[PATCH] user/bsps/arm: Second Ethernet on i.MX

[Chris Johns]

OK push.

(I am not familiar with these devices so ...) Is the needed device tree
fragments easily available to the user?

Thanks
Chris

On 9/6/2022 5:03 pm, Christian Mauderer wrote:
> This adds information how to use a second Ethernet controller on the
> i.MX BSPs.
> ---
>  user/bsps/arm/imx.rst | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/user/bsps/arm/imx.rst b/user/bsps/arm/imx.rst
> index ee98f0b..e2fd7f2 100644
> --- a/user/bsps/arm/imx.rst
> +++ b/user/bsps/arm/imx.rst
> @@ -174,6 +174,23 @@ config like that:
>      SYSINIT_DRIVER_REFERENCE(ksz8091rnb, miibus);
>      #include <machine/rtems-bsd-config.h>
>  
> +On chips with two Ethernet controllers, the MDIO lines are shared between the
> +two controllers for a number of chips variants. This is currently supported with
> +some restrictions on the initialization order. For this configuration to work,
> +you have to make sure that the pins are assigned to the Ethernet controller that
> +is initialized first. The initialization order in `libbsd` depends on the order
> +of the Ethernet controllers in the device tree. So if (for example) `fec2` is
> +defined in the device tree sources before `fec1`, make sure that the MDIO lines
> +are routed to `fec2` and that the Ethernet PHYs are a sub-node of `fec2` in the
> +device tree.
> +
> +Note that the clock for the second Ethernet controller is not necessarily
> +enabled in the `CCM`. On the i.MX6UL/ULL, the clock will be enabled by the
> +startup code if the node that is compatible with `fsl,imx6ul-anatop` can be
> +found in the device tree. If you have trouble with the second Ethernet
> +controller make sure that the `ENET2_125M_EN` bit in the `CCM_ANALOG_PLL_ENET`
> +register is set as expected.
> +
>  MMC/SDCard Driver
>  -----------------
>