Re: [PATCH 0/2] PCI: dwc: Expose integrated DesignWare eDMA windows

[Frank Li]

On Mon, Jan 26, 2026 at 04:55:58PM +0900, Koichiro Den wrote:
> On Mon, Jan 26, 2026 at 04:15:48PM +0900, Koichiro Den wrote:
> > This series adds small, query-only helper APIs to the DesignWare PCIe
> > endpoint controller driver to expose resources of an integrated
> > DesignWare eDMA instance. Specifically, it allows querying:
> >
> >   - the physical base address and size of the integrated eDMA register
> >     aperture, and
> >   - the per-channel linked-list (LL) region base and size, keyed by
> >     transfer direction and hardware channel identifier.
> >
> > The motivation is that some DesignWare PCIe endpoint platforms integrate
> > an eDMA engine that can be driven either locally by the endpoint or
> > remotely by the host. Remote eDMA use cases (e.g. [1]) need to expose
> > the eDMA register block and LL regions to the host through PCIe BARs,
> > while still allowing the endpoint to boot with a standard EP settings,
> > without DT changes to hide the eDMA instance from the endpoint itself.
> >
> > The hardware channel identifier used by the LL-region helper can be
> > obtained via dma_get_slave_caps().hw_id, introduced by a dmaengine
> > series posted separately.
>
> For reference, the series has been submitted here:
>
>   [PATCH 0/5] dmaengine: dw-edma: Add helpers for remote eDMA use scenarios
>   https://lore.kernel.org/dmaengine/20260126073652.3293564-1-den@xxxxxxxxxxxxx/

It'd better post together. It needs API user.

Frank
>
> Kind regards,
> Koichiro
>
> >
> > [1] [RFC PATCH v4 00/38] NTB transport backed by PCI EP embedded DMA
> >     https://lore.kernel.org/linux-pci/20260118135440.1958279-1-den@xxxxxxxxxxxxx/
> >
> > Developed on PCI controller/dwc:
> >   commit 0ecd890e3cf5 ("PCI: dwc: Rename dw_pcie_rp::has_msi_ctrl to
> >                         dw_pcie_rp::use_imsi_rx for clarity")
> >
> > Kind regards,
> >
> > Koichiro Den (2):
> >   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/pci/controller/dwc/pcie-designware.c | 74 ++++++++++++++++++++
> >  drivers/pci/controller/dwc/pcie-designware.h |  2 +
> >  include/linux/pcie-dwc-edma.h                | 72 +++++++++++++++++++
> >  4 files changed, 149 insertions(+), 1 deletion(-)
> >  create mode 100644 include/linux/pcie-dwc-edma.h
> >
> > --
> > 2.51.0
> >