Commit Graph

166 Commits

Author SHA1 Message Date
Dan Williams
729b5d1b8e dmaengine: allow dma support for async_tx to be toggled
Provide a config option for blocking the allocation of dma channels to
the async_tx api.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-25 09:13:25 -07:00
Dan Williams
ccccce229c dmaengine: initialize tx_list in dma_async_tx_descriptor_init
Centralize this common initialization (and one case where ipu_idmac is
duplicating ->chan initialization).

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-25 09:13:24 -07:00
Guennadi Liakhovetski
8d47bae004 dma: i.MX31 IPU DMA robustness improvements
Add DMA error handling to the ISR, move common code fragments to functions, fix
scatter-gather element queuing in the ISR, survive channel freeing and
re-allocation in a quick succession.

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-25 09:13:24 -07:00
Guennadi Liakhovetski
234f2df56f dma: improve section assignment in i.MX31 IPU DMA driver
The i.MX31 IPU DMA driver is a platform driver, but doesn't need hotplug, so we
can use __init and __exit function attributes.

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-25 09:13:24 -07:00
Guennadi Liakhovetski
0149f7d5dc dma: ipu_idmac driver cosmetic clean-up
Remove superfluous semicolons, update comments.

Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-25 09:13:23 -07:00
Dan Williams
257b17ca03 dmaengine: fail device registration if channel registration fails
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>
2009-03-25 09:13:23 -07:00
Linus Torvalds
5dc18f51a2 Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx
* 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx:
  dmatest: fix use after free in dmatest_exit
  ipu_idmac: fix spinlock type
  iop-adma, mv_xor: fix mem leak on self-test setup failure
  fsldma: fix off by one in dma_halt
  I/OAT: fail self-test if callback test reaches timeout
  I/OAT: update driver version and copyright dates
  I/OAT: list usage cleanup
  I/OAT: set tcp_dma_copybreak to 256k for I/OAT ver.3
  I/OAT: cancel watchdog before dma remove
  I/OAT: fail initialization on zero channels detection
  I/OAT: do not set DCACTRL_CMPL_WRITE_ENABLE for I/OAT ver.3
  I/OAT: add verification for proper APICID_TAG_MAP setting by BIOS
  dmaengine: update kerneldoc
2009-03-08 10:23:05 -07:00
Dan Williams
7cbd4877e5 dmatest: fix use after free in dmatest_exit
dmatest_cleanup_chanel will free dtc, so grab ->chan before it goes away
and use it to do the release.

Reported-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:06:03 -07:00
Luotao Fu
c74ef1f867 ipu_idmac: fix spinlock type
fix a probably accidently dropped reference operator while calling
spin_unlock_restore to an ipu lock.

Signed-off-by: Luotao Fu <l.fu@pengutronix.de>
Cc: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:04:41 -07:00
Roel Kluin
a09b09ae51 iop-adma, mv_xor: fix mem leak on self-test setup failure
iop_adma_zero_sum_self_test has the brackets in the wrong place for the
setup failure deallocation path.  This error was duplicated in
mv_xor_xor_self_test.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:04:40 -07:00
Dan Williams
900325a6ce fsldma: fix off by one in dma_halt
Prevent dev_err from firing even if we successfully detected 'dma-idle'
before the full 1ms timeout has elapsed.

Acked-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:04:40 -07:00
Dan Williams
0c33e1ca3d I/OAT: fail self-test if callback test reaches timeout
If we miss interrupts in the self test then fail registration of this
channel as it is unsuitable for use as a public channel.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:04:40 -07:00
Maciej Sosnowski
211a22ce08 I/OAT: update driver version and copyright dates
Together with new fixes update driver version
and extend copyright dates ranges.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:04:40 -07:00
Eric Sesterhenn
aa2d0b8b97 I/OAT: list usage cleanup
Trivial cleanup, list_del(); list_add_tail() is equivalent
to list_move_tail(). Semantic patch for coccinelle can be
found at www.cccmz.de/~snakebyte/list_move_tail.spatch

Signed-off-by: Eric Sesterhenn <snakebyte@gmx.de>
Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:04:40 -07:00
Maciej Sosnowski
5de22343b2 I/OAT: set tcp_dma_copybreak to 256k for I/OAT ver.3
Upcoming server platforms from Intel based on the Nehalem performance
have significantly improved CPU based copy performance.
However, the DMA engine can still be effective at higher I/O sizes
for TCP traffic and at this time copybreak
should be set to 256k for TCP traffic only.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:04:40 -07:00
Maciej Sosnowski
2b8a6bf896 I/OAT: cancel watchdog before dma remove
Channel watchdog should be canceled before the rest of dma remove stuff.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:04:40 -07:00
Maciej Sosnowski
8b794b141c I/OAT: fail initialization on zero channels detection
On some systems with I/OAT ver.2 when DCA is disabled in BIOS
situations have been observed
that zero DMA channels are detected instead of four.
To avoid kernel panic driver should fail gracefully with appropriate message.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:04:39 -07:00
Maciej Sosnowski
ea9c717d01 I/OAT: do not set DCACTRL_CMPL_WRITE_ENABLE for I/OAT ver.3
Flag DCACTRL_CMPL_WRITE_ENABLE is valid only for I/OAT ver.2
so it should not be set for I/OAT ver.3.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:04:39 -07:00
Maciej Sosnowski
49bc46360d I/OAT: add verification for proper APICID_TAG_MAP setting by BIOS
BIOS versions for systems with I/OAT ver.2 have been found
which fail to program APICID_TAG_MAP for DCA.
The ioatdma driver should recognize incorrectly set APICID_TAG_MAP
and disable DCA in that case.

