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

From: Tom Rix
Date: Tue Feb 22 2022 - 11:11:29 EST


On 2/21/22 7:11 PM, Zhang, Tianfei wrote:

-----Original Message-----
From: Tom Rix <trix@xxxxxxxxxx>
Sent: Tuesday, February 22, 2022 2:10 AM
To: matthew.gerlach@xxxxxxxxxxxxxxx
Cc: Zhang, Tianfei <tianfei.zhang@xxxxxxxxx>; Wu, Hao <hao.wu@xxxxxxxxx>;
mdf@xxxxxxxxxx; Xu, Yilun <yilun.xu@xxxxxxxxx>; linux-fpga@xxxxxxxxxxxxxxx;
linux-doc@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; corbet@xxxxxxx
Subject: Re: [PATCH v1 7/7] fpga: dfl: pci: Add generic OFS PCI PID


On 2/21/22 9:50 AM, matthew.gerlach@xxxxxxxxxxxxxxx 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@xxxxxxxxxx>
Sent: Wednesday, February 16, 2022 12:16 AM
To: Zhang, Tianfei <tianfei.zhang@xxxxxxxxx>; Wu, Hao
<hao.wu@xxxxxxxxx>; mdf@xxxxxxxxxx; Xu, Yilun <yilun.xu@xxxxxxxxx>;
linux-fpga@xxxxxxxxxxxxxxx; linux-doc@xxxxxxxxxxxxxxx;
linux-kernel@xxxxxxxxxxxxxxx
Cc: corbet@xxxxxxx; Matthew Gerlach
<matthew.gerlach@xxxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxx>
Signed-off-by: Tianfei Zhang <tianfei.zhang@xxxxxxxxx>
---
   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.

What I mean there is heterogeneous set of cards in one machine, how do you tell which card is which ?

Or in a datacenter where the machines are all remote and admin has to flash just the n6000's ?

How could she find just the n6000's with lspci ?

How would the driver know ?

Tom


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);