About
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wARM is a combination of library and Linux kernel module for ARM processor
control. It was created because ARM processor allows to perform certain
operations in privileged modes only, and ARM Linux kernel is only providing
limited functionality through some private system calls. The code was
developed for GPH GP2X/Wiz consoles, but it should be possible to use it
on other ARM Linux systems (probably with modifications).
Currently wARM provides various cache control operations and supports only
ARM9 family processors.
Usage
-----
The library consists of just 2 files: warm.c and warm.h, which should be
compiled into your program. The library performs module loading and
communication with it all by itself, you just need to call the right
functions. You will need to have a matching kernel module available for
kernel running on your device, several precompiled modules can be found
in bin/ directory:
warm_2.4.25.o - for GP2X F100/F200 GPH firmwares
warm_2.4.26-open2x.o - for GP2X F100/F200 Open2x firmware
warm_2.6.24.ko - for Wiz GPH firmwares
When the module is loaded into kernel, it creates /proc/warm file, which
can be read for some information about the CPU.
API
---
warm_init - must be called on startup. You must do it with current working
directory set to where kernel module can be found.
warm_finish - should be called before exit to close internal files and unload
the module.
warm_cache_op_range -
call to perform cache invalidation or clean operations (can
specify both with binary or - '|') for virtual address ranges.
In all cases write buffer is flushed (no operation can be
specified to just flush the write buffer).
warm_cache_op_all -
same as above, only affects the whole cache.
warm_change_cb_range -
set or clear C and/or B bits for memory region (if is_set is
nonzero, sets, else clears). The meaning of C and B bit
combinations is processor specific, for ARM9 C enables both
caching and buffering, B enables write buffer (when C is
cleared), or enables write-back caching (when C is set).
Note that in some cases the region needs to be accessed
before calling this function, so that kernel maps actual pages.
warm_change_cb_upper -
same as above, only affects "upper" memory (RAM memory above
Linux accessible range, can be found in GP2X and Wiz).
warm_virt2phys -
Converts virtual address to physical address. Note that the
returned address is only valid for one page where the address
points to (4KB in Linux). Next page will most likely point to
completely different physical memory location, instead of next
one.
note: all operations except warm_cache_op_all() affect calling process only.
License
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* Copyright (c) Gražvydas "notaz" Ignotas, 2009
* notasas a gmail d com
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* * Neither the name of the organization nor the
* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.