Kintis EMAC is consuming 16 rinbuffers for input, and 8 buffers for output.
This is over-use because input packets are immediately allocated from
heap when passed to LwIP. Therefore the number can be creatly reduced.
Currently, if all TX descriptors are in use and IP stack calls K64F/K66F
ethernet driver link out, link out drops the packet. Added 10ms delay
to link out to wait for a descriptor to become available before dropping
the packet.
Changed K64F/K66F power up to return without waiting for link up i.e. for
the ethernet cable to be connected. This is needed for non-blocking use
of driver e.g. for using the driver from event queue.
TX pointer array was using RX ring length in its declaration.
Wasted memory if RX ring > TX ring, as is the default, but would
be broken if RX ring < TX ring.
16 RX buffers and 8 TX buffers is probably excessive. Nanostack
version of driver successfully used 4+4, and data pump should be
broadly equivalent.
This means that switching K64F devices from Nanostack to EMAC increases
base heap usage by 18K - observed in Nanostack border router builds.
Add a config option to make it possible to lower the number of buffers.
Defer consideration of lowering the default to later.
Just checking "does the chip have an EMAC" doesn't work - there are
targets using those chips which do not have an Ethernet connector and
don't provide the necessary surrounding infrastructure (eg DISCO_F429ZI,
not providing the board emac config call, and HEXIWEAR not providing PHY
info).
Make the targets that actually do want EMAC define their own local
Freescale_EMAC and STM_EMAC labels, and move the drivers into
the corresponding TARGET_ directories, removing the #ifdefs.
Seppo Takalo
Martin Kojtal
Mika Leppänen
Kevin Bracey
Mahesh Mahadevan