Add c2 port support

C2port 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 through sysfs
interface but extensions shoud be easy to add.

Signed-off-by: Rodolfo Giometti <giometti@linux.it>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 178 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/sysfs-c2port b/Documentation/ABI/testing/sysfs-c2port
new file mode 100644
index 000000000000..716cffc457e9
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-c2port
@@ -0,0 +1,88 @@
+What:           /sys/class/c2port/
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/ directory will contain files and
+                directories that will provide a unified interface to
+                the C2 port interface.
+
+What:           /sys/class/c2port/c2portX
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/c2portX/ directory is related to X-th
+                C2 port into the system. Each directory will contain files to
+                manage and control its C2 port.
+
+What:           /sys/class/c2port/c2portX/access
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/c2portX/access file enable the access
+                to the C2 port from the system. No commands can be sent
+                till this entry is set to 0.
+
+What:           /sys/class/c2port/c2portX/dev_id
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/c2portX/dev_id file show the device ID
+                of the connected micro.
+
+What:           /sys/class/c2port/c2portX/flash_access
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/c2portX/flash_access file enable the
+                access to the on-board flash of the connected micro.
+                No commands can be sent till this entry is set to 0.
+
+What:           /sys/class/c2port/c2portX/flash_block_size
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/c2portX/flash_block_size file show
+                the on-board flash block size of the connected micro.
+
+What:           /sys/class/c2port/c2portX/flash_blocks_num
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/c2portX/flash_blocks_num file show
+                the on-board flash blocks number of the connected micro.
+
+What:           /sys/class/c2port/c2portX/flash_data
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/c2portX/flash_data file export
+                the content of the on-board flash of the connected micro.
+
+What:           /sys/class/c2port/c2portX/flash_erase
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/c2portX/flash_erase file execute
+                the "erase" command on the on-board flash of the connected
+                micro.
+
+What:           /sys/class/c2port/c2portX/flash_erase
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/c2portX/flash_erase file show the
+                on-board flash size of the connected micro.
+
+What:           /sys/class/c2port/c2portX/reset
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/c2portX/reset file execute a "reset"
+                command on the connected micro.
+
+What:           /sys/class/c2port/c2portX/rev_id
+Date:           October 2008
+Contact:        Rodolfo Giometti <giometti@linux.it>
+Description:
+                The /sys/class/c2port/c2portX/rev_id file show the revision ID
+                of the connected micro.
diff --git a/Documentation/c2port.txt b/Documentation/c2port.txt
new file mode 100644
index 000000000000..d9bf93ea4398
--- /dev/null
+++ b/Documentation/c2port.txt
@@ -0,0 +1,90 @@
+                        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 (http://www.silabs.com)
+Silicon Laboratories site], see:
+
+- AN127: FLASH Programming via the C2 Interface at
+http://www.silabs.com/public/documents/tpub_doc/anote/Microcontrollers/Small_Form_Factor/en/an127.pdf, and
+
+- C2 Specification at
+http://www.silabs.com/public/documents/tpub_doc/spec/Microcontrollers/en/C2spec.pdf,
+
+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