forked from luck/tmp_suning_uos_patched
f5899b5d4f
The udelay() inline for ia64 uses the ITC. If CONFIG_PREEMPT is enabled and the platform has unsynchronized ITCs and the calling task migrates to another CPU while doing the udelay loop, then the effective delay may be too short or very, very long. This patch disables preemption around 100 usec chunks of the overall desired udelay time. This minimizes preemption-holdoffs. udelay() is now too big to be inline, move it out of line and export it. Signed-off-by: John Hawkes <hawkes@sgi.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
90 lines
1.7 KiB
C
90 lines
1.7 KiB
C
#ifndef _ASM_IA64_DELAY_H
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#define _ASM_IA64_DELAY_H
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/*
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* Delay routines using a pre-computed "cycles/usec" value.
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*
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* Copyright (C) 1998, 1999 Hewlett-Packard Co
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* David Mosberger-Tang <davidm@hpl.hp.com>
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* Copyright (C) 1999 VA Linux Systems
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* Copyright (C) 1999 Walt Drummond <drummond@valinux.com>
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* Copyright (C) 1999 Asit Mallick <asit.k.mallick@intel.com>
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* Copyright (C) 1999 Don Dugger <don.dugger@intel.com>
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*/
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#include <linux/config.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/compiler.h>
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#include <asm/intrinsics.h>
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#include <asm/processor.h>
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static __inline__ void
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ia64_set_itm (unsigned long val)
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{
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ia64_setreg(_IA64_REG_CR_ITM, val);
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ia64_srlz_d();
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}
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static __inline__ unsigned long
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ia64_get_itm (void)
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{
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unsigned long result;
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result = ia64_getreg(_IA64_REG_CR_ITM);
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ia64_srlz_d();
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return result;
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}
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static __inline__ void
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ia64_set_itv (unsigned long val)
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{
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ia64_setreg(_IA64_REG_CR_ITV, val);
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ia64_srlz_d();
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}
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static __inline__ unsigned long
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ia64_get_itv (void)
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{
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return ia64_getreg(_IA64_REG_CR_ITV);
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}
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static __inline__ void
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ia64_set_itc (unsigned long val)
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{
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ia64_setreg(_IA64_REG_AR_ITC, val);
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ia64_srlz_d();
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}
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static __inline__ unsigned long
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ia64_get_itc (void)
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{
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unsigned long result;
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result = ia64_getreg(_IA64_REG_AR_ITC);
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ia64_barrier();
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#ifdef CONFIG_ITANIUM
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while (unlikely((__s32) result == -1)) {
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result = ia64_getreg(_IA64_REG_AR_ITC);
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ia64_barrier();
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}
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#endif
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return result;
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}
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extern void ia64_delay_loop (unsigned long loops);
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static __inline__ void
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__delay (unsigned long loops)
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{
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if (unlikely(loops < 1))
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return;
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ia64_delay_loop (loops - 1);
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}
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extern void udelay (unsigned long usecs);
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#endif /* _ASM_IA64_DELAY_H */
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