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Diffstat (limited to 'Documentation/misc-devices/c2port.rst')
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diff --git a/Documentation/misc-devices/c2port.rst b/Documentation/misc-devices/c2port.rst new file mode 100644 index 000000000000..7e4f6a79418a --- /dev/null +++ b/Documentation/misc-devices/c2port.rst @@ -0,0 +1,94 @@ +.. 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 |