Unlike TX interrupt, ST201 does not provide any mechanism to
suppress RX interrupts. ste(4) can generate more than 70k RX
interrupts under heavy RX traffics such that these excessive
interrupts make system useless to process other useful things.
Maybe this was the major reason why polling support code was
introduced to ste(4).
The STE_COUNTDOWN register provides a programmable counter that
will generate an interrupt upon its expiration. We program
STE_DMACTL register to use 3.2us clock rate to drive the counter
register. Whenever ste(4) serves RX interrupt, the driver rearm
the timer to expire after STE_IM_RX_TIMER_DEFAULT time and disables
further generation of RX interrupts. This trick seems to work well
and ste(4) generates less than 8k RX interrupts even under 64 bytes
UDP torture test. Combined with TX interrupts, the total number of
interrupts are less than 10k which looks reasonable on heavily
loaded controller.
The default RX interrupt moderation time is 150us. Users can change
the value at any time with dev.ste.%d.int_rx_mod sysctl node.
Setting it 0 effectively disables the RX interrupt moderation
feature. Now we have both TX/RX interrupt moderation code so remove
loop of interrupt handler which resulted in sub-optimal performance
as well as more register accesses.
transmitted frames. So request interrupt for every 16th frames. Due
to the limitation of hardware we can't suppress the interrupt as
driver should have to check TX status register. The TX status
register can store up to 31 TX status so driver can't send more
than 31 frames without reading TX status register.
With this change controller would not generate TX completion
interrupt for every frame, so reclaim transmitted frames in
ste_tick().
used to return success without respect to the result.
While I'm here use mii_mediachg() in ste_init_locked which allows
driver to use currently configured media. ste_ifmedia_upd() is
supposed to be called whenever user changes current media settings.
o Let RX filter handler program promiscuous/multicast filter as
well as broadcasting.
o Remove unnecessary register access.
o Simplify ioctl handler and have set_rxfilter to handle
IFF_PROMISC and IFF_ALLMULTI change instead of directly
programming the controller.
o Removed unnecessary error variable reinitialization in ioctl
handler.
o Add IFF_DRV_RUNNING check before programming multicast filter.
o Configure maximum allowed frame length before enabling MAC.
Datasheet didn't say the exact ordering of programming sequence
but it looks more natural to set maximum allowed frame length
first prior to enabling controller.
1ms. Since we switched to memory register mapping make sure to
flush PCI posted write by reading the register again.
While I'm here add additional delays in loop while driver waits the
completion of the reset.
If ste(4) encounter TX underrun or excessive collisions the TX MAC
of controller is stalled so driver should wake it up again. TX
underrun requires increasing TX threshold value to minimize
further TX underruns. Previously ste(4) used to reset controller
to recover from TX underrun, excessive collision and reclaiming
error. However datasheet says only TX underrun requires resetting
entire controller. So implement ste_restart_tx() that restarts TX
MAC and do not perform full reset except TX underrun case.
Now ste(4) uses CSR_READ_2 instead of CSR_READ_1 to read
STE_TX_STATUS register. This way ste(4) will also read frame id
value and we can write the same value back to STE_TX_FRAMEID
register instead of overwriting it to 0. The datasheet was wrong
in write back of STE_TX_STATUS so add some comments why we do so.
Also always invoke ste_txeoc() after ste_txeof() in ste_poll as
without reading TX status register can stall TX MAC.
receiving incoming traffics, try harder to gracefully stop active
DMA cycles and then stop MACs. This is the way what datasheet
recommends and seems to work reliably. Resetting controller while
active DMAs are in progress is bad thing as we can't predict how
DMAs touche allocated TX/RX buffers. This change ensures controller
stop state before attempting to release allocated TX/RX buffers.
Also update MAC statistics which could have been updated during the
wait time of MAC stop.
While I'm here remove unnecessary controller resets in various
location. ste(4) no longer relies on hard controller reset to stop
controller and resetting controller also clears all configured
settings which makes it hard to implement WOL in near future.
