linux-kernel - Re: [PATCH 1/5] PCI: endpoint: functions/pci-epf-test: Add DMA support to transfer data

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Message-ID: <eb57e52a-be34-dd2c-3820-21fe7dc68185@ti.com>
Date:   Wed, 4 Mar 2020 10:45:16 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Alan Mikhak <alan.mikhak@...ive.com>
CC:     <amurray@...goodpenguin.co.uk>, <arnd@...db.de>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        <gregkh@...uxfoundation.org>, <linux-kernel@...r.kernel.org>,
        linux-pci <linux-pci@...r.kernel.org>,
        <lorenzo.pieralisi@....com>
Subject: Re: [PATCH 1/5] PCI: endpoint: functions/pci-epf-test: Add DMA
 support to transfer data

Hi Alan,

On 04/03/20 5:27 am, Alan Mikhak wrote:
> On Wed, Feb 26, 2020 at 9:39 AM Alan Mikhak <alan.mikhak@...ive.com> wrote:
>>
>> On Tue, Feb 25, 2020 at 9:27 PM Kishon Vijay Abraham I <kishon@...com> wrote:
>>>
>>> Hi Alan,
>>>
>>> On 26/02/20 2:41 am, Alan Mikhak wrote:
>>>> @@ -380,6 +572,7 @@ static void pci_epf_test_unbind(struct pci_epf *epf)
>>>>         int bar;
>>>>
>>>>         cancel_delayed_work(&epf_test->cmd_handler);
>>>> +       pci_epf_clean_dma_chan(epf_test);
>>>>         pci_epc_stop(epc);
>>>>         for (bar = 0; bar < PCI_STD_NUM_BARS; bar++) {
>>>>                 epf_bar = &epf->bar[bar];
>>>> @@ -550,6 +743,12 @@ static int pci_epf_test_bind(struct pci_epf *epf)
>>>>                 }
>>>>         }
>>>>
>>>> +       epf_test->dma_supported = true;
>>>> +
>>>> +       ret = pci_epf_init_dma_chan(epf_test);
>>>> +       if (ret)
>>>> +               epf_test->dma_supported = false;
>>>> +
>>>>         if (linkup_notifier) {
>>>>                 epf->nb.notifier_call = pci_epf_test_notifier;
>>>>                 pci_epc_register_notifier(epc, &epf->nb);
>>>>
>>>> Hi Kishon,
>>>>
>>>> Looking forward to building and trying this patch series on
>>>> a platform I work on.
> 
> Hi Kishon,
> 
> I applied this v1 patch series to kernel.org linux 5.6-rc3 and built for
> x86_64 Debian and riscv. I verified that when I execute the pcitest
> command on the x86_64 host with -d flag, the riscv endpoint performs
> the transfer by using an available dma channel.

Thank you for testing this.
I've posted a new version after renaming the function names to
pci_epf_test_init_dma_chan() and pci_epf_test_cleanup_dma_chan() [1]
Can you add your "Tested-by: " tag in that series so that Lorenzo can
pick it up?

Thanks
Kishon

[1] -> http://lore.kernel.org/r/20200303103752.13076-1-kishon@ti.com

> 
> Regards,
> Alan
> 
>>>>
>>>> Would you please point me to where I can find the patches
>>>> which add pci_epf_init_dma_chan() and pci_epf_clean_dma_chan()
>>>> to Linux PCI Endpoint Framework?
>>>
>>> I've added these functions in pci-epf-test itself instead of adding in
>>> the core files. I realized adding it in core files may not be helpful if
>>> the endpoint function decides to use more number of DMA channels etc.,
>>
>> Thanks Kishon,
>>
>> I now realize they are in [PATCH 1/5] of this series. May I suggest renaming
>> them to pci_epf_test_init_dma_chan() and pci_epf_test_cleanup_dma_chan()?
>> With just pci_epf in their name, I was looking for them in pci-epf-core.c.
>>
>> Regards,
>> Alan
>>
>>>
>>> Thanks
>>> Kishon