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* Merge branch 'next' of ↵Linus Torvalds2011-05-281-91/+181
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx: (33 commits) x86: poll waiting for I/OAT DMA channel status maintainers: add dma engine tree details dmaengine: add TODO items for future work on dma drivers dmaengine: Add API documentation for slave dma usage dmaengine/dw_dmac: Update maintainer-ship dmaengine: move link order dmaengine/dw_dmac: implement pause and resume in dwc_control dmaengine/dw_dmac: Replace spin_lock* with irqsave variants and enable submission from callback dmaengine/dw_dmac: Divide one sg to many desc, if sg len is greater than DWC_MAX_COUNT dmaengine/dw_dmac: set residue as total len in dwc_tx_status if status is !DMA_SUCCESS dmaengine/dw_dmac: don't call callback routine in case dmaengine_terminate_all() is called dmaengine: at_hdmac: pause: no need to wait for FIFO empty pch_dma: modify pci device table definition pch_dma: Support new device ML7223 IOH pch_dma: Support I2S for ML7213 IOH pch_dma: Fix DMA setting issue pch_dma: modify for checkpatch pch_dma: fix dma direction issue for ML7213 IOH video-in dmaengine: at_hdmac: use descriptor chaining help function dmaengine: at_hdmac: implement pause and resume in atc_control ... Fix up trivial conflict in drivers/dma/dw_dmac.c
| * dmaengine/dw_dmac: Update maintainer-shipViresh Kumar2011-05-251-0/+2
| | | | | | | | | | | | | | | | | | | | Nobody is currently maintaining dw_dmac. We are using dw_dmac for SPEAr13xx and are currently maintaining it. After discussing with Vinod, sending this patch to update maintainer-ship of dw_dmac. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Acked-by: Havard Skinnemoen <hskinnemoen@gmail.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
| * dmaengine/dw_dmac: implement pause and resume in dwc_controlLinus Walleij2011-05-131-20/+39
| | | | | | | | | | | | | | | | | | | | Some peripherals like amba-pl011 needs pause to be implemented in DMA controller drivers. This also returns correct status from dwc_tx_status() in case chan is paused. Signed-off-by: Linus Walleij <linus.walleij@linaro.org> Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
| * dmaengine/dw_dmac: Replace spin_lock* with irqsave variants and enable ↵Viresh Kumar2011-05-131-39/+77
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | submission from callback dmaengine routines can be called from interrupt context and with interrupts disabled. Whereas spin_unlock_bh can't be called from such contexts. So this patch converts all spin_*_bh routines to irqsave variants. Also, spin_lock() used in tasklet is converted to irqsave variants, as tasklet can be interrupted, and dma requests from such interruptions may also call spin_lock. Now, submission from callbacks are permitted as per dmaengine framework. So we shouldn't hold any locks while calling callbacks. As locks were taken by parent routines, so releasing them before calling callbacks doesn't look clean enough. So, locks are taken inside all routine now, whereever they are required. And dwc_descriptor_complete is always called without taking locks. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
| * dmaengine/dw_dmac: Divide one sg to many desc, if sg len is greater than ↵Viresh Kumar2011-05-131-21/+44
| | | | | | | | | | | | | | | | | | | | | | DWC_MAX_COUNT If len passed in sg for slave_sg transfers is greater than DWC_MAX_COUNT, then driver programmes controller incorrectly. This patch adds code to handle this situation by allocation more than one desc for same sg. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
| * dmaengine/dw_dmac: set residue as total len in dwc_tx_status if status is ↵Viresh Kumar2011-05-131-1/+5
| | | | | | | | | | | | | | | | | | | | !DMA_SUCCESS If transfer status is !=DMA_SUCCESS, return total transfer len as residue, instead of zero. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
| * dmaengine/dw_dmac: don't call callback routine in case ↵Viresh Kumar2011-05-131-14/+13
| | | | | | | | | | | | | | | | | | | | | | dmaengine_terminate_all() is called If dmaengine_terminate_all() is called for dma channel, then it doesn't make much sense to call registered callback routine. While in case of success or failure it must be called. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
