blob: 93a67cc60a4af7f69fb2245b69d8dff58127a16e [file] [log] [blame]
# -*- coding: utf-8 -*-
# Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Memory module for accessing the memory for IO.
This module uses C library to direct access the memory.
Usage:
import mem
# Control IO registers of controllers.
memory = mem.MemoryForController
value = memory.Read(address)
"""
import ctypes
import time
from . import chameleon_common # pylint: disable=W0611
from chameleond.utils.common import lazy
class _Memory(object):
"""A class to abstract the memory access for IO."""
_REG_SET_DELAY = 0.001
def __init__(self, start_address, size):
"""Constructs a _Memory object.
Args:
start_address: the start address of mmap.
size: the size in bytes of mmap.
Raises:
IOError if failed to open /dev/mem.
"""
self._mmap_start = start_address
self._mmap_size = size
# mmap end address (exclusive)
self._mmap_end = self._mmap_start + self._mmap_size
libc = ctypes.cdll.LoadLibrary('libc.so.6')
O_RDWR = 0o0000002
O_SYNC = 0o4000000 | 0o0010000
fd = libc.open('/dev/mem', O_RDWR | O_SYNC)
if fd == -1:
raise IOError('Failed to open /dev/mem')
PROT_READ = 0x1
PROT_WRITE = 0x2
MAP_SHARED = 0x01
self._memory = libc.mmap(0, self._mmap_size, PROT_READ | PROT_WRITE,
MAP_SHARED, fd, self._mmap_start)
if self._memory == -1:
raise IOError('Failed to call mmap()')
def _GetLocalAddress(self, address):
"""Gets the local mmapped address for a given memory address.
Args:
address: The memory address.
Returns:
A local mmapped address.
"""
assert self._memory != -1
assert self._mmap_start <= address < self._mmap_end
return self._memory + (address - self._mmap_start)
def Read(self, address):
"""Reads the 32-bit integer from the given memory address.
Args:
address: The memory address.
Returns:
An integer.
"""
local_addr = self._GetLocalAddress(address)
return ctypes.c_uint.from_address(local_addr).value # pylint: disable=E1101
def Write(self, address, data):
"""Writes the given 32-bit integer to the given memory address.
Args:
address: The memory address.
data: The 32-bit integer to write.
"""
local_addr = self._GetLocalAddress(address)
ctypes.c_uint.from_address(local_addr).value = data # pylint: disable=E1101
def SetMask(self, address, mask):
"""Sets the mask on the given memory address.
Args:
address: The memory address.
mask: The bitwise mask.
"""
self.Write(address, self.Read(address) | mask)
def ClearMask(self, address, mask):
"""Clears the mask on the given memory address.
Args:
address: The memory address.
mask: The bitwise mask.
"""
self.Write(address, self.Read(address) & ~mask)
def SetAndClearMask(self, address, mask, delay_secs=_REG_SET_DELAY):
"""Sets and then clears the mask on the given memory address.
It is a blocking call for at least delay_secs seconds.
Args:
address: The memory address.
mask: The bitwise mask.
delay_secs: The time between set and clear. Default: _REG_SET_DELAY
"""
self.SetMask(address, mask)
time.sleep(delay_secs)
self.ClearMask(address, mask)
def ClearAndSetMask(self, address, mask, delay_secs=_REG_SET_DELAY):
"""Clears and then sets the mask on the given memory address.
It is a blocking call for at least delay_secs seconds.
Args:
address: The memory address.
mask: The bitwise mask.
delay_secs: The time between clear and set. Default: _REG_SET_DELAY
"""
self.ClearMask(address, mask)
time.sleep(delay_secs)
self.SetMask(address, mask)
def Fill(self, address, data):
"""Fills memory with data.
Args:
address: The memory address.
data: The data to be filled to memory starting from that address.
"""
local_addr = self._GetLocalAddress(address)
end_addr = address + len(data)
if end_addr >= self._mmap_end:
raise IOError(
'Address %r exceeds end of mmap %r' % (end_addr, self._mmap_end))
ctypes.memmove(local_addr, data, len(data))
# Address space for memory-mapped I/O for controller.
_MMAP_START_CONTROLLER = 0xff210000
_MMAP_SIZE_CONTROLLER = 0x10000
_MMAP_START_DUMPER = 0xc0000000
_MMAP_SIZE_DUMPER = 0x3c000000
_MMAP_START_HPS = 0xfc000000
_MMAP_SIZE_HPS = 0x4000000
# Lazy instantiation of the memory singletons since they are not supported
# on a platform such as chromeos.
MemoryForController = lazy(_Memory)(
_MMAP_START_CONTROLLER, _MMAP_SIZE_CONTROLLER)
MemoryForDumper = lazy(_Memory)(_MMAP_START_DUMPER, _MMAP_SIZE_DUMPER)
MemoryForHPS = lazy(_Memory)(_MMAP_START_HPS, _MMAP_SIZE_HPS)