| /* |
| * This file is part of the libpayload project. |
| * |
| * Copyright (C) 2008 Advanced Micro Devices, Inc. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in the |
| * documentation and/or other materials provided with the distribution. |
| * 3. The name of the author may not be used to endorse or promote products |
| * derived from this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND |
| * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE |
| * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| */ |
| |
| #include <libpayload.h> |
| #include <arch/rdtsc.h> |
| |
| static unsigned int cpu_khz; |
| |
| /** |
| * Calculate the speed of the processor for use in delays. |
| * |
| * @return The CPU speed in kHz. |
| */ |
| unsigned int get_cpu_speed(void) |
| { |
| unsigned long long start, end; |
| |
| /* Set up the PPC port - disable the speaker, enable the T2 gate. */ |
| outb((inb(0x61) & ~0x02) | 0x01, 0x61); |
| |
| /* Set the PIT to Mode 0, counter 2, word access. */ |
| outb(0xB0, 0x43); |
| |
| /* Load the counter with 0xffff. */ |
| outb(0xff, 0x42); |
| outb(0xff, 0x42); |
| |
| /* Read the number of ticks during the period. */ |
| start = rdtsc(); |
| while (!(inb(0x61) & 0x20)) ; |
| end = rdtsc(); |
| |
| /* |
| * The clock rate is 1193180 Hz, the number of miliseconds for a |
| * period of 0xffff is 1193180 / (0xFFFF * 1000) or .0182. |
| * Multiply that by the number of measured clocks to get the kHz value. |
| */ |
| cpu_khz = (unsigned int)((end - start) * 1193180U / (1000 * 0xffff)); |
| |
| return cpu_khz; |
| } |
| |
| static inline void _delay(unsigned int delta) |
| { |
| unsigned long long timeout = rdtsc() + delta; |
| while (rdtsc() < timeout) ; |
| } |
| |
| void ndelay(unsigned int n) |
| { |
| _delay(n * cpu_khz / 1000000); |
| } |
| |
| void mdelay(unsigned int m) |
| { |
| _delay(m * cpu_khz); |
| } |
| |
| void delay(unsigned int s) |
| { |
| _delay(s * cpu_khz * 1000); |
| } |