The same message "qp %d: Link Down\n" was printed at two locations in
ntb_transport.  Change the messages so they are distinct.
Signed-off-by: NAllen Hubbe <Allen.Hubbe@emc.com>
Signed-off-by: NJon Mason <jdmason@kudzu.us>

The transport was writing and then reading the peer scratch pad,
essentially reading what it just wrote instead of exchanging any
information with the peer.  The transport expects the peer values to be
the same as the local values, so this issue was not obvious.
Signed-off-by: NDave Jiang <dave.jiang@intel.com>
Signed-off-by: NJon Mason <jdmason@kudzu.us>

Change ntb_hw_intel to use the new NTB hardware abstraction layer.

Split ntb_transport into its own driver.  Change it to use the new NTB
hardware abstraction layer.
Signed-off-by: NAllen Hubbe <Allen.Hubbe@emc.com>
Signed-off-by: NJon Mason <jdmason@kudzu.us>

This patch only moves files to their new locations, before applying the
next two patches adding the NTB Abstraction layer.  Splitting this patch
from the next is intended make distinct which code is changed only due
to moving the files, versus which are substantial code changes in adding
the NTB Abstraction layer.
Signed-off-by: NAllen Hubbe <Allen.Hubbe@emc.com>
Signed-off-by: NJon Mason <jdmason@kudzu.us>

The NTB translate register must have the value to be BAR size aligned.
This alignment check make sure that the DMA memory allocated has the
proper alignment. Another requirement for NTB to function properly with
memory window BAR size greater or equal to 4M is to use the CMA feature
in 3.16 kernel with the appropriate CONFIG_CMA_ALIGNMENT and
CONFIG_CMA_SIZE_MBYTES set.
Signed-off-by: NDave Jiang <dave.jiang@intel.com>
Signed-off-by: NJon Mason <jdmason@kudzu.us>

The detection of an uneven number of queues on the given memory windows
was not correct.  The mw_num is zero based and the mod should be
division to spread them evenly over the mw's.
Signed-off-by: NJon Mason <jon.mason@intel.com>

Some white space and 80 char overruns corrected.
Signed-off-by: NJon Mason <jon.mason@intel.com>

Provide a better event interface between the client and transport
Signed-off-by: NJon Mason <jon.mason@intel.com>

Disable interrupts and poll under high load
Signed-off-by: NJon Mason <jon.mason@intel.com>

dmaengine_get() causes the initialization of the per-cpu channel tables.
It needs to be called prior to dma_find_channel().

Initial version by Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NJon Mason <jon.mason@intel.com>

A WARN_ON is being hit in ntb_qp_link_work due to the NTB transport link
being down while the ntb qp link is still active.  This is caused by the
transport link being brought down prior to the qp link worker thread
being terminated.  To correct this, shutdown the qp's prior to bringing
the transport link down.  Also, only call the qp worker thread if it is
in interrupt context, otherwise call the function directly.
Signed-off-by: NJon Mason <jon.mason@intel.com>

Remove no longer needed DMA unmap flags:
- DMA_COMPL_SKIP_SRC_UNMAP
- DMA_COMPL_SKIP_DEST_UNMAP
- DMA_COMPL_SRC_UNMAP_SINGLE
- DMA_COMPL_DEST_UNMAP_SINGLE

Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Tomasz Figa <t.figa@samsung.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NJon Mason <jon.mason@intel.com>
Acked-by: NMark Brown <broonie@linaro.org>
[djbw: clean up straggling skip unmap flags in ntb]
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Use the generic unmap object to unmap dma buffers.

Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Tomasz Figa <t.figa@samsung.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com>
Acked-by: NJon Mason <jon.mason@intel.com>
[djbw: fix up unmap len, and GFP flags]
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Add "data" ntb_register_db_callback parameter description comment and
correct poor spelling.
Signed-off-by: NJon Mason <jon.mason@intel.com>

Remove unused pci_dev variable from ntb_transport_free()
Signed-off-by: NJon Mason <jon.mason@intel.com>

Many variable names in the NTB driver refer to the primary or secondary
side.  However, these variables will be used to access the reverse case
when in NTB-RP mode.  Make these names more generic in anticipation of
NTB-RP support.
Signed-off-by: NJon Mason <jon.mason@intel.com>

Allocate and use a DMA engine channel to transmit and receive data over
NTB.  If none is allocated, fall back to using the CPU to transfer data.
Signed-off-by: NJon Mason <jon.mason@intel.com>
Reviewed-by: NDan Williams <dan.j.williams@intel.com>
Reviewed-by: NDave Jiang <dave.jiang@intel.com>

There is a Xeon hardware errata related to writes to SDOORBELL or
B2BDOORBELL in conjunction with inbound access to NTB MMIO Space, which
may hang the system.  To workaround this issue, use one of the memory
windows to access the interrupt and scratch pad registers on the remote
system.  This bypasses the issue, but removes one of the memory windows
from use by the transport.  This reduction of MWs necessitates adding
some logic to determine the number of available MWs.

Since some NTB usage methodologies may have unidirectional traffic, the
ability to disable the workaround via modparm has been added.

See BF113 in
http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/xeon-c5500-c3500-spec-update.pdf
See BT119 in
http://www.intel.com/content/dam/www/public/us/en/documents/specification-updates/xeon-e5-family-spec-update.pdfSigned-off-by: NJon Mason <jon.mason@intel.com>

Debugfs was setup in NTB to only have a single debugfs directory.  This
resulted in the leaking of debugfs directories and files when multiple
NTB devices were present, due to each device stomping on the variables
containing the previous device's values (thus preventing them from being
freed on cleanup).  Correct this by creating a secondary directory of
the PCI BDF for each device present, and nesting the previously existing
information in those directories.
Signed-off-by: NJon Mason <jon.mason@intel.com>

Fix issue with adding multiple ntb client devices to the ntb virtual
bus.  Previously, multiple devices would be added with the same name,
resulting in crashes.  To get around this issue, add a unique number to
the device when it is added.
Signed-off-by: NJon Mason <jon.mason@intel.com>

The system will appear to lockup for long periods of time due to the NTB
driver spending too much time in memcpy.  Avoid this by reducing the
number of packets that can be serviced on a given interrupt.
Signed-off-by: NJon Mason <jon.mason@intel.com>

The ring logic of the NTB receive buffer/transmit memory window requires
there to be at least 2 payload sized allotments.  For the minimal size
case, split the buffer into two and set the transport_mtu to the
appropriate size.
Signed-off-by: NJon Mason <jon.mason@intel.com>

If the NTB link toggles, the driver could stop receiving due to the
tx_index not being set to 0 on the transmitting size on a link-up event.
This is due to the driver expecting the incoming data to start at the
beginning of the receive buffer and not at a random place.
Signed-off-by: NJon Mason <jon.mason@intel.com>

Each link-up will allocate a new NTB receive buffer when the NTB
properties are negotiated with the remote system.  These allocations did
not check for existing buffers and thus did not free them.  Now, the
driver will check for an existing buffer and free it if not of the
correct size, before trying to alloc a new one.
Signed-off-by: NJon Mason <jon.mason@intel.com>

64bit BAR sizes are permissible with an NTB device.  To support them
various modifications and clean-ups were required, most significantly
using 2 32bit scratch pad registers for each BAR.

