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   1 /*
   2  *  linux/arch/arm/mach-integrator/cpu.c
   3  *
   4  *  Copyright (C) 2001-2002 Deep Blue Solutions Ltd.
   5  *
   6  *  $Id: cpu.c,v 1.6 2002/07/18 13:58:51 rmk Exp $
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * CPU support functions
  13  */
  14 #include <linux/module.h>
  15 #include <linux/types.h>
  16 #include <linux/kernel.h>
  17 #include <linux/cpufreq.h>
  18 #include <linux/slab.h>
  19 #include <linux/sched.h>
  20 #include <linux/smp.h>
  21 #include <linux/init.h>
  22
  23 #include <asm/hardware.h>
  24 #include <asm/io.h>
  25 #include <asm/mach-types.h>
  26 #include <asm/hardware/icst525.h>
  27
  28 static struct cpufreq_driver integrator_driver;
  29
  30 #define CM_ID   (IO_ADDRESS(INTEGRATOR_HDR_BASE)+INTEGRATOR_HDR_ID_OFFSET)
  31 #define CM_OSC  (IO_ADDRESS(INTEGRATOR_HDR_BASE)+INTEGRATOR_HDR_OSC_OFFSET)
  32 #define CM_STAT (IO_ADDRESS(INTEGRATOR_HDR_BASE)+INTEGRATOR_HDR_STAT_OFFSET)
  33 #define CM_LOCK (IO_ADDRESS(INTEGRATOR_HDR_BASE)+INTEGRATOR_HDR_LOCK_OFFSET)
  34
  35 static const struct icst525_params lclk_params = {
  36         .ref            = 24000,
  37         .vco_max        = 320000,
  38         .vd_min         = 8,
  39         .vd_max         = 132,
  40         .rd_min         = 24,
  41         .rd_max         = 24,
  42 };
  43
  44 static const struct icst525_params cclk_params = {
  45         .ref            = 24000,
  46         .vco_max        = 320000,
  47         .vd_min         = 12,
  48         .vd_max         = 160,
  49         .rd_min         = 24,
  50         .rd_max         = 24,
  51 };
  52
  53 /*
  54  * Validate the speed policy.
  55  */
  56 static int integrator_verify_policy(struct cpufreq_policy *policy)
  57 {
  58         struct icst525_vco vco;
  59
  60         cpufreq_verify_within_limits(policy,
  61                                      policy->cpuinfo.min_freq,
  62                                      policy->cpuinfo.max_freq);
  63
  64         vco = icst525_khz_to_vco(&cclk_params, policy->max);
  65         policy->max = icst525_khz(&cclk_params, vco);
  66
  67         vco = icst525_khz_to_vco(&cclk_params, policy->min);
  68         policy->min = icst525_khz(&cclk_params, vco);
  69
  70         cpufreq_verify_within_limits(policy,
  71                                      policy->cpuinfo.min_freq,
  72                                      policy->cpuinfo.max_freq);
  73
  74         return 0;
  75 }
  76
  77
  78 static int integrator_set_target(struct cpufreq_policy *policy,
  79                                  unsigned int target_freq,
  80                                  unsigned int relation)
  81 {
  82         cpumask_t cpus_allowed;
  83         int cpu = policy->cpu;
  84         struct icst525_vco vco;
  85         struct cpufreq_freqs freqs;
  86         u_int cm_osc;
  87
  88         /*
  89          * Save this threads cpus_allowed mask.
  90          */
  91         cpus_allowed = current->cpus_allowed;
  92
  93         /*
  94          * Bind to the specified CPU.  When this call returns,
  95          * we should be running on the right CPU.
  96          */
  97         set_cpus_allowed(current, cpumask_of_cpu(cpu));
  98         BUG_ON(cpu != smp_processor_id());
  99
 100         /* get current setting */
 101         cm_osc = __raw_readl(CM_OSC);
 102
 103         if (machine_is_integrator()) {
 104                 vco.s = (cm_osc >> 8) & 7;
 105         } else if (machine_is_cintegrator()) {
 106                 vco.s = 1;
 107         }
 108         vco.v = cm_osc & 255;
 109         vco.r = 22;
 110         freqs.old = icst525_khz(&cclk_params, vco);
 111
 112         /* icst525_khz_to_vco rounds down -- so we need the next
 113          * larger freq in case of CPUFREQ_RELATION_L.
