linux/drivers/dma/dmaengine.c, branch v4.6

dmaengine: core: expose max burst capability to clients

2016-02-09T03:31:41Z

This patch add max_burst to dma_get_slave_caps for clients to get the burst capability of slave dma controller. Signed-off-by: Shawn Lin Signed-off-by: Caesar Wang Signed-off-by: Vinod Koul

Merge branch 'topic/async' into for-linus

2016-01-06T09:47:47Z

Merge branch 'topic/univ_api' into for-linus

2016-01-06T09:47:32Z

dmaengine: core: Introduce new, universal API to request a channel

2015-12-18T05:47:26Z

The two API function can cover most, if not all current APIs used to request a channel. With minimal effort dmaengine drivers, platforms and dmaengine user drivers can be converted to use the two function. struct dma_chan *dma_request_chan_by_mask(const dma_cap_mask_t *mask); To request any channel matching with the requested capabilities, can be used to request channel for memcpy, memset, xor, etc where no hardware synchronization is needed. struct dma_chan *dma_request_chan(struct device *dev, const char *name); To request a slave channel. The dma_request_chan() will try to find the channel via DT, ACPI or in case if the kernel booted in non DT/ACPI mode it will use a filter lookup table and retrieves the needed information from the dma_slave_map provided by the DMA drivers. This legacy mode needs changes in platform code, in dmaengine drivers and finally the dmaengine user drivers can be converted: For each dmaengine driver an array of DMA device, slave and the parameter for the filter function needs to be added: static const struct dma_slave_map da830_edma_map[] = { { "davinci-mcasp.0", "rx", EDMA_FILTER_PARAM(0, 0) }, { "davinci-mcasp.0", "tx", EDMA_FILTER_PARAM(0, 1) }, { "davinci-mcasp.1", "rx", EDMA_FILTER_PARAM(0, 2) }, { "davinci-mcasp.1", "tx", EDMA_FILTER_PARAM(0, 3) }, { "davinci-mcasp.2", "rx", EDMA_FILTER_PARAM(0, 4) }, { "davinci-mcasp.2", "tx", EDMA_FILTER_PARAM(0, 5) }, { "spi_davinci.0", "rx", EDMA_FILTER_PARAM(0, 14) }, { "spi_davinci.0", "tx", EDMA_FILTER_PARAM(0, 15) }, { "da830-mmc.0", "rx", EDMA_FILTER_PARAM(0, 16) }, { "da830-mmc.0", "tx", EDMA_FILTER_PARAM(0, 17) }, { "spi_davinci.1", "rx", EDMA_FILTER_PARAM(0, 18) }, { "spi_davinci.1", "tx", EDMA_FILTER_PARAM(0, 19) }, }; This information is going to be needed by the dmaengine driver, so modification to the platform_data is needed, and the driver map should be added to the pdata of the DMA driver: da8xx_edma0_pdata.slave_map = da830_edma_map; da8xx_edma0_pdata.slavecnt = ARRAY_SIZE(da830_edma_map); The DMA driver then needs to configure the needed device -> filter_fn mapping before it registers with dma_async_device_register() : ecc->dma_slave.filter_map.map = info->slave_map; ecc->dma_slave.filter_map.mapcnt = info->slavecnt; ecc->dma_slave.filter_map.fn = edma_filter_fn; When neither DT or ACPI lookup is available the dma_request_chan() will try to match the requester's device name with the filter_map's list of device names, when a match found it will use the information from the dma_slave_map to get the channel with the dma_get_channel() internal function. Signed-off-by: Peter Ujfalusi Reviewed-by: Arnd Bergmann Signed-off-by: Vinod Koul

dmaengine: core: Move and merge the code paths using private_candidate

2015-12-18T05:47:26Z

Channel matching with private_candidate() is used in two paths, the error checking is slightly different in them and they are duplicating code also. Move the code under find_candidate() to provide consistent execution and going to allow us to reuse this mode of channel lookup later. Signed-off-by: Peter Ujfalusi Reviewed-by: Andy Shevchenko Reviewed-by: Arnd Bergmann Signed-off-by: Vinod Koul

dmaengine: core: Skip mask matching when it is not provided to private_candidate

2015-12-18T05:47:26Z

If mask is NULL skip the mask matching against the DMA device capabilities. Signed-off-by: Peter Ujfalusi Reviewed-by: Andy Shevchenko Reviewed-by: Arnd Bergmann Signed-off-by: Vinod Koul

