https://github.com/kylemanna/pydevmem

Python interface to /dev/mem
https://github.com/kylemanna/pydevmem

devmem embedded embedded-systems linux memory python

Last synced: 11 months ago
JSON representation

Python interface to /dev/mem

• Host: GitHub
• URL: https://github.com/kylemanna/pydevmem
• Owner: kylemanna
• License: mit
• Created: 2011-11-28T06:52:24.000Z (over 14 years ago)
• Default Branch: master
• Last Pushed: 2020-10-27T04:18:56.000Z (over 5 years ago)
• Last Synced: 2025-04-04T20:51:26.262Z (about 1 year ago)
• Topics: devmem, embedded, embedded-systems, linux, memory, python
• Language: Python
• Homepage:
• Size: 36.1 KB
• Stars: 51
• Watchers: 8
• Forks: 29
• Open Issues: 5
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

Awesome Lists containing this project

README

          
Python DevMem

=============

[![](https://img.shields.io/pypi/v/devmem.svg?maxAge=3600)](https://pypi.org/project/devmem/)

This is designed primarily for use with accessing /dev/mem on OMAP platforms.

It should work on other platforms and work to mmap() files rather then just

/dev/mem, but these use cases aren't well tested.

All file accesses are aligned to DevMem.word bytes, which is 4 bytes on ARM

platforms to avoid data abort faults when accessing peripheral registers.

Usage

-----

    Usage: devmem.py [options]

    Options:

      -h, --help            show this help message and exit

      -r ADDR, --read=ADDR  read a value

      -w ADDR VALUE, --write=ADDR VALUE

    						write a value

      -n NUM, --num=NUM     number of words to read

      -s WORD_SIZE, --word-size=WORD_SIZE

    						size of word when displayed

      -m FILE, --mmap=FILE  file to open with mmap()

      -v                    provide more information regarding operation

      -d                    provide debugging information

Speed

-----

Initial testing on a BeagleBoard-xM (Cortex-A8 in a TI DM3730) shows that

starting up the python interpreter is pretty slow:

    # time (echo | python)

    real    0m0.859s

    user    0m0.750s

    sys     0m0.102s

    # time python ./pydevmem.py -r 0x4830a204 -n 8

    0x4830a204:   1b89102f  00000000  00000000  000000f0

    0x4830a214:   cafeb891  0c030016  015739eb  1ff00000

    real    0m1.109s

    user    0m0.977s

    sys     0m0.133s

    # time python -S ./pydevmem.py -r 0x4830a204 -n 8

    0x4830a204:   1b89102f  00000000  00000000  000000f0

    0x4830a214:   cafeb891  0c030016  015739eb  1ff00000

    real    0m0.659s

    user    0m0.602s

    sys     0m0.047s

    # time python -S ./pydevmem.pyc -r 0x4830a204 -n 8

    0x4830a204:   1b89102f  00000000  00000000  000000f0

    0x4830a214:   cafeb891  0c030016  015739eb  1ff00000

    real    0m0.647s

    user    0m0.508s

    sys     0m0.133s

System information for those tests:

    Linux omap 3.0.6-x3 #1 SMP Wed Oct 5 07:19:24 UTC 2011 armv7l GNU/Linux

    python              2.7.2-7ubuntu2

    python-configobj    4.7.2+ds-3

    python-minimal      2.7.2-7ubuntu2

    python2.7           2.7.2-5ubuntu1

    python2.7-minimal   2.7.2-5ubuntu1

Something needs to be sped up to make python start-up in a reasonable amount

of time.