Dump device feature list (Python code) - list PCI feature devices

dump_dev_feature_list.py

#!/usr/bin/python
"""Dump Device Feature List"""
# Copyright(c) 2015-2017, Intel Corporation
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import mmap, sys, binascii, struct, os

MAPMASK = mmap.PAGESIZE-1

def decode_dfh(data):
    retval = {
        "Raw DFH                               " : data,
        "Feature Type                          " : (data >> 60) & 0xF,
        "AFU Minor Revision                    " : (data >> 48) & 0xF,
        "End of List                           " : (data >> 40) & 0x1,
        "Next DFH Byte Offset                  " : (data >> 16) & 0xFFFFFF,
        "AFU Major Revision / Feature Revision " : (data >> 12) & 0xF,
        "Feature ID                            " : data & 0xFFF
    }
    return retval


def print_dfh(fields, offset):
    for key, value in fields.iteritems():
        print key + ": " + hex(value)


def walk_dfl(mm, base, offset): 
    print "==== DFH at " + hex(base + offset) + "===="
    # read data (64 bit)
    data_mm = mm[offset:offset+8]
    data_bin = struct.unpack('<Q', data_mm)[0]

    fields = decode_dfh(data_bin)
    print_dfh(fields, offset)

    eol = (data_bin >> 40) & 0x1
    next_dfh = (data_bin >> 16) & 0xFFFFFF

    if eol != 1 and next_dfh > 0:
        walk_dfl(mm, base, offset+next_dfh)


if __name__ == "__main__":

    if len(sys.argv) < 3:
        sys.stderr.write("USAGE: dump_dfl.py <resource> <offset>\n")
        sys.exit(-1)

    address = int(sys.argv[2], 0)
    base = address & ~MAPMASK
    offset = address & MAPMASK

    # mmap PCI resource
    with open(sys.argv[1], "rb", 0) as f:
        size = os.path.getsize(sys.argv[1])
        mm = mmap.mmap(f.fileno(), size-base, mmap.MAP_SHARED, mmap.PROT_READ, 0, base)

        walk_dfl(mm, base, offset)

        # close mapping
        mm.close()