MFC r344955 (by imp):
Don't print all the I/O we abort on a reset, unless we're out of
retries.

When resetting the controller, we abort I/O. Prior to this fix, we
printed a ton of abort messages for I/O that we're going to
retry. This imparts no useful information. Stop printing them unless
our retry count is exhausted. Clarify code for when we don't retry,
and remove useless arg to a routine that's always called with it
as 'true'. All the other debug is still printed (including multiple
reset messages if we have multiple timeouts before the taskqueue
runs the actual reset) so that we know when we reset.

MFC r344642 (by imp):
Unconditionally support unmapped BIOs. This was another shim for
supporting older kernels. However, all supported versions of FreeBSD
have unmapped I/Os (as do several that have gone EOL), remove it. It's
unlikely the driver would work on the older kernels anyway at this
point.

MFC r344640 (by imp):
Remove #ifdef code to support FreeBSD versions that haven't been
supported in years. A number of changes have been made to the driver
that likely wouldn't work on those older versions that aren't properly
ifdef'd and it's project policy to GC such code once it is stale.

MFC r339775: Put a workaround in for command timeout malfunctioning

At least one NVMe drive has a bug that makeing the Command Time Out
PCIe feature unreliable. The workaround is to disable this
feature. The driver wouldn't deal correctly with a timeout anyway.
Only do this for drives that are known bad.

MFC r331046 (by imp): Try polling the qpairs on timeout.

On some systems, we're getting timeouts when we use multiple queues on
drives that work perfectly well on other systems. On a hunch, Jim
Harris suggested I poll the completion queue when we get a timeout.
This patch polls the completion queue if no fatal status was
indicated. If it had pending I/O, we complete that request and
return. Otherwise, if aborts are enabled and no fatal status, we abort
the command and return. Otherwise we reset the card.

This may clear up the problem, or we may see it result in lots of
timeouts and a performance problem. Either way, we'll know the next
step. We may also need to pay attention to the fatal status bit
of the controller.

Revert r330897:

This was intended to be a non-functional change. It wasn't. The commit
message was thus wrong. In addition it broke arm, and merged crypto
related code.

Revert with prejudice.

This revert skips files touched in r316370 since that commit was since
MFCed. This revert also skips files that require $FreeBSD$ property
changes.

Thank you to those who helped me get out of this mess including but not
limited to gonzo, kevans, rgrimes.

Requested by: gjb (re)

Partial merge of the SPDX changes

These changes are incomplete but are making it difficult
to determine what other changes can/should be merged.

No objections from: pfg

MFC r328521 (by imp):
Use atomic load and stores to ensure that the compiler doesn't
optimize away these loops. Change boolean to int to match what atomic
API supplies. Remove wmb() since the atomic_store_rel() on status.done
ensure the prior writes to status. It also fixes the fact that there
wasn't a rmb() before reading done. This should also be more efficient
since wmb() is fairly heavy weight.

MFC r326937, r326940 (by imp):
When we're disabling the nvme device, some drives have a controller
bug that requires 'hands off' for a period of time (2.3s) before we
check the RDY bit. Sicne this is a very odd quirk for a very limited
selection of drives, do this as a quirk. This prevented a successful
reset of the card when the card wedged.

Also, make sure that we comply with the advice from section 3.1.5 of
the 1.3 spec says that transitioning CC.EN from 0 to 1 when CSTS.RDY
is 1 or transitioning CC.EN from 1 to 0 when CSTS.RDY is 0 "has
undefined results". Short circuit when EN == RDY == desired state.

Finally, fail the reset if the disable fails. This will lead to a
failed device, which is what we want. (note: nda device needs
work for coping with a failed device).

MFC r324633 (by imp):
Create general polling function for the nvme controller. Use it when
we're doing the various pin-based interrupt modes. Adjust
nvme_ctrlr_intx_handler to use nvme_ctrlr_poll.

MFC r322997: Add CAM/NVMe support for CAM_DATA_SG

This adds support in pass(4) for data to be described with a
scatter-gather list (sglist) to augment the existing (single) virtual
address.

MFC r322994: Set the max transactions for NVMe drives better.

