sdchi encapsulates a generic SD Host Controller logic that relies on
actual hardware driver for register access.
sdhci_pci implements driver for PCI SDHC controllers using new SDHCI
interface
No kernel config modifications are required, but if you load sdhc
as a module you must switch to sdhci_pci instead.
- Use device_printf() and device_get_unit() instead of storing the unit
number in the softc.
- Remove use of explicit bus space handles and tags.
- Remove the global dpt_softcs list and use devclass_get_device() instead.
- Use pci_enable_busmaster() rather than frobbing the PCI command register
directly.
Tested by: no one
- Use device_printf() and device_get_unit() instead of storing the unit
number in the softc.
- Remove use of explicit bus space handles and tags.
- Return an errno value from bt_eisa_attach() if an error occurs rather
than -1.
- Use BUS_PROBE_DEFAULT rather than 0.
Tested by: no one
- Move 'free_scbs' into the softc rather than having it be a global list
and convert it to an SLIST instead of a hand-rolled linked-list.
- Use device_printf() and device_get_unit() instead of storing the unit
number in the softc.
- Remove use of explicit bus space handles and tags.
- Don't call device_set_desc() in the pccard attach routine, instead
set a default description during the pccard probe if the matching
product doesn't have a name.
Tested by: no one
- Use device_printf() and device_get_unit() instead of storing the unit
number in the softc.
- Remove use of explicit bus space handles and tags.
- Compare pointers against NULL.
- Let new-bus allocate a softc rather than doing it by hand.
Tested by: no one
- Use device_printf() and device_get_nameunit() instead of adw_name().
- Remove use of explicit bus space handles and tags.
- Use pci_enable_busmaster() rather than frobbing the PCI command register
directly.
- Use the softc provided by new-bus rather than allocating a new one.
Tested by: no one
stashed away in ath_node.
As much as I tried to stuff that behind the ATH_NODE lock, unfortunately
the locking is just too plain hairy (for me! And I wrote it!) to do
cleanly. Hence using atomics here instead of a lock. The ATH_NODE lock
just isn't currently used anywhere besides the rate control updates.
If in the future everything gets migrated back to using a single ATH_NODE
lock or a single global ATH_TX lock (ie, a single TX lock for all TX and
TX completion) then fine, I'll remove the atomics.
it run out of multiple concurrent contexts.
Right now the ath(4) TX processing is a bit hairy. Specifically:
* It was running out of ath_start(), which could occur from multiple
concurrent sending processes (as if_start() can be started from multiple
sending threads nowdays.. sigh)
* during RX if fast frames are enabled (so not really at the moment, not
until I fix this particular feature again..)
* during ath_reset() - so anything which calls that
* during ath_tx_proc*() in the ath taskqueue - ie, TX is attempted again
after TX completion, as there's now hopefully some ath_bufs available.
* Then, the ic_raw_xmit() method can queue raw frames for transmission
at any time, from any net80211 TX context. Ew.
This has caused packet ordering issues in the past - specifically,
there's absolutely no guarantee that preemption won't occuring _during_
ath_start() by the TX completion processing, which will call ath_start()
again. It's a mess - 802.11 really, really wants things to be in
sequence or things go all kinds of loopy.
So:
* create a new task struct for TX'ing;
* make the if_start method simply queue the task on the ath taskqueue;
* make ath_start() just be called by the new TX task;
* make ath_tx_kick() just schedule the ath TX task, rather than directly
calling ath_start().
Now yes, this means that I've taken a step backwards in terms of
concurrency - TX -and- RX now occur in the same single-task taskqueue.
But there's nothing stopping me from separating out the TX / TX completion
code into a separate taskqueue which runs in parallel with the RX path,
if that ends up being appropriate for some platforms.
This fixes the CCMP/seqno concurrency issues that creep up when you
transmit large amounts of uni-directional UDP traffic (>200MBit) on a
FreeBSD STA -> AP, as now there's only one TX context no matter what's
going on (TX completion->retry/software queue,
userland->net80211->ath_start(), TX completion -> ath_start());
but it won't fix any concurrency issues between raw transmitted frames
and non-raw transmitted frames (eg EAPOL frames on TID 16 and any other
TID 16 multicast traffic that gets put on the CABQ.) That is going to
require a bunch more re-architecture before it's feasible to fix.
In any case, this is a big step towards making the majority of the TX
path locking irrelevant, as now almost all TX activity occurs in the
taskqueue.
Phew.
Right now processing a full 512 frame queue takes quite a while (measured
on the order of milliseconds.) Because of this, the TX processing ends up
sometimes preempting the taskqueue:
* userland sends a frame
* it goes in through net80211 and out to ath_start()
* ath_start() will end up either direct dispatching or software queuing a
frame.
If TX had to wait for RX to finish, it would add quite a few ms of
additional latency to the packet transmission. This in the past has
caused issues with TCP throughput.
Now, as part of my attempt to bring sanity to the TX/RX paths, the first
step is to make the RX processing happen in smaller 'parts'. That way
when TX is pushed into the ath taskqueue, there won't be so much latency
in the way of things.
The bigger scale change (which will come much later) is to actually
process the frames in the ath_intr taskqueue but process _frames_ in
the ath driver taskqueue. That would reduce the latency between
processing and requeuing new descriptors. But that'll come later.
The actual work:
* Add ATH_RX_MAX at 128 (static for now);
* break out of the processing loop if npkts reaches ATH_RX_MAX;
* if we processed ATH_RX_MAX or more frames during the processing loop,
immediately reschedule another RX taskqueue run. This will handle
the further frames in the taskqueue.
This should have very minimal impact on the general throughput case,
unless the scheduler is being very very strange or the ath taskqueue
ends up spending a lot of time on non-RX operations (such as TX
completion.)
and Sierra Wireless MC8790V. Also implement the .ucom_poll method.
Note: This makes it possible to use lqr/echo in ppp.conf. And it
resolves ppp hanging during the PPp> phase.
Reviewed by: hps
MFC after: 1 week
- Disable the support for the second channel on twin-channel EISA cards as
the current incarnation can't possibly work correctly (it hasn't worked
since switching to new-bus where new-bus allocates the softc). If anyone
bothers to test this again it can be fixed properly and brought back.
- Use device_printf() and device_get_nameunit() instead of adv_name().
- Remove use of explicit bus space handles and tags.
- Use PCI bus accessors and helper routines rather than accessing
config registers directly.
- Handle failures from adv_attach().
