dmaengine: dw-edma: Prepare for PCI EP DMA (part 1/3)

Hi,

This is part 1 of three series for PCI endpoint DMA.

The three series are:

  * part 1: dmaengine: dw-edma: Prepare for PCI EP DMA
  * part 2: PCI: endpoint: Expose endpoint DMA resources
  * part 3: PCI: endpoint: Add PCI DMA endpoint function

This first series contains the dmaengine and dw-edma groundwork needed
to let a PCI endpoint function delegate selected endpoint-integrated DMA
channels to a PCI host. It does not add the endpoint function itself.


Background
==========

I previously posted this RFC:

  [PATCH 00/15] PCI: endpoint: Remote DMA support via vNTB
  https://lore.kernel.org/linux-pci/20260312165005.1148676-...

That design exposed the endpoint-local PCIe DMA engine through
vNTB. This version moves the DMA engine into its own endpoint function
instead. The host then sees a DMA controller PCI function, and vNTB does
not need to carry a DMA-specific ABI.

The immediate motivation is NTB transport between a directly attached EP
and RC. The goal is to use the endpoint-local DMA engine and avoid the
extra CPU copy in both directions.


Scope
=====

This series:

  * makes dma_get_slave_channel() available outside dmaengine core so an
    endpoint function can reserve exact channels before delegation,
  * adds dw-edma helpers for channel lookup and per-channel interrupt routing,
  * adds a partial channel ownership mode for delegated channel sets, and
  * prepares dw-edma-pcie to describe device-specific DMA layouts through
    match data.

The PCI endpoint metadata format, DesignWare endpoint resource exposure,
and the endpoint function driver are added by parts 2 and 3.


Dependencies
============

This series is based on dmaengine/next at:

  362ee0c0dc52 ("dmaengine: Move MODULE_DEVICE_TABLE next to the table itself")

Parts 2 and 3 depend on this series.


Best regards,
Koichiro


Koichiro Den (12):
  dmaengine: Make dma_get_slave_channel() public
  dmaengine: dw-edma: Add channel lookup helper
  dmaengine: dw-edma: Add per-channel interrupt routing control
  dmaengine: dw-edma: Add partial channel ownership mode
  dmaengine: dw-edma-pcie: Add capability match data
  dmaengine: dw-edma-pcie: Rename DMA data copy
  dmaengine: dw-edma-pcie: Add default IRQ match data
  dmaengine: dw-edma-pcie: Add raw slave address match flag
  dmaengine: dw-edma-pcie: Add register offset match flag
  dmaengine: dw-edma-pcie: Factor descriptor block addresses
  dmaengine: dw-edma-pcie: Handle optional data blocks
  dmaengine: dw-edma-pcie: Add chip flags match data

 drivers/dma/dmaengine.h               |   1 -
 drivers/dma/dw-edma/dw-edma-core.c    | 134 ++++++++++++--
 drivers/dma/dw-edma/dw-edma-core.h    |  13 ++
 drivers/dma/dw-edma/dw-edma-pcie.c    | 240 +++++++++++++++++---------
 drivers/dma/dw-edma/dw-edma-v0-core.c |  26 ++-
 include/linux/dma/edma.h              |  52 ++++++
 include/linux/dmaengine.h             |   6 +
 7 files changed, 369 insertions(+), 103 deletions(-)

-- 
2.51.0