90 lines
3.3 KiB
ReStructuredText
90 lines
3.3 KiB
ReStructuredText
.. include:: <isonum.txt>
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========================
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Linux kernel WiMAX stack
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========================
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:Copyright: |copy| 2008 Intel Corporation < linux-wimax@intel.com >
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This provides a basic Linux kernel WiMAX stack to provide a common
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control API for WiMAX devices, usable from kernel and user space.
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1. Design
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=========
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The WiMAX stack is designed to provide for common WiMAX control
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services to current and future WiMAX devices from any vendor.
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Because currently there is only one and we don't know what would be the
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common services, the APIs it currently provides are very minimal.
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However, it is done in such a way that it is easily extensible to
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accommodate future requirements.
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The stack works by embedding a struct wimax_dev in your device's
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control structures. This provides a set of callbacks that the WiMAX
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stack will call in order to implement control operations requested by
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the user. As well, the stack provides API functions that the driver
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calls to notify about changes of state in the device.
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The stack exports the API calls needed to control the device to user
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space using generic netlink as a marshalling mechanism. You can access
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them using your own code or use the wrappers provided for your
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convenience in libwimax (in the wimax-tools package).
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For detailed information on the stack, please see
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include/linux/wimax.h.
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2. Usage
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========
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For usage in a driver (registration, API, etc) please refer to the
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instructions in the header file include/linux/wimax.h.
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When a device is registered with the WiMAX stack, a set of debugfs
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files will appear in /sys/kernel/debug/wimax:wmxX can tweak for
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control.
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2.1. Obtaining debug information: debugfs entries
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-------------------------------------------------
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The WiMAX stack is compiled, by default, with debug messages that can
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be used to diagnose issues. By default, said messages are disabled.
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The drivers will register debugfs entries that allow the user to tweak
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debug settings.
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Each driver, when registering with the stack, will cause a debugfs
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directory named wimax:DEVICENAME to be created; optionally, it might
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create more subentries below it.
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2.1.1. Increasing debug output
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------------------------------
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The files named *dl_* indicate knobs for controlling the debug output
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of different submodules of the WiMAX stack::
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# find /sys/kernel/debug/wimax\:wmx0 -name \*dl_\*
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/sys/kernel/debug/wimax:wmx0/wimax_dl_stack
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/sys/kernel/debug/wimax:wmx0/wimax_dl_op_rfkill
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/sys/kernel/debug/wimax:wmx0/wimax_dl_op_reset
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/sys/kernel/debug/wimax:wmx0/wimax_dl_op_msg
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/sys/kernel/debug/wimax:wmx0/wimax_dl_id_table
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/sys/kernel/debug/wimax:wmx0/wimax_dl_debugfs
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/sys/kernel/debug/wimax:wmx0/.... # other driver specific files
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NOTE:
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Of course, if debugfs is mounted in a directory other than
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/sys/kernel/debug, those paths will change.
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By reading the file you can obtain the current value of said debug
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level; by writing to it, you can set it.
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To increase the debug level of, for example, the id-table submodule,
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just write:
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$ echo 3 > /sys/kernel/debug/wimax:wmx0/wimax_dl_id_table
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Increasing numbers yield increasing debug information; for details of
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what is printed and the available levels, check the source. The code
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uses 0 for disabled and increasing values until 8.
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