linux-stable-rt/arch/v850
Nick Piggin 5bfb5d690f [PATCH] sched: disable preempt in idle tasks
Run idle threads with preempt disabled.

Also corrected a bugs in arm26's cpu_idle (make it actually call schedule()).
How did it ever work before?

Might fix the CPU hotplugging hang which Nigel Cunningham noted.

We think the bug hits if the idle thread is preempted after checking
need_resched() and before going to sleep, then the CPU offlined.

After calling stop_machine_run, the CPU eventually returns from preemption and
into the idle thread and goes to sleep.  The CPU will continue executing
previous idle and have no chance to call play_dead.

By disabling preemption until we are ready to explicitly schedule, this bug is
fixed and the idle threads generally become more robust.

From: alexs <ashepard@u.washington.edu>

  PPC build fix

From: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>

  MIPS build fix

Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Yoichi Yuasa <yuasa@hh.iij4u.or.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-11-09 07:56:33 -08:00
..
configs [PATCH] v850: Update defconfigs 2005-09-02 00:57:31 -07:00
kernel [PATCH] sched: disable preempt in idle tasks 2005-11-09 07:56:33 -08:00
lib
Kconfig [NET]: add a top-level Networking menu to *config 2005-07-11 21:03:49 -07:00
Kconfig.debug
Makefile kbuild: v850 use generic asm-offsets.h support 2005-09-09 21:39:46 +02:00
README [PATCH] v850: Add defconfigs 2005-07-27 16:26:02 -07:00

README

This port to the NEC V850E processor supports the following platforms:

   "sim"
	The gdb v850e simulator (CONFIG_V850E_SIM).

   "rte-ma1-cb"
	The Midas labs RTE-V850E/MA1-CB and RTE-V850E/NB85E-CB evaluation
	boards (CONFIG_RTE_CB_MA1 and CONFIG_RTE_CB_NB85E).  This support
	has only been tested when running with the Multi-debugger monitor
	ROM (for the Green Hills Multi debugger).  The optional NEC
	Solution Gear RTE-MOTHER-A motherboard is also supported, which
	allows PCI boards to be used (CONFIG_RTE_MB_A_PCI).

   "rte-me2-cb"
	The Midas labs RTE-V850E/ME2-CB evaluation board (CONFIG_RTE_CB_ME2).
     	This has only been tested using a kernel downloaded via an ICE
     	connection using the Multi debugger.  Support for the RTE-MOTHER-A is
     	present, but hasn't been tested (unlike the other Midas labs cpu
     	boards, the RTE-V850E/ME2-CB includes an ethernet adaptor).

   "as85ep1"
	The NEC AS85EP1 V850E evaluation chip/board (CONFIG_V850E_AS85EP1).

   "anna"
	The NEC `Anna' (board/chip) implementation of the V850E2 processor
	(CONFIG_V850E2_ANNA).

   "sim85e2c", "sim85e2s"
   	The sim85e2c and sim85e2s simulators, which are verilog simulations
	of the V850E2 NA85E2C/NA85E2S cpu cores (CONFIG_V850E2_SIM85E2C and
	CONFIG_V850E2_SIM85E2S).

   "fpga85e2c"
	A FPGA implementation of the V850E2 NA85E2C cpu core
	(CONFIG_V850E2_FPGA85E2C).

To get a default kernel configuration for a particular platform, you can
use a <platform>_defconfig make target (e.g., "make rte-me2-cb_defconfig");
to see which default configurations are possible, look in the directory
"arch/v850/configs".

Porting to anything with a V850E/MA1 or MA2 processor should be simple.
See the file <asm-v850/machdep.h> and the files it includes for an example of
how to add platform/chip-specific support.