pexpert/ppc/pe_clock_speed.c

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_OSREFERENCE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License.  The rights granted to you under the
  10  * License may not be used to create, or enable the creation or
  11  * redistribution of, unlawful or unlicensed copies of an Apple operating
  12  * system, or to circumvent, violate, or enable the circumvention or
  13  * violation of, any terms of an Apple operating system software license
  14  * agreement.
  15  *
  16  * Please obtain a copy of the License at
  17  * http://www.opensource.apple.com/apsl/ and read it before using this
  18  * file.
  19  *
  20  * The Original Code and all software distributed under the License are
  21  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  22  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  23  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  24  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  25  * Please see the License for the specific language governing rights and
  26  * limitations under the License.
  27  *
  28  * @APPLE_LICENSE_OSREFERENCE_HEADER_END@
  29  */
  30 /*
  31  *  pe_clock_speed.c - Determine the best guess for the processor and bus
  32  *                     speed buy using the values returned by run_clock_test.
  33  *
  34  *  (c) Apple Computer, Inc. 1998-2002
  35  *
  36  *  Writen by:   Josh de Cesare
  37  *
  38  */
  39
  40 #include <pexpert/pexpert.h>
  41
  42 #include <ppc/machine_routines.h>
  43
  44 // prototypes
  45 extern void pe_run_clock_test(void *tmp);
  46 void pe_do_clock_test(unsigned int via_addr,
  47                       int num_speeds, unsigned long *speed_list);
  48
  49 // Threshold for bus speed matches.
  50 #define kMaxFreqDiff  (30000)
  51
  52 // This is the structure for the data that get passed to pe_run_clock_test.
  53 struct clock_test_data {
  54   unsigned int via_addr;
  55   unsigned int via_ticks;
  56   unsigned int dec_ticks;
  57 };
  58
  59 // glocal variables to simplify some stuff.
  60 static long bus_freq_num, bus_freq_den, cpu_pll;
  61
  62 // PE_Determine_Clock_Speeds is called by the via driver in IOKit
  63 // It uses the numbers generated by pe_do_clock_test and reports
  64 // the cleaned up values to the rest of the OS.
  65 void PE_Determine_Clock_Speeds(unsigned int via_addr, int num_speeds,
  66                                unsigned long *speed_list)
  67 {
  68   boolean_t          oldLevel;
  69   unsigned long      tmp_bus_speed, tmp_cpu_speed;
  70   unsigned long long tmp;
  71
  72   oldLevel = ml_set_interrupts_enabled(FALSE);
  73   pe_do_clock_test(via_addr, num_speeds, speed_list);
  74   ml_set_interrupts_enabled(oldLevel);
  75
  76   tmp_bus_speed = bus_freq_num / bus_freq_den;
  77   tmp = ((unsigned long long)bus_freq_num * cpu_pll) / (bus_freq_den * 2);
  78   tmp_cpu_speed = (unsigned long)tmp;
  79
  80   // Report the bus clock rate as is.
  81   gPEClockFrequencyInfo.bus_clock_rate_num = bus_freq_num;
  82   gPEClockFrequencyInfo.bus_clock_rate_den = bus_freq_den;
  83
  84   // pll multipliers are in halfs so set the denominator to 2.
  85   gPEClockFrequencyInfo.bus_to_cpu_rate_num = cpu_pll;
  86   gPEClockFrequencyInfo.bus_to_cpu_rate_den = 2;
  87
  88   // The decrementer rate is one fourth the bus rate.
  89   gPEClockFrequencyInfo.bus_to_dec_rate_num = 1;
  90   gPEClockFrequencyInfo.bus_to_dec_rate_den = 4;
  91
  92   // Assume that the timebase frequency is derived from the bus clock.
  93   gPEClockFrequencyInfo.timebase_frequency_num = bus_freq_num;
  94   gPEClockFrequencyInfo.timebase_frequency_den = bus_freq_den * 4;
  95
  96   // Set the truncated numbers in gPEClockFrequencyInfo.