Signed-off-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Shannon Nelson <shannon.nelson@intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-03-04 16:04:39 -07:00
Russell King
bdf602bd73 [ARM] fix lots of ARM __devexit sillyness
`iop_adma_remove' referenced in section `.data' of drivers/built-in.o: defined in discarded section `.devexit.text' of drivers/built-in.o
`mv_xor_remove' referenced in section `.data' of drivers/built-in.o: defined in discarded section `.devexit.text' of drivers/built-in.o
`mv64xxx_i2c_unmap_regs' referenced in section `.devinit.text' of drivers/built-in.o: defined in discarded section `.devexit.text' of drivers/built-in.o
`mv64xxx_i2c_remove' referenced in section `.data' of drivers/built-in.o: defined in discarded section `.devexit.text' of drivers/built-in.o
`orion_nand_remove' referenced in section `.data' of drivers/built-in.o: defined in discarded section `.devexit.text' of drivers/built-in.o
`pxafb_remove' referenced in section `.data' of drivers/built-in.o: defined in discarded section `.devexit.text' of drivers/built-in.o

Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2009-03-03 21:04:04 +00:00
Dan Williams
287d859222 atmel-mci: fix initialization of dma slave data
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>
2009-02-18 15:37:55 -08:00
Guennadi Liakhovetski
5296b56d1b i.MX31: Image Processing Unit DMA and IRQ drivers
i.MX3x SoCs contain an Image Processing Unit, consisting of a Control
Module (CM), Display Interface (DI), Synchronous Display Controller (SDC),
Asynchronous Display Controller (ADC), Image Converter (IC), Post-Filter
(PF), Camera Sensor Interface (CSI), and an Image DMA Controller (IDMAC).
CM contains, among other blocks, an Interrupt Generator (IG) and a Clock
and Reset Control Unit (CRCU). This driver serves IDMAC and IG. They are
supported over dmaengine and irq-chip APIs respectively.

IDMAC is a specialised DMA controller, its DMA channels cannot be used for
general-purpose operations, even though it might be possible to configure
a memory-to-memory channel for memcpy operation. This driver will not work
with generic dmaengine clients, clients, wishing to use it must use
respective wrapper structures, they also must specify which channels they
require, as channels are hard-wired to specific IPU functions.

Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Guennadi Liakhovetski <lg@denx.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-19 15:36:21 -07:00
Dan Williams
83436a0560 dmaengine: kill some dubious WARN_ONCEs
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>
2009-01-19 14:39:10 -07:00
Peter Korsgaard
169d5f6637 fsldma: print correct IRQ on mpc83xx
The mpc83xx variant uses a shared IRQ for all channels, so the individual
channel nodes don't have an interrupt property. Fix the code to print the
controller IRQ instead if there isn't any for the channel.

Acked-by: Timur Tabi <timur@freescale.com>
Acked-by: Li Yang <leoli@freescale.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-15 23:50:22 -07:00
Peter Korsgaard
6782dfe44a fsldma: check for NO_IRQ in fsl_dma_chan_remove()
There's no per-channel IRQ on mpc83xx, so only call free_irq if we have one.

Acked-by: Timur Tabi <timur@freescale.com>
Acked-by: Li Yang <leoli@freescale.com>
Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-14 22:32:58 -07:00
Atsushi Nemoto
d86be86e9a dmatest: Use custom map/unmap for destination buffer
The dmatest driver should use DMA_BIDIRECTIONAL on the destination buffer
to ensure that the poison values are written to RAM and not just written
to cache and discarded.

Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-13 09:22:20 -07:00
Dan Williams
6527de6d6d fsldma: use a valid 'device' for dma_pool_create
The dmaengine sysfs implementation was fixed to support proper
lifetime rules which means that the current:

new_fsl_chan->dev = &new_fsl_chan->common.dev->device;

...retrieves a NULL pointer because new_fsl_chan->common.dev has not
been allocated at this point.  So, set new_fsl_chan->dev to a valid
device.

