1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
|
#
# Copyright 2017 Ettus Research, a National Instruments Company
#
# SPDX-License-Identifier: GPL-3.0-or-later
#
"""
Access to UIO mapped memory.
"""
import os
from contextlib import contextmanager
from builtins import object
import pyudev
import usrp_mpm.libpyusrp_periphs as lib
from usrp_mpm.mpmlog import get_logger
UIO_SYSFS_BASE_DIR = '/sys/class/uio'
UIO_DEV_BASE_DIR = '/dev'
@contextmanager
def open_uio(label=None, path=None, length=None, read_only=True, offset=None):
"""Convenience function for creating a UIO object.
Use this like you would open() for a file"""
uio_obj = UIO(label, path, length, read_only, offset)
uio_obj._open()
try:
yield uio_obj
finally:
uio_obj._close()
def get_all_uio_devs():
"""
Return a list of all uio devices. Will look something like
['uio0', 'uio1', ...].
"""
try:
context = pyudev.Context()
paths = [os.path.split(device.device_node)[-1]
for device in context.list_devices(subsystem="uio")]
return paths
except OSError:
# Typically means UIO devices
return []
def get_uio_map_info(uio_dev, map_num):
"""
Returns all the map info for a given UIO device and map number.
Example: If uio_dev is 'uio0', and map_num is 0, it will list all files
in /sys/class/uio/uio0/maps/map0/ and create a dictionary with filenames
as keys and content as value.
Numbers are casted to numbers automatically. Strings remain strings.
"""
map_info = {}
map_info_path = os.path.join(
UIO_SYSFS_BASE_DIR, uio_dev, 'maps', 'map{0}'.format(map_num)
)
for info_file in os.listdir(map_info_path):
map_info_value = open(os.path.join(map_info_path, info_file), 'r').read().strip()
try:
map_info[info_file] = int(map_info_value, 0)
except ValueError:
map_info[info_file] = map_info_value
return map_info
def find_uio_device(label, logger=None):
"""
Given a label, returns a tuple (uio_device, map_info).
uio_device is something like '/dev/uio0'. map_info is a dictionary with
information regarding the UIO device read from the map info sysfs dir.
Note: We assume a single map (map0) for all UIO devices here.
"""
uio_devices = get_all_uio_devs()
if logger:
logger.trace("Found the following UIO devices: `{0}'".format(','.join(uio_devices)))
for uio_device in uio_devices:
map0_info = get_uio_map_info(uio_device, 0)
if logger:
logger.trace("{0} has map info: {1}".format(uio_device, map0_info))
if map0_info.get('name') == label:
if logger:
logger.trace("Device matches label: `{0}'".format(uio_device))
return os.path.join(UIO_DEV_BASE_DIR, uio_device), map0_info
if logger:
logger.warning("Found no matching UIO device for label `{0}'".format(label))
return None, None
class UIO(object):
"""
Provides peek/poke interfaces for uio-mapped memory.
This object will not, by default, open the associated UIO device. To
actually open the device, you have two options:
- Use the instantiation of this class as a context manager (using a `with`
statement), like this:
>>> uio0 = UIO(path="/dev/uio0"):
>>> with uio0:
>>> uio0.peek32(addr)
>>> uio0.poke32(addr, value)
Or like this:
>>> with UIO(path="/dev/uio0") as uio0:
>>> uio0.peek32(addr)
>>> uio0.poke32(addr, value)
- This is Highly Discouraged, but if you need to, manually call _open() and _close():
>>> uio0 = UIO(path="/dev/uio0")
>>> uio0._open()
>>> uio0.peek32(addr)
>>> uio0.poke32(addr, value)
>>> uio0._close()
Arguments:
label -- Label of the UIO device. The label is set in the device tree
overlay
path -- Path to UIO device, e.g. '/dev/uio0'. This is ignored if 'label' is
provided.
length -- Number of bytes in the address space (is passed to mmap.mmap).
This is usually automatically determined. No need to set it.
Unless you really know what you're doing.
read_only -- Boolean; True == ro, False == rw
offset -- Passed to mmap.mmap.
This is usually automatically determined. No need to set it.
Unless you really know what you're doing.
"""
def __init__(self, label=None, path=None, length=None, read_only=True, offset=None):
self.log = get_logger('UIO')
if label is None:
self._path = path
self.log.trace("Using UIO device `{0}'".format(path))
uio_device = os.path.split(path)[-1]
self.log.trace("Getting map info for UIO device `{0}'".format(uio_device))
map_info = get_uio_map_info(uio_device, 0)
# Python can't tell the size of a uio device by itself
assert length is not None
else:
self.log.trace("Using UIO device by label `{0}'".format(label))
self._path, map_info = find_uio_device(label, self.log)
# TODO If we ever support multiple maps, check if this is correct...
offset = offset or map_info['offset']
assert offset == 0 # ...and then remove this line
length = length or map_info['size']
self.log.trace("UIO device is being opened read-{0}.".format(
"only" if read_only else "write"))
if self._path is None:
self.log.error("Could not find a UIO device for label {0}".format(label))
raise RuntimeError("Could not find a UIO device for label {0}".format(label))
self._read_only = read_only
# Our UIO objects are managed in C++ land, which gives us more granular control over
# opening and closing
self._uio = lib.types.mmap_regs_iface(self._path, length, offset, self._read_only, False)
# Reference counter for safely __enter__ and __exit__-ing
self._ref_count = 0
def __enter__(self):
return self._open()
def __exit__(self, exc_type, exc_value, traceback):
self._close()
return exc_type is None
def _open(self):
"""Actually open the UIO device.
You need to call this before doing peeks and pokes. See also close().
If you're using the UIO object as a context manager, it will open the
file automatically.
"""
if self._ref_count == 0:
self._uio.open()
self._ref_count += 1
return self
def _close(self):
"""Close a UIO device.
UIO devices can be problematic with regards to file descriptor leakage,
so it is recommended to close a UIO device when it is no longer needed.
"""
self._ref_count -= 1
if self._ref_count == 0:
self._uio.close()
def peek32(self, addr):
"""
Returns the 32-bit value starting at address addr as an integer
"""
return self._uio.peek32(addr)
def poke32(self, addr, val):
"""
Writes the 32-bit value val to address starting at addr.
Will throw if read_only was set to True.
A value that exceeds 32 bits will be truncated to 32 bits.
"""
assert not self._read_only
return self._uio.poke32(addr, val)
|
