15487b4817
git-svn-id: http://svn.lfbs.rwth-aachen.de/svn/scc/trunk/MetalSVM@369 315a16e6-25f9-4109-90ae-ca3045a26c18
87 lines
2 KiB
C
87 lines
2 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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#ifdef CONFIG_ROCKCREEK
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#include <asm/scc.h>
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#endif
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static uint32_t cpu_freq = 0;
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/* disable optimization for the following functions */
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uint32_t detect_cpu_frequency(void) __attribute__((optimize(0)));
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void udelay(uint32_t usecs) __attribute__((optimize(0)));
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uint32_t detect_cpu_frequency(void)
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{
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#ifdef CONFIG_ROCKCREEK
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if (cpu_freq > 0)
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return cpu_freq;
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cpu_freq = scc_info.tile_frequency;
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return cpu_freq;
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#else
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uint64_t start, end, diff;
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uint64_t ticks, old;
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if (BUILTIN_EXPECT(cpu_freq > 0, 0))
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return cpu_freq;
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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 a second 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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diff = end > start ? end - start : start - end;
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cpu_freq = (uint32_t) (diff / (uint64_t) 1000000);
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return cpu_freq;
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#endif
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}
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uint32_t 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(uint32_t usecs)
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{
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uint64_t diff, end, start = rdtsc();
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uint64_t deadline = get_cpu_frequency() * usecs;
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do {
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end = rdtsc();
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diff = end > start ? end - start : start - end;
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} while(diff < deadline);
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}
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