user/bsps/arm: Second Ethernet on i.MX

This adds information how to use a second Ethernet controller on the
i.MX BSPs.
This commit is contained in:
Christian Mauderer
2022-06-09 09:02:03 +02:00
parent 9f431e7ebc
commit be4b767011

View File

@@ -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
-----------------