mpm: Added uio control class

1 files changed, 68 insertions, 0 deletions

diff --git a/mpm/python/usrp_mpm/uio.py b/mpm/python/usrp_mpm/uio.py
new file mode 100644
index 000000000..18a894e9c
--- /dev/null
+++ b/mpm/python/usrp_mpm/uio.py
@@ -0,0 +1,68 @@
+#
+# 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
+
+class uio(object):
+    """
+    Provides peek/poke interfaces for uio-mapped memory.
+
+    Arguments:
+    path -- Path to UIO device, e.g. '/dev/uio0'
+    length -- Number of bytes in the address space (is passed to mmap.mmap).
+              Must be at least one page size
+    read_only -- Boolean, True == ro, False == rw
+    offset -- Passed to mmap.mmap
+    """
+    def __init__(self, path, length, read_only=True, offset=None):
+        # Python can't tell the size of a uio device
+        assert length >= mmap.PAGESIZE
+        offset = offset or 0
+        self._path = path
+        self._read_only = read_only
+        self._fd = os.open(path, os.O_RDONLY if read_only else os.O_RDWR)
+        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 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),
+        )
+