 114          */
 115         if (relation == CPUFREQ_RELATION_L)
 116                 target_freq += 999;
 117         if (target_freq > policy->max)
 118                 target_freq = policy->max;
 119         vco = icst525_khz_to_vco(&cclk_params, target_freq);
 120         freqs.new = icst525_khz(&cclk_params, vco);
 121
 122         freqs.cpu = policy->cpu;
 123
 124         if (freqs.old == freqs.new) {
 125                 set_cpus_allowed(current, cpus_allowed);
 126                 return 0;
 127         }
 128
 129         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 130
 131         cm_osc = __raw_readl(CM_OSC);
 132
 133         if (machine_is_integrator()) {
 134                 cm_osc &= 0xfffff800;
 135                 cm_osc |= vco.s << 8;
 136         } else if (machine_is_cintegrator()) {
 137                 cm_osc &= 0xffffff00;
 138         }
 139         cm_osc |= vco.v;
 140
 141         __raw_writel(0xa05f, CM_LOCK);
 142         __raw_writel(cm_osc, CM_OSC);
 143         __raw_writel(0, CM_LOCK);
 144
 145         /*
 146          * Restore the CPUs allowed mask.
 147          */
 148         set_cpus_allowed(current, cpus_allowed);
 149
 150         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 151
 152         return 0;
 153 }
 154
 155 static unsigned int integrator_get(unsigned int cpu)
 156 {
 157         cpumask_t cpus_allowed;
 158         unsigned int current_freq;
 159         u_int cm_osc;
 160         struct icst525_vco vco;
 161
 162         cpus_allowed = current->cpus_allowed;
 163
 164         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 165         BUG_ON(cpu != smp_processor_id());
 166
 167         /* detect memory etc. */
 168         cm_osc = __raw_readl(CM_OSC);
 169
 170         if (machine_is_integrator()) {
 171                 vco.s = (cm_osc >> 8) & 7;
 172         } else if (machine_is_cintegrator()) {
 173                 vco.s = 1;
 174         }
 175         vco.v = cm_osc & 255;
 176         vco.r = 22;
 177
 178         current_freq = icst525_khz(&cclk_params, vco); /* current freq */
 179
 180         set_cpus_allowed(current, cpus_allowed);
 181
 182         return current_freq;
 183 }
 184
 185 static int integrator_cpufreq_init(struct cpufreq_policy *policy)
 186 {
 187
 188         /* set default policy and cpuinfo */
 189         policy->governor = CPUFREQ_DEFAULT_GOVERNOR;
 190         policy->cpuinfo.max_freq = 160000;
 191         policy->cpuinfo.min_freq = 12000;
 192         policy->cpuinfo.transition_latency = 1000000; /* 1 ms, assumed */
 193         policy->cur = policy->min = policy->max = integrator_get(policy->cpu);
 194
 195         return 0;
 196 }
 197
 198 static struct cpufreq_driver integrator_driver = {
 199         .verify         = integrator_verify_policy,
 200         .target         = integrator_set_target,
 201         .get            = integrator_get,
 202         .init           = integrator_cpufreq_init,
 203         .name           = "integrator",
 204 };
 205
 206 static int __init integrator_cpu_init(void)
 207 {
 208         return cpufreq_register_driver(&integrator_driver);
 209 }
 210
 211 static void __exit integrator_cpu_exit(void)
 212 {
 213         cpufreq_unregister_driver(&integrator_driver);
 214 }
 215
 216 MODULE_AUTHOR ("Russell M. King");
 217 MODULE_DESCRIPTION ("cpufreq driver for ARM Integrator CPUs");
 218 MODULE_LICENSE ("GPL");
 219
 220 module_init(integrator_cpu_init);
 221 module_exit(integrator_cpu_exit);