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

[Sascha Dewald]

Hello,

is there any progress yet ?

Regards,
Sascha

Am Fr., 22. Nov. 2019 um 00:27 Uhr schrieb André Przywara <
andre.przywara at arm.com>:

> On 21/11/2019 21:46, Sascha Dewald wrote:
>
> Hi,
>
> > could someone give me a summary which is missing in u-boot and what
> > needs to be ported ?
>
> The PHY is pretty much standard and already supported, as far as I can
> see, the MAC is not.
>
> > I found other broadcom drivers, which are already in u-boot.
>
> The RPi4 uses a Broadcom GENETv5 IP (with a slight tweak). The Linux
> driver is quite sophisticated: it supports older revisions (v1..v4),
> makes clever use of multiple priority queues and is of course fully
> interrupt driven, including napi shortcuts, also enjoys all the glory of
> the full Linux driver framework galore.
> For U-Boot we can get away with a MUCH simpler driver. Amit and I spent
> a while understanding the hardware based on the Linux driver, and Amit
> saw the first ARP packet from U-Boot on his laptop yesterday. He is
> currently working on the recv() function.
>
> > How difficult is it, to strip the drivers down, from the linux kernel to
> > work with u-boot?
>
> As mentioned, stripping the driver down (as in copying and editing) is
> not a good idea, but the basic driver is already somewhat working
> (probing, instantiation, sending packets), so we are not far away.
>
> If I could ask for just for a few more days of patience, then I am
> looking forward for your help with review and testing!
>
> Cheers,
> Andre
>
> > Am Mi., 20. Nov. 2019 um 12:21 Uhr schrieb Andre Przywara
> > <andre.przywara at arm.com <mailto:andre.przywara at arm.com>>:
> >
> >     On Wed, 20 Nov 2019 12:13:55 +0100
> >     Matthias Brugger <mbrugger at suse.com <mailto: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 <mailto: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
> >     > >> _______________________________________________
> >     > >> U-Boot-Board-Maintainers mailing list
> >     > >> U-Boot-Board-Maintainers at lists.denx.de
> >     <mailto:U-Boot-Board-Maintainers at lists.denx.de>
> >     > >> https://lists.denx.de/listinfo/u-boot-board-maintainers
> >     > >>
> >     > >
> >
>
>
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