Now resetting a controller is performed in ste_init_locked().
interrupt. If we want to use link state change interrupt ste(4)
should also implement auto-negotiation complete handler as well as
various PHY access handling. Now link state change is handled by
mii(4) polling so it will automatically update link state UP/DOWN
events which in turn make ste(4) usable with lagg(4).
r199559 added a private timer to drive watchdog and the timer also
used to drive MAC statistics update. Because the MAC statistics
update is called whenever statistics counter reaches near-full, it
drove watchdog timer too fast such that it caused false watchdog
timeouts under heavy TX traffic conditions.
Fix the regression by separating ste_stats_update() from driving
watchdog timer and introduce a new function ste_tick() that handles
periodic job such as driving watchdog, MAC statistics update and
link state check etc.
While I'm here clear armed watchdog timer in ste_stop().
link state and PHY related information.
Remove ste_link and ste_one_phy variable of softc as it's not used
anymore.
While I'm here add IFF_DRV_RUNNING check in ste_start_locked().
o Sorted includes and added missing header files.
o Added basic endianness support. In theory ste(4) should work on
any architectures.
o Remove the use of contigmalloc(9), contigfree(9) and vtophys(9).
o Added 8 byte alignment limitation of TX/RX descriptor.
o Added 1 byte alignment requirement for TX/RX buffers.
o ste(4) controllers does not support DAC. Limit DMA address space
to be within 32bit address.
o Added spare DMA map to gracefully recover from DMA map failure.
o Removed dead code for checking STE_RXSTAT_DMADONE bit. The bit
was already checked in each iteration of loop so it can't be true.
o Added second argument count to ste_rxeof(). It is used to limit
number of iterations done in RX handler. ATM polling is the only
consumer.
o Removed ste_rxeoc() which was added to address RX stuck issue
(cvs rev 1.66). Unlike TX descriptors, ST201 supports chaining
descriptors to form a ring for RX descriptors. If RX descriptor
chaining is not supported it's possible for controller to stop
receiving incoming frames once controller pass the end of RX
descriptor which in turn requires driver post new RX
descriptors to receive more frames. For TX descriptors which
does not support chaning, we exactly do manual chaining in
driver by concatenating new descriptors to the end of previous
TX chain.
Maybe the workaround was borrowed from other drivers that does
not support RX descriptor chaining, which is not valid for ST201
controllers. I still have no idea how this address RX stuck
issue and I can't reproduce the RX stuck issue on DFE-550TX
controller.
o Removed hw.ste_rxsyncs sysctl as the workaround was removed.
o TX/RX side bus_dmamap_load_mbuf_sg(9) support.
o Reimplemented optimized ste_encap().
o Simplified TX logic of ste_start_locked().
o Added comments for TFD/RFD requirements.
o Increased number of RX descriptors to 128 from 64. 128 gave much
better performance than 64 under high network loads.
if_watchdog and if_timer.
- Fix some issues in detach for sn(4), ste(4), and ti(4). Primarily this
means calling ether_ifdetach() before anything else.
IF_ADDR_UNLOCK() across network device drivers when accessing the
per-interface multicast address list, if_multiaddrs. This will
allow us to change the locking strategy without affecting our driver
programming interface or binary interface.
For two wireless drivers, remove unnecessary locking, since they
don't actually access the multicast address list.
Approved by: re (kib)
MFC after: 6 weeks
CPU for too long period than necessary. Additively, interfaces are kept
polled (in the tick) even if no more packets are available.
In order to avoid such situations a new generic mechanism can be
implemented in proactive way, keeping track of the time spent on any
packet and fragmenting the time for any tick, stopping the processing
as soon as possible.
In order to implement such mechanism, the polling handler needs to
change, returning the number of packets processed.
While the intended logic is not part of this patch, the polling KPI is
broken by this commit, adding an int return value and the new flag
IFCAP_POLLING_NOCOUNT (which will signal that the return value is
meaningless for the installed handler and checking should be skipped).
Bump __FreeBSD_version in order to signal such situation.
Reviewed by: emaste
Sponsored by: Sandvine Incorporated
