On 3 Apr 2023 17:47:50 +0200 Paul Cercueil <paul@xxxxxxxxxxxxxxx> > This function can be used to initiate a scatter-gather DMA transfer > where the DMA addresses and lengths are located inside arrays. > > The major difference with dmaengine_prep_slave_sg() is that it supports > specifying the lengths of each DMA transfer; as trying to override the > length of the transfer with dmaengine_prep_slave_sg() is a very tedious > process. The introduction of a new API function is also justified by the > fact that scatterlists are on their way out. Given sg's wayout and conceptually iovec and kvec (in include/linux/uio.h), what you add should have been dma_vec to ease people making use of it. struct dma_vec { dma_addr_t addr; size_t len; }; > > Signed-off-by: Paul Cercueil <paul@xxxxxxxxxxxxxxx> > > --- > v3: New patch > --- > include/linux/dmaengine.h | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h > index c3656e590213..62efa28c009a 100644 > --- a/include/linux/dmaengine.h > +++ b/include/linux/dmaengine.h > @@ -912,6 +912,11 @@ struct dma_device { > struct dma_async_tx_descriptor *(*device_prep_dma_interrupt)( > struct dma_chan *chan, unsigned long flags); > > + struct dma_async_tx_descriptor *(*device_prep_slave_dma_array)( > + struct dma_chan *chan, dma_addr_t *addrs, > + size_t *lengths, size_t nb, > + enum dma_transfer_direction direction, > + unsigned long flags); Then the callback looks like struct dma_async_tx_descriptor *(*device_prep_slave_vec)( struct dma_chan *chan, struct dma_vec *vec, int nvec, enum dma_transfer_direction direction, unsigned long flags);