[PATCH 0/8] dmaengine: Add new API to combine onfiguration and descriptor preparation

Frank Li
2025-12-08T17:10:18Z

Previously, configuration and preparation required two separate calls. This
works well when configuration is done only once during initialization.

However, in cases where the burst length or source/destination address must
be adjusted for each transfer, calling two functions is verbose.

if (dmaengine_slave_config(chan, &sconf)) {
dev_err(dev, "DMA slave config fail\n");
return -EIO;
}

tx = dmaengine_prep_slave_single(chan, dma_local, len, dir, flags);

After new API added

tx = dmaengine_prep_slave_single(chan, dma_local, len, dir, flags, &sconf);

Additional, prevous two calls requires additional locking to ensure both
steps complete atomically.

mutex_lock()
dmaengine_slave_config()
dmaengine_prep_slave_single()
mutex_unlock()

after new API added, mutex lock can be moved. See patch
nvmet: pci-epf: Use dmaengine_prep_slave_single_config() API

Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Frank Li (8):
dmaengine: Add API to combine configuration and preparation (sg and single)
PCI: endpoint: pci-epf-test: use new DMA API to simple code
dmaengine: dw-edma: Use new .device_prep_slave_sg_config() callback
dmaengine: dw-edma: Pass dma_slave_config to dw_edma_device_transfer()
nvmet: pci-epf: Remove unnecessary dmaengine_terminate_sync() on each DMA transfer
nvmet: pci-epf: Use dmaengine_prep_slave_single_config() API
PCI: epf-mhi:Using new API dmaengine_prep_slave_single_config() to simple code.
crypto: atmel: Use dmaengine_prep_slave_single_config() API

drivers/crypto/atmel-aes.c | 10 ++---
drivers/dma/dw-edma/dw-edma-core.c | 38 +++++++++++-----
drivers/nvme/target/pci-epf.c | 21 +++------
drivers/pci/endpoint/functions/pci-epf-mhi.c | 52 +++++++---------------
drivers/pci/endpoint/functions/pci-epf-test.c | 8 +---
include/linux/dmaengine.h | 64 ++++++++++++++++++++++++---
6 files changed, 111 insertions(+), 82 deletions(-)
---
base-commit: bc04acf4aeca588496124a6cf54bfce3db327039
change-id: 20251204-dma_prep_config-654170d245a2

Best regards,
--
Frank Li <Frank.Li@nxp.com>