| * dmaengine/dw_dmac fix: dwc_scan_descriptors must compare first desc address ↵Viresh Kumar2011-03-311-0/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | also with llp dwc_scan_descriptors scans all descriptors from active_list in case transfer is not completed. It compares first_desc->lli.llp, and then all childrens of its tx_list. But it doesn't compare its own address, i.e. first_desc->txd.phys, as this is what we have initially programmed into the controller register. So this causes dma to stop and finish a transfer, which was never started. And thus fail. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
* | Haavard Skinnemoen has left AtmelJean Delvare2011-05-181-1/+1
|/ | | | | | | | Haavard's e-mail address at Atmel is no longer valid. Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Havard Skinnemoen <hskinnemoen@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* dw_dmac: Setting Default Burst length for transfers as 16.Viresh Kumar2011-03-071-2/+2
| | | | | | | | This patch sets default Burst length for all transfer to 16. This will enhance performance when user doesn't have any chan->private data. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
* dw_dmac: Allow src/dst msize & flow controller to be configured at runtimeViresh KUMAR2011-03-071-6/+8
| | | | | | | | | | | | | Msize or Burst Size is peripheral dependent in case of prep_slave_sg and cyclic_prep transfers, and in case of memcpy transfers it is platform dependent. So msize configuration must come from platform data. Also some peripherals (ex: JPEG), need to be flow controller for dma transfers, so this information in case of slave_sg & cyclic_prep transfers must come from platform data. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
* dw_dmac: Pass Channel Priority from platform_dataViresh Kumar2011-03-071-1/+10
| | | | | | | | | | In Synopsys designware, channel priority is programmable. This patch adds support for passing channel priority through platform data. By default Ascending channel priority will be followed, i.e. channel 0 will get highest priority and channel 7 will get lowest. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
* dw_dmac: Pass Channel Allocation Order from platform_dataViresh Kumar2011-03-071-1/+5
| | | | | | | | | | In SPEAr Platform channels 4-7 have more Fifo depth. So we must get better channel first. This patch introduces concept of channel allocation order in dw_dmac. If user doesn't pass anything or 0, than normal (ascending) channel allocation will follow, else channels will be allocated in descending order. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
* dw_dmac: Mark all tx_descriptors with DMA_CRTL_ACK after xfer finishViresh Kumar2011-03-071-0/+7
| | | | | | | | | | dwc_desc_get checks all descriptors for DMA_CTRL_ACK before allocating them for transfers. And descriptors are not marked with DMA_CRTL_ACK after transfer finishes. Thus descriptor once used is not usable again. This patch marks descriptors with DMA_CRTL_ACK after dma xfer finishes Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
* dw_dmac: Change value of DWC_MAX_COUNT to 4095.Viresh Kumar2011-03-071-3/+2
| | | | | | | | Every descriptor can transfer a maximum count of 4095 (12 bits, in control reg), So we must have DWC_MAX_COUNT as 4095 instead of 2048. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
* dw_dmac: Adding support for 64 bit access width for memcpy xfersViresh Kumar2011-03-071-1/+3
| | | | | Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
* dw_dmac: Calling dwc_scan_descriptors from dwc_tx_status() after taking lockViresh Kumar2011-03-071-0/+2
| | | | | | | | | | Lock must be taken before calling dwc_scan_descriptors, as this may access/modify shared data and queues. dwc_tx_status wasn't taking lock before calling this routine. This patch add code that takes lock before calling dwc_scan_descriptors. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
* dw_dmac: Move single descriptor from dwc->queue to dwc->active_list in ↵Viresh Kumar2011-03-071-12/+8
| | | | | | | | | | | dwc_complete_all dwc_complete_all and other routines was removing all descriptors from dwc->queue and pushing them to dwc->active_list. Only one was required to be removed. Also we are calling dwc_dostart, once list is fixed. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
