From d8095f94e19581057bcad35b8a725aa739e77595 Mon Sep 17 00:00:00 2001 From: Marek Szyprowski Date: Mon, 2 Jul 2018 15:08:10 +0200 Subject: dmaengine: add support for reporting pause and resume separately 'cmd_pause' DMA channel capability means that respective DMA engine supports both pausing and resuming given DMA channel. However, in some cases it is important to know if DMA channel can be paused without the need to resume it. This is a typical requirement for proper residue reading on transfer timeout in UART drivers. There are also some DMA engines with limited hardware, which doesn't really support resuming. Reporting pause and resume capabilities separately allows UART drivers to properly check for the really required capabilities and operate in DMA mode also in systems with limited DMA hardware. On the other hand drivers, which rely on full channel suspend/resume support, should now check for both 'pause' and 'resume' features. Existing clients of dma_get_slave_caps() have been checked and the only driver which rely on proper channel resuming is soc-generic-dmaengine-pcm driver, which has been updated to check the newly added capability. Existing 'cmd_pause' now only indicates that DMA engine support pausing given DMA channel. Signed-off-by: Marek Szyprowski Acked-by: Mark Brown Signed-off-by: Vinod Koul --- include/linux/dmaengine.h | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'include/linux/dmaengine.h') diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 861be5cab1df..c8c3a7a93802 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -415,7 +415,9 @@ enum dma_residue_granularity { * each type, the dma controller should set BIT() and same * should be checked by controller as well * @max_burst: max burst capability per-transfer - * @cmd_pause: true, if pause and thereby resume is supported + * @cmd_pause: true, if pause is supported (i.e. for reading residue or + * for resume later) + * @cmd_resume: true, if resume is supported * @cmd_terminate: true, if terminate cmd is supported * @residue_granularity: granularity of the reported transfer residue * @descriptor_reuse: if a descriptor can be reused by client and @@ -427,6 +429,7 @@ struct dma_slave_caps { u32 directions; u32 max_burst; bool cmd_pause; + bool cmd_resume; bool cmd_terminate; enum dma_residue_granularity residue_granularity; bool descriptor_reuse; -- cgit v1.2.3 From f39b948dbeaf9da0dfd17e68704f38fe4237788f Mon Sep 17 00:00:00 2001 From: Huang Shijie Date: Thu, 26 Jul 2018 14:45:53 +0800 Subject: dmaengine: add a new helper dmaenginem_async_device_register This patch adds the dmaenginem_async_device_register for DMA code. Use the Devres to call the release for the DMA engine driver. Signed-off-by: Huang Shijie Signed-off-by: Vinod Koul --- Documentation/driver-model/devres.txt | 1 + drivers/dma/dmaengine.c | 35 +++++++++++++++++++++++++++++++++++ include/linux/dmaengine.h | 1 + 3 files changed, 37 insertions(+) (limited to 'include/linux/dmaengine.h') diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt index 7c1bb3d0c222..43681ca0837f 100644 --- a/Documentation/driver-model/devres.txt +++ b/Documentation/driver-model/devres.txt @@ -240,6 +240,7 @@ CLOCK devm_of_clk_add_hw_provider() DMA + dmaenginem_async_device_register() dmam_alloc_coherent() dmam_alloc_attrs() dmam_declare_coherent_memory() diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 504420f213ff..272bed6c8ba7 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -1141,6 +1141,41 @@ void dma_async_device_unregister(struct dma_device *device) } EXPORT_SYMBOL(dma_async_device_unregister); +static void dmam_device_release(struct device *dev, void *res) +{ + struct dma_device *device; + + device = *(struct dma_device **)res; + dma_async_device_unregister(device); +} + +/** + * dmaenginem_async_device_register - registers DMA devices found + * @device: &dma_device + * + * The operation is managed and will be undone on driver detach. + */ +int dmaenginem_async_device_register(struct dma_device *device) +{ + void *p; + int ret; + + p = devres_alloc(dmam_device_release, sizeof(void *), GFP_KERNEL); + if (!p) + return -ENOMEM; + + ret = dma_async_device_register(device); + if (!ret) { + *(struct dma_device **)p = device; + devres_add(device->dev, p); + } else { + devres_free(p); + } + + return ret; +} +EXPORT_SYMBOL(dmaenginem_async_device_register); + struct dmaengine_unmap_pool { struct kmem_cache *cache; const char *name; diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index c8c3a7a93802..d49ec5c31944 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -1406,6 +1406,7 @@ static inline int dmaengine_desc_free(struct dma_async_tx_descriptor *desc) /* --- DMA device --- */ int dma_async_device_register(struct dma_device *device); +int dmaenginem_async_device_register(struct dma_device *device); void dma_async_device_unregister(struct dma_device *device); void dma_run_dependencies(struct dma_async_tx_descriptor *tx); struct dma_chan *dma_get_slave_channel(struct dma_chan *chan); -- cgit v1.2.3