[PATCH 6/9] dmaengine: Create a generic dma_slave_caps callback
From: Maxime Ripard <hidden>
Date: 2014-09-27 08:58:32
Also in:
lkml
Subsystem:
dma generic offload engine subsystem, the rest · Maintainers:
Vinod Koul, Linus Torvalds
dma_slave_caps is very important to the generic layers that might interact with dmaengine, such as ASoC. Unfortunately, it has been added as yet another dma_device callback, and most of the existing drivers haven't implemented it, reducing its reliability. Introduce a generic behaviour, pre-filling the dma_slave_caps struct with what it knows about the dma controller, before calling the dma_device callback, both to maintain a backward compatibility and to make sure that drivers can override that generic behaviour. Signed-off-by: Maxime Ripard <redacted> --- include/linux/dmaengine.h | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-)
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 4d0294ec3567..cfcbee145898 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h@@ -772,17 +772,24 @@ static inline struct dma_async_tx_descriptor *dmaengine_prep_interleaved_dma( static inline int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps) { + struct dma_device *device; + if (!chan || !caps) return -EINVAL; + device = chan->device; + /* check if the channel supports slave transactions */ - if (!test_bit(DMA_SLAVE, chan->device->cap_mask.bits)) + if (!test_bit(DMA_SLAVE, device->cap_mask.bits)) return -ENXIO; - if (chan->device->device_slave_caps) - return chan->device->device_slave_caps(chan, caps); + caps->cmd_pause = !!device->device_pause; + caps->cmd_terminate = !!device->device_terminate_all; + + if (device->device_slave_caps) + return device->device_slave_caps(chan, caps); - return -ENXIO; + return 0; } static inline int dmaengine_terminate_all(struct dma_chan *chan)
--
2.1.0