DMA_NAK is now useless.  We can just use a bool instead.
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Reference counting is done at the module level so clients need not worry
that a channel will leave while they are actively using dmaengine.
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

All users have been converted to either the general-purpose allocator,
dma_find_channel, or dma_request_channel.
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Now that clients no longer need to be notified of channel arrival
dma_async_client_register can simply increment the dmaengine_ref_count.
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

dma_request_channel provides an exclusive channel, so we no longer need to
pass slave data through dmaengine.

Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

This interface is primarily for device-to-memory clients which need to
search for dma channels with platform-specific characteristics.  The
prototype is:

struct dma_chan *dma_request_channel(dma_cap_mask_t mask,
                                     dma_filter_fn filter_fn,
                                     void *filter_param);

When the optional 'filter_fn' parameter is set to NULL
dma_request_channel simply returns the first channel that satisfies the
capability mask.  Otherwise, when the mask parameter is insufficient for
specifying the necessary channel, the filter_fn routine can be used to
disposition the available channels in the system. The filter_fn routine
is called once for each free channel in the system.  Upon seeing a
suitable channel filter_fn returns DMA_ACK which flags that channel to
be the return value from dma_request_channel.  A channel allocated via
this interface is exclusive to the caller, until dma_release_channel()
is called.

To ensure that all channels are not consumed by the general-purpose
allocator the DMA_PRIVATE capability is provided to exclude a dma_device
from general-purpose (memory-to-memory) consideration.
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

async_tx and net_dma each have open-coded versions of issue_pending_all,
so provide a common routine in dmaengine.

The implementation needs to walk the global device list, so implement
rcu to allow dma_issue_pending_all to run lockless.  Clients protect
themselves from channel removal events by holding a dmaengine reference.
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Allowing multiple clients to each define their own channel allocation
scheme quickly leads to a pathological situation.  For memory-to-memory
offload all clients can share a central allocator.

This simply moves the existing async_tx allocator to dmaengine with
minimal fixups:
* async_tx.c:get_chan_ref_by_cap --> dmaengine.c:nth_chan
* async_tx.c:async_tx_rebalance --> dmaengine.c:dma_channel_rebalance
* split out common code from async_tx.c:__async_tx_find_channel -->
  dma_find_channel
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Simply, if a client wants any dmaengine channel then prevent all dmaengine
modules from being removed.  Once the clients are done re-enable module
removal.

Why?, beyond reducing complication:
1/ Tracking reference counts per-transaction in an efficient manner, as
   is currently done, requires a complicated scheme to avoid cache-line
   bouncing effects.
2/ Per-transaction ref-counting gives the false impression that a
   dma-driver can be gracefully removed ahead of its user (net, md, or
   dma-slave)
3/ None of the in-tree dma-drivers talk to hot pluggable hardware, but
   if such an engine were built one day we still would not need to notify
   clients of remove events.  The driver can simply return NULL to a
   ->prep() request, something that is much easier for a client to handle.
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

async_tx.ko is a consumer of dma channels.  A circular dependency arises
if modules in drivers/dma rely on common code in async_tx.ko.  It
prevents either module from being unloaded.

Move dma_wait_for_async_tx and async_tx_run_dependencies to dmaeninge.o
where they should have been from the beginning.
Reviewed-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

There is a possibility to have two devices registered with the same id.

Cc: <stable@kernel.org>
Acked-by: NMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Acked-by: NGreg Kroah-Hartman <gregkh@suse.de>
Acked-by: NMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

This patch adds the necessary interfaces to the DMA Engine framework
to use functionality found on most embedded DMA controllers: DMA from
and to I/O registers with hardware handshaking.

In this context, hardware hanshaking means that the peripheral that
owns the I/O registers in question is able to tell the DMA controller
when more data is available for reading, or when there is room for
more data to be written. This usually happens internally on the chip,
but these signals may also be exported outside the chip for things
like IDE DMA, etc.

A new struct dma_slave is introduced. This contains information that
the DMA engine driver needs to set up slave transfers to and from a
slave device. Most engines supporting DMA slave transfers will want to
extend this structure with controller-specific parameters.  This
additional information is usually passed from the platform/board code
through the client driver.

A "slave" pointer is added to the dma_client struct. This must point
to a valid dma_slave structure iff the DMA_SLAVE capability is
requested.  The DMA engine driver may use this information in its
device_alloc_chan_resources hook to configure the DMA controller for
slave transfers from and to the given slave device.

A new operation for preparing slave DMA transfers is added to struct
dma_device. This takes a scatterlist and returns a single descriptor
representing the whole transfer.

Another new operation for terminating all pending transfers is added as
well. The latter is needed because there may be errors outside the scope
of the DMA Engine framework that may require DMA operations to be
terminated prematurely.

