whenever the link state is changed. Using software based polling
for media status tracking is known to cause MII access failure
under certain conditions once link is established so vge(4) used to
rely on link status change interrupt.
However DEVICE_POLLING completely disables generation of all kind
of interrupts on vge(4) such that this resulted in not detecting
link state change event. This means vge(4) does not correctly
detect established/lost link with DEVICE_POLLING. Losing the
interrupt made vge(4) not to send any packets to peer since vge(4)
does not try to send any packets when there is no established link.
Work around the issue by generating link state change interrupt
with DEVICE_POLLING.
PR: kern/160442
Approved by: re (kib)
controllers. TX/RX interrupt mitigation is controlled by
VGE_TXSUPPTHR and VGE_RXSUPPTHR register. These registers suppress
generation of interrupts until the programmed frames counter equals
to the registers. VT61xx also supports interrupt hold off timer
register. If this interrupt hold off timer is active all interrupts
would be disabled until the timer reaches to 0. The timer value is
reloaded whenever VGE_ISR register written. The timer resolution is
about 20us.
Previously vge(4) used single shot timer to reduce Tx completion
interrupts. This required VGE_CRS1 register access in Tx
start/completion handler to rearm new timeout value and it did not
show satisfactory result(more than 50k interrupts under load). Rx
interrupts was not moderated at all such that vge(4) used to
generate too many interrupts which in turn made polling(4) better
approach under high network load.
This change activates all interrupt moderation mechanism and
initial values were tuned to generate interrupt less than 8k per
second. That number of interrupts wouldn't add additional packet
latencies compared to polling(4). These interrupt parameters could
be changed with sysctl.
dev.vge.%d.int_holdoff
dev.vge.%d.rx_coal_pkt
dev.vge.%d.tx_coal_pkt
Interface has be brought down and up again before change take
effect.
With interrupt moderation there is no more need to loop in
interrupt handler. This loop always added one more register access.
While I'm here remove dead code which tried to implement subset of
interrupt moderation.
o Separate TX/RX buffer DMA tag from TX/RX descriptor ring DMA tag.
o Separate RX buffer DMA tag from common buffer DMA tag. RX DMA
tag has different restriction compared to TX DMA tag.
o Add 40bit DMA address support.
o Adjust TX/RX descriptor ring alignment to 64 bytes from 256
bytes as documented in datasheet.
o Added check to ensure TX/RX ring reside within a 4GB boundary.
Since TX/RX ring shares the same high address register they
should have the same high address.
o TX/RX side bus_dmamap_load_mbuf_sg(9) support.
o Add lock assertion to vge_setmulti().
o Add RX spare DMA map to recover from DMA map load failure.
o Add optimized RX buffer handler, vge_discard_rxbuf which is
activated when vge(4) sees bad frames.
o Don't blindly update VGE_RXDESC_RESIDUECNT register. Datasheet
says the register should be updated only when number of
available RX descriptors are multiple of 4.
o Use __NO_STRICT_ALIGNMENT instead of defining VGE_FIXUP_RX which
is only set for i386 architecture. Previously vge(4) also
performed expensive copy operation to align IP header on amd64.
This change should give RX performance boost on amd64
architecture.
o Don't reinitialize controller if driver is already running. This
should reduce number of link state flipping.
o Since vge(4) drops a driver lock before passing received frame
to upper layer, make sure vge(4) is still running after
re-acquiring driver lock.
o Add second argument count to vge_rxeof(). The argument will
limit number of packets could be processed in RX handler.
o Rearrange vge_rxeof() not to allocate RX buffer if received
frame was bad packet.
o Removed if_printf that prints DMA map failure. This type of
message shouldn't be used in fast path of driver.
o Reduce number of allowed TX buffer fragments to 6 from 7. A TX
descriptor allows 7 fragments of a frame. However the CMZ field
of descriptor has just 3bits and the controller wants to see
fragment + 1 in the field. So if we have 7 fragments the field
value would be 0 which seems to cause unexpected results under
certain conditions. This change should fix occasional TX hang
observed on vge(4).
o Simplify vge_stat_locked() and add number of available TX
descriptor check.
o vge(4) controllers lack padding short frames. Make sure to fill
zero for the padded bytes. This closes unintended information
disclosure.
o Don't set VGE_TDCTL_JUMBO flag. Datasheet is not clear whether
this bit should be set by driver or write-back status bit after
transmission. At least vendor's driver does not set this bit so
remove it. Without this bit vge(4) still can send jumbo frames.
o Don't start driver when vge(4) know there are not enough RX
buffers.
o Remove volatile keyword in RX descriptor structure. This should
be handled by bus_dma(9).
o Collapse two 16bits member of TX/RX descriptor into single 32bits
member.
o Reduce number of RX descriptors to 252 from 256. The
VGE_RXDESCNUM is 16bits register but only lower 8bits are valid.
So the maximum number of RX descriptors would be 255. However
the number of should be multiple of 4 as controller wants to
update 4 RX descriptors at a time. This limits the maximum
number of RX descriptor to be 252.
Tested by: Dewayne Geraghty (dewayne.geraghty <> heuristicsystems dot com dot au)
Carey Jones (m.carey.jones <> gmail dot com)
Yoshiaki Kasahara (kasahara <> nc dor kyushu-u dot ac dotjp)
VT6122 gigabit ethernet chip and integrated 10/100/1000 copper PHY.
The vge driver has been added to GENERIC for i386, pc98 and amd64,
but not to sparc or ia64 since I don't have the ability to test
it there. The vge(4) driver supports VLANs, checksum offload and
jumbo frames.
Also added the lge(4) and nge(4) drivers to GENERIC for i386 and
pc98 since I was in the neighborhood. There's no reason to leave them
out anymore.
