[PATCH v2 0/7] dmaengine: dw-edma, PCI: dwc: Enable remote use of integrated DesignWare eDMA

[Koichiro Den]

Hi,

Per Frank Li's suggestion [1], this revision combines the previously posted
PCI/dwc helper series and the dmaengine/dw-edma series into a single
7-patch set. This series therefore supersedes the two earlier postings:

  - [PATCH 0/5] dmaengine: dw-edma: Add helpers for remote eDMA use scenarios
    https://lore.kernel.org/dmaengine/20260126073652.3293564-1-den@xxxxxxxxxxxxx/
  - [PATCH 0/2] PCI: dwc: Expose integrated DesignWare eDMA windows
    https://lore.kernel.org/linux-pci/20260126071550.3233631-1-den@xxxxxxxxxxxxx/

[1] https://lore.kernel.org/linux-pci/aXeoxxG+9cFML1sx@lizhi-Precision-Tower-5810/

Some DesignWare PCIe endpoint platforms integrate a DesignWare eDMA
instance alongside the PCIe controller. In remote eDMA use cases, the host
needs access to the eDMA register block and the per-channel linked-list
(LL) regions via PCIe BARs, while the endpoint may still boot with a
standard EP configuration (and may also use dw-edma locally).

This series provides the following building blocks:

  * dmaengine: Add an optional dma_slave_caps.hw_id so DMA providers can expose
    a provider-defined hardware channel identifier to clients, and report it
    from dw-edma. This allows users to correlate a DMA channel with
    hardware-specific resources such as per-channel LL regions.

  * dmaengine/dw-edma: Add features useful for remote-controlled EP eDMA usage:
      - per-channel interrupt routing control (configured via dmaengine_slave_config(),
        passing a small dw-edma-specific structure through
        dma_slave_config.peripheral_config / dma_slave_config.peripheral_size),
      - optional completion polling when local IRQ handling is disabled, and
      - notify-only channels for cases where the local side needs interrupt
	notification without cookie-based accounting (i.e. its peer
	prepares and submits the descriptors), useful when host-to-endpoint
	interrupt delivery is difficult or unavailable without it.

  * PCI: dwc: Add query-only helper APIs to expose resources of an integrated
    DesignWare eDMA instance:
      - the physical base/size of the eDMA register window, and
      - the per-channel LL region base/size, keyed by transfer direction and
        the hardware channel identifier (hw_id).

The first real user will likely be the DesignWare backend in the NTB transport work:

  [RFC PATCH v4 25/38] NTB: hw: Add remote eDMA backend registry and DesignWare backend
  https://lore.kernel.org/linux-pci/20260118135440.1958279-26-den@xxxxxxxxxxxxx/

    (Note: the implementation in this series has been updated since that
    RFC v4, so the RFC series will also need some adjustments. I have an
    updated RFC series locally and can post an RFC v5 if that would help
    review/testing.)

Apply/merge notes:
  - Patches 1-5 apply cleanly on dmaengine.git next.
  - Patches 6-7 apply cleanly on pci.git controller/dwc.

Changes in v2:
  - Combine the two previously posted series into a single set (per Frank's
    suggestion). Order dmaengine/dw-edma patches first so hw_id support
    lands before the PCI LL-region helper, which assumes
    dma_slave_caps.hw_id availability.

Thanks for reviewing,


Koichiro Den (7):
  dmaengine: Add hw_id to dma_slave_caps
  dmaengine: dw-edma: Report channel hw_id in dma_slave_caps
  dmaengine: dw-edma: Add per-channel interrupt routing control
  dmaengine: dw-edma: Poll completion when local IRQ handling is
    disabled
  dmaengine: dw-edma: Add notify-only channels support
  PCI: dwc: Add helper to query integrated dw-edma register window
  PCI: dwc: Add helper to query integrated dw-edma linked-list region

 MAINTAINERS                                  |   2 +-
 drivers/dma/dmaengine.c                      |   1 +
 drivers/dma/dw-edma/dw-edma-core.c           | 167 +++++++++++++++++--
 drivers/dma/dw-edma/dw-edma-core.h           |  21 +++
 drivers/dma/dw-edma/dw-edma-v0-core.c        |  26 ++-
 drivers/pci/controller/dwc/pcie-designware.c |  74 ++++++++
 drivers/pci/controller/dwc/pcie-designware.h |   2 +
 include/linux/dma/edma.h                     |  57 +++++++
 include/linux/dmaengine.h                    |   2 +
 include/linux/pcie-dwc-edma.h                |  72 ++++++++
 10 files changed, 398 insertions(+), 26 deletions(-)
 create mode 100644 include/linux/pcie-dwc-edma.h

-- 
2.51.0