Provided a better estimate for the number of transactions that can be
pending at one time. This will be number of queues * number of
trackers / 4, as suggested by Jim Harris. This gives a better estimate
of the number of transactions that CAM should queue before applying
back pressure. This should be revisted when we have real multi-queue
support in CAM and the upper layers of the I/O stack.

MFC r322902 (by imp):
NVME Namespace ID is 32-bits, so widen interface to reflect that.

MFC r308431 (by scottl):
Convert the Q-Pair and PRP list memory allocations to use BUSDMA. Add a
bunch of safery belts and error handling in related codepaths.

MFC r303126 (by imp):
Actually import nvme_sim so the CAM attachment for NVME (nda) actually
works.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Commit the bits of nda that were missed. This should fix the build.

Approved by: re@

nvme: do not revert o single I/O queue when per-CPU queues not possible

Previously nvme(4) would revert to a signle I/O queue if it could not
allocate enought interrupt vectors or NVMe submission/completion queues
to have one I/O queue per core. This patch determines how to utilize a
smaller number of available interrupt vectors, and assigns (as closely
as possible) an equal number of cores to each associated I/O queue.

MFC after: 3 days
Sponsored by: Intel

nvme: do not pre-allocate MSI-X IRQ resources

The issue referenced here was resolved by other changes
in recent commits, so this code is no longer needed.

MFC after: 3 days
Sponsored by: Intel

nvme: remove per_cpu_io_queues from struct nvme_controller

Instead just use num_io_queues to make this determination.

This prepares for some future changes enabling use of multiple
queues when we do not have enough queues or MSI-X vectors
for one queue per CPU.

MFC after: 3 days
Sponsored by: Intel

nvme: remove CHATHAM related code

Chatham was an internal NVMe prototype board used for
early driver development.

MFC after: 1 week
Sponsored by: Intel

nvme: create separate DMA tag for non-payload DMA buffers

Submission and completion queue memory need to use a
separate DMA tag for mappings than payload buffers,
to ensure mappings remain contiguous even with DMAR
enabled.

Submitted by: kib
MFC after: 1 week
Sponsored by: Intel

nvme: Allocate all MSI resources up front so that we can fall back to
INTx if necessary.

Sponsored by: Intel
MFC after: 3 days

nvme: Close hole where nvd(4) would not be notified of all nvme(4)
instances if modules loaded during boot.

Sponsored by: Intel
MFC after: 3 days

Log and then disable asynchronous notification of persistent events after
they occur.

This prevents repeated notifications of the same event.

Status of these events may be viewed at any time by viewing the
SMART/Health Info Page using nvmecontrol, whether or not asynchronous
events notifications for those events are enabled. This log page can
be viewed using:

nvmecontrol logpage -p 2 <ctrlr id>

Future enhancements may re-enable these notifications on a periodic basis
so that if the notified condition persists, it will continue to be logged.

Sponsored by: Intel
Reviewed by: carl
Approved by: re (hrs)
MFC after: 1 week

Add driver-assisted striping for upcoming Intel NVMe controllers that can
benefit from it.

Sponsored by: Intel
Reviewed by: kib (earlier version), carl
Approved by: re (hrs)
MFC after: 1 week

Send a shutdown notification in the driver unload path, to ensure
notification gets sent in cases where system shuts down with driver
unloaded.

Sponsored by: Intel
Reviewed by: carl
MFC after: 3 days

Add comment explaining why CACHE_LINE_SIZE is defined in nvme_private.h
if not already defined elsewhere.

Requested by: attilio
MFC after: 3 days

Update copyright dates.

MFC after: 3 days

Remove remaining uio-related code.

The nvme_physio() function was removed quite a while ago, which was the
only user of this uio-related code.

Sponsored by: Intel
MFC after: 3 days

Use MAXPHYS to specify the maximum I/O size for nvme(4).

Also allow admin commands to transfer up to this maximum I/O size, rather
than the artificial limit previously imposed. The larger I/O size is very
beneficial for upcoming firmware download support. This has the added
benefit of simplifying the code since both admin and I/O commands now use
the same maximum I/O size.

Sponsored by: Intel
MFC after: 3 days

Move the busdma mapping functions to nvme_qpair.c.

This removes nvme_uio.c completely.

Sponsored by: Intel

Add a mutex to each namespace, for general locking operations on the namespace.

Sponsored by: Intel

Rename the controller's fail_req_lock, so that it can be used for other
locking operations on the controller.

