RE: [PATCH v1 7/7] fpga: dfl: pci: Add generic OFS PCI PID

["Zhang, Tianfei" <tianfei.zhang@intel.com>]

> -----Original Message-----
> From: Tom Rix <trix@redhat.com>
> Sent: Tuesday, February 22, 2022 2:10 AM
> To: matthew.gerlach@linux.intel.com
> Cc: Zhang, Tianfei <tianfei.zhang@intel.com>; Wu, Hao <hao.wu@intel.com>;
> mdf@kernel.org; Xu, Yilun <yilun.xu@intel.com>; linux-fpga@vger.kernel.org;
> linux-doc@vger.kernel.org; linux-kernel@vger.kernel.org; corbet@lwn.net
> Subject: Re: [PATCH v1 7/7] fpga: dfl: pci: Add generic OFS PCI PID
> 
> 
> On 2/21/22 9:50 AM, matthew.gerlach@linux.intel.com wrote:
> >
> >
> > On Fri, 18 Feb 2022, Tom Rix wrote:
> >
> >>
> >> On 2/18/22 1:03 AM, Zhang, Tianfei wrote:
> >>>
> >>>> -----Original Message-----
> >>>> From: Tom Rix <trix@redhat.com>
> >>>> Sent: Wednesday, February 16, 2022 12:16 AM
> >>>> To: Zhang, Tianfei <tianfei.zhang@intel.com>; Wu, Hao
> >>>> <hao.wu@intel.com>; mdf@kernel.org; Xu, Yilun <yilun.xu@intel.com>;
> >>>> linux-fpga@vger.kernel.org; linux-doc@vger.kernel.org;
> >>>> linux-kernel@vger.kernel.org
> >>>> Cc: corbet@lwn.net; Matthew Gerlach
> >>>> <matthew.gerlach@linux.intel.com>
> >>>> Subject: Re: [PATCH v1 7/7] fpga: dfl: pci: Add generic OFS PCI PID
> >>>>
> >>>>
> >>>> On 2/14/22 3:26 AM, Tianfei zhang wrote:
> >>>>> From: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> >>>>>
> >>>>> Add the PCI product id for an Open FPGA Stack PCI card.
> >>>> Is there a URL to the card ?
> >>> This PCIe Device IDs have registered by Intel.
> >> A URL is useful to introduce the board, Is there one ?
> >>>
> >>>>> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> >>>>> Signed-off-by: Tianfei Zhang <tianfei.zhang@intel.com>
> >>>>> ---
> >>>>>    drivers/fpga/dfl-pci.c | 4 ++++
> >>>>>    1 file changed, 4 insertions(+)
> >>>>>
> >>>>> diff --git a/drivers/fpga/dfl-pci.c b/drivers/fpga/dfl-pci.c index
> >>>>> 83b604d6dbe6..cb2fbf3eb918 100644
> >>>>> --- a/drivers/fpga/dfl-pci.c
> >>>>> +++ b/drivers/fpga/dfl-pci.c
> >>>>> @@ -76,12 +76,14 @@ static void cci_pci_free_irq(struct pci_dev
> >>>>> *pcidev)
> >>>>>    #define PCIE_DEVICE_ID_INTEL_PAC_D5005        0x0B2B
> >>>>>    #define PCIE_DEVICE_ID_SILICOM_PAC_N5010    0x1000
> >>>>>    #define PCIE_DEVICE_ID_SILICOM_PAC_N5011    0x1001
> >>>>> +#define PCIE_DEVICE_ID_INTEL_OFS        0xbcce
> >>>> INTEL_OFS is a generic name, pci id's map to specific cards
> >>>>
> >>>> Is there a more specific name for this card ?
> >>> I think using INTEL_OFS is better, because INTEL_OFS is the Generic
> >>> development platform can support multiple cards which using OFS
> >>> specification, like Intel PAC N6000 card.
> >>
> >> I would prefer something like PCIE_DEVICE_ID_INTEL_PAC_N6000 because
> >> it follows an existing pattern.  Make it easy on a developer, they
> >> will look at their board or box, see X and try to find something
> >> similar in the driver source.
> >>
> >> To use OSF_ * the name needs a suffix to differentiate it from future
> >> cards that will also use ofs.
> >>
> >> If this really is a generic id please explain in the doc patch how
> >> every future board with use this single id and how a driver could
> >> work around a hw problem in a specific board with a pci id covering
> >> multiple boards.
> >>
> >> Tom
> >
> > Hi Tom,
> >
> > The intent is to have a generic device id that can be used with many
> > different boards.  Currently, we have FPGA implementations for 3
> > different boards using this generic id.  We may need a better name for
> > device id than OFS.  More precisely this generic device id means a PCI
> > function that is described by a Device Feature List (DFL).  How about
> > PCIE_DEVICE_ID_INTEL_DFL?
> >
> > With a DFL device id, the functionality of the PF/VF is determined by
> > the contents of the DFL.  Each Device Feature Header (DFH) in the DFL
> > has a revision field that can be used identify "broken" hw, or new
> > functionality added to a feature.  Additionally, since the DFL is
> > typically used in a FPGA, the broken hardware, can and should be fixed
> > in most cases.
> 
> How is lspci supposed to work ?

