linux-toradex.git/drivers/misc/mic/scif, branch v4.4.2

misc: mic/scif: fix error code in scif_create_remote_lookup()

2015-10-18T04:49:48+00:00

We should be returning -ENOMEM here instead of success.

Fixes: ba612aa8b487 ('misc: mic: SCIF memory registration and unregistration')
Signed-off-by: Dan Carpenter 
Reviewed-by: Sudeep Dutt 
Signed-off-by: Greg Kroah-Hartman

misc: mic/scif: re-take a lock on error path

2015-10-18T04:49:48+00:00

The caller expects that we take this lock again before returning
otherwise it you get double unlocks and races.

Fixes: ba612aa8b487 ('misc: mic: SCIF memory registration and unregistration')
Signed-off-by: Dan Carpenter 
Reviewed-by: Sudeep Dutt 
Signed-off-by: Greg Kroah-Hartman

misc: mic: fix memory leak

2015-10-18T04:42:29+00:00

In scif_node_connect() we were returning if the initialization of p2p_ji
fails. But at that time p2p_ij has already been initialized and
resources allocated for it. And since p2p_ij is not added to the list
till now so we will have a leak.
Lets deinitialize and release the resources connected to p2p_ij.

Signed-off-by: Sudip Mukherjee 
Reviewed-by: Sudeep Dutt 
Signed-off-by: Greg Kroah-Hartman

misc: mic: SCIF RMA nodeqp and minor miscellaneous changes

2015-10-04T11:54:54+00:00

This patch adds the SCIF kernel node QP control messages required to
enable SCIF RMAs. Examples of such node QP control messages include
registration, unregistration, remote memory allocation requests,
remote memory unmap and SCIF remote fence requests.

The patch also updates the SCIF driver with minor changes required to
enable SCIF RMAs by adding the new files to the build, initializing
RMA specific information during SCIF endpoint creation, reserving SCIF
DMA channels, initializing SCIF RMA specific global data structures,
adding the IOCTL hooks required for SCIF RMAs and updating RMA
specific debugfs hooks.

Reviewed-by: Ashutosh Dixit 
Reviewed-by: Nikhil Rao 
Signed-off-by: Sudeep Dutt 
Signed-off-by: Greg Kroah-Hartman

misc: mic: SCIF fence

2015-10-04T11:54:54+00:00

This patch implements the fence APIs required to synchronize
DMAs. SCIF provides an interface to return a "mark" for all DMAs
programmed at the instant the API was called. Users can then "wait" on
the mark provided previously by blocking inside the kernel. Upon
receipt of a DMA completion interrupt the waiting thread is woken
up. There is also an interface to signal DMA completion by polling for
a location to be updated via a "signal" cookie to avoid the interrupt
overhead in the mark/wait interface. SCIF allows programming fences on
both the local and the remote node for both the mark/wait or the fence
signal APIs.

Reviewed-by: Ashutosh Dixit 
Reviewed-by: Nikhil Rao 
Signed-off-by: Jacek Lawrynowicz 
Signed-off-by: Sudeep Dutt 
Signed-off-by: Greg Kroah-Hartman

misc: mic: SCIF DMA and CPU copy interface

2015-10-04T11:54:54+00:00

SCIF allows users to read from or write to registered remote memory
via CPU copies or DMA. The API verifies that both local and remote
windows are valid before initiating the CPU or DMA transfers. SCIF has
optimized algorithms for handling byte aligned as well as cache line
aligned DMA engines. A registration cache is maintained to avoid the
overhead of pinning pages repeatedly if buffers are reused. The
registration cache is invalidated upon receipt of MMU notifier
callbacks.  SCIF windows are destroyed and the pages are unpinned only
once all prior DMAs initiated using that window are drained. Users can
request synchronous DMA operations as well as tail byte ordering if
required. CPU copies are always performed synchronously.

Reviewed-by: Ashutosh Dixit 
Reviewed-by: Nikhil Rao 
Signed-off-by: Sudeep Dutt 
Signed-off-by: Greg Kroah-Hartman

misc: mic: SCIF remote memory map/unmap interface

2015-10-04T11:54:54+00:00

This patch implements the SCIF mmap/munmap interface. A similar
capability is provided to kernel clients via the
scif_get_pages()/scif_put_pages() APIs. The SCIF mmap interface
queries to check if a window is valid and then remaps the local
virtual address to the remote physical pages. These mappings are
subsequently destroyed upon receipt of the VMA close operation or
scif_get_pages().  This functionality allows SCIF users to directly
access remote memory without any driver interaction once the mappings
are created thereby providing bare-metal PCIe latency. These mappings
are zapped to avoid RMA accesses from user space, if a Coprocessor is
reset.

Reviewed-by: Ashutosh Dixit 
Reviewed-by: Nikhil Rao 
Signed-off-by: Sudeep Dutt 
Signed-off-by: Greg Kroah-Hartman

misc: mic: SCIF RMA list operations

2015-10-04T11:54:54+00:00

This patch adds the implementation for operations performed on the
list of SCIF windows. Examples of such operations includes adding the
windows to the list of registered (or cached) windows, querying the
list of self or remote windows and unregistering windows. The query
operation is used by SCIF APIs which initiate DMAs, CPU copies or
fences to ensure that a window remains valid during a transfer.

Reviewed-by: Ashutosh Dixit 
Signed-off-by: Nikhil Rao 
Signed-off-by: Sudeep Dutt 
Signed-off-by: Greg Kroah-Hartman

misc: mic: SCIF memory registration and unregistration

2015-10-04T11:54:54+00:00

This patch implements the SCIF APIs required to pin and unpin
pages. SCIF registration locks down the pages. It then sends a remote
window allocation request to the peer. Once the peer has allocated
memory, the local SCIF endpoint copies the pinned page information to
the peer and notifies the peer once the copy has complete. The peer
upon receipt of the registration notification adds the new remote
window to its list. At this point the window page information is
available on both self and remote nodes so that they can start
performing SCIF DMAs, CPU copies and fences. The unregistration API
tears down the registration at both self and remote nodes.

Reviewed-by: Nikhil Rao 
Reviewed-by: Ashutosh Dixit 
Signed-off-by: Sudeep Dutt 
Signed-off-by: Greg Kroah-Hartman

misc: mic: SCIF RMA header file

2015-10-04T11:54:54+00:00

This patch adds the internal data structures required to perform SCIF
RMAs. The data structures required to maintain per SCIF endpoint, RMA
information are contained in scif_endpt_rma_info. scif_pinned_pages
describes a set of SCIF pinned pages maintained locally. The
scif_window is a data structure which contains all the fields required
to describe a SCIF registered window on self and remote nodes. It
contains an offset which is used as a key to perform SCIF DMAs and CPU
copies between self and remote registered windows.

Reviewed-by: Nikhil Rao 
Reviewed-by: Ashutosh Dixit 
Signed-off-by: Sudeep Dutt 
Signed-off-by: Greg Kroah-Hartman