Tested by: no one (hope it works)
virtqueue: Fix non-indirect virtqueues
We really must walk the entire descriptor chain in order
to append the to be free'd chain to the existing free
chain.
Submitted by: Bryan Venteicher (bryanv@daemoninthecloset.org)
Reported by: cognet
This change will enable IPMI access on 5717/5718/5719/5720 and 5761
controllers. Because ASF is not available when APE firmware is
present, bge_allow_asf tunable is ignored when driver detects APE
firmware. Also bge(4) no longer performs two resets(one blind
reset and the other reset with firmware in mind) in device attach.
Now bge(4) performs a reset with enough information in bge_reset().
The APE firmware also needs special handling to make suspend/resume
work but it was not implemented yet.
With this change, bge(4) should work on any 5717/5718/5719/5720
controllers. Special thanks to Mike Hibler at Emulab who setup
remote debugging on Dell R820. Without his help I couldn't be able
to address several issues happened on Dell Rx20 systems. And many
thanks to Broadcom for continuing to support FreeBSD!
Submitted by: davidch (initial version)
H/W donated by: Broadcom
Tested by: many
Tested on: Del R820/R720/R620/R420/R320 and HP Proliant DL 360 G8
handling(jumbo, wire speed etc) in brgphy_reset(). Touching
BRGPHY_MII_AUXCTL register seems to confuse APE firmware such that
it couldn't establish a link.
BGE_PCI_PCISTATE register before issuing global reset. After
issuing reset, it reads BGE_PCI_PCISTATE register again and
compares the saved register value and current value. It was used to
know whether the global reset operation was completed or not.
Unfortunately, this logic caused several issues on recent BCM5717/
5718/5719 and BCM5720 controllers. It seems APE firmware accesses
some registers while global reset is in progress such that reading
BGE_PCI_PCISTATE register after reset does not yield old pre-reset
state value. This resulted in consuming too much time in global
reset and sometimes it couldn't successfully complete reset.
The BGE_MISCCFG_RESET_CORE_CLOCKS of BGE_MISC_CFG register is
self-clearing bit so driver is able to know the reset completion.
But the core-lock reset will disable indirect/flat/standard access
modes such that driver cannot poll BGE_MISCCFG_RESET_CORE_CLOCKS
bit of BGE_MISC_CFG register. So just wait enough time for
core-clock reset to complete.
Data sheet says driver should wait 100us for PCI/PCI-X devices and
100ms for PCIe devices. I chose 1ms for PCI/PCI-X since this value
was used for many years in bge(4). For PCIe devices, use 100ms as
recommended by data sheet.
bge_chipinit() also cleared BGE_MAC_MODE register which shall clear
firmware configured mode information. I think this will result in
losing ASF/IPMI link in device attachment. Let bge_reset() honor
firmware configured BGE_MAC_MODE register and don't announce driver
is UP in bge_reset(). Firmware should have control over driver until
it's fully initialized by driver.
While I'm here, enable workaround for PCI-X BCM5704 A0 in
bge_reset(). This will prevent internal arbitration logic from
switching to the other DMA engine after a retry cycle.
set not-NULL during SIM registration and set to UMASS_GONE on destruction.
Debug messages there look broken for at least 9 years, as they dereference
softc value that was just checked to be equal to NULL.
- Remove magic pointer value UMASS_GONE and use simple NULL instead.
Found by: Clang Static Analyzer
While here, change ISCI_LED to ISCI_PHY since conceptually the hardware
ties the LEDs to a phy and the LEDs for a given phy cannot be controlled
independently.
Submitted by: Paul Maulberger <Paul.Maulberger at gmx.de> (with modifications)
This lets userspace read arbitrary information from the SFP+ modules
etc. on this bus.
Reading multiple bytes in the same transaction isn't possible right now.
I'll update the driver once the chip's firmware supports this.
MFC after: 3 days
that requires 10ms delay after device reset. Because that code was
there from day 1, I guess it was added to give enough settlement
time after updating BGE_MAC_MODE register.
The recommended delay time for BGE_MAC_MODE after updating is 40us
and it was already done in r241219.
The VCPU(Virtual CPU) of BCM5906 is used to provide a mechanism to
control the bootcode execution and to pick up configuration data
stored inside the EEPROM.
The bootcode of BCM5906 will check the BGE_VCPU_STATUS_DRV_RESET
bit to decide which booting procedure to choose.
Data sheet indicates the VCPU of BCM5906 should set
BGE_VCPU_STATUS_DRV_RESET bit *before* VCPU reset or global reset.
water mark to 256 bytes. Otherwise controller will encounter DMA
write under run errors and would result in RX DMA hang. If the
maximum payload size is 128 bytes, the water mark is set to 128
bytes as usual.
While here, set maximum read request size to 2048 for BCM5719/BCM5720.
For other PCIe devices, use 4096. And reprogram the maximum read
request size whenever device reset is performed.
make analog input loopback and dual-stream playback work by enabling
signal mixing by nid 22, as it should be according to info returned by
the CODEC. Otherwise pin nid 28 receives only signal from DAC nid 16.
PR: kern/169124
MFC after: 1 week
the ATH_TXQ_* macros.
* Introduce the new macros;
* rename the TID queue and TID filtered frame queue so the compiler
tells me I'm using the wrong macro.
These should correspond 1:1 to the existing code.
to 32k swamped the controller causing firmware hangs. Instead, round
requests smaller than 64k up to the next power of 2 as a general rule.
To handle the one known special case of a command that accepts a 12k
buffer returning a 24k-ish reply, round requests between 8k and 16k up
to 32k rather than 16k. The result is that commands less than 8k should
now be rounded up to a smaller size (either 4k or 8k) rather than 32k.
PR: kern/155658
Tested by: Andreas Longwitz
MFC after: 1 week
AR5416 and AR9280, but leave it disabled by default.
TL;DR: don't enable this code at all unless you go through the process
of getting the NIC re-certified. This is purely to be used as a
reference and NOT a certified solution by any stretch of the imagination.
The background:
The AR5112 RF synth right up to the AR5133 RF synth (used on the AR5416,
derivative is used for the AR9130/AR9160) only implement down to 2.5MHz
channel spacing in 5GHz. Ie, the RF synth is programmed in steps of 2.5MHz
(or 5, 10, 20MHz.) So they can't represent the quarter rate channels
in the 4.9GHz PSB (which end in xxx2MHz and xxx7MHz). They support
fractional spacing in 2GHz (1MHz spacing) (or things wouldn't work,
right?)
So instead of doing this, the RF synth programming for the AR5112 and
later code will round to the nearest available frequency.
