Re: [PATCH v4 6/6] PCI: dwc: Implement endpoint DMA channel delegation

[sashiko-bot@kernel.org]

> Implement the EPC DMA channel delegation operations for DesignWare
> endpoint controllers. The DWC backend uses the local DesignWare eDMA
> provider to reserve the requested hardware channel and returns it as an
> opaque EPC DMA channel handle to generic endpoint functions.
> 
> Validate the requested direction and hardware channel against the
> linked-list channel counts before delegation.
> 
> DWC eDMA/HDMA generates DMA requests with a programmable requester
> function number. For delegated channels, the host-side dw-edma-pcie
> instance bound to the exposed DMA function reserves the channel and
> programs its own PCI_FUNC() into the per-channel requester field; the
> endpoint-side chip func_no does not participate in that handoff.
> 
> Reject VF requests because the RC-programmable DWC eDMA/HDMA register
> window is assigned to a PF BAR only.
> 
> Reclaim releases the delegated local channel through the DesignWare eDMA
> provider, which returns it to endpoint ownership. Propagate the EPC
> quiesce request so bind failure paths can release unexposed reservations
> without touching DMA engine state.
> 
> Signed-off-by: Koichiro Den <den@valinux.co.jp>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20260710082156.2395844-1-den@valinux.co.jp?part=6