  97   gPEClockFrequencyInfo.bus_clock_rate_hz = tmp_bus_speed;
  98   gPEClockFrequencyInfo.cpu_clock_rate_hz = tmp_cpu_speed;
  99   gPEClockFrequencyInfo.dec_clock_rate_hz = tmp_bus_speed / 4;
 100   gPEClockFrequencyInfo.timebase_frequency_hz = tmp_bus_speed / 4;
 101
 102   gPEClockFrequencyInfo.bus_frequency_hz = tmp_bus_speed;
 103   gPEClockFrequencyInfo.bus_frequency_min_hz = tmp_bus_speed;
 104   gPEClockFrequencyInfo.bus_frequency_max_hz = tmp_bus_speed;
 105   gPEClockFrequencyInfo.cpu_frequency_hz = tmp_cpu_speed;
 106   gPEClockFrequencyInfo.cpu_frequency_min_hz = tmp_cpu_speed;
 107   gPEClockFrequencyInfo.cpu_frequency_max_hz = tmp_cpu_speed;
 108
 109   PE_call_timebase_callback();
 110 }
 111
 112 // pe_do_clock_test uses the number from pe_run_clock_test to
 113 // find a best fit guess for the bus speed.
 114 void pe_do_clock_test(unsigned int via_addr,
 115                       int num_speeds, unsigned long *speed_list)
 116 {
 117   struct clock_test_data clock_test_data;
 118   long cnt, diff, raw_cpu_freq, raw_bus_freq, tmp_bus_freq,
 119     last_bus_freq, tries = 10;
 120
 121   // Save the via addr so the asm part can use it.
 122   clock_test_data.via_addr = via_addr;
 123
 124   // Keep looping until it matches the last try.
 125   bus_freq_num = 0;
 126   do {
 127     last_bus_freq = bus_freq_num;
 128
 129     // The the asm part to do the real work.
 130     pe_run_clock_test((void *)&clock_test_data);
 131
 132     // First find the pll mode.  Allow any integer times two.
 133     cpu_pll = 10000000 / clock_test_data.dec_ticks;
 134     cpu_pll = (cpu_pll / 2) + (cpu_pll & 1);
 135
 136     // Using 64 bit math figure out the raw bus speed.
 137     // 0xBF401675E5DULL is 1 / 1.27655us times 2 ^ 24.
 138     raw_bus_freq = ((0xBF401675E5DULL * clock_test_data.dec_ticks) /
 139                     clock_test_data.via_ticks) >> 22;
 140
 141     // use the pll mode and the raw bus speed to find the raw cpu speed.
 142     raw_cpu_freq = raw_bus_freq * cpu_pll / 2;
 143
 144     // Look to see if the bus speed is close to one of the
 145     // speeds in the table.
 146     for (cnt = 0; cnt < num_speeds; cnt++) {
 147       bus_freq_num = speed_list[cnt * 2];
 148       bus_freq_den = speed_list[cnt * 2 + 1];
 149       diff = bus_freq_num - raw_bus_freq * bus_freq_den;
 150       if (diff < 0) diff = -diff;
 151
 152       if (diff < kMaxFreqDiff * bus_freq_den) break;
 153     }
 154     if (cnt != num_speeds) continue;
 155
 156     // Look to see if the bus speed is close to n * 0.5 MHz
 157     tmp_bus_freq = ((raw_bus_freq + 250000) / 500000) * 500000;
 158
 159     diff = tmp_bus_freq - raw_bus_freq;
 160     if (diff < 0) diff = -diff;
 161
 162     if (diff < kMaxFreqDiff) {
 163       bus_freq_num = tmp_bus_freq;
 164       bus_freq_den = 1;
 165       continue;
 166     }
 167
 168     // Look to see if the bus speed is close to n * 50/3 MHz
 169     tmp_bus_freq = ((raw_bus_freq * 3 + 25000000) / 50000000) * 50000000;
 170
 171     diff = tmp_bus_freq - raw_bus_freq * 3;
 172     if (diff < 0) diff = -diff;
 173
 174     if (diff < kMaxFreqDiff * 3) {
 175       bus_freq_num = tmp_bus_freq;
 176       bus_freq_den = 3;
 177       continue;
 178     }
 179
 180     // Since all else failed return the raw bus speed
 181     bus_freq_num = raw_bus_freq;
 182     bus_freq_den = 1;
 183   } while ((bus_freq_num != last_bus_freq) && tries--);
 184 }