Re: [RFC PATCH 0/3] Deal with alignment restriction on EP side

[Bjorn Helgaas]

On Fri, Jan 13, 2023 at 06:03:47PM +0900, Shunsuke Mie wrote:
> Some PCIe EPC controllers have restriction to map PCIe address space to the
> local memory space. The mapping is needed to access memory of other side.
> On epf test, RC module prepares an aligned memory, and EP module maps the
> region. However, a EP module which emulate a device (e.g. VirtIO, NVMe and
> etc) cannot expect that a driver for the device prepares an aligned memory.
> So, a EP side should deal with the alignment restriction.
> 
> This patchset addresses with the alignment restriction on EP size. A
> content as follows:
> 1. Improve a pci epc unmap/map functions to cover the alignment restriction
> with adding epc driver support as EPC ops.
> 2. Implement the support function for DWC EPC driver.
> 3. Adapt the pci-epf-test to the map/unmap function updated at first patch.
> 
> I tested this changes on RENESAS board has DWC PCIeC.
> 
> This is a RFC, and it has patches for testing only. Following changes are
> not included yet:
> 1. Removing alignment codes on RC side completely
> 2. Adapting map/unmap() changes to pci-epf-ntb/vntb
> 
> Best,
> Shunsuke
> 
> Shunsuke Mie (3):
>   PCI: endpoint: support an alignment aware map/unmaping
>   PCI: dwc: support align_mem() callback for pci_epc_epc
>   PCI: endpoint: support pci_epc_mem_map/unmap API changes

s/unmaping/unmapping/

Capitalize subject lines ("Support ...").

Would be nice to say something more specific than "support ... API
changes."

The last patch seems to be for a test case.  Some previous changes to
it use the "PCI: pci-epf-test" prefix so it's distinct from the
pci-epc-core changes.

>  .../pci/controller/dwc/pcie-designware-ep.c   | 13 +++
>  drivers/pci/endpoint/functions/pci-epf-test.c | 89 +++++--------------
>  drivers/pci/endpoint/pci-epc-core.c           | 57 +++++++++---
>  include/linux/pci-epc.h                       | 10 ++-
>  4 files changed, 90 insertions(+), 79 deletions(-)
> 
> -- 
> 2.25.1
>