If all NICs were RF5112 or later, they'll inter-operate fine - they all
program the same. (And for reference, only the latest revision of the
RF5111 NICs do it, but the driver doesn't yet implement the programming.)
However:
* The AR5416 programming didn't at all implement the fractional synth
work around as above;
* The AR9280 programming actually programmed the accurate centre frequency
and thus wouldn't inter-operate with the legacy NICs.
So this patch:
* Implements the 4.9GHz PSB fractional synth workaround, exactly as the
RF5112 and later code does;
* Adds a very dirty workaround from me to calculate the same channel
centre "fudge" to the AR9280 code when operating on fractional frequencies
in 5GHz.
HOWEVER however:
It is disabled by default. Since the HAL didn't implement this feature,
it's highly unlikely that the AR5416 and AR928x has been tested in these
centre frequencies. There's a lot of regulatory compliance testing required
before a NIC can have this enabled - checking for centre frequency,
for drift, for synth spurs, for distortion and spectral mask compliance.
There's likely a lot of other things that need testing so please don't
treat this as an exhaustive, authoritative list. There's a perfectly good
process out there to get a NIC certified by your regulatory domain, please
go and engage someone to do that for you and pay the relevant fees.
If a company wishes to grab this work and certify existing 802.11n NICs
for work in these bands then please be my guest. The AR9280 works fine
on the correct fractional synth channels (49x2 and 49x7Mhz) so you don't
need to get certification for that. But the 500KHz offset hack may have
the above issues (spur, distortion, accuracy, etc) so you will need to
get the NIC recertified.
Please note that it's also CARD dependent. Just because the RF synth
will behave correctly doesn't at all mean that the card design will also
behave correctly. So no, I won't enable this by default if someone
verifies a specific AR5416/AR9280 NIC works. Please don't ask.
Tested:
I used the following NICs to do basic interoperability testing at
half and quarter rates. However, I only did very minimal spectrum
analyser testing (mostly "am I about to blow things up" testing;
not "certification ready" testing):
* AR5212 + AR5112 synth
* AR5413 + AR5413 synth
* AR5416 + AR5113 synth
* AR9280
net80211 node power save state.
* Add an ATH_NODE_UNLOCK_ASSERT() check
* Add a new node field - an_is_powersave
* Pause/unpause the queue based on the node state
* Attempt to handle net80211 concurrency issues so the queue
doesn't get paused/unpaused more than once at a time from
the net80211 power save code.
Whilst here (and breaking my usual rule), set CLRDMASK when a queue
is unpaused, regardless of whether the queue has some pending traffic.
This means the first frame from that TID (now or later) will hvae
CLRDMASK set.
Also whilst here, bump the swretrymax counters whenever the
filtered frames code expires a frame. Again, breaking my rule, but
this is just a statistics thing rather than a functional change.
This doesn't fix ps-poll (but it doesn't break it too much worse
than it is at the present) or correcting the TID updates.
That's next on the list.
Tested:
* AR9220 AP (Atheros AP96 reference design)
* Macbook Pro and LG Optimus 1 Android phone, both setting
and clearing power save state (but not using PS-POLL.)
tree used it incorrectly, which lead to inaccurate overrated
if_obytes accounting. The drbr(9) used to update ifnet stats on
drbr_enqueue(), which is not accurate since enqueuing doesn't
imply successful processing by driver. Dequeuing neither mean
that. Most drivers also called drbr_stats_update() which did
accounting again, leading to doubled if_obytes statistics. And
in case of severe transmitting, when a packet could be several
times enqueued and dequeued it could have been accounted several
times.
o Thus, make drbr(9) API thinner. Now drbr(9) merely chooses between
ALTQ queueing or buf_ring(9) queueing.
- It doesn't touch the buf_ring stats any more.
- It doesn't touch ifnet stats anymore.
- drbr_stats_update() no longer exists.
o buf_ring(9) handles its stats itself:
- It handles br_drops itself.
- br_prod_bytes stats are dropped. Rationale: no one ever
reads them but update of a common counter on every packet
negatively affects performance due to excessive cache
invalidation.
- buf_ring_enqueue_bytes() reduced to buf_ring_enqueue(), since
we no longer account bytes.
o Drivers handle their stats theirselves: if_obytes, if_omcasts.
o mlx4(4), igb(4), em(4), vxge(4), oce(4) and ixv(4) no longer
use drbr_stats_update(), and update ifnet stats theirselves.
o bxe(4) was the most correct driver, it didn't call
drbr_stats_update(), thus it was the only driver accurate under
moderate load. Now it also maintains stats itself.
o ixgbe(4) had already taken stats from hardware, so just
- drop software stats updating.
- take multicast packet count from hardware as well.
o mxge(4) just no longer needs NO_SLOW_STATS define.
o cxgb(4), cxgbe(4) need no change, since they obtain stats
from hardware.
Reviewed by: jfv, gnn
bits under #ifdef _KERNEL but leave definitions for various structures
defined by standards ($PIR table, SMAP entries, etc.) available to
userland.
- Consolidate duplicate SMBIOS table structure definitions in ipmi(4)
and smbios(4) in <machine/pc/bios.h> and make them available to
userland.
MFC after: 2 weeks
This doesn't specifically fix the issue(s) i'm seeing in this 2GHz
environment (where setting/increasing spur immunity causes OFDM restart
errors to skyrocket through the roof; but leaving it at 0 would leave
the environment cleaner..)
Pointy-hat-to: me, for committing this broken code in the first place.
- Use a dedicated task to handle deferred transmits from the if_transmit
method instead of reusing the existing per-queue interrupt task.
Reusing the per-queue interrupt task could result in both an interrupt
thread and the taskqueue thread trying to handle received packets on a
single queue resulting in out-of-order packet processing and lock
contention.
- Don't define ixgbe_start() at all where if_transmit is used.
Tested by: Vijay Singh
Reviewed by: jfv
MFC after: 2 weeks
Device nodes are in the format /dev/led/isci.busX.portY.locate.
Sponsored by: Intel
Requested by: Paul Maulberger <paul dot maulberger at gmx dot de>
MFC after: 1 week
things like EAPOL frames make it out.
After a whole bunch of hacking/testing, I discovered that they weren't
being early-dropped by the stack (but I should look at ensuring that
later..) but were even making to the hardware transmit queue.
They were mostly even being received by the remote end. However, the
remote end was completely ignoring them.