Also, modify the driver to allow more than 2 Memory Windows.
Signed-off-by: NJon Mason <jon.mason@intel.com>

->remote_rx_info and ->rx_info are struct ntb_rx_info pointers.  If we
add sizeof(struct ntb_rx_info) then it goes too far.
Signed-off-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJon Mason <jon.mason@intel.com>

Correct instances of variable dereferencing before checking its value on
the functions exported to the client drivers.  Also, add sanity checks
for all exported functions.
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: NJon Mason <jon.mason@intel.com>

Address the sparse warnings and resulting fallout
Signed-off-by: NJon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

If the NTB client driver enqueues the maximum number of rx buffers, it
will not be able to re-enqueue another in its callback handler due to a
lack of free entries.  This can be avoided by adding the current entry
to the free queue prior to calling the client callback handler.  With
this change, ntb_netdev will no longer encounter a rx error on its first
packet.
Signed-off-by: NJon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

CPU reads across NTB are slow(er) and can hang the local system if an
ECC error is encountered on the remote.  To work around the need for a
read, have the remote side write its current position in the rx buffer
to the local system's buffer and use that to see if there is room when
transmitting.
Signed-off-by: NJon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Correct gcc warning of using too much stack debugfs_read.  This is done
by kmallocing the buffer instead of using the char array on stack.
Also, shrinking the buffer to something closer to what is currently
being used.
Signed-off-by: NJon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Whitespace cleanups found via `indent`
Signed-off-by: NJon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Declare ntb_bus_type static to remove it from name space, and remove
unused ntb_get_max_spads function.  Found via `make namespacecheck`.
Signed-off-by: NJon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Use simple_open for debugfs instead of recreating it in the NTB driver.
Caught by coccicheck.
Signed-off-by: NJon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Move all cancel_delayed_work_sync to a work thread to prevent sleeping
in interrupt context (when the NTB link goes down).  Caught via
'Sleep inside atomic section checking'
Signed-off-by: NJon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Since it is possible for the memory windows on the two NTB connected
systems to be different sizes, the divergent sizes must be accounted for
in the segmentation of the MW's on each side.  Create separate size
variables and initialization as necessary.
Signed-off-by: NJon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

mmiowb is not sufficient to flush the data and is causing data
corruption.  Change to wmb and the data corruption is no more.
Signed-off-by: NJon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Attempts to probe client ntb drivers without ntb hardware present will
result in null pointer dereference due to the lack of the ntb bus device
being registers.  Check to see if this is the case, and fail all calls
by the clients registering their drivers.
Signed-off-by: NJon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

These are now gone from the kernel, so remove them from the newly-added
drivers before they start to cause build errors for people.

Cc: Jon Mason <jon.mason@intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

A PCI-Express non-transparent bridge (NTB) is a point-to-point PCIe bus
connecting 2 systems, providing electrical isolation between the two subsystems.
A non-transparent bridge is functionally similar to a transparent bridge except
that both sides of the bridge have their own independent address domains.  The
host on one side of the bridge will not have the visibility of the complete
memory or I/O space on the other side of the bridge.  To communicate across the
non-transparent bridge, each NTB endpoint has one (or more) apertures exposed to
the local system.  Writes to these apertures are mirrored to memory on the
remote system.  Communications can also occur through the use of doorbell
registers that initiate interrupts to the alternate domain, and scratch-pad
registers accessible from both sides.

The NTB device driver is needed to configure these memory windows, doorbell, and
scratch-pad registers as well as use them in such a way as they can be turned
into a viable communication channel to the remote system.  ntb_hw.[ch]
determines the usage model (NTB to NTB or NTB to Root Port) and abstracts away
the underlying hardware to provide access and a common interface to the doorbell
registers, scratch pads, and memory windows.  These hardware interfaces are
exported so that other, non-mainlined kernel drivers can access these.
ntb_transport.[ch] also uses the exported interfaces in ntb_hw.[ch] to setup a
communication channel(s) and provide a reliable way of transferring data from
one side to the other, which it then exports so that "client" drivers can access
them.  These client drivers are used to provide a standard kernel interface
(i.e., Ethernet device) to NTB, such that Linux can transfer data from one
system to the other in a standard way.
Signed-off-by: NJon Mason <jon.mason@intel.com>
Reviewed-by: NNicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>