* dw_dmac: Replace module_init() with subsys_initcall()Viresh Kumar2011-03-071-1/+1
| | | | | | | | | | In some cases users of dw_dmac are initialized before dw_dmac, and if they try to use dw_dmac, they simply fail. So its better we register init() routine of driver using subsys_initcall() instead of module_init(), so that dma driver is available at the earliest possible. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
* dmaengine/dw_dmac: provide a mechanism to indicate private devicesJamie Iles2011-01-291-0/+2
| | | | | | | | | | | Some platforms (e.g. Picochip PC3XX) have multiple DMA controllers where some may be used for slave transfers and others for general purpose memcpy type transfers. Add a .is_private boolean to the platform data structure so that controllers can be marked as private so that the DMA_PRIVATE capability will be set for that controller. Signed-off-by: Jamie Iles <jamie.iles@picochip.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* dmaengine/dw_dmac: allow src/dst masters to be configured at runtimeJamie Iles2011-01-291-14/+17
| | | | | | | | | | | | | | Some platforms have flexible mastering capabilities and this needs to be selected at runtime. If the platform has specified private data in the form of the dw_dma_slave then fetch the source and destination masters from here. If this isn't present, default to the previous of 0 and 1. v2: cleanup whitespace Acked-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Signed-off-by: Jamie Iles <jamie.iles@picochip.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* dmaengine/dw_dmac: don't scan descriptors if no xfers in progressJamie Iles2011-01-291-0/+3
| | | | | | | | | | | | | | Some hardware (picoChip picoXCell in particular) sometimes has the block transfer complete bit being set for a channel after the whole transfer has completed. If we don't have any transfers in the active list then don't bother to scan the descriptors. This often happens in normal operation and doesn't require the channel to be reset. v2: cleanup whitespace Signed-off-by: Jamie Iles <jamie.iles@picochip.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* DMAENGINE: extend the control command to include an argLinus Walleij2010-05-171-1/+2
| | | | | | | | | | | This adds an argument to the DMAengine control function, so that we can later provide control commands that need some external data passed in through an argument akin to the ioctl() operation prototype. [dan.j.williams@intel.com: fix up some missed conversions] Signed-off-by: Linus Walleij <linus.walleij@stericsson.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* dmaengine: provide helper for setting txstateDan Williams2010-03-261-5/+1
| | | | | | Simple conditional struct filler to cut out some duplicated code. Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* DMAENGINE: generic channel status v2Linus Walleij2010-03-261-8/+9
| | | | | | | | | | | | | | | | | | | | | | | | Convert the device_is_tx_complete() operation on the DMA engine to a generic device_tx_status()operation which can return three states, DMA_TX_RUNNING, DMA_TX_COMPLETE, DMA_TX_PAUSED. [dan.j.williams@intel.com: update for timberdale] Signed-off-by: Linus Walleij <linus.walleij@stericsson.com> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Maciej Sosnowski <maciej.sosnowski@intel.com> Cc: Nicolas Ferre <nicolas.ferre@atmel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Li Yang <leoli@freescale.com> Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Cc: Magnus Damm <damm@opensource.se> Cc: Liam Girdwood <lrg@slimlogic.co.uk> Cc: Joe Perches <joe@perches.com> Cc: Roland Dreier <rdreier@cisco.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* DMAENGINE: generic slave control v2Linus Walleij2010-03-261-2/+8
