| From: |
| Frank.Li-AT-oss.nxp.com |
| To: |
| Vinod Koul <vkoul-AT-kernel.org>, Manivannan Sadhasivam <mani-AT-kernel.org>, Krzysztof Wilczyński <kwilczynski-AT-kernel.org>, Kishon Vijay Abraham I <kishon-AT-kernel.org>, Bjorn Helgaas <bhelgaas-AT-google.com>, Christoph Hellwig <hch-AT-lst.de>, Sagi Grimberg <sagi-AT-grimberg.me>, Chaitanya Kulkarni <kch-AT-nvidia.com>, Herbert Xu <herbert-AT-gondor.apana.org.au>, "David S. Miller" <davem-AT-davemloft.net>, Nicolas Ferre <nicolas.ferre-AT-microchip.com>, Alexandre Belloni <alexandre.belloni-AT-bootlin.com>, Claudiu Beznea <claudiu.beznea-AT-tuxon.dev>, Koichiro Den <den-AT-valinux.co.jp>, Niklas Cassel <cassel-AT-kernel.org> |
| Subject: |
| [PATCH v6 0/9] dmaengine: Add new API to combine configuration and descriptor preparation |
| Date: |
| Wed, 20 May 2026 18:00:41 -0400 |
| Message-ID: |
| <20260520-dma_prep_config-v6-0-06e49b7acb38@nxp.com> |
| Cc: |
| dmaengine-AT-vger.kernel.org, linux-kernel-AT-vger.kernel.org, linux-pci-AT-vger.kernel.org, linux-nvme-AT-lists.infradead.org, mhi-AT-lists.linux.dev, linux-arm-msm-AT-vger.kernel.org, linux-crypto-AT-vger.kernel.org, linux-arm-kernel-AT-lists.infradead.org, imx-AT-lists.linux.dev, Frank Li <Frank.Li-AT-nxp.com>, Damien Le Moal <dlemoal-AT-kernel.org> |
| Archive-link: |
| Article |
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_config_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_config_single_safe() API
Signed-off-by: Frank Li <Frank.Li@nxp.com>
---
Changes in v6:
- Fix sashaki AI report problem, detail see each patch's change log
- Link to v5: https://lore.kernel.org/r/20260512-dma_prep_config-v5-0-2...
Changes in v5:
- collect Mani's reviewed-by tags
- use kernel doc for new APIs.
- Link to v4: https://lore.kernel.org/r/20260506-dma_prep_config-v4-0-8...
Changes in v4:
- remove void* context in config_prep() callback
- use spin lock to protect config() and prep().
- Link to v3: https://lore.kernel.org/r/20260105-dma_prep_config-v3-0-a...
Changes in v3:
- collect review tags
- create safe version in framework
- Link to v2: https://lore.kernel.org/r/20251218-dma_prep_config-v2-0-c...
Changes in v2:
- Use name dmaengine_prep_config_single() and dmaengine_prep_config_sg()
- Add _safe version to avoid confuse, which needn't additional mutex.
- Update document/
- Update commit message. add () for function name. Use upcase for subject.
- Add more explain for remove lock.
- Link to v1: https://lore.kernel.org/r/20251208-dma_prep_config-v1-0-5...
---
Frank Li (9):
dmaengine: Add API to combine configuration and preparation (sg and single)
dmaengine: Add safe API to combine configuration and preparation
PCI: endpoint: pci-epf-test: Use dmaenigne_prep_config_single() to simplify code
dmaengine: dw-edma: Use new .device_prep_config_sg() 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_config_single_safe() API
PCI: epf-mhi: Use dmaengine_prep_config_single() to simplify code
crypto: atmel: Use dmaengine_prep_config_sg() API
Documentation/driver-api/dmaengine/client.rst | 9 ++
drivers/crypto/atmel-aes.c | 10 +-
drivers/dma/dmaengine.c | 2 +
drivers/dma/dw-edma/dw-edma-core.c | 41 +++++--
drivers/nvme/target/pci-epf.c | 24 +----
drivers/pci/endpoint/functions/pci-epf-mhi.c | 52 +++------
drivers/pci/endpoint/functions/pci-epf-test.c | 8 +-
include/linux/dmaengine.h | 149 ++++++++++++++++++++++++--
8 files changed, 208 insertions(+), 87 deletions(-)
---
base-commit: 254f49634ee16a731174d2ae34bc50bd5f45e731
change-id: 20251204-dma_prep_config-654170d245a2
Best regards,
--
Frank Li <Frank.Li@nxp.com>
