pexpert/ppc/pe_clock_speed.c

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