Cc: Li Yang <leoli@freescale.com>
Cc: Zhang Wei <zw@zh-kernel.org>
Reported-by: Ira Snyder <iws@ovro.caltech.edu>
Tested-by: Ira Snyder <iws@ovro.caltech.edu>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-12 15:20:42 -07:00
Yuri Tikhonov
dd59b8537f dmaengine: fix dependency chaining
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>
2009-01-12 15:19:29 -07:00
Dan Williams
b9bdcbba01 ioat: fix self test for multi-channel case
In the multiple device case we need to re-arm the completion and protect
against concurrent self-tests.  The printk from the test callback is
removed as it can arbitrarily delay completion of the test.

Cc: <stable@kernel.org>
Cc: Maciej Sosnowski <maciej.sosnowski@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06 11:38:22 -07:00
Dan Williams
652afc27b2 dmaengine: bump initcall level to arch_initcall
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>
2009-01-06 11:38:22 -07:00
Dan Williams
e2346677af dmaengine: advertise all channels on a device to dma_filter_fn
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>
2009-01-06 11:38:21 -07:00
Dan Williams
864498aaa9 dmaengine: use idr for registering dma device numbers
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>
2009-01-06 11:38:21 -07:00
Dan Williams
41d5e59c12 dmaengine: add a release for dma class devices and dependent infrastructure
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>
2009-01-06 11:38:21 -07:00
Dan Williams
4fac7fa57c ioat: do not perform removal actions at shutdown
Unregistering services should only happen at "remove" time.  This prevents
the device from being unregistered while dmaengine clients are still
active.  Also, the comment on ioat_remove is stale since removal is prevented
while a channel may be in use.

Reported-by: Alexander Beregalov <a.beregalov@gmail.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06 11:38:20 -07:00
Dan Williams
630738b9a5 iop-adma: enable module removal
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06 11:38:20 -07:00
Dan Williams
0d603f611d iop-adma: kill debug BUG_ON
This BUG_ON caught problems in early development but now it is in the
way as it invalidly triggers when trying to remove the module.

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06 11:38:20 -07:00
Dan Williams
f38822033d iop-adma: let devm do its job, don't duplicate free
No need to free stuff that the devm infrastructure will take care of...

Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2009-01-06 11:38:19 -07:00
Dan Williams
7dd6025101 dmaengine: kill enum dma_state_client
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>
2009-01-06 11:38:19 -07:00
Dan Williams
f27c580c36 dmaengine: remove 'bigref' infrastructure
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>
2009-01-06 11:38:18 -07:00
Dan Williams
aa1e6f1a38 dmaengine: kill struct dma_client and supporting infrastructure
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>
2009-01-06 11:38:17 -07:00
Dan Williams
209b84a88f dmaengine: replace dma_async_client_register with dmaengine_get
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>
2009-01-06 11:38:17 -07:00
Dan Williams
74465b4ff9 atmel-mci: convert to dma_request_channel and down-level dma_slave
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>
2009-01-06 11:38:16 -07:00
Dan Williams
33df8ca068 dmatest: convert to dma_request_channel
Replace the client registration infrastructure with a custom loop to
poll for channels.  Once dma_request_channel returns NULL stop asking
for channels.  A userspace side effect of this change if that loading
the dmatest module before loading a dma driver will result in no
channels being found, previously dmatest would get a callback.  To
facilitate testing in the built-in case dmatest_init is marked as a
late_initcall.  Another side effect is that channels under test can not
be used for any other purpose.

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>
2009-01-06 11:38:15 -07:00
Dan Williams
59b5ec2144 dmaengine: introduce dma_request_channel and private channels
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>
2009-01-06 11:38:15 -07:00
Dan Williams
2ba05622b8 dmaengine: provide a common 'issue_pending_all' implementation
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>
2009-01-06 11:38:14 -07:00
Dan Williams
bec085134e dmaengine: centralize channel allocation, introduce dma_find_channel
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>
2009-01-06 11:38:14 -07:00
Dan Williams
6f49a57aa5 dmaengine: up-level reference counting to the module level
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>
2009-01-06 11:38:14 -07:00
Dan Williams
07f2211e4f dmaengine: remove dependency on async_tx
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>
2009-01-05 18:10:19 -07:00
Dan Williams
a06d568f7c async_xor: dma_map destination DMA_BIDIRECTIONAL
Mapping the destination multiple times is a misuse of the dma-api.
Since the destination may be reused as a source, ensure that it is only
mapped once and that it is mapped bidirectionally.  This appears to add
ugliness on the unmap side in that it always reads back the destination
address from the descriptor, but gcc can determine that dma_unmap is a
nop and not emit the code that calculates its arguments.

Cc: <stable@kernel.org>
Cc: Saeed Bishara <saeed@marvell.com>
Acked-by: Yuri Tikhonov <yur@emcraft.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2008-12-08 13:46:00 -07:00
Dan Williams
b0b42b16ff dmaengine: protect 'id' from concurrent registrations
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>
2008-12-03 17:25:36 -07:00