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* MIPS: sync-r4k: reduce skew while synchronizationHuacai Chen2016-01-241-24/+8
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | While synchronization, count register will go backwards for the master. If synchronise_count_master() runs before synchronise_count_slave(), skew becomes even more. The skew is very harmful for CPU hotplug (CPU0 do synchronization with CPU1, then CPU0 do synchronization with CPU2 and CPU0's count goes backwards, so it will be out of sync with CPU1). After the commit cf9bfe55f24973a8f40e2 (MIPS: Synchronize MIPS count one CPU at a time), we needn't evaluate count_reference at the beginning of synchronise_count_master() any more. Thus, we evaluate the initcount (It seems like count_reference is redundant) in the 2nd loop. Since we write the count register in the last loop, we don't need additional barriers (the existing memory barriers are enough). Moreover, I think we loop 3 times is enough to get a primed instruction cache, this can also get less skew than looping 5 times. Comments are also updated in this patch. Signed-off-by: Huacai Chen <chenhc@lemote.com> Cc: Aurelien Jarno <aurelien@aurel32.net> Cc: Steven J. Hill <Steven.Hill@imgtec.com> Cc: linux-mips@linux-mips.org Cc: Fuxin Zhang <zhangfx@lemote.com> Cc: Zhangjin Wu <wuzhangjin@gmail.com> Patchwork: https://patchwork.linux-mips.org/patch/12163/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: MT: Remove SMTC supportRalf Baechle2014-05-241-18/+0
| | | | | | | | | | | | | | | Nobody is maintaining SMTC anymore and there also seems to be no userbase. Which is a pity - the SMTC technology primarily developed by Kevin D. Kissell <kevink@paralogos.com> is an ingenious demonstration for the MT ASE's power and elegance. Based on Markos Chandras <Markos.Chandras@imgtec.com> patch https://patchwork.linux-mips.org/patch/6719/ which while very similar did no longer apply cleanly when I tried to merge it plus some additional post-SMTC cleanup - SMTC was a feature as tricky to remove as it was to merge once upon a time. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* mips: delete non-required instances of include <linux/init.h>Paul Gortmaker2014-01-241-1/+0
| | | | | | | | | | | None of these files are actually using any __init type directives and hence don't need to include <linux/init.h>. Most are just a left over from __devinit and __cpuinit removal, or simply due to code getting copied from one driver to the next. Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Signed-off-by: John Crispin <blogic@openwrt.org> Patchwork: http://patchwork.linux-mips.org/patch/6320/
* MIPS: Delete __cpuinit/__CPUINIT usage from MIPS codePaul Gortmaker2013-07-141-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | commit 3747069b25e419f6b51395f48127e9812abc3596 upstream. The __cpuinit type of throwaway sections might have made sense some time ago when RAM was more constrained, but now the savings do not offset the cost and complications. For example, the fix in commit 5e427ec2d0 ("x86: Fix bit corruption at CPU resume time") is a good example of the nasty type of bugs that can be created with improper use of the various __init prefixes. After a discussion on LKML[1] it was decided that cpuinit should go the way of devinit and be phased out. Once all the users are gone, we can then finally remove the macros themselves from linux/init.h. Note that some harmless section mismatch warnings may result, since notify_cpu_starting() and cpu_up() are arch independent (kernel/cpu.c) and are flagged as __cpuinit -- so if we remove the __cpuinit from the arch specific callers, we will also get section mismatch warnings. As an intermediate step, we intend to turn the linux/init.h cpuinit related content into no-ops as early as possible, since that will get rid of these warnings. In any case, they are temporary and harmless. Here, we remove all the MIPS __cpuinit from C code and __CPUINIT from asm files. MIPS is interesting in this respect, because there are also uasm users hiding behind their own renamed versions of the __cpuinit macros. [1] https://lkml.org/lkml/2013/5/20/589 [ralf@linux-mips.org: Folded in Paul's followup fix.] Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/5494/ Patchwork: https://patchwork.linux-mips.org/patch/5495/ Patchwork: https://patchwork.linux-mips.org/patch/5509/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Whitespace cleanup.Ralf Baechle2013-02-011-1/+1
| | | | | | | | Having received another series of whitespace patches I decided to do this once and for all rather than dealing with this kind of patches trickling in forever. Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: Synchronize MIPS count one CPU at a timeJayachandran C2012-08-171-15/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | The current implementation of synchronise_count_{master,slave} blocks slave CPUs in early boot until all of them come up. This no longer works because blocking a CPU with interrupts off after notifying the CPU to be online causes problems with the current kernel. Specifically, after the workqueue changes (commit a08489c569dc1 "Pull workqueue changes from Tejun Heo") the CPU_ONLINE notification callback workqueue_cpu_up_callback() will hang on wait_for_completion(&idle_rebind.done), if the slave CPUs are blocked for synchronize_count_slave(). The changes are to update synchronize_count_{master,slave}() to handle one CPU at a time and to call synchronise_count_master() in __cpu_up() so that the CPU_ONLINE notification goes out only after the COP0 COUNT register is synchronized. [ralf@linux-mips.org: This matter only to those few platforms which are using the cp0 counter as their clocksource which are XLP, XLR and MIPS' CMP solution.] Signed-off-by: Jayachandran C <jchandra@broadcom.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/4216/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* MIPS: sync-r4k: remove redundant irq operationYong Zhang2012-07-191-5/+0
| | | | | | | | | | Since we have delayed irq enabling to ->smp_finish() Signed-off-by: Yong Zhang <yong.zhang0@gmail.com> Cc: Sergei Shtylyov <sshtylyov@mvista.com> Cc: David Daney <david.daney@cavium.com> Acked-by: David Daney <david.daney@cavium.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* atomic: use <linux/atomic.h>Arun Sharma2011-07-261-1/+1
| | | | | | | | | | | | | | This allows us to move duplicated code in <asm/atomic.h> (atomic_inc_not_zero() for now) to <linux/atomic.h> Signed-off-by: Arun Sharma <asharma@fb.com> Reviewed-by: Eric Dumazet <eric.dumazet@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: David Miller <davem@davemloft.net> Cc: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: Mike Frysinger <vapier@gentoo.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* MIPS: CMP: Update sync-r4k for current kernelTim Anderson2009-07-031-15/+16
| | | | | | | | This revises the sync-4k so it will boot and operate since the removal of expirelo from the timer code. Signed-off-by: Tim Anderson <tanderson@mvista.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
* [MIPS] Add support for MIPS CMP platform.Ralf Baechle2008-04-281-0/+159
Signed-off-by: Chris Dearman <chris@mips.com> Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
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