DMA Engine drivers may extend the dma_device, dma_chan and/or
dma_slave_descriptor structures to allow controller-specific
operations. The client driver can detect such extensions by looking at
the DMA Engine's struct device, or it can request a specific DMA
Engine device by setting the dma_dev field in struct dma_slave.

dmaslave interface changes since v4:
  * Fix checkpatch errors
  * Fix changelog (there are no slave descriptors anymore)

dmaslave interface changes since v3:
  * Use dma_data_direction instead of a new enum
  * Submit slave transfers as scatterlists
  * Remove the DMA slave descriptor struct

dmaslave interface changes since v2:
  * Add a dma_dev field to struct dma_slave. If set, the client can
    only be bound to the DMA controller that corresponds to this
    device.  This allows controller-specific extensions of the
    dma_slave structure; if the device matches, the controller may
    safely assume its extensions are present.
  * Move reg_width into struct dma_slave as there are currently no
    users that need to be able to set the width on a per-transfer
    basis.

dmaslave interface changes since v1:
  * Drop the set_direction and set_width descriptor hooks. Pass the
    direction and width to the prep function instead.
  * Declare a dma_slave struct with fixed information about a slave,
    i.e. register addresses, handshake interfaces and such.
  * Add pointer to a dma_slave struct to dma_client. Can be NULL if
    the DMA_SLAVE capability isn't requested.
  * Drop the set_slave device hook since the alloc_chan_resources hook
    now has enough information to set up the channel for slave
    transfers.
Acked-by: NMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: NHaavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

A DMA controller capable of doing slave transfers may need to know a
few things about the slave when preparing the channel. We don't want
to add this information to struct dma_channel since the channel hasn't
yet been bound to a client at this point.

Instead, pass a reference to the client requesting the channel to the
driver's device_alloc_chan_resources hook so that it can pick the
necessary information from the dma_client struct by itself.

[dan.j.williams@intel.com: fixed up fsldma and mv_xor]
Acked-by: NMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: NHaavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Haavard's dma-slave interface would like to test for exclusive access to a
channel.  The standard channel refcounting is not sufficient in that it
tracks more than just client references, it is also inaccurate as reference
counts are percpu until the channel is removed.

This change also enables a future fix to deallocate resources when a client
declines to use a capable channel.
Acked-by: NHaavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Set the 'parent' field of channel class devices to point to the
physical DMA device initialized by the DMA engine driver.

This allows drivers to use chan->dev.parent for syncing DMA buffers
and adds a 'device' symlink to the real device in
/sys/class/dma/dmaXchanY.
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Spelling fixes for dmaengine.[ch]
Signed-off-by: NSebastian Siewior <bigeasy@linutronix.de>
Acked-by: NMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: NJesper Juhl <jesper.juhl@gmail.com>

'ack' is currently a simple integer that flags whether or not a client is done
touching fields in the given descriptor.  It is effectively just a single bit
of information.  Converting this to a flags parameter allows the other bits to
be put to use to control completion actions, like dma-unmap, and capture
results, like xor-zero-sum == 0.

Changes are one of:
1/ convert all open-coded ->ack manipulations to use async_tx_ack
   and async_tx_test_ack.
2/ set the ack bit at prep time where possible
3/ make drivers store the flags at prep time
4/ add flags to the device_prep_dma_interrupt prototype
Acked-by: NMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

DMA drivers no longer need to be notified of dependency submission
events as async_tx_run_dependencies and async_tx_channel_switch will
handle the scheduling and execution of dependent operations.

[sfr@canb.auug.org.au: extend this for fsldma]
Acked-by: NShannon Nelson <shannon.nelson@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

Shrink struct dma_async_tx_descriptor and introduce
async_tx_channel_switch to properly inject a channel switch interrupt in
the descriptor stream.  This simplifies the locking model as drivers no
longer need to handle dma_async_tx_descriptor.lock.
Acked-by: NShannon Nelson <shannon.nelson@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The device->device_prep_dma_interrupt function is used by
DMA_INTERRUPT capability, not DMA_ZERO_SUM.
Signed-off-by: NZhang Wei <wei.zhang@freescale.com>
Acked-by: NMaciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>

The tx_set_src and tx_set_dest methods were originally implemented to allow
an array of addresses to be passed down from async_xor to the dmaengine
driver while minimizing stack overhead.  Removing these methods allows
drivers to have all transaction parameters available at 'prep' time, saves
two function pointers in struct dma_async_tx_descriptor, and reduces the
number of indirect branches..

A consequence of moving this data to the 'prep' routine is that
multi-source routines like async_xor need temporary storage to convert an
array of linear addresses into an array of dma addresses.  In order to keep
the same stack footprint of the previous implementation the input array is
reused as storage for the dma addresses.  This requires that
sizeof(dma_addr_t) be less than or equal to sizeof(void *).  As a
consequence CONFIG_DMADEVICES now depends on !CONFIG_HIGHMEM64G.  It also
requires that drivers be able to make descriptor resources available when
the 'prep' routine is polled.
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NShannon Nelson <shannon.nelson@intel.com>

Signed-off-by: NTony Jones <tonyj@suse.de>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Cc: Shannon Nelson <shannon.nelson@intel.com>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

When a DMA device is unregistered, its reference count is decremented twice
for each channel: Once dma_class_dev_release() and once in
dma_chan_cleanup().  This may result in the DMA device driver's remove()
function completing before all channels have been cleaned up, causing lots
of use-after-free fun.

