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

[Shunsuke Mie]

On 2023/01/18 5:32, Bjorn Helgaas wrote:
> 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."
I'll reflect this remarks.
> 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.
I'll follow the previous 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
Best,

Shunsuke