Reads the PMTable on Cezanne

pmtable.py

import os
import struct
import sys

SMN_INDEX_REG = 0x60
SMN_DATA_REG = 0x64

SMN_MSG_REG = 0x3b10a20
SMN_RSP_REG = 0x3b10a80
SMN_ARG_REG = 0x3b10a88

SMN_STATUS_OK = 1

SMN_CMD_TRANSFER_TABLE = 0x65
SMN_CMD_GET_TABLE_BASE_ADDRESS = 0x66
SMN_CMD_GET_TABLE_VERSION = 0x6

config = os.open('/sys/devices/pci0000:00/0000:00:00.0/config', os.O_RDWR)


def smn_read(address):
    os.pwrite(config, struct.pack('I', address), SMN_INDEX_REG)
    return struct.unpack('I', os.pread(config, 4, SMN_DATA_REG))[0]


def smn_write(address, data):
    os.pwrite(config, struct.pack('I', address), SMN_INDEX_REG)
    os.pwrite(config, struct.pack('I', data), SMN_DATA_REG)


def smn_send_msg(msg, *args):
    status = 0
    smn_write(SMN_RSP_REG, status)

    for j, arg in enumerate(args):
        smn_write(SMN_ARG_REG + (j << 2), arg)

    smn_write(SMN_MSG_REG, msg)

    while (status := smn_read(SMN_RSP_REG)) == 0:
        pass

    if status != SMN_STATUS_OK:
        return []

    return [smn_read(SMN_ARG_REG + (k << 2)) for k in range(5)]


base_address = smn_send_msg(SMN_CMD_GET_TABLE_BASE_ADDRESS, 1, 1)
table_base_address = base_address[1] << 32 | base_address[0]

print(f'base address (high): {hex(base_address[1])}, (low): {hex(base_address[0])}')

table_version = smn_send_msg(SMN_CMD_GET_TABLE_VERSION)[0]
print(f'table version: {hex(table_version)}')
print(f'table base address: {hex(table_base_address)}')

print(f'transfer table: {smn_send_msg(SMN_CMD_TRANSFER_TABLE)}')

devmem = os.open('/dev/mem', os.O_RDONLY)
os.lseek(devmem, table_base_address, os.SEEK_SET)

for i in range(0, 0xAA4, 4):
    print(f"{i:04X}: {struct.unpack('f', os.read(devmem, 4))[0]}")

os.close(devmem)
os.close(config)