On Fri, Sep 13, 2019 at 5:11 AM Kishon Vijay Abraham I <kishon@xxxxxx> wrote: > > + Haotian Wang > > On 03/06/19 11:12 PM, Alan Mikhak wrote: > > On Sun, Jun 2, 2019 at 9:43 PM Kishon Vijay Abraham I <kishon@xxxxxx> wrote: > >> Hi Alan, > >> On 31/05/19 11:46 PM, Alan Mikhak wrote: > >>> On Thu, May 30, 2019 at 10:08 PM Kishon Vijay Abraham I <kishon@xxxxxx> wrote: > >>>> Hi Alan, > >>>>> Hi Kishon, > >>>> > >>>> I still have to look closer into your DMA patch but linked-list mode or single > >>>> block mode shouldn't be an user select-able option but should be determined by > >>>> the size of transfer. > >>> > >>> Please consider the following when taking a closer look at this patch. > >> > >> After seeing comments from Vinod and Arnd, it looks like the better way of > >> adding DMA support would be to register DMA within PCI endpoint controller to > >> DMA subsystem (as dmaengine) and use only dmaengine APIs in pci_epf_test. > > > > Thanks Kishon. That makes it clear where these pieces should go. > > > >>> In my specific use case, I need to verify that any valid block size, > >>> including a one byte transfer, can be transferred across the PCIe bus > >>> by memcpy_toio/fromio() or by DMA either as a single block or as > >>> linked-list. That is why, instead of deciding based on transfer size, > >>> this patch introduces the '-L' flag for pcitest to communicate the > >>> user intent across the PCIe bus to pci-epf-test so the endpoint can > >>> initiate the DMA transfer using a single block or in linked-list mode. > >> The -L option seems to select an internal DMA configuration which might be > >> specific to one implementation. As Gustavo already pointed, we should have only > >> generic options in pcitest. This would no longer be applicable when we move to > >> dmaengine. > > > > Single-block DMA seemed as generic as linked-list DMA and > > memcpy_toio/fromio. It remains unclear how else to communicate that > > intent to pci_epf_test each time I invoke pcitest. > > > > Regards, > > Alan > > Hi Kishon, FYI, I integrated your changes for DMAengine client support to PCI endpoint framework into my development branch. The following is the link you provided earlier as reference. I have been using it with good results. Haotian Wang also used it in a recent patch for PCI endpoint function for virtnet. Would you be able to comment on if and when your DMAengine client support may be submitted upstream? http://git.ti.com/cgit/cgit.cgi/ti-linux-kernel/ti-linux-kernel.git/tree/drivers/pci/endpoint/pci-epf-core.c?h=ti-linux-4.19.y Regards, Alan Mikhak
