109 lines
2.4 KiB
C
109 lines
2.4 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/RCCE_lib.h>
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#endif
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cpu_info_t cpu_info = { 0, 0 };
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static uint32_t cpu_freq = 0;
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int cpu_detection(void)
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{
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uint32_t a, b, cr4;
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cpuid(1, &a, &b, &cpu_info.feature2, &cpu_info.feature1);
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cr4 = read_cr4();
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if (has_fxsr())
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cr4 |= 0x200; // set the OSFXSR bit
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if (has_xmm())
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cr4 |= 0x400; // set the OSXMMEXCPT bit
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write_cr4(cr4);
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if (has_avx())
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kprintf("The CPU owns the Advanced Vector Extensions (AVX). However, MetalSVM doesn't support AVX!\n");
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if (has_fpu())
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asm volatile ("fninit");
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return 0;
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}
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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 = RC_REFCLOCKMHZ;
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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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HALT;
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mb();
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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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HALT;
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mb();
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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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mb();
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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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