forked from luck/tmp_suning_uos_patched
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- 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
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95 lines
2.9 KiB
ReStructuredText
.. SPDX-License-Identifier: GPL-2.0
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.. include:: <isonum.txt>
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===============
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C2 port support
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===============
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(C) Copyright 2007 Rodolfo Giometti <giometti@enneenne.com>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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Overview
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--------
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This driver implements the support for Linux of Silicon Labs (Silabs)
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C2 Interface used for in-system programming of micro controllers.
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By using this driver you can reprogram the in-system flash without EC2
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or EC3 debug adapter. This solution is also useful in those systems
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where the micro controller is connected via special GPIOs pins.
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References
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----------
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The C2 Interface main references are at (https://www.silabs.com)
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Silicon Laboratories site], see:
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- AN127: FLASH Programming via the C2 Interface at
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https://www.silabs.com/Support Documents/TechnicalDocs/an127.pdf
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- C2 Specification at
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https://www.silabs.com/pages/DownloadDoc.aspx?FILEURL=Support%20Documents/TechnicalDocs/an127.pdf&src=SearchResults
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however it implements a two wire serial communication protocol (bit
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banging) designed to enable in-system programming, debugging, and
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boundary-scan testing on low pin-count Silicon Labs devices. Currently
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this code supports only flash programming but extensions are easy to
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add.
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Using the driver
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----------------
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Once the driver is loaded you can use sysfs support to get C2port's
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info or read/write in-system flash::
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# ls /sys/class/c2port/c2port0/
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access flash_block_size flash_erase rev_id
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dev_id flash_blocks_num flash_size subsystem/
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flash_access flash_data reset uevent
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Initially the C2port access is disabled since you hardware may have
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such lines multiplexed with other devices so, to get access to the
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C2port, you need the command::
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# echo 1 > /sys/class/c2port/c2port0/access
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after that you should read the device ID and revision ID of the
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connected micro controller::
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# cat /sys/class/c2port/c2port0/dev_id
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8
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# cat /sys/class/c2port/c2port0/rev_id
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1
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However, for security reasons, the in-system flash access in not
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enabled yet, to do so you need the command::
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# echo 1 > /sys/class/c2port/c2port0/flash_access
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After that you can read the whole flash::
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# cat /sys/class/c2port/c2port0/flash_data > image
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erase it::
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# echo 1 > /sys/class/c2port/c2port0/flash_erase
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and write it::
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# cat image > /sys/class/c2port/c2port0/flash_data
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after writing you have to reset the device to execute the new code::
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# echo 1 > /sys/class/c2port/c2port0/reset
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