- Move hardware counter reading/zeroing to hme_tick(). This saves
8 register access per interrupt. [1]
- Use imax macro for getting max. argument between two integers.
- Invoke bus_dmamap_sync(9) first before freeing mbuf.
- Check driver queue first to reduce locking operation in hme_start_locked()
and interrupt handler.
- Simplyfy watchdog timer setup in interrupt handler.
- Don't log normal errors such as RX overrun. If we have DMA stuck
condition, reinitialize the driver and log it.
Reviewed by: marius
Obtained from: OpenBSD [1]