[SOLVED] How to get Vendor ID and Device ID of all PCI Devices?

How to get Vendor ID and Device ID of all PCI Devices?

I need to get Vendor ID and Device ID of all PCI bus Devices from Linux using C/C++ (inline asm allowed), but I can't even understand from what to start.

Please, give me some pieces of advice or code parts.

Solution

How to get Vendor ID and Device ID of all PCI Devices?

In short, you have to write a C program that does:

grep PCI_ID /sys/bus/pci/devices/*/uevent

Sample output lines:

/sys/bus/pci/devices/0000:00:00.0/uevent:PCI_ID=1022:14E8
/sys/bus/pci/devices/0000:00:00.2/uevent:PCI_ID=1022:14E9
/sys/bus/pci/devices/0000:00:01.0/uevent:PCI_ID=1022:14EA
/sys/bus/pci/devices/0000:00:02.0/uevent:PCI_ID=1022:14EA

And extract relevant data after = and after :.

So what you have to do is:

iterate over directories in /sys/bus/pci/devices with readdir_r
for each directory
- open the uevent file from inside that directory
- read lines from the file until PCI_ID is found
- if found - basically match the line with sscanf(line, "PCI_ID=%4x:%4x\n", &vendor_id, &device_id)

I couldn't find any documentation about uevent inside /sys/bus/pci/devices. This answer is based on reverse engineering busybox lspci.c sources.