The tx_list attribute of struct dma_async_tx_descriptor is common to
most, but not all dma driver implementations. None of the upper level
code (dmaengine/async_tx) uses it, so allow drivers to implement it
locally if they need it. This saves sizeof(struct list_head) bytes for
drivers that do not manage descriptors with a linked list (e.g.: ioatdma
v2,3).
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
as reported by Alexander Beregalov <a.beregalov@gmail.com>
ioatdma 0000:00:08.0: DMA-API: device driver frees DMA memory with
wrong function [device address=0x000000007f76f800] [size=2000 bytes]
[map
ped as single] [unmapped as page]
The ioatdma driver was unmapping all regions
(either allocated as page or single) using unmap_page.
This patch lets dma driver recognize if unmap_single or unmap_page should be used.
It introduces two new dma control flags:
DMA_COMPL_SRC_UNMAP_SINGLE and DMA_COMPL_DEST_UNMAP_SINGLE.
They should be set to indicate dma driver to do dma-unmapping as single
(first one for the source, tha latter for the destination).
If respective flag is not set, the driver assumes dma-unmapping as page.
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Tested-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Currently dma_request_channel() set DMA_PRIVATE capability but never
clear it. So if a public channel was once grabbed by
dma_request_channel(), the device stay PRIVATE forever. Add
privatecnt member to dma_device to correctly revert it.
[lg@denx.de: fix bad usage of 'chan' in dma_async_device_register]
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Centralize this common initialization (and one case where ipu_idmac is
duplicating ->chan initialization).
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Atsushi points out:
"If alloc_percpu or kzalloc failed, chan_id does not match with its
position in device->channels list.
And above "continue" looks buggy anyway. Keeping incomplete channels
in device->channels list looks very dangerous..."
Also, fix up leakage of idr_ref in the idr_pre_get() and channel init
fail cases.
Reported-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
The conversion of atmel-mci to dma_request_channel missed the
initialization of the channel dma_slave information. The filter_fn passed
to dma_request_channel is responsible for initializing the channel's
private data. This implementation has the additional benefit of enabling
a generic client-channel data passing mechanism.
Reviewed-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Haavard Skinnemoen <hskinnemoen@atmel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
dma_find_channel and dma_issue_pending_all are good places to warn about
improper api usage. However, warning correctly means synchronizing with
dma_list_mutex, i.e. too much overhead for these fast-path calls.
Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
In dmaengine we track the dependencies between the descriptors
using the 'next' pointers of the structure. These pointers are
set to NULL as soon as the corresponding descriptor has been
submitted to the channel (in dma_run_dependencies()).
But, the first 'next' in chain is still remaining set, regardless
the fact, that tx->next has been already submitted. This may lead to
multiple submissions of the same descriptor. This patch fixes this.
Actually, some previous implementation of the xxx_run_dependencies()
function already had this fix in place. The fdb..0eaf3 commit, beside the
correct things, broke this.
Cc: <stable@kernel.org>
Signed-off-by: Yuri Tikhonov <yur@emcraft.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Allow dma_filter_fn routines to disambiguate multiple channels on a device
rather than assuming that all channels on a device are equal.
Cc: Maciej Sosnowski <maciej.sosnowski@intel.com>
Reported-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This brings some predictability to dma device numbers, i.e. an rmmod/insmod
cycle may now result in /sys/class/dma/dma0chan0 being restored rather than
/sys/class/dma/dma1chan0 appearing.
Cc: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Resolves:
WARNING: at drivers/base/core.c:122 device_release+0x4d/0x52()
Device 'dma0chan0' does not have a release() function, it is broken and must be fixed.
The dma_chan_dev object is introduced to gear-match sysfs kobject and
dmaengine channel lifetimes. When a channel is removed access to the
sysfs entries return -ENODEV until the kobject can be released.
The bulk of the change is updates to existing code to handle the extra
layer of indirection between a dma_chan and its struct device.
Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Acked-by: Stephen Hemminger <shemminger@vyatta.com>
Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Dan 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan 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: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan 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: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan 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: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Dan Williams
Maciej Sosnowski
Atsushi Nemoto
Yuri Tikhonov
Kay Sievers
Haavard Skinnemoen