[U-Boot-Board-Maintainers] Raspberry pi 4 - u-boot - genet / scb
Andreas Färber
afaerber at suse.de
Sat Dec 7 10:27:55 CET 2019
Sascha,
Am 07.12.19 um 07:23 schrieb Sascha Dewald:
> Hello,
>
> is there any progress yet ?
There is absolutely no reason to annoy all the board maintainers on this
mailing list with nagging about an unimplemented driver for one board!
Especially not with HTML mail and top-posting!!! Please take this
discussion to the u-boot mailing list (Reply-to set).
Regards,
Andreas
> Am Fr., 22. Nov. 2019 um 00:27 Uhr schrieb André Przywara
> <andre.przywara at arm.com <mailto: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>
> <mailto: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>
> <mailto: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>
> <mailto: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>
> > <mailto: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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