This didn't happen under 150-170MBit TCP tests as I'm guessing the TX
queue stayed very busy and the STA didn't do any scanning. However, when
doing 100Mbit/s of TCP traffic, the STA would do background scanning -
which involves it coming in and out of powersave mode with the AP.
Now, this is a total and utter hack around the real problems, which are:
* I need to implement proper power save handling and integrate it into
the filtered frames support, so the driver/stack doesn't send frames
whilst the station is actually in sleep;
* .. but frames were actually making it to the STA (macbook pro) and
the AP did receive an ACK; but a tcpdump on the receiving side showed
the EAPOL frame never made it. So the stack was dropping it for
some reason;
* Importantly - the EAPOL frames are currently going into the non-QoS
TID, which maps to the BE queue and is susceptible to that queue being
busy doing other things, but;
* There's other traffic going on in the non-QoS TID from other contexts
when scanning is going on and it's possible there's some races causing
sequence number/IV issues, but;
* Importantly importantlly, I think the interaction with TID 16 multicast
traffic in power save mode is causing issues - since I -believe- the
sequence number space being used by the EAPOL frames on TID 16 overlaps
with the multicast frames that have sequence numbers allocated and
are then stuffed on the cabq. Since with EAPOL frames being in TID 16
and queued to the BE queue, it's going to be waiting to be serviced
with all of the aggregate traffic going on - and if the CABQ gets
emptied beforehand, those TID 16 multicast frames with sequence numbers
will go out beforehand.
Now, there's quite likely a bunch of "stuff happening slightly out of
sequence" going on due to the nature of the TX path (read: lots of
overlapping and concurrent ath_start() and ath_raw_xmit() calls going
on, sigh) but I thought I had caught them all and stuffed each TID TX
behind a lock (that lasted as long as it needed to in order to get
the frame onto the relevant destination queue - thus keeping things
in order.)
Unfortunately the last problem is the big one and I'm going to stare at
it some more. If it _is_
So this is a work around for now to ensure that EAPOL frames actually
make it out before any other stuff in the non-QoS TID and HOPEFULLY
before the CABQ gets active.
I'm now going to spend a little time in the TX path figuring out exactly
why the sender is rejecting things. There's two (well, three if you count
EAPOL contents invalid) possibilities:
* The sequence number is out of order (ie, something else like the multicast
traffic on CABQ) is going out first on TID 16;
* The CCMP IV is out of order (similar to above - but less likely, as the
TX key for multicast traffic is different to unicast traffic);
* EAPOL contents strangely invalid.
AP: Ubiquiti RSPRO, AR9160/AR9220 NICs
STA: Macbook Pro, Broadcom 11n NIC
lock may be held.
Kim reported that the TID lock wasn't held when ath_tx_update_clrdmask()
was called. Well, the underlying hardware TXQ for that TID.
I'm betting it's the cabq stuff. ath_tx_xmit_normal() can be called
for both real and software cabq. For software cabq, the real destination
txq is different to the txq. So, the lock check will fail.
Reported by: Kim Culhan <w8hdkim@gmail.com>
offline in response to a INQUIRY command that does not retreive vital
product data(I personally have observed the behaviour on an Adaptec 2405
and a 5805). Force the peripheral qualifier to "connected" so that upper
layers correctly recognize that a disk is present.
This bug was uncovered by r216236. Prior to that fix, aac(4) was
accidentally clearing the peripheral qualifier for all inquiry commands.
This fixes an issue where passthrough devices were not created for
disks behind aac(4) controllers suffering from the bug. I have
verified that if a disk is not present that we still properly detect
that and not create the passthrough device.
Sponsored by: Sandvine Incorporated
MFC after: 1 week
LUNs respectively. This removes a huge number of error messages
from CAM during bus scans.
Copied almost verbatim from mav's commit r237460.
Submitted by: Mike Tancsa <mike at sentex dot net>
MFC after: 3 days
immediately panics on boot with INVARIANTS enabled. The driver already
clearly expects to be able to recurse on this mutex - the main I/O
is always recursing on this lock.
Reported and tested by: Mike Tancsa <mike at sentex dot net>
MFC after: 1 week
This should eventually be unified with ATH_DEBUG() so I can get both
from one macro; that may take some time.
Add some new probes for TX and TX completion.
* use the correct frame status - although the completion descriptor is
the _last_ in the frame/aggregate, the status is currently stored in
the _first_ buffer.
* Print out ath_buf specific fields once, not per descriptor in an ath_buf.
at r230551.
Also while there, make sense polling use reported for each node separately
instead of reporting accumulated total status.
Submitted by: Barbara <barbara.freebsd@gmail.com> (1)
MFC after: 3 days
it's disabled.
The previous commit to enable CLRDMASK setting didn't do it at all
correctly for non-aggregate sessions - so the CLRDMASK bit would be
cleared and never re-set.
* move ath_tx_update_clrdmask() to be called by functions that setup
descriptors and queue frames to the hardware, rather than scattered
everywhere.
* Force CLRDMASK to be set on all non-aggregate session frames being
transmitted.
* Use ath_tx_normal_comp() now on non-aggregate sessoin frames
that are queued via ath_tx_xmit_normal(). That way the TID hwq is
updated and they can trigger (eventual) filter frame queue resets
and software retransmits.
There's still a bit more work to do in this area to reverse the silly
short-sightedness on my part, however it's likely going to be better
to fix this now than just reverting the patch.
Thanks to people on the freebsd-wireless@ mailing list for promptly
pointing this out.
adapter->dropped_pkts instead of if_ierrors because if_ierrors is
overwritten by hw stats collection.
Submitted by: Andrew Boyer <aboyer@averesystems.com>
Reviewed by: Jack F Vogel <jfv@freebsd.org>
MFC after: 2 weeks
gone rule. Optimise use of channels so that when a channel
is not ready another channel is used. Instead of using the SOF interrupt
use the system timer to drive the host statemachine. This might
give lower throughput and higher latency, but reduces the CPU usage
significantly. The DWC OTG host mode support should not be considered
for serious USB host controller applications. Some problems are still
seen with LOW speed USB devices.
frames to occur.
* Create a new function which will set the bf_flags CLRDMASK bit
if required.
* For raw frames, always set CLRDMASK.
* For BAR, ADDBA frames, always set CLRDMASK.
* For everything else, check if CLRDMASK needs to be set before
calling tx_setds() or tx_setds11n().
* When unpausing a queue or drain/resetting it, set tid->clrdmask=1
just to ensure traffic starts flowing.
What I need to do:
* Modify that function to _clear_ the CLRDMASK if it's not required,
or retried frames may have CLRDMASK set when they don't need to.
