There are DMA devices (like ours version of Synopsys DW DMAC) which have DMA capabilities non-uniformly redistributed amongst the device channels. In order to provide a way of exposing the channel-specific parameters to the DMA engine consumers, we introduce a new DMA-device callback. In case if provided it gets called from the dma_get_slave_caps() method and is able to override the generic DMA-device capabilities.
Signed-off-by: Serge Semin <[email protected]> Cc: Alexey Malahov <[email protected]> Cc: Thomas Bogendoerfer <[email protected]> Cc: Arnd Bergmann <[email protected]> Cc: Andy Shevchenko <[email protected]> Cc: Rob Herring <[email protected]> Cc: [email protected] Cc: [email protected] --- Changelog v3: - This is a new patch created as a result of the discussion with Vinod and Andy in the framework of DW DMA burst and LLP capabilities. --- drivers/dma/dmaengine.c | 3 +++ include/linux/dmaengine.h | 2 ++ 2 files changed, 5 insertions(+) diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index ad56ad58932c..edbb11d56cde 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -599,6 +599,9 @@ int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps) caps->cmd_resume = !!device->device_resume; caps->cmd_terminate = !!device->device_terminate_all; + if (device->device_caps) + device->device_caps(chan, caps); + return 0; } EXPORT_SYMBOL_GPL(dma_get_slave_caps); diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index a7e4d8dfdd19..b303e59929e5 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -899,6 +899,8 @@ struct dma_device { struct dma_chan *chan, dma_addr_t dst, u64 data, unsigned long flags); + void (*device_caps)(struct dma_chan *chan, + struct dma_slave_caps *caps); int (*device_config)(struct dma_chan *chan, struct dma_slave_config *config); int (*device_pause)(struct dma_chan *chan); -- 2.26.2