There is an example for one card using IOFS and DFL.

# lspci | grep acc
b1:00.0 Processing accelerators: Intel Corporation Device bcce (rev 01)
b1:00.1 Processing accelerators: Intel Corporation Device bcce
b1:00.2 Processing accelerators: Intel Corporation Device bcce
b1:00.3 Processing accelerators: Red Hat, Inc. Virtio network device
b1:00.4 Processing accelerators: Intel Corporation Device bcce

Note: There 5 PFs in this card, it exports the management functions via PF0(b1:00.0),
Other PFs like b1:00.1, b1:00.2, b1:00.4, are using for testing, which depends on RTL designer
or project requirement. The PF3 instance a VirtIO net device for example, will bind with virtio-net driver
presenting itself as a network interface to the OS.

> 
> A dfl set can change with fw updates and in theory different boards could have
> the same set.
> 
> Tom
> 
> >
> > Matthew
> >>
> >>>
> >>>> Tom
> >>>>
> >>>>>    /* VF Device */
> >>>>>    #define PCIE_DEVICE_ID_VF_INT_5_X        0xBCBF
> >>>>>    #define PCIE_DEVICE_ID_VF_INT_6_X        0xBCC1
> >>>>>    #define PCIE_DEVICE_ID_VF_DSC_1_X        0x09C5
> >>>>>    #define PCIE_DEVICE_ID_INTEL_PAC_D5005_VF    0x0B2C
> >>>>> +#define PCIE_DEVICE_ID_INTEL_OFS_VF        0xbccf
> >>>>>
> >>>>>    static struct pci_device_id cci_pcie_id_tbl[] = {
> >>>>>        {PCI_DEVICE(PCI_VENDOR_ID_INTEL,
> >>>>> PCIE_DEVICE_ID_PF_INT_5_X),},
> >>>> @@
> >>>>> -95,6 +97,8 @@ static struct pci_device_id cci_pcie_id_tbl[] = {
> >>>>>        {PCI_DEVICE(PCI_VENDOR_ID_INTEL,
> >>>> PCIE_DEVICE_ID_INTEL_PAC_D5005_VF),},
> >>>>> {PCI_DEVICE(PCI_VENDOR_ID_SILICOM_DENMARK,
> >>>> PCIE_DEVICE_ID_SILICOM_PAC_N5010),},
> >>>>> {PCI_DEVICE(PCI_VENDOR_ID_SILICOM_DENMARK,
> >>>>> PCIE_DEVICE_ID_SILICOM_PAC_N5011),},
> >>>>> +    {PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCIE_DEVICE_ID_INTEL_OFS),},
> >>>>> +    {PCI_DEVICE(PCI_VENDOR_ID_INTEL,
> >>>> PCIE_DEVICE_ID_INTEL_OFS_VF),},
> >>>>>        {0,}
> >>>>>    };
> >>>>>    MODULE_DEVICE_TABLE(pci, cci_pcie_id_tbl);
> >>
> >>