(Which isn't a huge deal, but..)
Whilst I'm here:
* ath_tx_normal_xmit() should really act like the AMPDU session TX
functions - any incomplete frames will end up being assigned
ath_tx_normal_comp() which will decrement tid->hwq_depth - but that
won't have been incremented.
So whilst I'm here, add a comment to do that.
* Fix the debug print function to be slightly clearer about things;
it's not a good sign when I can't interpret my own debugging output.
I've done some testing on AR9280/AR5416/AR9160 STA and AP modes.
stack.
There are unfortunately quite a few odd cases in BAR TX and BAR TX
retransmission that I haven't yet fully diagnosed. So for now, add
this work-around so the resume() function isn't called too often,
decrementing pause to -1 (and causing things to stay paused.)
a 4kb buffer if a request uses a buffer size of 0. (The Linux ioctl path
already did this.)
PR: kern/155658
Submitted by: Andreas Longwitz
MFC after: 1 week
#defines. This also has the advantage that it makes the names more
compact, iand also allows us to correct the non-uniform naming of
the PCIM_LINK_* defines, making them all consistent amongst themselves.
This is a mostly mechanical rename:
s/PCIR_EXPRESS_/PCIER_/g
s/PCIM_EXP_/PCIEM_/g
s/PCIM_LINK_/PCIEM_LINK_/g
When this is MFC'd, #defines will be added for the old names to assist
out-of-tree drivers.
Discussed with: jhb
MFC after: 1 week
is done.
The aggregate path was definitely accessing 'ts' before it was actually
being assigned.
This had the side effect of over-filtering frames, since occasionally that
bit would be '1'.
Whilst here, do the same thing in the non-aggregate completion function -
as calling the filter function may also invalidate bf.
Pointy hat to: adrian, for not noticing this over many, many code reviews.
This fixes issue in nvmecontrol(8), where clang throws a cast-align
warning when casting a __packed structure pointer to a uint32_t
pointer as part of printing raw hex output.
Reported by: dhw
The hardware can optionally "filter" frames if successive transmissions
to a given node (ie, "entry in the keycache") fail. That way the hardware
can implement a kind of early abort of all the other frames queued to
that destination, rather than simply trying to TX each frame to that
destination (and failing.)
The background:
* If a frame comes back as being filtered, the hardware didn't try to
TX it (or it was outside the TX burst opportunity.) So, take it as a hint
that some (but not all, see below) frames to the destination may be
filtered.
* If the CLRDMASK bit is set in a TX descriptor, the "filter to this
destination" bit in the keycache entry is cleared and TX to that host
will be unconditionally retried.
* Right now everything has the CLRDMASK bit set, so filtered frames
tend to be aggregates and frames that fall outside of the WME burst
window. It was a bit worse in the past as I had messed up the TX
flags and CLRDMASK wasn't being set on aggregate frames.
The annoying bits:
* It's easy (ish) to do for aggregate session frames - firstly, they
can be retried in any order as long as they're within the BAW, and
there's already a bunch of infrastructure tracking how many frames
the TID has queued to the hardware (tid->hwq_depth.) However, for
frames that bypassed the software queue, hwq_depth doesn't get
incremented. I'll fix that in a subsequent commit.
* For non-aggregate session frames, the only retries that can occur
are ones for sequence numbers that hvaen't successfully been TXed yet.
Since there's no re-ordering going on in non-aggregate sessions, if any
subsequent seqno frames make it out, any filtered frames before that
seqno need to be dropped.
Hence why this initially is just for aggregate session frames.
* Since there may be intermediary frames to the destination that
have CLRDMASK set - for example, any directly dispatched management
frames to that destination - it's possible that there will be some
filtered frames followed up by some non filtered frames. Thus,
it can't be assumed that once you see a filtered frame for the given
destination node, all subsequent frames for all TIDs will be filtered.
Ok, with that in mind:
* Create a per-TID filtered frame queue for frames that the hardware
returns as filtered.
* Track filtered frames per-tid, rather than per-node. It just makes
the locking much easier.
* When a filtered frame appears in the completion function, the node
transitions to "filtered", and all subsequent completed error frames
(filtered or otherwise) are put on the filtered frame queue. The TID
is paused once (during the transition from non-filtered to filtered).
* If a filtered frame retry count exceeds SWMAX_RETRIES, a BAR should be
sent.
* Once all the frames queued to the hardware for the given filtered frame
TID, transition back from filtered frame to non-filtered frame, which
means pre-pending all the filtered frames onto the head of the software
queue, clearing the filtered frame state and unpausing the TID.
Things get quite hairy around handling completion (aggr, non-aggr, norm,
direct-dispatched frames to a hardware queue); whether it's an "error",
"cleanup" or "BAR" state as well as filtered, which order to do things
in (eg do filtered BEFORE checking for BAR, as the filter completion
may be needed to actually transmit a BAR frame.)
This work has definitely reminded me that I have to tidy up all the locking
and remove some of the ridiculous lock/unlock/lock/unlock going on in the
completion functions.
It's also reminded me that I should really split out TID versus hardware TXQ
locking, even if the underlying locking is still the destination hardware TXQ.
Finally, this is all pre-requisite for working on AP mode power save support
(PS-POLL, uAPSD) as well as improving performance to misbehaving nodes (as
they can transition into filter mode, stopping any TX until everything has
caught up.)
Finally (ish) - this should also be done for non-aggregate sessions as
there are still plenty of laptops and mobile devices that don't speak
802.11n but do wish for stable, useful power save AP support where packets
aren't simply dropped. This requires software retransmission for
non-aggregate sessions to be implemented, which includes the caveats I've
mentioned above.
Finally finally - this doesn't yet do anything about the CLRDMASK bit in the
TX descriptor. That's still unconditionally set to 1. I'll debug the
current work (mostly ensuring I haven't busted up the hairy transitions
between BAR, filtered, error (all frames in an aggregate failing) and
cleanup (when transitioning from aggregation -> non-aggregation.))
Finally finally finally - this is all original work by yours truely, rather
than ported from the Atheros internal driver codebase or Linux ath9k.
Tested:
* AR9280, AR5416 in STA mode
* AR9280, AR9130 in hostap mode
* Lots and lots of iperf testing in very marginal and non-marginal conditions,
complete with inducing filtered frames + BAR TX conditions.
support to FreeBSD. A full description of the overall functionality
being added is below. nvmexpress.org defines NVM Express as "an optimized
register interface, command set and feature set fo PCI Express (PCIe)-based
Solid-State Drives (SSDs)."
