From: Alan Mikhak <alan.mikhak@sifive.com>
To: Kishon Vijay Abraham I <kishon@ti.com>
Cc: Gustavo Pimentel <Gustavo.Pimentel@synopsys.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
"arnd@arndb.de" <arnd@arndb.de>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
"jingoohan1@gmail.com" <jingoohan1@gmail.com>,
"bhelgaas@google.com" <bhelgaas@google.com>,
"wen.yang99@zte.com.cn" <wen.yang99@zte.com.cn>,
"kjlu@umn.edu" <kjlu@umn.edu>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"palmer@sifive.com" <palmer@sifive.com>,
"paul.walmsley@sifive.com" <paul.walmsley@sifive.com>,
Vinod Koul <vkoul@kernel.org>
Subject: Re: [PATCH] PCI: endpoint: Add DMA to Linux PCI EP Framework
Date: Mon, 3 Jun 2019 10:42:34 -0700 [thread overview]
Message-ID: <CABEDWGx2N66L=27JY6Ywbfny78UaxENkxBTqxU37PfuQO-ZMZw@mail.gmail.com> (raw)
In-Reply-To: <6e692ff6-e64f-e651-c8ae-34d0034ad7b9@ti.com>
On Sun, Jun 2, 2019 at 9:43 PM Kishon Vijay Abraham I <kishon@ti.com> 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@ti.com> 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
next prev parent reply other threads:[~2019-06-03 17:42 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-23 22:24 [PATCH] PCI: endpoint: Add DMA to Linux PCI EP Framework Alan Mikhak
2019-05-24 8:59 ` Gustavo Pimentel
2019-05-24 19:42 ` Alan Mikhak
2019-05-27 9:09 ` Gustavo Pimentel
2019-05-29 22:37 ` Alan Mikhak
2019-05-30 5:46 ` Kishon Vijay Abraham I
2019-05-30 17:56 ` Alan Mikhak
2019-05-31 5:06 ` Kishon Vijay Abraham I
2019-05-31 18:16 ` Alan Mikhak
2019-06-03 4:41 ` Kishon Vijay Abraham I
2019-06-03 17:42 ` Alan Mikhak [this message]
2019-09-13 12:11 ` Kishon Vijay Abraham I
2019-09-13 17:39 ` Alan Mikhak
2019-05-31 5:07 ` Vinod Koul
2019-05-31 5:20 ` Kishon Vijay Abraham I
2019-05-31 6:32 ` Vinod Koul
2019-05-31 7:49 ` Arnd Bergmann
2019-06-03 4:29 ` Kishon Vijay Abraham I
2019-06-03 4:24 ` Kishon Vijay Abraham I
2019-06-03 4:42 ` Vinod Koul
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