Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 94 insertions, 0 deletions

diff --git a/Documentation/misc-devices/c2port.rst b/Documentation/misc-devices/c2port.rst
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+.. 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