This commit adds nvme(4) and nvd(4) driver source code and Makefiles
to the tree.
Full NVMe functionality description:
Add nvme(4) and nvd(4) drivers and nvmecontrol(8) for NVM Express (NVMe)
device support.
There will continue to be ongoing work on NVM Express support, but there
is more than enough to allow for evaluation of pre-production NVM Express
devices as well as soliciting feedback. Questions and feedback are welcome.
nvme(4) implements NVMe hardware abstraction and is a provider of NVMe
namespaces. The closest equivalent of an NVMe namespace is a SCSI LUN.
nvd(4) is an NVMe consumer, surfacing NVMe namespaces as GEOM disks.
nvmecontrol(8) is used for NVMe configuration and management.
The following are currently supported:
nvme(4)
- full mandatory NVM command set support
- per-CPU IO queues (enabled by default but configurable)
- per-queue sysctls for statistics and full command/completion queue
dumps for debugging
- registration API for NVMe namespace consumers
- I/O error handling (except for timeoutsee below)
- compilation switches for support back to stable-7
nvd(4)
- BIO_DELETE and BIO_FLUSH (if supported by controller)
- proper BIO_ORDERED handling
nvmecontrol(8)
- devlist: list NVMe controllers and their namespaces
- identify: display controller or namespace identify data in
human-readable or hex format
- perftest: quick and dirty performance test to measure raw
performance of NVMe device without userspace/physio/GEOM
overhead
The following are still work in progress and will be completed over the
next 3-6 months in rough priority order:
- complete man pages
- firmware download and activation
- asynchronous error requests
- command timeout error handling
- controller resets
- nvmecontrol(8) log page retrieval
This has been primarily tested on amd64, with light testing on i386. I
would be happy to provide assistance to anyone interested in porting
this to other architectures, but am not currently planning to do this
work myself. Big-endian and dmamap sync for command/completion queues
are the main areas that would need to be addressed.
The nvme(4) driver currently has references to Chatham, which is an
Intel-developed prototype board which is not fully spec compliant.
These references will all be removed over time.
Sponsored by: Intel
Contributions from: Joe Golio/EMC <joseph dot golio at emc dot com>
- Use callout(9) rather than timeout(9).
- Add a mutex as an I/O lock that protects the adapter and is used
for the I/O path.
- Add an sx lock as a configuration lock that protects the relationship
of configured volumes.
- Freeze the request queue when a DMA load is deferred with EINPROGRESS
and unfreeze the queue when the DMA callback is invoked.
- Explicitly poll the hardware while waiting to submit a command to
allow completed commands to free up slots in the command ring.
- Remove driver-wide 'initted' variable from mlx_*_fw_handshake() routines.
That state should be per-controller instead. Add it as an argument
since the first caller knows when it is the first caller.
- Remove explicit bus_space tag/handle and use bus_*() rather than
bus_space_*().
- Move duplicated PCI device ID probing into a mlx_pci_match() routine.
- Don't check for PCIM_CMD_MEMEN (the PCI bus will enable that when
allocating the resource) and use pci_enable_busmaster() rather than
manipulating the register directly.
Tested by: no one despite multiple requests (hope it works)
These are intended for software TX filtering support, where the NIC
decides there has been too many successive failues to a destination
and will filter it.
Although the filtering is done per-destination (via the keycache),
the state and queue is kept per-TID for now. It simplifies the overall
architecture design and locking.
Whilst here, add ATH_TID_UNLOCK_ASSERT().
* Don't treat high percentage failures as "sucessive failures" - high
MCS rates are very picky and will quite happily "fade" from low
to high failure % and back again within a few seconds. If they really
don't work, the aggregate will just plain fail.
* Only sample MCS rates +/- 3 from the current MCS. Sample will back off
quite quickly, so there's no need to sample _all_ MCS rates between
a high MCS rate and MCS0; there may be a lot of them.
* Modify the smoothing rate to be 75% rather than 95% - it's more adaptive
but it comes with a cost of being slightly less stable at times.
A per-node, hysterisis behaviour would be nicer.
(download microcode with offsets, save, and activate).
SATI translation layer was incorrectly using allocation length instead
of blocks, and was constructing the ATA command incorrectly.
Also change #define to specify that the 512 block size here is
specific for DOWNLOAD_MICROCODE, and does not relate to the device's
logical block size.
Submitted by: scottl (with small modifications)
MFC after: 3 days
trap checks (eg. printtrap()).
Generally this check is not needed anymore, as there is not a legitimate
case where curthread != NULL, after pcpu 0 area has been properly
initialized.
Reviewed by: bde, jhb
MFC after: 1 week
- Add constants for the rest of the fields in the PCI-express device
capability and control registers.
- Tweak some of the recently added PCI-e capability constants (always
use hex for offsets in config space, and include a shortened
version of the relevant register in the name of field constants).
MFC after: 1 week
I'm not sure where in the deep, distant past I found the AR_PHY_MODE
registers for half/quarter rate mode, but unfortunately that doesn't
seem to work "right" for non-AR9280 chips.
Specifically:
* don't touch AR_PHY_MODE
* set the PLL bits when configuring half/quarter rate
I've verified this on the AR9280 (5ghz fast clock) and the AR5416.
The AR9280 works in both half/quarter rate; the AR5416 unfortunately
only currently works at half rate. It fails to calibrate on quarter rate.
No, this isn't HT/5 and HT/10 support. This is the 11a half/quarter
rate support primarily used by the 4.9GHz and GSM band regulatory
domains.
This is definitely a work in progress.
TODO:
* everything in the last commit;
* lots more interoperability testing with the AR5212 half/quarter rate
support for the relevant chips;
* Do some interop testing on half/quarter rate support between _all_
the 11n chips - AR5416, AR9160, AR9280 (and AR9285/AR9287 when 2GHz
half/quarter rate support is coded up.)
used when running the chips in half/quarter rate.
This sets up some default parameters which are then overridden by the
driver (which manually configures things like slot timing at interface
start time.)
Although this is a copy-and-modify from the AR5212 HAL, I did peek
at the reference HAL and the ath9k driver to see what they did.
Ath9k in particular doesn't hard-code this - instead, their version
of ar5416InitUserSettings() does all of the relevant math.
TODO:
* do the math, not hard code things!
* fix the mac clock calculation for the AR9287; since it runs the
MAC clock at a higher rate, requiring all the duration calculations
to change;
* Do a whole lot more validation for half/quarter rates.
