Python script to read/write physical address (depends on python-mmap)

other/mem.py

+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# Copyright (C) 2013, Elphel.inc.
+# configuration of the DDR-related registers
+# 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/>.
+ 
+__author__ = "Andrey Filippov"
+__copyright__ = "Copyright 2014, Elphel, Inc."
+__license__ = "GPL"
+__version__ = "3.0+"
+__maintainer__ = "Andrey Filippov"
+__email__ = "andrey@elphel.com"
+__status__ = "Development"
+import mmap
+import sys
+import struct
+PAGE_SIZE=4096
+endian="<" # little, ">" for big
+if len(sys.argv)<1:
+    print "Usage: ", sys.argv[0]+" address [data]"
+    exit (0)
+addr=int(sys.argv[1],16) & 0xfffffffc
+data=0
+writeMode=len(sys.argv)>2
+if (writeMode):
+    data=int(sys.argv[2],16)
+with open("/dev/mem", "r+b") as f:
+    page_addr=addr & (~(PAGE_SIZE-1))
+    page_offs=addr-page_addr
+    if (page_addr>=0x80000000):
+        page_addr-= (1<<32)
+    mm = mmap.mmap(f.fileno(), PAGE_SIZE, offset=page_addr)
+    if writeMode:
+        packedData=struct.pack(endian+"L",data)
+        d=struct.unpack(endian+"L",packedData)[0]
+        mm[page_offs:page_offs+4]=packedData
+        print ("0x%08x <== 0x%08x (%d)"%(addr,d,d))
+    else:
+        data=struct.unpack(endian+"L",mm[page_offs:page_offs+4])
+        d=data[0]
+        print ("0x%08x ==> 0x%08x (%d)"%(addr,d,d))
+    mm.close()