Fix it by incrementing the device's reference count twice for each
channel during registration.

[dan.j.williams@intel.com: kill unnecessary client refcounting]
Signed-off-by: NHaavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Signed-off-by: NShannon Nelson <shannon.nelson@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The current implementation assumes that a channel will only be used by one
client at a time.  In order to enable channel sharing the dmaengine core is
changed to a model where clients subscribe to channel-available-events.
Instead of tracking how many channels a client wants and how many it has
received the core just broadcasts the available channels and lets the
clients optionally take a reference.  The core learns about the clients'
needs at dma_event_callback time.

In support of multiple operation types, clients can specify a capability
mask to only be notified of channels that satisfy a certain set of
capabilities.

Changelog:
* removed DMA_TX_ARRAY_INIT, no longer needed
* dma_client_chan_free -> dma_chan_release: switch to global reference
  counting only at device unregistration time, before it was also happening
  at client unregistration time
* clients now return dma_state_client to dmaengine (ack, dup, nak)
* checkpatch.pl fixes
* fixup merge with git-ioat

Cc: Chris Leech <christopher.leech@intel.com>
Signed-off-by: NShannon Nelson <shannon.nelson@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>

The current dmaengine interface defines mutliple routines per operation,
i.e. dma_async_memcpy_buf_to_buf, dma_async_memcpy_buf_to_page etc.  Adding
more operation types (xor, crc, etc) to this model would result in an
unmanageable number of method permutations.

	Are we really going to add a set of hooks for each DMA engine
	whizbang feature?
		- Jeff Garzik

The descriptor creation process is refactored using the new common
dma_async_tx_descriptor structure.  Instead of per driver
do_<operation>_<dest>_to_<src> methods, drivers integrate
dma_async_tx_descriptor into their private software descriptor and then
define a 'prep' routine per operation.  The prep routine allocates a
descriptor and ensures that the tx_set_src, tx_set_dest, tx_submit routines
are valid.  Descriptor creation and submission becomes:

struct dma_device *dev;
struct dma_chan *chan;
struct dma_async_tx_descriptor *tx;

tx = dev->device_prep_dma_<operation>(chan, len, int_flag)
tx->tx_set_src(dma_addr_t, tx, index /* for multi-source ops */)
tx->tx_set_dest(dma_addr_t, tx, index)
tx->tx_submit(tx)

In addition to the refactoring, dma_async_tx_descriptor also lays the
groundwork for definining cross-channel-operation dependencies, and a
callback facility for asynchronous notification of operation completion.

Changelog:
* drop dma mapping methods, suggested by Chris Leech
* fix ioat_dma_dependency_added, also caught by Andrew Morton
* fix dma_sync_wait, change from Andrew Morton
* uninline large functions, change from Andrew Morton
* add tx->callback = NULL to dmaengine calls to interoperate with async_tx
  calls
* hookup ioat_tx_submit
* convert channel capabilities to a 'cpumask_t like' bitmap
* removed DMA_TX_ARRAY_INIT, no longer needed
* checkpatch.pl fixes
* make set_src, set_dest, and tx_submit descriptor specific methods
* fixup git-ioat merge
* move group_list and phys to dma_async_tx_descriptor

Cc: Jeff Garzik <jeff@garzik.org>
Cc: Chris Leech <christopher.leech@intel.com>
Signed-off-by: NShannon Nelson <shannon.nelson@intel.com>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NDavid S. Miller <davem@davemloft.net>

From: Jeff Garzik <jeff@garzik.org>
Signed-off-by: NJeff Garzik <jeff@garzik.org>
Signed-off-by: NChris Leech <christopher.leech@intel.com>

This removes several pointless exports from drivers/dma/dmaengine.c; the
dma_async_memcpy_*() functions are inlined by <linux/dmaengine.h> so those
exports are inappropriate.

It also moves the existing EXPORT_SYMBOL declarations next to their functions,
so it's now trivial to confirm one-to-one correspondence between exports and
nonstatic symbols.
Signed-off-by: NDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: NDan Williams <dan.j.williams@intel.com>
Acked-by: NChris Leech <christopher.leech@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix kernel-doc warnings in drivers/dma/:
- use correct function & parameter names
- add descriptions where omitted
Signed-off-by: NRandy Dunlap <rdunlap@xenotime.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

for_each_cpu() is going away (and is gone in -mm).
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NChris Leech <christopher.leech@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Provides an API for offloading memory copies to DMA devices
Signed-off-by: NChris Leech <christopher.leech@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>