[LEDE-DEV] [PATCH] imx6: add DSA driver for MV88E6176 switch

[Tim Harvey]

On Fri, Mar 10, 2017 at 7:49 AM, Rafał Miłecki <zajec5 at gmail.com> wrote:
> On 10 March 2017 at 16:01, Tim Harvey <tharvey at gateworks.com> wrote:
>> The MV88E6176 switch is present on the GW16083 and the GW5904
>>
>> As of a5c32a1f1996f4f75504c4a9abd1c99eaa598df1 these drivers are to be
>> enabled static in per-target kernels.
>
> A standard kernel syntax may be preferred:
> commit a5c32a1f1996 ("kernel: remove switch driver kmod packages")

I can update the commit log if the patch requires rework.

honestly, I'm not all that happy about 'commit a5c32a1f1996 ("kernel:
remove switch driver kmod packages")' which removed selecting dsa
kernel modules because of perceived bloat but instead this puts bloat
into the static kernel of other imx6 boards that dont' have DSA. At
least before the modules were selectable.

>
> So does imx6 already work with DSA/switchdev driver? Can you configure
> switch in /etc/config/network? I didn't track recent progress on this.

With DSA/switchdev the uplink CPU port must be up first, then the port
interfaces can come up.

There are two hardware examples of this currently on IMX6 I know of:

1. GW5904 (patch just posted) with IMX6 FEC (eth0) to switch and 4
ports on front panel (lan1, lan2, lan3, lan4). So in this case eth0
must be up first (with no IP config), then lan1-lan4 can be brought
up. I'm not sure how to best handle this in /etc/config/network

2. GW5xxx baseboard + GW16083 Ethernet expansion board (patches not
posted to LEDE yet). The GW16083 expansion board has an i210 on the
PCIe bus as the CPU uplink, 4 phy-less ports to RJ45's, and 2
phy-ports to RJ45/SFP. Various GW5xxx boards a PCIe switch and an
expansion connector providing PCI/I2C on a connector to support this.
Depending on the baseboard the GW16083 is added to the cpu uplink port
may be eth1, or eth2.

Tim