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path: root/drivers/dma
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2014-07-28dmaengine: edma: Support to suppress the period interrupts in cyclic modePeter Ujfalusi1-3/+3
If the client (audio) does not request interrupts for every period we can disable them. With updated audio driver stack we can play audio w/o the need to process any edma interrupts. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-28dmaengine: edma: Update caps->residue_granularity to match with realityPeter Ujfalusi1-1/+1
The edma can report accurate DMA position so update the residue_granularity to DMA_RESIDUE_GRANULARITY_BURST. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-28dmaengine: sun61: fix warning on bad print specfierVinod Koul1-2/+2
The sg_dma_len() returns unsigned int but we had driver print it as %zu, use %u as documented in Documentation/printk-formats.txt drivers/dma/sun6i-dma.c: In function ‘sun6i_dma_prep_slave_sg’: drivers/dma/sun6i-dma.c:643: warning: format ‘%zu’ expects type ‘size_t’, but argument 8 has type ‘unsigned int’ drivers/dma/sun6i-dma.c:661: warning: format ‘%zu’ expects type ‘size_t’, but argument 8 has type ‘unsigned int’ Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-28dmaengine: sun6i: fix build failure on x86, xilinx targetsVinod Koul1-2/+2
Since the driver defined COMPILE_TEST, it gets compiled for different arch's The driver uses __virt_to_phys() insteadof virt_to_phys, so replace it drivers/dma/sun6i-dma.c: In function ‘sun6i_dma_dump_chan_regs’: drivers/dma/sun6i-dma.c:203: error: implicit declaration of function '__virt_to_phys' Reported-by: kbuild test robot <fengguang.wu@intel.com> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-25dmaengine: mpc512x: register for device tree channel lookupAlexander Popov1-1/+12
Register the controller for device tree based lookup of DMA channels (non-fatal for backwards compatibility with older device trees) and provide the '#dma-cells' property in the shared mpc5121.dtsi file Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-25dmaengine: of: add common xlate function for matching by channel idAlexander Popov1-0/+35
This patch adds a new common OF dma xlate callback function which will match a channel by it's id. The binding expects one integer argument which it will use to lookup the channel by the id. Unlike of_dma_simple_xlate this function is able to handle a system with multiple DMA controllers. When registering the of dma provider with of_dma_controller_register a pointer to the dma_device struct which is associated with the dt node needs to passed as the data parameter. New function will use this pointer to match only channels which belong to the specified DMA controller. Signed-off-by: Alexander Popov <a13xp0p0v88@gmail.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-25dmaengine: sun6i: Add driver for the Allwinner A31 DMA controllerMaxime Ripard3-0/+1068
The Allwinner A31 has a 16 channels DMA controller that it shares with the newer A23. Although sharing some similarities with the DMA controller of the older Allwinner SoCs, it's significantly different, I don't expect it to be possible to share the driver for these two. The A31 Controller is able to memory-to-memory or memory-to-device transfers on the 16 channels in parallel. Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com> Acked-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-25dmaengine: ipu: use return value of request_irqVinod Koul1-4/+10
Commit - 653e67f7e5: "dmaengine: inherit debug settings from the subsystem for subdirectories" introduced debug option for subdirectories too This exposed issue with ipu driver not using return value For now just warn users about it Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-25dmaengine: jz4740: Fix GPL v2 license string typoBjorn Helgaas1-1/+1
Per license_is_gpl_compatible(), the MODULE_LICENSE() string for GPL v2 is "GPL v2", not "GPLv2". Use "GPL v2" so this module doesn't taint the kernel. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Acked-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-25dmaengine: fsl-edma: fix dmamux index calculating errorJingchang Lu1-2/+4
Signed-off-by: Jingchang Lu <jingchang.lu@freescale.com> Tested-by: Stefan Agner <stefan@agner.ch> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-25dmaengine: imx-sdma: Add a new DMATYPE for Shared Peripheral ASRCNicolin Chen1-0/+5
Shared Peripheral ASRC, running on SPBA, needs to use shp sciprts for DMA transfer. So this patch just adds a new DMATYPE for it. Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com> Acked-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-25dmaengine: imx-sdma: Save imx_dma_data into sdmacNicolin Chen1-1/+4
