driver-api/pci/p2pdma.rst

1 .. SPDX-License-Identifier: GPL-2.0
4 PCI Peer-to-Peer DMA Support
7 The PCI bus has pretty decent support for performing DMA transfers
9 called Peer-to-Peer (or P2P). However, there are a number of issues that
10 make P2P transactions tricky to do in a perfectly safe way.
36 * Provider - A driver which provides or publishes P2P resources like
38 * Client - A driver which makes use of a resource by setting up a
39   DMA transaction to or from it.
40 * Orchestrator - A driver which orchestrates the flow of data between
54   can DMA directly to the memory exposed by the NVMe device.
67 ----------------
70 as a P2P DMA resource using :c:func:`pci_p2pdma_add_resource()`.
84 --------------
86 A client driver typically only has to conditionally change its DMA map
95 given request is P2P memory and map appropriately. It is important to
102 --------------------
122 allocating scatter-gather lists with P2P memory.
125 -------------------
137 P2P DMA Support Library
140 .. kernel-doc:: drivers/pci/p2pdma.c