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

[Christian MAUDERER]

Hello Chris,

Am 09.06.22 um 09:20 schrieb Chris Johns:
> OK push.

Thanks.

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

The device tree for the i.MX6 and i.MX7 series are basically just the 
ones from FreeBSD or Linux. So there are a lot of examples available. 
With the additional hints that I added with this patch, it should be 
possible to create one that is working well for a custom board.

Best regards

Christian

> 
> 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
>>   -----------------
>>   

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