The filter() function is currently called by xlate() while it transfers imx_dma_data as a local variable to the filter() but releases the data right after returning a DMA channel pointer, which results chan->private pointing an invalid memory space. So this patch just stores the imx_dma_data into sdmac to make usre the private pointer valid as long as the channel exists. Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-22dmaengine: pl330: Check if the DMA descriptor is NULLJavier Martinez Canillas1-1/+6
Commit 6079d38 ("dmaengine: pl330: Remove useless xfer_cb indirection") removed the __callback() function which created an unnecessary level of indirection to execute the tranfer callback .xfer_cb Unfortunately the commit also changed the semantics slightly since that function used to check if the request was not NULL before attempting to execute the callback function. Not checking this could lead to a kernel NULL pointer dereference error. Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk> Acked-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-21Merge commit 'renesas-shdma-for-v3.17' into for-linusVinod Koul2-10/+9
2014-07-17dma: Fix MIC X100 DMA Driver Kconfig optionSudeep Dutt1-2/+1
Select DMA_ENGINE instead of DMAENGINE and delete the default line as the default is 'n' anyways. Link: https://lkml.org/lkml/2014/7/14/90 Reported-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Sudeep Dutt <sudeep.dutt@intel.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-15dmaengine: dw: don't perform DMA when dmaengine_submit is calledAndy Shevchenko2-13/+7
Accordingly to discussion [1] and followed up documentation the DMA controller driver shouldn't start any DMA operations when dmaengine_submit() is called. This patch fixes the workflow in dw_dmac driver to follow the documentation. [1] http://www.spinics.net/lists/arm-kernel/msg125987.html Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: dw: add debug message to dwc_dostart_first_queuedAndy Shevchenko1-1/+5
It would be useful to know when the first descriptor in the queue is started along with its cookie. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: dw: introduce dwc_dostart_first_queued() helperAndy Shevchenko1-8/+11
We have a duplicate code which starts first descriptor in the queue. Let's make this as a separate helper that can be used in future as well. Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Remove pl330_chan_ctrl()Lars-Peter Clausen1-61/+10
The pl330_chan_ctrl() function has 3 internal code paths which, except for the locking, do not share any code outside of their sections. One code path is never exercised and can be removed. The other two are mostly just forwards to the _start() and _stop() calls. This patch modifies the code to instead of going via pl330_chan_ctrl() to call _start() and _stop() directly. This allows to completely remove pl330_chan_ctrl(). Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Simplify marking a request as unusedLars-Peter Clausen1-38/+13
Instead of storing a special instruction in the command buffer to mark a request as currently unused just set the descriptor field to NULL. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Embed pl330_req directly into dma_pl330_descLars-Peter Clausen1-90/+69
The pl330_req struct is embedded into the dma_pl330_desc struct. But half of the pl330_req struct are pointers to other fields of the dma_pl330_desc struct it is embedded to. By directly embedding the fields from the pl330_req struct into the dma_pl330_desc struct and reworking the code to work with the dma_pl330_desc struct those pointers can be eliminated. This slightly simplifies the code. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Merge dma_pl330_dmac and pl330_dmac structsLars-Peter Clausen1-280/+192
Both the dma_pl330_dmac and the pl330_dmac struct have the same lifetime and the separation of them is a relict of this having been two different drivers in the past. Merging them into one struct makes the code a bit simpler as it for example allows to remove the pointers going back and forth between the two structs. While we are at it also directly embed the pl330_info struct into the pl330_dmac struct as this allows to remove some more redundant fields. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Simplify is_manager()Lars-Peter Clausen1-7/+1
Since we keep a pointer to the manager thread it is fairly easy to check if a thread is the manager thread. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Remove uneccessary ccr validationLars-Peter Clausen1-23/+0
We know that we do not create invalid ccr settings in this driver. There is no need to validate them. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Change type pl330_chid from void * to struct pl330_thread *Lars-Peter Clausen1-20/+17
