[U-Boot-Board-Maintainers] Raspberry pi 4 - u-boot - genet / scb

[Andre Przywara]

On Wed, 20 Nov 2019 12:13:55 +0100
Matthias Brugger <mbrugger at suse.com> wrote:

Hi,

> Adding Andre as he helps in the effort to port the driver. More comments inline.
> 
> On 19/11/2019 22:46, Heinrich Schuchardt wrote:
> > On 11/19/19 9:48 PM, Simon Glass wrote:  
> >> Hi Sascha,
> >>
> >> On Tue, 19 Nov 2019 at 10:10, Sascha Dewald <sascha.dewald at gmail.com> wrote:  
> >>>
> >>> Hi Simon,
> >>>
> >>> it uses bcmgenet.
> >>>
> >>> Below some information from "hwinfo" and "dmesg"
> >>>  
> >>
> >> OK, well I think this is in linux as drivers/net/ethernet/broadcom/genet
> >>
> >> I'm not sure about the PHY but it looks like there is no driver for
> >> genet in U-Boot. I suggest poriting it over.  

Amit (CC:ed) is working on that. That is still quite rough and not really working yet, but as of yesterday he saw the first (empty) packets on the line at least.
I would assume we get something working still this year.

> > In linux-next/next-20191119
> > arch/arm64/boot/dts/broadcom/bcm2711-rpi-4-b.dtb
> > there is no network device.
> >   
> Florian send a new pull request, I think yesterday which adds the genet driver
> to RPi4.

I found the burst length quirk together with the new compatible string in David's net-next/master two days ago.

> > On Raspbian you can find for RPi4:
> > 
> > compatible = "brcm,genet-v5"
> > relating to Linux drivers/net/ethernet/broadcom/genet/bcmgenet.c
> > CONFIG_BCMGENET "Broadcom GENET internal MAC support"
> >   
> 
> RPi4 is a special case as DMA burst size is different from plain genet-v5
> driver. But that might be of no relevance for U-Boot.

Yeah, since there is no other user, we could just go ahead and fix the smaller burst length of 8 in U-Boot. I guess we don't care about the performance impact that has.

Cheers,
Andre.

> 
> > compatible = "ethernet-phy-ieee802.3-c22";
> > relating to Linux drivers/of/of_mdio.c.
> > CONFIG_OF_MDIO OpenFirmware MDIO bus (Ethernet PHY) accessors
> > 
> > compatible = "brcm,genet-mdio-v5";
> > relating to Linux drivers/net/phy/mdio-bcm-unimac.c
> > CONFIG_MDIO_BCM_UNIMAC "Broadcom UniMAC MDIO bus controller"
> > 
> > So wouldn't we need all three drivers?
> > 
> > Maybe Joe can tell us.
> > 
> > Best regards
> > 
> > Heinrich
> > 
> >   
> >>
> >> Regards,
> >> Simon
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> >>  
> >