Expose the auto-negotiation feature of the Ethernet device via the
pseudo-module stm32_eth_auto. With this enabled, the static speed configuration
set in the boards periph_conf.h will only be used if the PHY lacks
auto-negotiation capabilities - which is unlikely to ever happen.
Previously, only an link-up event was triggered, not an link down event. And
additionally, once the link-up event was sent, the link status was no longer
monitored. As a result, once a link-up was sent, no further link event were
triggered.
The methods to read from / write to MII registers had an address argument to
allow specifying the PHY to communicate with. However, only a single PHY is
available on all boards supported and the driver is not able to operate with
multiple PHYs anyway - thus, drop this parameter for ease of use.
This fixes a bug in the _get_link_status() function, which used hard coded the
address 0; which might not be correct for all boards.
The link status was previously not returned via the value parameter, as required
by the netdev_driver_t API. As a result, e.g. the `ifconfig` shell command
showed garbage.
Using the TER bit in the TX descriptors when only using a single descriptor for
sending triggered a hardware bug. Thus, stop using the TER bit and store the
currently active TX descriptor in RAM instead.
The stm32_eth driver was build on top of the internal API periph_eth, which
was unused anywhere. (Additionally, with two obscure exceptions, no functions
where declared in headers, making them pretty hard to use anyway.)
The separation of the driver into two layers incurs overhead, but does not
result in cleaner structure or reuse of code. Thus, this artificial separation
was dropped.
The Ethernet DMA is capable of collecting a frame from multiple chunks, just
like the send function of the netdev interface passes. The send function was
rewritten to just set up the Ethernet DMA up to collect the outgoing frame
while sending. As a result, the send function blocks until the frame is
sent to keep control over the buffers.
This frees 6 KiB of RAM previously used for TX buffers.
1. Move buffer configuration from boards to cpu/stm32
2. Allow overwriting buffer configuration
- If the default configuration ever needs touching, this will be due to a
use case and should be done by the application rather than the board
3. Reduce default RX buffer size
- Now that handling of frames split up into multiple DMA descriptors works,
we can make use of this
Note: With the significantly smaller RX buffers the driver will now perform
much worse when receiving data at maximum throughput. But as long as frames
are small (which is to be expected for IoT or boarder gateway scenarios) the
performance should not be affected.
