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path: root/drivers/dma/dmaengine.c
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2009-01-19dmaengine: kill some dubious WARN_ONCEsDan Williams
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>
2009-01-12dmaengine: fix dependency chainingYuri Tikhonov
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>
2009-01-06dmaengine: bump initcall level to arch_initcallDan Williams
There are dmaengine users that would like to register dma devices at subsys_initcall time to ensure channels are available by device_initcall time. Cc: Maciej Sosnowski <maciej.sosnowski@intel.com> Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Cc: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06dmaengine: advertise all channels on a device to dma_filter_fnDan Williams
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>
2009-01-06dmaengine: use idr for registering dma device numbersDan Williams
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>
2009-01-06dmaengine: add a release for dma class devices and dependent infrastructureDan Williams
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>
2009-01-06dmaengine: kill enum dma_state_clientDan Williams
DMA_NAK is now useless. We can just use a bool instead. Reviewed-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06dmaengine: remove 'bigref' infrastructureDan Williams
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>
2009-01-06dmaengine: kill struct dma_client and supporting infrastructureDan Williams
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>
2009-01-06dmaengine: replace dma_async_client_register with dmaengine_getDan Williams
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>
2009-01-06atmel-mci: convert to dma_request_channel and down-level dma_slaveDan Williams
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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06dmaengine: introduce dma_request_channel and private channelsDan Williams
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>
2009-01-06dmaengine: provide a common 'issue_pending_all' implementationDan Williams
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>
2009-01-06dmaengine: centralize channel allocation, introduce dma_find_channelDan Williams
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>
2009-01-06dmaengine: up-level reference counting to the module levelDan Williams
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>
2009-01-05dmaengine: remove dependency on async_txDan Williams
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>
2008-12-03dmaengine: protect 'id' from concurrent registrationsDan Williams
There is a possibility to have two devices registered with the same id. Cc: <stable@kernel.org> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-11-11dmaengine: struct device - replace bus_id with dev_name(), dev_set_name()Kay Sievers
Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-07-08dmaengine: Add slave DMA interfaceHaavard Skinnemoen
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>
2008-07-08dmaengine: Add dma_client parameter to device_alloc_chan_resourcesHaavard Skinnemoen
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: 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>
2008-07-08dmaengine: track the number of clients using a channelDan Williams
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: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-07-08dmaengine: Couple DMA channels to their physical DMA deviceHaavard Skinnemoen
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: Haavard Skinnemoen <hskinnemoen@atmel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-04-21DMA engine: typo fixesSebastian Siewior
Spelling fixes for dmaengine.[ch] Signed-off-by: Sebastian Siewior <bigeasy@linutronix.de> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
2008-04-17dmaengine: ack to flags: make use of the unused bits in the 'ack' fieldDan Williams
'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: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-04-17async_tx: kill ->device_dependency_addedDan Williams
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: Shannon Nelson <shannon.nelson@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-04-17async_tx: fix multiple dependency submissionDan Williams
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: Shannon Nelson <shannon.nelson@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-03-13dmaengine: Fix a bug about BUG_ON() on DMA engine capability DMA_INTERRUPT.Zhang Wei
The device->device_prep_dma_interrupt function is used by DMA_INTERRUPT capability, not DMA_ZERO_SUM. Signed-off-by: Zhang Wei <wei.zhang@freescale.com> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-02-06async_tx: kill tx_set_src and tx_set_dest methodsDan Williams
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: Dan Williams <dan.j.williams@intel.com> Acked-by: Shannon Nelson <shannon.nelson@intel.com>
2008-01-24DMA: Convert from class_device to device for DMA engineTony Jones
Signed-off-by: Tony Jones <tonyj@suse.de> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Cc: Shannon Nelson <shannon.nelson@intel.com> Cc: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2007-11-14dmaengine: fix broken device refcountingHaavard Skinnemoen
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: Haavard Skinnemoen <hskinnemoen@atmel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Shannon Nelson <shannon.nelson@intel.com> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-13dmaengine: make clients responsible for managing channelsDan Williams
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: Shannon Nelson <shannon.nelson@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: David S. Miller <davem@davemloft.net>
2007-07-13dmaengine: refactor dmaengine around dma_async_tx_descriptorDan Williams
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: Shannon Nelson <shannon.nelson@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: David S. Miller <davem@davemloft.net>
2007-07-11drivers/dma: handle sysfs errorsJeff Garzik
From: Jeff Garzik <jeff@garzik.org> Signed-off-by: Jeff Garzik <jeff@garzik.org> Signed-off-by: Chris Leech <christopher.leech@intel.com>
2007-03-16[PATCH] rm pointless dmaengine exportsDavid Brownell
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: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Dan Williams <dan.j.williams@intel.com> Acked-by: Chris Leech <christopher.leech@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-07-03[IOAT]: fix kernel-doc in source filesRandy Dunlap
Fix kernel-doc warnings in drivers/dma/: - use correct function & parameter names - add descriptions where omitted Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17[I/OAT]: Do not use for_each_cpu().Andrew Morton
for_each_cpu() is going away (and is gone in -mm). Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Chris Leech <christopher.leech@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2006-06-17[I/OAT]: DMA memcpy subsystemChris Leech
Provides an API for offloading memory copies to DMA devices Signed-off-by: Chris Leech <christopher.leech@intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>