Re: [PATCH v9 23/27] dmaengine: dw-edma: Add mem-mapped LL-entries support

Vinod Koul
2023-02-22T16:17:05Z

On 21-02-23, 17:00, Bjorn Helgaas wrote:
> On Fri, Jan 13, 2023 at 08:14:05PM +0300, Serge Semin wrote:
> > Currently the DW eDMA driver only supports the linked lists memory
> > allocated locally with respect to the remote eDMA engine setup. It means
> > the linked lists will be accessible by the CPU via the MMIO space only. If
> > eDMA is embedded into the DW PCIe Root Ports or local End-points (which
> > support will be added in one of the following up commits) the linked lists
> > are supposed to be allocated in the CPU memory. In that case the
> > LL-entries can be directly accessed meanwhile the former case implies
> > using the MMIO-accessors for that.
> >
> > In order to have both cases supported by the driver the dw_edma_region
> > descriptor should be fixed to contain the MMIO-backed and just
> > memory-based virtual addresses. The linked lists initialization procedure
> > will use one of them depending on the eDMA device nature. If the eDMA
> > engine is embedded into the local DW PCIe RP/EP controllers then the list
> > entries will be directly accessed by referencing the corresponding
> > structure fields. Otherwise the MMIO accessors usage will be preserved.
> >
> > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
>
> Hi Vinod, I just realized that I didn't solicit your ack for this
> patch and the following one (which I ended up splitting into two), and
> I hate to ask Linus to pull them without your OK.
>
> Here are the current versions in the PCI tree:
>
> https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git/commit/?id=b47364a83054
> https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git/commit/?id=157ce95927c1
> https://git.kernel.org/pub/scm/linux/kernel/git/pci/pci.git/commit/?id=536e6529e975
>
> If you ack them, I will update them to reflect that.

Thanks for letting me know:

Acked-by: Vinod Koul <vkoul@kernel.org>

--
~Vinod