The pl330_chid field of the dma_pl330_chan struct always holds a pointer to the thread that is associated with the channel. Changing its type form void * to struct pl330_thread makes things more type safe and removes the need for unnecessary typecasts. While we are at it also rename the field from the cryptic pl330_chid to thread. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Remove useless xfer_cb indirectionLars-Peter Clausen1-38/+24
The xfer_cb callback of the pl330_req struct is always set to the same function. This adds an unnecessary step of indirection. Instead just call the callback function directly. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Remove unused mc_len field from _pl330_req structLars-Peter Clausen1-4/+1
The mc_len is initialized but its value is never read again, so remove it. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Remove unused next field form pl330_xfer structLars-Peter Clausen1-15/+5
The next field is always NULL, so we can remove it. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Remove unused client_data field form pl330_infoLars-Peter Clausen1-2/+0
The field is completely unused, remove it. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Remove unused dmac_reset callbackLars-Peter Clausen1-12/+0
The dmac_reset() callaback of the pl330_info struct is always set to NULL, so remove it. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Remove unused pl330_chanstatus structLars-Peter Clausen1-29/+0
The pl330_chanstatus struct is completely unused, so remove it. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Remove duplicated cachecontrol enumLars-Peter Clausen1-28/+17
The settings for destination and source cache control are exactly the same. This patch removes the duplicated enum and uses the same for both destination and source cache control. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: pl330: Use dma_transfer_direction instead of custom pl330_reqtypeLars-Peter Clausen1-17/+8
The pl330 driver has the custom pl330_reqtype enum which has the same possible settings as the generic dma_transfer_direction enum. Switching over to the generic enum internally makes it possible to directly initialize it from the transfer request direction. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: inherit debug settings from the subsystem for subdirectoriesWolfram Sang1-2/+2
To be able to see debug messages during boot, enable the debug settings from Kconfig also for drivers in subdirectories. Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-15dmaengine: shdma: Use defines instead of hardcoded numbersGeert Uytterhoeven2-4/+3
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
2014-07-14dmaengine: Use dma_zalloc_coherentJoe Perches2-8/+5
Use the zeroing function instead of dma_alloc_coherent & memset(,0,) Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-14dmaengine: qcom_bam_dma: Add descriptor flagsAndy Gross1-2/+18
This patch adds support for end of transaction (EOT) and notify when done (NWD) hardware descriptor flags. The EOT flag requests that the peripheral assert an end of transaction interrupt when that descriptor is complete. It also results in special signaling protocol that is used between the attached peripheral and the core using the DMA controller. Clients will specify DMA_PREP_INTERRUPT to enable this flag. The NWD flag requests that the peripheral wait until the data has been fully processed by the peripheral before moving on to the next descriptor. Clients will specify DMA_PREP_FENCE to enable this flag. Signed-off-by: Andy Gross <agross@codeaurora.org> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-14dmaengine: Freescale: change descriptor release process for supporting async_txHongbo Zhang2-55/+159
Fix the potential risk when enable config NET_DMA and ASYNC_TX. Async_tx is lack of support in current release process of dma descriptor, all descriptors will be released whatever is acked or no-acked by async_tx, so there is a potential race condition when dma engine is uesd by others clients (e.g. when enable NET_DMA to offload TCP). In our case, a race condition which is raised when use both of talitos and dmaengine to offload xor is because napi scheduler will sync all pending requests in dma channels, it affects the process of raid operations due to ack_tx is not checked in fsl dma. The no-acked descriptor is freed which is submitted just now, as a dependent tx, this freed descriptor trigger BUG_ON(async_tx_test_ack(depend_tx)) in async_tx_submit(). TASK = ee1a94a0[1390] 'md0_raid5' THREAD: ecf40000 CPU: 0 GPR00: 00000001 ecf41ca0 ee44/921a94a0 0000003f 00000001 c00593e4 00000000 00000001 GPR08: 00000000 a7a7a7a7 00000001 045/920000002 42028042 100a38d4 ed576d98 00000000 GPR16: ed5a11b0 00000000 2b162000 00000200 046/920000000 2d555000 ed3015e8 c15a7aa0 GPR24: 00000000 c155fc40 00000000 ecb63220 ecf41d28 e47/92f640bb0 ef640c30 ecf41ca0 