Sponsored by: Intel

Add unmapped bio support to nvme(4) and nvd(4).

Sponsored by: Intel

Add "type" to nvme_request, signifying if its payload is a VADDR, UIO, or
NULL. This simplifies decisions around if/how requests are routed through
busdma. It also paves the way for supporting unmapped bios.

Sponsored by: Intel

Clean up debug prints.

1) Consistently use device_printf.
2) Make dump_completion and dump_command into something more
human-readable.

Sponsored by: Intel
Reviewed by: carl

Move common code from the different nvme_allocate_request functions into a
separate function.

Sponsored by: Intel
Suggested by: carl
Reviewed by: carl

Replace usages of mtx_pool_find used for admin commands with a polling
mechanism.

Now that all requests are timed, we are guaranteed to get a completion
notification, even if it is an abort status due to a timed out admin
command.

This has the effect of simplifying the controller and namespace setup
code, so that it reads straight through rather than broken up into
a bunch of different callback functions.

Sponsored by: Intel
Reviewed by: carl

Add the ability to internally mark a controller as failed, if it is unable to
start or reset. Also add a notifier for NVMe consumers for controller fail
conditions and plumb this notifier for nvd(4) to destroy the associated
GEOM disks when a failure occurs.

This requires a bit of work to cover the races when a consumer is sending
I/O requests to a controller that is transitioning to the failed state. To
help cover this condition, add a task to defer completion of I/Os submitted
to a failed controller, so that the consumer will still always receive its
completions in a different context than the submission.

Sponsored by: Intel
Reviewed by: carl

Remove the is_started flag from struct nvme_controller.

This flag was originally added to communicate to the sysctl code
which oids should be built, but there are easier ways to do this. This
needs to be cleaned up prior to adding new controller states - for example,
controller failure.

Sponsored by: Intel
Reviewed by: carl

Ensure the controller's MDTS is accounted for in max_xfer_size.

The controller's IDENTIFY data contains MDTS (Max Data Transfer Size) to
allow the controller to specify the maximum I/O data transfer size. nvme(4)
already provides a default maximum, but make sure it does not exceed what
MDTS reports.

Sponsored by: Intel
Reviewed by: carl

Cap the number of retry attempts to a configurable number. This ensures
that if a specific I/O repeatedly times out, we don't retry it indefinitely.

The default number of retries will be 4, but is adjusted using hw.nvme.retry_count.

Sponsored by: Intel
Reviewed by: carl

Pass associated log page data to async event consumers, if requested.

Sponsored by: Intel
Reviewed by: carl

When an asynchronous event request is completed, automatically fetch the
specified log page.

This satisfies the spec condition that future async events of the same type
will not be sent until the associated log page is fetched.

Sponsored by: Intel
Reviewed by: carl

Add structure definitions and controller command function for firmware
log pages.

Sponsored by: Intel
Reviewed by: carl

Add structure definitions and a controller command function for
error log pages.

Sponsored by: Intel
Reviewed by: carl

Make nvme_ctrlr_reset a nop if a reset is already in progress.

This protects against cases where a controller crashes with multiple
I/O outstanding, each timing out and requesting controller resets
simultaneously.

While here, remove a debugging printf from a previous commit, and add
more logging around I/O that need to be resubmitted after a controller
reset.

Sponsored by: Intel
Reviewed by: carl

By default, always escalate to controller reset when an I/O times out.

While aborts are typically cleaner than a full controller reset, many times
an I/O timeout indicates other controller-level issues where aborts may not
work. NVMe drivers for other operating systems are also defaulting to
controller reset rather than aborts for timed out I/O.

Sponsored by: Intel
Reviewed by: carl

Add a tunable for the I/O timeout interval. Default is still 30 seconds,
but can be adjusted between a min/max of 5 and 120 seconds.

Sponsored by: Intel
Reviewed by: carl

Add handling for controller fatal status (csts.cfs).

On any I/O timeout, check for csts.cfs==1. If set, the controller
is reporting fatal status and we reset the controller immediately,
rather than trying to abort the timed out command.

This changeset also includes deferring the controller start portion
of the reset to a separate task. This ensures we are always performing
a controller start operation from a consistent context.