| | | | | | | | | | | | | | | | | | | | | | | | | Convert the device_terminate_all() operation on the DMA engine to a generic device_control() operation which can now optionally support also pausing and resuming DMA on a certain channel. Implemented for the COH 901 318 DMAC as an example. [dan.j.williams@intel.com: update for timberdale] Signed-off-by: Linus Walleij <linus.walleij@stericsson.com> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Cc: Maciej Sosnowski <maciej.sosnowski@intel.com> Cc: Nicolas Ferre <nicolas.ferre@atmel.com> Cc: Pavel Machek <pavel@ucw.cz> Cc: Li Yang <leoli@freescale.com> Cc: Guennadi Liakhovetski <g.liakhovetski@gmx.de> Cc: Paul Mundt <lethal@linux-sh.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Cc: Magnus Damm <damm@opensource.se> Cc: Liam Girdwood <lrg@slimlogic.co.uk> Cc: Joe Perches <joe@perches.com> Cc: Roland Dreier <rdreier@cisco.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* Merge branch 'fixes' of ↵Linus Torvalds2009-12-301-2/+0
|\ | | | | | | | | | | | | | | | | | | | | | | | | 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: drivers/dma: Correct use after free drivers/dma: drop unnecesary memset ioat2,3: put channel hardware in known state at init async_tx: expand async raid6 test to cover ioatdma corner case ioat3: fix p-disabled q-continuation sh: fix DMA driver's descriptor chaining and cookie assignment dma: at_hdmac: correct incompatible type for argument 1 of 'spin_lock_bh'
| * drivers/dma: drop unnecesary memsetJulia Lawall2009-12-221-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | memset of 0 is not needed after kzalloc The semantic patch that makes this change is as follows: (http://coccinelle.lip6.fr/) // <smpl> @@ expression x; statement S; @@ x = kzalloc(...); if (x == NULL) S ... when != x -memset(x,0,...);// </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* | const: constify remaining dev_pm_opsAlexey Dobriyan2009-12-151-1/+1
|/ | | | | | Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'next' of ↵NeilBrown2009-09-231-21/+29
|\ | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx into for-linus
| * dmaengine: Move all map_sg/unmap_sg for slave channel to its clientAtsushi Nemoto2009-09-081-12/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Dan Williams wrote: ... DMA-slave clients request specific channels and know the hardware details at a low level, so it should not be too high an expectation to push dma mapping responsibility to the client. Also this patch includes DMA_COMPL_{SRC,DEST}_UNMAP_SINGLE support for dw_dmac driver. Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * dw_dmac: implement a private tx_listDan Williams2009-09-081-9/+10
| | | | | | | | | | | | | | | | | | Drop dw_dmac's use of tx_list from struct dma_async_tx_descriptor in preparation for removal of this field. Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* | DMA: Rework dw_dmac suspend_late()/resume_early()Magnus Damm2009-07-221-5/+10
|/ | | | | | | | | | | | | | This patch reworks platform driver power management code for dw_dmac from legacy late/early callbacks to dev_pm_ops. The callbacks are converted for CONFIG_SUSPEND like this: suspend_late() -> suspend_noirq() resume_early() -> resume_noirq() Signed-off-by: Magnus Damm <damm@igel.co.jp> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Acked-by: Pavel Machek <pavel@ucw.cz> Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
* Merge branch 'next' of ↵Linus Torvalds2009-04-031-2/+331
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx * 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx: dma: Add SoF and EoF debugging to ipu_idmac.c, minor cleanup dw_dmac: add cyclic API to DW DMA driver dmaengine: Add privatecnt to revert DMA_PRIVATE property dmatest: add dma interrupts and callbacks dmatest: add xor test dmaengine: allow dma support for async_tx to be toggled async_tx: provide __async_inline for HAS_DMA=n archs dmaengine: kill some unused headers dmaengine: initialize tx_list in dma_async_tx_descriptor_init dma: i.MX31 IPU DMA robustness improvements dma: improve section assignment in i.MX31 IPU DMA driver dma: ipu_idmac driver cosmetic clean-up dmaengine: fail device registration if channel registration fails
| * dw_dmac: add cyclic API to DW DMA driverHans-Christian Egtvedt2009-04-011-1/+331
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds a cyclic DMA interface to the DW DMA driver. This is very useful if you want to use the DMA controller in combination with a sound device which uses cyclic buffers. Using a DMA channel for cyclic DMA will disable the possibility to use it as a normal DMA engine until the user calls the cyclic free function on the DMA channel. Also a cyclic DMA list can not be prepared if the channel is already active. Signed-off-by: Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Acked-by: Maciej Sosnowski <maciej.sosnowski@intel.com> Signed-off-by: Dan Williams <dan.j.williams@intel.com>
