information that was available, it was
impossible to say what the correct architecture should be.

     Andrew