Sponsored by: Intel
Reviewed by: carl

Add controller reset capability to nvme(4) and ability to explicitly
invoke it from nvmecontrol(8).

Controller reset will be performed in cases where I/O are repeatedly
timing out, the controller reports an unrecoverable condition, or
when explicitly requested via IOCTL or an nvme consumer. Since the
controller may be in such a state where it cannot even process queue
deletion requests, we will perform a controller reset without trying
to clean up anything on the controller first.

Sponsored by: Intel
Reviewed by: carl

Keep a doubly-linked list of outstanding trackers.

This enables in-order re-submission of I/O after a controller reset.

Sponsored by: Intel

Expose the get/set features API to nvme consumers.

Sponsored by: Intel

Add an interface for nvme shim drivers (i.e. nvd) to register for
notifications when new nvme controllers are added to the system.

Sponsored by: Intel

Enable asynchronous event requests on non-Chatham devices.

Also add logic to clean up all outstanding asynchronous event requests
when resetting or shutting down the controller, since these requests
will not be explicitly completed by the controller itself.

Sponsored by: Intel

Move controller destruction code from nvme_detach() to new nvme_ctrlr_destruct()
function.

Sponsored by: Intel

Specify command timeout interval on a per-command type basis.

This is primarily driven by the need to disable timeouts for asynchronous
event requests, which by nature should not be timed out.

Sponsored by: Intel

Add support for ABORT commands, including issuing these commands when
an I/O times out.

Also ensure that we retry commands that are aborted due to a timeout.

Sponsored by: Intel

Map BAR 4/5, because NVMe spec says devices may place the MSI-X table
behind BAR 4/5, rather than in BAR 0/1 with the control/doorbell registers.

Sponsored by: Intel

Do not use taskqueue to defer completion work when using INTx. INTx now
matches MSI-X behavior.

Sponsored by: Intel

Add PCI device ID for 8-channel IDT NVMe controller, and clarify that the
previously defined IDT PCI device ID was for a 32-channel controller.

Submitted by: Joe Golio <joseph.golio@isilon.com>

Add ability to queue nvme_request objects if no nvme_trackers are available.

This eliminates the need to manage queue depth at the nvd(4) level for
Chatham prototype board workarounds, and also adds the ability to
accept a number of requests on a single qpair that is much larger
than the number of trackers allocated.

Sponsored by: Intel

Preallocate a limited number of nvme_tracker objects per qpair, rather
than dynamically creating them at runtime.

Sponsored by: Intel

Create nvme_qpair_submit_request() which eliminates all of the code
duplication between the admin and io controller-level submit
functions.

Sponsored by: Intel

Cleanup uio-related code to use struct nvme_request and
nvme_ctrlr_submit_io_request().

While here, also fix case where a uio may have more than 1 iovec.
NVMe's definition of SGEs (called PRPs) only allows for the first SGE to
start on a non-page boundary. The simplest way to handle this is to
construct a temporary uio for each iovec, and submit an NVMe request
for each.

Sponsored by: Intel

Add nvme_ctrlr_submit_[admin|io]_request functions which consolidates
code for allocating nvme_tracker objects and making calls into
bus_dmamap_load for commands which have payloads.

Sponsored by: Intel

Add struct nvme_request object which contains all of the parameters passed
from an NVMe consumer.

This allows us to mostly build NVMe command buffers without holding the
qpair lock, and also allows for future queueing of nvme_request objects
in cases where the submission queue is full and no nvme_tracker objects
are available.

Sponsored by: Intel

Merge struct nvme_prp_list into struct nvme_tracker.

This simplifies the driver significantly where it is constructing
commands to be submitted to hardware. By reducing the number of
PRPs (NVMe parlance for SGE) from 128 to 32, it ensures we do not
allocate too much memory for more common smaller I/O sizes, while
still supporting up to 128KB I/O sizes.

This also paves the way for pre-allocation of nvme_tracker objects
for each queue which will simplify the I/O path even further.

Sponsored by: Intel

Count number of times each queue pair's interrupt handler is invoked.

Also add sysctls to query and reset each queue pair's stats, including
the new count added here.

Sponsored by: Intel

Put the nvme_qpair mutex on its own cacheline.

Sponsored by: Intel

This is the first of several commits which will add NVM Express (NVMe)
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>