182 lines
4.5 KiB
C
182 lines
4.5 KiB
C
/* $NetBSD: clock.c,v 1.5 1998/02/02 04:59:19 sakamoto Exp $ */
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/* $OpenBSD: clock.c,v 1.3 1997/10/13 13:42:53 pefo Exp $ */
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/*
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* Copyright (C) 1995, 1996 Wolfgang Solfrank.
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* Copyright (C) 1995, 1996 TooLs GmbH.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by TooLs GmbH.
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* 4. The name of TooLs GmbH may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY TOOLS GMBH ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL TOOLS GMBH BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
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* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
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* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/param.h>
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#include <sys/kernel.h>
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#include <machine/bootinfo.h>
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#include <machine/pio.h>
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/*
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* Initially we assume a processor with a bus frequency of 12.5 MHz.
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*/
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u_long ticks_per_sec;
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u_long ns_per_tick;
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static long ticks_per_intr;
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static volatile u_long lasttb;
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void
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decr_intr(frame)
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struct clockframe *frame;
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{
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int msr;
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int pri;
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u_long tb;
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long tick;
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int nticks;
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extern long intrcnt[];
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/*
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* Check whether we are initialized.
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*/
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if (!ticks_per_intr)
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return;
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/*
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* Based on the actual time delay since the last decrementer reload,
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* we arrange for earlier interrupt next time.
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*/
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asm ("mftb %0; mfdec %1" : "=r"(tb), "=r"(tick));
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for (nticks = 0; tick < 0; nticks++)
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tick += ticks_per_intr;
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asm volatile ("mtdec %0" :: "r"(tick));
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/*
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* lasttb is used during microtime. Set it to the virtual
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* start of this tick interval.
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*/
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lasttb = tb + tick - ticks_per_intr;
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intrcnt[CNT_CLOCK]++;
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pri = splclock();
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if (pri & SPL_CLOCK)
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tickspending += nticks;
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else {
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nticks += tickspending;
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tickspending = 0;
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/*
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* Reenable interrupts
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*/
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asm volatile ("mfmsr %0; ori %0, %0, %1; mtmsr %0"
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: "=r"(msr) : "K"(PSL_EE));
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/*
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* Do standard timer interrupt stuff.
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* Do softclock stuff only on the last iteration.
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*/
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frame->pri = pri | SINT_CLOCK;
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while (--nticks > 0)
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hardclock(frame);
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frame->pri = pri;
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hardclock(frame);
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}
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splx(pri);
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}
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void
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cpu_initclocks()
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{
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int msr, scratch;
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ticks_per_intr = ticks_per_sec / hz;
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asm volatile ("mftb %0" : "=r"(lasttb));
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asm volatile ("mtdec %0" :: "r"(ticks_per_intr));
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}
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static inline u_quad_t
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mftb()
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{
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u_long scratch;
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u_quad_t tb;
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asm ("1: mftbu %0; mftb %0+1; mftbu %1; cmpw %0,%1; bne 1b"
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: "=r"(tb), "=r"(scratch));
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return tb;
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}
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/*
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* Fill in *tvp with current time with microsecond resolution.
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*/
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void
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microtime(tvp)
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struct timeval *tvp;
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{
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u_long tb;
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u_long ticks;
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int msr, scratch;
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asm volatile ("mfmsr %0; andi. %1,%0,%2; mtmsr %1"
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: "=r"(msr), "=r"(scratch) : "K"((u_short)~PSL_EE));
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asm ("mftb %0" : "=r"(tb));
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ticks = (tb - lasttb) * ns_per_tick;
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*tvp = time;
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asm volatile ("mtmsr %0" :: "r"(msr));
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ticks /= 1000;
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tvp->tv_usec += ticks;
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while (tvp->tv_usec > 1000000) {
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tvp->tv_usec -= 1000000;
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tvp->tv_sec++;
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}
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}
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/*
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* Wait for about n microseconds (at least!).
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*/
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void
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delay(n)
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int n;
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{
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u_quad_t tb;
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u_long tbh, tbl, scratch;
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tb = mftb();
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tb += (n * 1000 + ns_per_tick - 1) / ns_per_tick;
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tbh = tb >> 32;
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tbl = tb;
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asm ("1: mftbu %0; cmpw %0,%1; blt 1b; bgt 2f; mftb %0; cmpw %0,%2; blt 1b; 2:"
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:: "r"(scratch), "r"(tbh), "r"(tbl));
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}
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/*
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* Nothing to do.
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*/
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void
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setstatclockrate(arg)
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int arg;
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{
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/* Do nothing */
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}
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