Changes since v1: - Use the existing dma_transaction_type enums instead of adding the mostly duplicated dmaengine_apis enums This series adds a new dmaengine api, dma_get_channels_caps(), which may be used by a driver to get channel-specific capabilities. This is based on a starting point suggested by Vinod Koul, but only implements the minimal sets of channel capabilities to fulfill the needs of the EDMA DMA Engine driver at this time. Specifically, this implementation supports reporting of a set of transfer type operations, maximum number of SG segments, and the maximum size of an SG segment that a channel can support. The call is implemented as follows: struct dmaengine_chan_caps *dma_get_channel_caps(struct dma_chan *chan, enum dma_transfer_direction dir); The dma transfer direction parameter may appear a bit out of place but it is necessary since the direction field in struct dma_slave_config was deprecated. In some cases, EDMA for one, it is necessary for the dmaengine driver to have the burst and address width slave configuration parameters available in order to compute the maximum segment size that can be handle. Due to this requirement, the calling order of this api is as follows: 1. Allocate a DMA slave channel 1a. [Optionally] Get channel capabilities 2. Set slave and controller specific parameters 3. Get a descriptor for transaction 4. Submit the transaction 5. Issue pending requests and wait for callback notification Along with the API implementation, this series implements the backend device_channel_caps() in the EDMA DMA Engine driver and converts the davinci_mmc driver to use dma_get_channel_caps() to replace hardcoded limits. This is tested on the AM1808-EVM. Matt Porter (3): dmaengine: add dma_get_channel_caps() dma: edma: add device_channel_caps() support mmc: davinci: get SG segment limits with dma_get_channel_caps() drivers/dma/edma.c | 27 ++++++++++++ drivers/mmc/host/davinci_mmc.c | 66 +++++++++-------------------- include/linux/dmaengine.h | 40 +++++++++++++++++ include/linux/platform_data/mmc-davinci.h | 3 -- 4 files changed, 88 insertions(+), 48 deletions(-) -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