Obtained from: Qualcomm Atheros, Linux ath9k
Some of the math is a little wrong thanks to clocks in 11a mode running
at 44MHz when in fast clock mode (rather than 40MHz, which the chips
before AR9280 ran 11a in). That'll have to be addressed in a future commit.
This fixes the incorrect slot (and likely ACK/RTS timeout) values
which I see when enabling half/quarter rate support on the AR9280.
The resulting math matches the expected calculated default values.
of the DWC OTG is very simple in PIO mode, and we need to re-transmit
data when NAK is received among other things. We probably will need
to implement some kind of rate limitation on the NAK-ing.
drivers:
- Remove scsi_low_pisa.*, they were unused.
- Remove <compat/netbsd/physio_proc.h> and calls to the stubs in that
header. They were empty nops.
- Retire sl_xname and use device_get_nameunit() and device_printf() with
the underlying device_t instead.
- Remove unused {ct,ncv,nsp,stg}print() functions.
- Remove empty SOFT_INTR_REQUIRED() macro and the unused sl_irq member.
(1022) in HPET. But according to report they still haven't fixed problem
with level-triggered interrupts.
Make workaround used for earlier chipsets apply to this new ID also.
PR: amd64/171355
MFC after: 3 days
The DWC OTG host mode support should still be considered
experimental. Isochronous support for DWC OTG is not
fully implemented. Some code added derives from
Aleksandr Rybalko's dotg.c driver.
ath_buf and when forming a non-aggregate frame.
The non-11n setds function is called when TXing aggregate frames (and
yes, I should fix this!) and the non-11n TX aggregation code doesn't clear
the delimiter field. I figure it's nicer to do that.
This had the side effect of clearing HAL_TXDESC_CLRDMASK for a bunch of
frames, meaning they'd end up being potentially filtered if there were
an error. This is fine in the previous world as they'd just be
software retried but now that I'm working on filtered frames, these
descriptors would be endlessly retried until another valid frame would
come along that had CLRDMASK set.
do a BUS_DMASYNC_POSTWRITE over the DMA map. The way it currently is would
only do POSTREAD for read transactions.
Submitted by: Sascha Wildner
MFC after: 1 month
with the correct configuration.
Occasionally an aggregate TX would fail and the first frame would be
retransmitted as a non-AMPDU frame. Since bfs_aggr=1 and bfs_nframes > 1
(from the previous AMPDU attempt), the aggr completion function would be
called and be very confused about what's going on.
Noticed by: Kim <w8hdkim@gmail.com>
PR: kern/171394
NetBSD/pc98 was never merged into the main NetBSD tree and is no longer
developed. Adding locking to these drivers would have made the compat
shims hard to impossible to maintain, so remove the shims to ease
future changes.
These changes were verified by md5. Some additional shims can be removed
that do affect the compiled results that I will probably do in another
round.
Approved by: nyan (tentatively)
have been chosen based on the bit names in the PCI Express Base
Specification 3.0, and to match the predominant style of the existing
bit definitions.
MFC after: 1 week
twe_start() to simulate the behavior on 4.x where the driver dropped
spl to allow interrupts to run to free up space in the command
queue. Be careful to only poll if we are going to make at least
one more attempt to queue the current command. Also, when polling,
be careful to not call twe_startio() to queue more commands to avoid
recursion.
- Move the buffer for formatting AEN messages into the softc instead of
using a single driver-wide static buffer.
Requested by: scottl (1)
Tested by: Mike Tancsa @ Sentex
generator, found on IvyBridge and supposedly later CPUs, accessible
with RDRAND instruction.
From the Intel whitepapers and articles about Bull Mountain, it seems
that we do not need to perform post-processing of RDRAND results, like
AES-encryption of the data with random IV and keys, which was done for
Padlock. Intel claims that sanitization is performed in hardware.
Make both Padlock and Bull Mountain random generators support code
covered by kernel config options, for the benefit of people who prefer
minimal kernels. Also add the tunables to disable hardware generator
even if detected.
Reviewed by: markm, secteam (simon)
Tested by: bapt, Michael Moll <kvedulv@kvedulv.de>
MFC after: 3 weeks
Fix the strong signal diversity capability setting - I had totally
messed up the indentation.
Set the default values to match what's in the .ini for now, rather than
what values I had previously gleaned from places. This seems to work
quite well for the early AR5212 NICs I have. Of course, later NICs
have different PHYs and the radar configuration is very card/board
dependent..
Tested:
* ath1: AR5212 mac 5.3 RF5111 phy 4.1
ath1: 2GHz radio: 0x0023; 5GHz radio: 0x0017
This detects 1, 5, 25, 50, 75, 100uS pulses reliably (with no interference.)
However, 10uS pulses don't detect reliably. That may be around the
transition between short and long pulses so some further tuning may
improve things.
up on (at least) the AR5413.
The 30 second summary - if a CRC error frame comes in during PHY error
processing, that CRC bit will be set for all subsequent frames until
a non-CRC error frame is processed.
So to allow for accurate PHY error processing (Radar, and ANI on the AR5212
HAL chips) just tag the frame as being both CRC and PHY - let the driver
decide what to do with it.
PR: kern/169362
this case, allocate a plain mbuf and copy the frame into it, then send the
copy up the stack, leaving the original mbuf+cluster in place in the
receive ring for immediate re-use. This saves a trip through 2 of the
3 zones of the compound mbuf allocator, a trip through busdma, and a trip
through the 1 of the 3 mbuf destructors. For our load at Netflix, this can
lower CPU consumption by as much as 20%. The copy algorithm is based on
investigative work from Luigi Rizzo earlier in the year.
Reviewed by: jfv
Obtained from: Netflix
the interface is brought up. Without this, the boot time interrupt
round-robin assignment does not think the allocated interrupt resources
are active and leaves them assigned to CPU 0.
While here, add descriptive tags to each interrupt handler when MSI-X
is used.
Reviewed by: np
MFC after: 1 week
some HAL definitions rather than local definitions.
The original source (ath9k) pulled this stuff from the QCA driver and
removed the HAL_* prefix. I'm just restoring the correct order of things.
Obtained from: Qualcomm Atheros
This routine is intended only for commands such as INQUIRY where
the controller may fill out a smaller amount of data than allocated
by the host.
The end result of this bug was that isci(4) would report non-zero
resid for successful SCSI_UNMAP commands.
Sponsored by: Intel
MFC after: 3 days
In fact, bus_dmamem_alloc() happily NULLs the dmat pointer passed in,
before replacing it with its own.
