NTB: core: Add .get_dma_dev() callback to ntb_dev_ops

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Some NTB implementations are backed by a PCI function that is not the right
struct device to use with DMA API helpers (e.g. due to IOMMU topology, or
because the NTB device is virtual).

Add an optional .get_dma_dev() callback to struct ntb_dev_ops and provide a
helper, ntb_get_dma_dev(), so NTB clients can use the appropriate struct
device for DMA allocations and mappings.

If the callback is not implemented, ntb_get_dma_dev() returns the current
default (ntb->dev.parent). Drivers that implement .get_dma_dev() must
return a non-NULL device.

Suggested-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
[bhelgaas: format doc]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Link: https://patch.msgid.link/20260306031443.1911860-2-den@valinux.co.jp

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Koichiro Den 2026-03-06 12:14:41 +09:00 • committed by Bjorn Helgaas

parent 396d44dcaf

commit 362a4549f2

1 changed files with 24 additions and 0 deletions

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include/linux/ntb.h

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