NIP [c02b048c] async_tx_submit+0x6c/0x2b4 LR [c02b068c] async_tx_submit+0x26c/0x2b4 Call Trace: [ecf41ca0] [c02b068c] async_tx_submit+0x26c/0x2b448/92 (unreliable) [ecf41cd0] [c02b0a4c] async_memcpy+0x240/0x25c [ecf41d20] [c0421064] async_copy_data+0xa0/0x17c [ecf41d70] [c0421cf4] __raid_run_ops+0x874/0xe10 [ecf41df0] [c0426ee4] handle_stripe+0x820/0x25e8 [ecf41e90] [c0429080] raid5d+0x3d4/0x5b4 [ecf41f40] [c04329b8] md_thread+0x138/0x16c [ecf41f90] [c008277c] kthread+0x8c/0x90 [ecf41ff0] [c0011630] kernel_thread+0x4c/0x68 Another modification in this patch is the change of completed descriptors, there is a potential risk which caused by exception interrupt, all descriptors in ld_running list are seemed completed when an interrupt raised, it works fine under normal condition, but if there is an exception occured, it cannot work as our excepted. Hardware should not be depend on s/w list, the right way is to read current descriptor address register to find the last completed descriptor. If an interrupt is raised by an error, all descriptors in ld_running should not be seemed finished, or these unfinished descriptors in ld_running will be released wrongly. A simple way to reproduce: Enable dmatest first, then insert some bad descriptors which can trigger Programming Error interrupts before the good descriptors. Last, the good descriptors will be freed before they are processsed because of the exception intrerrupt. Note: the bad descriptors are only for simulating an exception interrupt. This case can illustrate the potential risk in current fsl-dma very well. Signed-off-by: Hongbo Zhang <hongbo.zhang@freescale.com> Signed-off-by: Qiang Liu <qiang.liu@freescale.com> Signed-off-by: Ira W. Snyder <iws@ovro.caltech.edu> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-14dmaengine: Freescale: add suspend resume functions for DMA driverHongbo Zhang2-0/+92
This patch adds suspend and resume functions for Freescale DMA driver. Signed-off-by: Hongbo Zhang <hongbo.zhang@freescale.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-14dmaengine: Freescale: use spin_lock_bh instead of spin_lock_irqsaveHongbo Zhang1-15/+10
The usage of spin_lock_irqsave() is a stronger locking mechanism than is required throughout the driver. The minimum locking required should be used instead. Interrupts will be turned off and context will be saved, it is unnecessary to use irqsave. This patch changes all instances of spin_lock_irqsave() to spin_lock_bh(). All manipulation of protected fields is done using tasklet context or weaker, which makes spin_lock_bh() the correct choice. Signed-off-by: Hongbo Zhang <hongbo.zhang@freescale.com> Signed-off-by: Qiang Liu <qiang.liu@freescale.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-14Merge 3.16-rc5 into char-misc-nextGreg Kroah-Hartman2-7/+28
This resolves a number of merge issues with changes in this tree and Linus's tree at the same time. Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-12dma: MIC X100 DMA DriverSiva Yerramreddy4-0/+1080
This patch implements DMA Engine API for DMA controller on MIC X100 Coprocessors. DMA h/w is shared between host and card s/w. Channels 0 to 3 are used by host and 4 to 7 are used by card. Since the DMA device doesn't show up as PCIe device, a virtual bus called mic bus is created and virtual devices are added on that bus to follow device model. Allowed dma transfer directions are host to card, card to host and card to card. Reviewed-by: Ashutosh Dixit <ashutosh.dixit@intel.com> Reviewed-by: Nikhil Rao <nikhil.rao@intel.com> Reviewed-by: Sudeep Dutt <sudeep.dutt@intel.com> Signed-off-by: Siva Yerramreddy <yshivakrishna@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2014-07-11dma: rcar-audmapp: add DT supportKuninori Morimoto1-14/+58
This patch adds DT support to Audio DMAC peri peri driver. Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> [horms+renesas@verge.net.au: Do not add trailing blank line to rcar-audmapp.txt] [horms+renesas@verge.net.au: squashed patch to add NULL terminater to audmapp_of_match] Signed-off-by: Simon Horman <horms+renesas@verge.net.au> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
2014-07-09dmaengine: shdma: Add more register documentationGeert Uytterhoeven1-6/+6
Also add a few definitions that were missing. Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
2014-07-08dma: rcar-audmapp: don't keep audmapp_slave_config for each channelesKuninori Morimoto1-9/+3
Current audmapp driver is keeping audmapp_slave_config for each channeles, but, nessasary information is only "chcr". Current style (= keeping audmapp_slave_config) is not good match for DT support. Keep "chcr" instead of audmapp_slave_config Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
2014-07-08dma: rcar-audmapp: enable .set_slaveKuninori Morimoto1-9/+25