This fixes a MIPS crash when kldload'ing if_ath/if_ath_pci -
bus_dmamap_destroy() was passed in a NULL dmat pointer and was doing
all kinds of very bad things.
Reviewed by: scottl
This is a re-implementation based on the reference carrier code
for the AR5413.
Tested:
* Pulse detection for AR5212 and AR5413, to ensure the
correct behaviour for both chips
PR: kern/170904
Obtained from: Qualcomm Atheros
The comparison assumes maxFirstepLevel is a count, rather than a maximum
value. The array is 3 entries in size however 'maxFirstepLevel' is 2.
This bug also exists in the AR5212 HAL.
MPSAFE.
- Preallocate a full set of QCBs during attach rather than allocating new
ones on demand to avoid allocations in the I/O path.
- Remove the explicit bus space tag/handle and use bus_*() on the
relevant 'struct resource' instead.
- Defer logical drive probing to an intrhook.
- Fix ida_detach() to detach and delete child devices (logical drives).
- Update the DMA handling to support EINPROGRESS by moving the work to
submit a mapped request into the bus_dma callback routine as well as
add support for freezing the queue when EINPROGRESS is encountered.
Tested by: Marco Steinbach coco executive-computing de
Terasic DE-4 board. Allow LED configuration to be set using loader
tunables, not just from userspace, and preconfigure LED 8 as a kernel
heartbeat. For now, this is a Nexus-attached, BERI-only driver, but it
could be used with other hard and soft cores on Altera FPGAs as well, in
principle.
Sponsored by: DARPA, AFRL
used with Terasic's DE-4 and other similar FPGA boards. This display
is 800x480 and includes a capacitive touch screen, multi-touch
gesture recognition, etc. This device driver depends on a Cambridge-
provided IP core that allows the MTL device to be hooked up to the
Altera Avalon SoC bus, and also provides a VGA-like text frame buffer.
Although it is compiled as a single device driver, it actually
implements a number of different device nodes exporting various
aspects of this multi-function device to userspace:
- Simple memory-mapped driver for the MTL 24-bit pixel frame buffer.
- Simple memory-mapped driver for the MTL control register set.
- Simple memory-mapped driver for the MTL text frame buffer.
- syscons attachment for the MTL text frame buffer.
This driver attaches directly to Nexus as is common for SoC device
drivers, and for the time being is considered BERI-specific, although
in principle it might be used with other hard and soft cores on
Altera FPGAs.
Control registers, including touchscreen input, are simply memory
mapped; in the future it would be desirable to hook up a more
conventional device node that can stream events, support kqueue(2)/
poll(2)/select(2), etc.
This is the first use of syscons on MIPS, as far as I can tell, and
there are some loose ends, such as an inability to use the hardware
cursor. More fundamentally, it appears that syscons(4) assumes that
either a host is PC-like (i386, amd64) *or* it must be using a
graphical frame buffer. While the MTL supports a graphical frame
buffer, using the text frame buffer is preferable for console use.
Fixing this issue in syscons(4) requires non-trivial changes, as the
text frame buffer support assumes that direct memory access can be
done to the text frame buffer without using bus accessor methods,
which is not the case on MIPS. As a workaround for this, we instead
double-buffer and pretend to be a graphical frame buffer exposing
text accessor methods, leading to some quirks in syscons behaviour.
Sponsored by: DARPA, AFRL
The driver attempts to support all documented parts, but has only been
tested with the 512Mbit part on the Terasic DE4 FPGA board. It should be
trivial to adapt the driver's attach routine to other embedded boards
using with any parts in the family.
Also import isfctl(8) which can be used to erase sections of the flash.
Sponsored by: DARPA, AFRL
which presents a UART-like interface over the Avalon bus that can be
addressed over JTAG. This IP core proves extremely useful, allowing us to
connect trivially to the FreeBSD console over JTAG for FPGA-embedded hard
and soft cores. As interrupts are optionally configured for this soft
core, we support both interrupt-driven and polled modes of operation,
which must be selected using device.hints. UART instances appear in /dev
as ttyu0, ttyu1, etc.
However, it also contains a number of quirks, which make it difficult to
tell when JTAG is connected, and some buffering issues. We work around
these as best we can, using various heuristics.
While the majority of this device driver is not only not BERI-specific,
but also not MIPS-specific, for now add its defines in the BERI files
list, as the console-level parts are aware of where the first JTAG UART
is mapped on Avalon, and contain MIPS-specific address translation, to
use before Newbus and device.hints are available.
Sponsored by: DARPA, AFRL
which can be synthesised in Altera FPGAs. An altera_sdcardc device
probes during the boot, and /dev/altera_sdcard devices come and go as
inserted and removed. The device driver attaches directly to the
Nexus, as is common for system-on-chip device drivers.
This IP core suffers a number of significant limitations, including a
lack of interrupt-driven I/O -- we must implement timer-driven polling,
only CSD 0 cards (up to 2G) are supported, there are serious memory
access issues that require the driver to verify writes to memory-mapped
buffers, undocumented alignment requirements, and erroneous error
returns. The driver must therefore work quite hard, despite a fairly
simple hardware-software interface. The IP core also supports at most
one outstanding I/O at a time, so is not a speed demon.
However, with the above workarounds, and subject to performance
problems, it works quite reliably in practice, and we can use it for
read-write mounts of root file systems, etc.
Sponsored by: DARPA, AFRL
CPU cores on Altera FPGAs. The device driver allows memory-mapped devices
on Altera's Avalon SoC bus to be exported to userspace via device nodes.
device.hints directories dictate device name, permissible access methods,
physical address and length, and I/O alignment. Devices can be accessed
using read(2)/write(2), but also memory mapped in userspace using mmap(2).
Devices attach directly to the Nexus, as is common for embedded device
drivers; in the future something more mature might be desirable. There is
currently no facility to support directing device-originated interrupts to
userspace.
In the future, this device driver may be renamed to socgen(4), as it can
in principle also be used with other system-on-chip (SoC) busses, such as
Axi on ASICs and FPGAs. However, we have only tested it on Avalon busses
with memory-mapped ROMs, frame buffers, etc.
Sponsored by: DARPA, AFRL
on PowerPC support. This was clearly not something syscons was
designed to do (very specific assumptions about the nature of VGA
consoles on PCs), but fortunately others have long since blazed
the way on making it work regardless of that.
Sponsored by: DARPA, AFRL
relative priority of the gxemul console in line with its role as a
"seiral console". This allows it to override video console drivers
that might otherwise take precdence, subject to that boot flag.
Sponsored by: DARPA, AFRL
