1 files changed, 167 insertions, 0 deletions
diff --git a/mpm/python/usrp_mpm/sys_utils/uio.py b/mpm/python/usrp_mpm/sys_utils/uio.py
new file mode 100644
index 000000000..c07227776
--- /dev/null
+++ b/mpm/python/usrp_mpm/sys_utils/uio.py
@@ -0,0 +1,167 @@
+#
+# Copyright 2017 Ettus Research (National Instruments)
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+"""
+Access to UIO mapped memory.
+"""
+
+import struct
+import os
+import mmap
+from builtins import hex
+from builtins import object
+import pyudev
+from usrp_mpm.mpmlog import get_logger
+
+UIO_SYSFS_BASE_DIR = '/sys/class/uio'
+UIO_DEV_BASE_DIR = '/dev'
+
+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)
+        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.
+
+    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)
+        offset = offset or map_info['offset'] # If we ever support multiple maps, check if this is correct...
+        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
+        self.log.trace("Opening UIO device file {}...".format(self._path))
+        self._fd = os.open(self._path, os.O_RDONLY if read_only else os.O_RDWR)
+        self.log.trace("Calling mmap({fd}, length={length}, offset={offset})".format(
+            fd=self._fd, length=hex(length), offset=hex(offset)
+        ))
+        self._mm = mmap.mmap(
+            self._fd,
+            length,
+            flags=mmap.MAP_SHARED,
+            prot=mmap.PROT_READ | (0 if read_only else mmap.PROT_WRITE),
+            offset=offset,
+        )
+
+    def __del__(self):
+        """
+        Destructor needs to close the uio-mapped memory
+        """
+        try:
+            self._mm.close()
+            os.close(self._fd)
+        except:
+            self.log.warning("Failed to properly destruct UIO object.")
+            pass
+
+    def peek32(self, addr):
+        """
+        Returns the 32-bit value starting at address addr as an integer
+        """
+        return struct.unpack('@I', self._mm[addr:addr+4])[0]
+
+    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
+        self._mm[addr:addr+4] = struct.pack(
+            '@I',
+            (val & 0xFFFFFFFF),
+        )
+