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authorwdenk <wdenk>2003-04-05 00:53:31 +0000
committerwdenk <wdenk>2003-04-05 00:53:31 +0000
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* Patch by Arun Dharankar, 4 Apr 2003:
Add IDMA example code (tested on 8260 only) * Add support for Purple Board (MIPS64 5Kc) * Add support for MIPS64 5Kc CPUs * Fix missing setting of "loadaddr" and "bootfile" on ARM and MIPS * Patch by Denis Peter, 04 Apr 2003: - update MIP405-4 board * Patches by Denis Peter, 03 April 2003: - fix PCI IRQs on MPL boards - fix two more un-relocated pointer problems * Fix behaviour of "run" command: - print error message iv variable does not exist - terminate processing of arguments in case of error * Patches by Peter Figuli, 10 Mar 2003 - Add support for BTUART on PXA platform - Add support for WEP EP250 (PXA) board * Fix flash problems on INCA-IP; add tool to allow bruning images to flash using a BDI2000 * Implement fix for I2C Edge Conditions problem for all boards that use the bit-banging driver (common/soft_i2c.c) * Add patches by Robert Schwebel, 31 Mar 2003: - csb226 board: bring in sync with innokom/memsetup.S - csb226 board: fix MDREFR handling - misc doc fixes / extensions - innokom board: cleanup, MDREFR fix in memsetup.S, config update - add BOOT_PROGRESS to armlinux.c
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+Notes on the scheduler in sched.c:
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+ 'sched.c' provides an very simplistic multi-threading scheduler.
+ See the example, function 'sched(...)', in the same file for its
+ API usage.
+
+ Until an exhaustive testing can be done, the implementation cannot
+ qualify as that of production quality. It works with the example
+ in 'sched.c', it may or may not work in other cases.
+
+
+Limitations:
+~~~~~~~~~~~~
+
+ - There are NO primitives for thread synchronization (locking,
+ notify etc).
+
+ - Only the GPRs and FPRs context is saved during a thread context
+ switch. Other registers on the PowerPC processor (60x, 7xx, 7xxx
+ etc) are NOT saved.
+
+ - The scheduler is NOT transparent to the user. The user
+ applications must invoke thread_yield() to allow other threads to
+ scheduler.
+
+ - There are NO priorities, and the scheduling policy is round-robin
+ based.
+
+ - There are NO capabilities to collect thread CPU usage, scheduler
+ stats, thread status etc.
+
+ - The semantics are somewhat based on those of pthreads, but NOT
+ the same.
+
+ - Only seven threads are allowed. These can be easily increased by
+ changing "#define MAX_THREADS" depending on the available memory.
+
+ - The stack size of each thread is 8KBytes. This can be easily
+ increased depending on the requirement and the available memory,
+ by increasing "#define STK_SIZE".
+
+ - Only one master/parent thread is allowed, and it cannot be
+ stopped or deleted. Any given thread is NOT allowed to stop or
+ delete itself.
+
+ - There NOT enough safety checks as are probably in the other
+ threads implementations.
+
+ - There is no parent-child relationship between threads. Only one
+ thread may thread_join, preferably the master/parent thread.
+
+(C) 2003 Arun Dharankar <ADharankar@ATTBI.Com>