dmaengine: enable DMA_CTRL_REUSE

2015-11-16T03:02:16Z

In the current state, the capability of transfer reuse can neither be set by a slave dmaengine driver, nor used by a client driver, because the capability is not available to dma_get_slave_caps(). Fix this by adding a way to declare the capability. Fixes: 272420214d26 ("dmaengine: Add DMA_CTRL_REUSE") Signed-off-by: Robert Jarzmik Signed-off-by: Vinod Koul

dmaengine: Add transfer termination synchronization support

2015-11-16T02:58:52Z

The DMAengine API has a long standing race condition that is inherent to the API itself. Calling dmaengine_terminate_all() is supposed to stop and abort any pending or active transfers that have previously been submitted. Unfortunately it is possible that this operation races against a currently running (or with some drivers also scheduled) completion callback. Since the API allows dmaengine_terminate_all() to be called from atomic context as well as from within a completion callback it is not possible to synchronize to the execution of the completion callback from within dmaengine_terminate_all() itself. This means that a user of the DMAengine API does not know when it is safe to free resources used in the completion callback, which can result in a use-after-free race condition. This patch addresses the issue by introducing an explicit synchronization primitive to the DMAengine API called dmaengine_synchronize(). The existing dmaengine_terminate_all() is deprecated in favor of dmaengine_terminate_sync() and dmaengine_terminate_async(). The former aborts all pending and active transfers and synchronizes to the current context, meaning it will wait until all running completion callbacks have finished. This means it is only possible to call this function from non-atomic context. The later function does not synchronize, but can still be used in atomic context or from within a complete callback. It has to be followed up by dmaengine_synchronize() before a client can free the resources used in a completion callback. In addition to this the semantics of the device_terminate_all() callback are slightly relaxed by this patch. It is now OK for a driver to only schedule the termination of the active transfer, but does not necessarily have to wait until the DMA controller has completely stopped. The driver must ensure though that the controller has stopped and no longer accesses any memory when the device_synchronize() callback returns. This was in part done since most drivers do not pay attention to this anyway at the moment and to emphasize that this needs to be done when the device_synchronize() callback is implemented. But it also helps with implementing support for devices where stopping the controller can require operations that may sleep. Signed-off-by: Lars-Peter Clausen Signed-off-by: Vinod Koul

Merge tag 'dmaengine-4.4-rc1' of git://git.infradead.org/users/vkoul/slave-dma

2015-11-10T18:05:17Z

Pull dmaengine updates from Vinod Koul: "This time we have a very typical update which is mostly fixes and updates to drivers and no new drivers. - the biggest change is coming from Peter for edma cleanup which even caused some last minute regression, things seem settled now - idma64 and dw updates - iotdma updates - module autoload fixes for various drivers - scatter gather support for hdmac" * tag 'dmaengine-4.4-rc1' of git://git.infradead.org/users/vkoul/slave-dma: (77 commits) dmaengine: edma: Add dummy driver skeleton for edma3-tptc Revert "ARM: DTS: am33xx: Use the new DT bindings for the eDMA3" Revert "ARM: DTS: am437x: Use the new DT bindings for the eDMA3" dmaengine: dw: some Intel devices has no memcpy support dmaengine: dw: platform: provide platform data for Intel dmaengine: dw: don't override platform data with autocfg dmaengine: hdmac: Add scatter-gathered memset support dmaengine: hdmac: factorise memset descriptor allocation dmaengine: virt-dma: Fix kernel-doc annotations ARM: DTS: am437x: Use the new DT bindings for the eDMA3 ARM: DTS: am33xx: Use the new DT bindings for the eDMA3 dmaengine: edma: New device tree binding dmaengine: Kconfig: edma: Select TI_DMA_CROSSBAR in case of ARCH_OMAP dmaengine: ti-dma-crossbar: Add support for crossbar on AM33xx/AM43xx dmaengine: edma: Merge the of parsing functions dmaengine: edma: Do not allocate memory for edma_rsv_info in case of DT boot dmaengine: edma: Refactor the dma device and channel struct initialization dmaengine: edma: Get qDMA channel information from HW also dmaengine: edma: Merge map_dmach_to_queue into assign_channel_eventq dmaengine: edma: Correct PaRAM access function names (_parm_ to _param_) ...

dmaengine: fix balance of privatecnt

2015-09-30T08:00:08Z

dma_release_channel() decrements privatecnt counter and almost all dma_get* function increments it with the exception of dma_get_slave_channel(). In most cases this does not cause issue since normally the channel is not requested and released, but if a driver requests DMA channel via dma_get_slave_channel() and releases the channel the privatecnt will be unbalanced and this will prevent for example getting channel for memcpy. Signed-off-by: Peter Ujfalusi Signed-off-by: Vinod Koul