c8c3035a4d
- MetalSVM detects the APIC and initializes the APIC timer - If an a APIC is available, the PIC timer will be disabled - SMP is currently not supported git-svn-id: http://svn.lfbs.rwth-aachen.de/svn/scc/trunk/MetalSVM@233 315a16e6-25f9-4109-90ae-ca3045a26c18
64 lines
1.5 KiB
C
64 lines
1.5 KiB
C
/*
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* Copyright 2010 Stefan Lankes, Chair for Operating Systems,
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* RWTH Aachen University
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* This file is part of MetalSVM.
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*/
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#include <metalsvm/stddef.h>
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#include <metalsvm/stdio.h>
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#include <metalsvm/time.h>
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#include <metalsvm/processor.h>
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static int cpu_freq = 0;
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int detect_cpu_frequency(void)
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{
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uint64_t start, end;
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uint64_t ticks, old;
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old = get_clock_tick();
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/* wait for the next time slice */
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while((ticks = get_clock_tick()) - old == 0)
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;
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start = rdtsc();
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/* wait 5 time slices to determine the frequency */
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while(get_clock_tick() - ticks < TIMER_FREQ)
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;
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end = rdtsc();
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cpu_freq = end - start;
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return cpu_freq;
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}
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int get_cpu_frequency(void)
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{
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if (cpu_freq > 0)
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return cpu_freq;
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return detect_cpu_frequency();
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}
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void udelay(unsigned int usecs)
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{
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uint64_t start = rdtsc();
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uint64_t deadline = (get_cpu_frequency()*usecs)/1000000;
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while(rdtsc() - start < deadline)
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;
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}
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