| * dmaengine: initialize tx_list in dma_async_tx_descriptor_initDan Williams2009-03-251-1/+0
| | | | | | | | | | | | | | | | Centralize this common initialization (and one case where ipu_idmac is duplicating ->chan initialization). Signed-off-by: Dan Williams <dan.j.williams@intel.com>
* | dma: struct device - replace bus_id with dev_name(), dev_set_name()Kay Sievers2009-03-241-1/+1
|/ | | | | | Cc: Dan Williams <dan.j.williams@intel.com> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
* atmel-mci: fix initialization of dma slave dataDan Williams2009-02-181-3/+2
| | | | | | | | | | | | | | 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>
* dmaengine: add a release for dma class devices and dependent infrastructureDan Williams2009-01-061-41/+50
| | | | | | | | | | | | | | | | | | | | | | 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>
* dmaengine: kill struct dma_client and supporting infrastructureDan Williams2009-01-061-2/+1
| | | | | | | | | | | | 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>
* atmel-mci: convert to dma_request_channel and down-level dma_slaveDan Williams2009-01-061-19/+6
| | | | | | | | | | | 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>
* dmaengine: up-level reference counting to the module levelDan Williams2009-01-061-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | 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>
* dw_dmac: fix copy/paste bug in taskletHaavard Skinnemoen2008-10-031-1/+1
| | | | | | | | | | | The tasklet checks RAW.BLOCK twice, and does not check RAW.XFER. This is obviously wrong, and could theoretically cause the driver to hang. Reported-by: Nicolas Ferre <nicolas.ferre@atmel.com> Signed-off-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> Acked-by: Dan Williams <dan.j.williams@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* dmaengine: Driver for the Synopsys DesignWare DMA controllerHaavard Skinnemoen2008-07-081-0/+1122
This adds a driver for the Synopsys DesignWare DMA controller (aka DMACA on AVR32 systems.) This DMA controller can be found integrated on the AT32AP7000 chip and is primarily meant for peripheral DMA transfer, but can also be used for memory-to-memory transfers. This patch is based on a driver from David Brownell which was based on an older version of the DMA Engine framework. It also implements the proposed extensions to the DMA Engine API for slave DMA operations. The dmatest client shows no problems, but there may still be room for improvement performance-wise. DMA slave transfer performance is definitely "good enough"; reading 100 MiB from an SD card running at ~20 MHz yields ~7.2 MiB/s average transfer rate. Full documentation for this controller can be found in the Synopsys DW AHB DMAC Databook: http://www.synopsys.com/designware/docs/iip/DW_ahb_dmac/latest/doc/dw_ahb_dmac_db.pdf The controller has lots of implementation options, so it's usually a good idea to check the data sheet of the chip it's intergrated on as well. The AT32AP7000 data sheet can be found here: http://www.atmel.com/dyn/products/datasheets.asp?family_id=682 Changes since v4: * Use client_count instead of dma_chan_is_in_use() * Add missing include * Unmap buffers unless client told us not to Changes since v3: * Update to latest DMA engine and DMA slave APIs * Embed the hw descriptor into the sw descriptor * Clean up and update MODULE_DESCRIPTION, copyright date, etc. Changes since v2: * Dequeue all pending transfers in terminate_all() * Rename dw_dmac.h -> dw_dmac_regs.h * Define and use controller-specific dma_slave data * Fix up a few outdated comments * Define hardware registers as structs (doesn't generate better code, unfortunately, but it looks nicer.) * Get number of channels from platform_data instead of hardcoding it based on CONFIG_WHATEVER_CPU. * Give slave clients exclusive access to the channel 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>
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