Current .set_slave callback did nothing, since it assumed src/dst address come from platform settings. But, it isn't good match to DT probing. This patch enables .set_slave callback to this issue. Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com> Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
2014-07-04dma: edma: Declare DMA_SLAVE_BUSWIDTH_3_BYTES as supported buswidthPeter Ujfalusi1-0/+1
eDMA can be configured for 3bytes word size for source and destination. Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com> Acked-by: Vinod Koul <vinod.koul@intel.com> Acked-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Mark Brown <broonie@linaro.org>
2014-07-01Update imx-sdma cyclic handling to report residueRussell King - ARM Linux1-4/+18
I received a report this morning from one of the Novena developers that the behaviour of the iMX6 ASoC codec driver (using imx-pcm-dma.c) was sub-optimal under high system load. While there are issues relating to system load remaining, upon reviewing the ASoC imx-pcm-dma.c driver, it was noticed that it not using the residue support, because SDMA doesn't support it. This has the effect that SDMA has to make multiple calls into the ASoC and ALSA code, one for each period. Since ALSA's snd_pcm_elapsed() does not need to be called multiple times and it is entirely sufficient to call it once to update ALSA with the current buffer position via the pointer method, we can do better here. We can also avoid stopping the DMA entirely, just like real cyclic DMA implementations behave. While this means that we replay some old samples, this is a nicer behaviour than having audio stop and restart. The changes to achieve this are relatively minor - imx-sdma.c can track where the DMA is to the nearest descriptor boundary - it does this already when deciding how many callbacks to issue. In doing this, buf_tail always points at the descriptor which will complete next. The residue is defined by the bytes remaining to the end of the buffer, when the buffer is viewed as a single block of memory [start...end]. So, when we start out, there's a full buffer worth of residue, and this counts down as we approach the end of the buffer, eventually becoming zero at the end, before returning to the full buffer worth when we wrap back to the start. Moving the walking of the descriptors into the interrupt handler means that we can update the BD_DONE flag at interrupt time, thus avoiding a delayed tasklet stopping the cyclic DMA. This means that the residue can be calculated from (total descriptors - buf_tail) * descriptor size. This is what the change below does. We update imx-pcm-dma.c to remove the NO_RESIDUE flag since we now provide the residue. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Tested-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-07-01dma: cppi41: handle 0-length packetsDaniel Mack1-3/+10
When a 0-length packet is received on the bus, desc->pd0 yields 1, which confuses the driver's users. This information is clearly wrong and not in accordance to the datasheet, but it's been observed on an AM335x board, very reproducible. Fix this by looking at bit 19 in PD2 of the completed packet. This bit will tell us if a zero-length packet was received on a queue. If it's set, ignore the value in PD0 and report a total length of 0 instead. Signed-off-by: Daniel Mack <zonque@gmail.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
2014-06-10Merge branch 'for-linus' of git://git.infradead.org/users/vkoul/slave-dmaLinus Torvalds19-374/+2270
Pull slave-dmaengine updates from Vinod Koul: - new Xilixn VDMA driver from Srikanth - bunch of updates for edma driver by Thomas, Joel and Peter - fixes and updates on dw, ste_dma, freescale, mpc512x, sudmac etc * 'for-linus' of git://git.infradead.org/users/vkoul/slave-dma: (45 commits) dmaengine: sh: don't use dynamic static allocation dmaengine: sh: fix print specifier warnings dmaengine: sh: make shdma_prep_dma_cyclic static dmaengine: Kconfig: Update MXS_DMA help text to include MX6Q/MX6DL of: dma: Grammar s/requests/request/, s/used required/required/ dmaengine: shdma: Enable driver compilation with COMPILE_TEST dmaengine: rcar-hpbdma: Include linux/err.h dmaengine: sudmac: Include linux/err.h dmaengine: sudmac: Keep #include sorted alphabetically dmaengine: shdmac: Include linux/err.h dmaengine: shdmac: Keep #include sorted alphabetically dmaengine: s3c24xx-dma: Add cyclic transfer support dmaengine: s3c24xx-dma: Process whole SG chain dmaengine: imx: correct sdmac->status for cyclic dma tx dmaengine: pch: fix compilation for alpha target dmaengine: dw: check return code of dma_async_device_register() dmaengine: dw: fix regression in dw_probe() function dmaengine: dw: enable clock before access dma: pch_dma: Fix Kconfig dependencies dmaengine: mpc512x: add support for peripheral transfers ...