mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-27 13:05:03 +08:00
433b1b0d75
- Use copyright symbol; - use title markups; - adjust indentation; - mark literal blocks as such. Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org> [jc: reverted |copy| change] Link: https://lore.kernel.org/r/b3b2f3f58a9a33f9e8526d4fa36bee305ea4da38.1592203650.git.mchehab+huawei@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
95 lines
2.9 KiB
ReStructuredText
95 lines
2.9 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
|
|
.. include:: <isonum.txt>
|
|
|
|
===============
|
|
C2 port support
|
|
===============
|
|
|
|
(C) Copyright 2007 Rodolfo Giometti <giometti@enneenne.com>
|
|
|
|
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 2 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.
|
|
|
|
|
|
|
|
Overview
|
|
--------
|
|
|
|
This driver implements the support for Linux of Silicon Labs (Silabs)
|
|
C2 Interface used for in-system programming of micro controllers.
|
|
|
|
By using this driver you can reprogram the in-system flash without EC2
|
|
or EC3 debug adapter. This solution is also useful in those systems
|
|
where the micro controller is connected via special GPIOs pins.
|
|
|
|
References
|
|
----------
|
|
|
|
The C2 Interface main references are at (https://www.silabs.com)
|
|
Silicon Laboratories site], see:
|
|
|
|
- AN127: FLASH Programming via the C2 Interface at
|
|
https://www.silabs.com/Support Documents/TechnicalDocs/an127.pdf
|
|
|
|
- C2 Specification at
|
|
https://www.silabs.com/pages/DownloadDoc.aspx?FILEURL=Support%20Documents/TechnicalDocs/an127.pdf&src=SearchResults
|
|
|
|
however it implements a two wire serial communication protocol (bit
|
|
banging) designed to enable in-system programming, debugging, and
|
|
boundary-scan testing on low pin-count Silicon Labs devices. Currently
|
|
this code supports only flash programming but extensions are easy to
|
|
add.
|
|
|
|
Using the driver
|
|
----------------
|
|
|
|
Once the driver is loaded you can use sysfs support to get C2port's
|
|
info or read/write in-system flash::
|
|
|
|
# ls /sys/class/c2port/c2port0/
|
|
access flash_block_size flash_erase rev_id
|
|
dev_id flash_blocks_num flash_size subsystem/
|
|
flash_access flash_data reset uevent
|
|
|
|
Initially the C2port access is disabled since you hardware may have
|
|
such lines multiplexed with other devices so, to get access to the
|
|
C2port, you need the command::
|
|
|
|
# echo 1 > /sys/class/c2port/c2port0/access
|
|
|
|
after that you should read the device ID and revision ID of the
|
|
connected micro controller::
|
|
|
|
# cat /sys/class/c2port/c2port0/dev_id
|
|
8
|
|
# cat /sys/class/c2port/c2port0/rev_id
|
|
1
|
|
|
|
However, for security reasons, the in-system flash access in not
|
|
enabled yet, to do so you need the command::
|
|
|
|
# echo 1 > /sys/class/c2port/c2port0/flash_access
|
|
|
|
After that you can read the whole flash::
|
|
|
|
# cat /sys/class/c2port/c2port0/flash_data > image
|
|
|
|
erase it::
|
|
|
|
# echo 1 > /sys/class/c2port/c2port0/flash_erase
|
|
|
|
and write it::
|
|
|
|
# cat image > /sys/class/c2port/c2port0/flash_data
|
|
|
|
after writing you have to reset the device to execute the new code::
|
|
|
|
# echo 1 > /sys/class/c2port/c2port0/reset
|