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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  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  * CPU support functions
  11  */
  12 #include <linux/module.h>
  13 #include <linux/types.h>
  14 #include <linux/kernel.h>
  15 #include <linux/cpufreq.h>
  16 #include <linux/slab.h>
  17 #include <linux/sched.h>
  18 #include <linux/smp.h>
  19 #include <linux/init.h>
  20 #include <linux/io.h>
  21
  22 #include <mach/hardware.h>
  23 #include <mach/platform.h>
  24 #include <asm/mach-types.h>
  25 #include <asm/hardware/icst525.h>
  26
  27 static struct cpufreq_driver integrator_driver;
  28
  29 #define CM_ID   IO_ADDRESS(INTEGRATOR_HDR_ID)
  30 #define CM_OSC  IO_ADDRESS(INTEGRATOR_HDR_OSC)
  31 #define CM_STAT IO_ADDRESS(INTEGRATOR_HDR_STAT)
  32 #define CM_LOCK IO_ADDRESS(INTEGRATOR_HDR_LOCK)
  33
  34 static const struct icst_params lclk_params = {
  35         .ref            = 24000000,
  36         .vco_max        = ICST525_VCO_MAX_5V,
  37         .vd_min         = 8,
  38         .vd_max         = 132,
  39         .rd_min         = 24,
  40         .rd_max         = 24,
  41 };
  42
  43 static const struct icst_params cclk_params = {
  44         .ref            = 24000000,
  45         .vco_max        = ICST525_VCO_MAX_5V,
  46         .vd_min         = 12,
  47         .vd_max         = 160,
  48         .rd_min         = 24,
  49         .rd_max         = 24,
  50 };
  51
  52 /*
  53  * Validate the speed policy.
  54  */
  55 static int integrator_verify_policy(struct cpufreq_policy *policy)
  56 {
  57         struct icst_vco vco;
  58
  59         cpufreq_verify_within_limits(policy,
  60                                      policy->cpuinfo.min_freq,
  61                                      policy->cpuinfo.max_freq);
  62
  63         vco = icst525_hz_to_vco(&cclk_params, policy->max * 1000);
  64         policy->max = icst525_hz(&cclk_params, vco) / 1000;
  65
  66         vco = icst525_hz_to_vco(&cclk_params, policy->min * 1000);
  67         policy->min = icst525_hz(&cclk_params, vco) / 1000;
  68
  69         cpufreq_verify_within_limits(policy,
  70                                      policy->cpuinfo.min_freq,
  71                                      policy->cpuinfo.max_freq);
  72
  73         return 0;
  74 }
  75
  76
  77 static int integrator_set_target(struct cpufreq_policy *policy,
  78                                  unsigned int target_freq,
  79                                  unsigned int relation)
  80 {
  81         cpumask_t cpus_allowed;
  82         int cpu = policy->cpu;
  83         struct icst_vco vco;
  84         struct cpufreq_freqs freqs;
  85         u_int cm_osc;
  86
  87         /*
  88          * Save this threads cpus_allowed mask.
  89          */
  90         cpus_allowed = current->cpus_allowed;
  91
  92         /*
  93          * Bind to the specified CPU.  When this call returns,
  94          * we should be running on the right CPU.
  95          */
  96         set_cpus_allowed(current, cpumask_of_cpu(cpu));
  97         BUG_ON(cpu != smp_processor_id());
  98
  99         /* get current setting */
 100         cm_osc = __raw_readl(CM_OSC);
 101
 102         if (machine_is_integrator()) {
 103                 vco.s = (cm_osc >> 8) & 7;
 104         } else if (machine_is_cintegrator()) {
 105                 vco.s = 1;
 106         }
 107         vco.v = cm_osc & 255;
 108         vco.r = 22;
 109         freqs.old = icst525_hz(&cclk_params, vco) / 1000;
 110
 111         /* icst525_hz_to_vco rounds down -- so we need the next
 112          * larger freq in case of CPUFREQ_RELATION_L.
 113          */
 114         if (relation == CPUFREQ_RELATION_L)
 115                 target_freq += 999;
 116         if (target_freq > policy->max)
 117                 target_freq = policy->max;
 118         vco = icst525_hz_to_vco(&cclk_params, target_freq * 1000);
 119         freqs.new = icst525_hz(&cclk_params, vco) / 1000;
 120
 121         freqs.cpu = policy->cpu;
 122
 123         if (freqs.old == freqs.new) {
 124                 set_cpus_allowed(current, cpus_allowed);
 125                 return 0;
 126         }
 127
 128         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 129
 130         cm_osc = __raw_readl(CM_OSC);
 131
 132         if (machine_is_integrator()) {
 133                 cm_osc &= 0xfffff800;
 134                 cm_osc |= vco.s << 8;
 135         } else if (machine_is_cintegrator()) {
 136                 cm_osc &= 0xffffff00;
 137         }
 138         cm_osc |= vco.v;
 139
 140         __raw_writel(0xa05f, CM_LOCK);
 141         __raw_writel(cm_osc, CM_OSC);
 142         __raw_writel(0, CM_LOCK);
 143
 144         /*
 145          * Restore the CPUs allowed mask.
 146          */
 147         set_cpus_allowed(current, cpus_allowed);
 148
 149         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 150
 151         return 0;
 152 }
 153
 154 static unsigned int integrator_get(unsigned int cpu)
 155 {
 156         cpumask_t cpus_allowed;
 157         unsigned int current_freq;
 158         u_int cm_osc;
 159         struct icst_vco vco;
 160
 161         cpus_allowed = current->cpus_allowed;
 162
 163         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 164         BUG_ON(cpu != smp_processor_id());
 165
 166         /* detect memory etc. */
 167         cm_osc = __raw_readl(CM_OSC);
 168
 169         if (machine_is_integrator()) {
 170                 vco.s = (cm_osc >> 8) & 7;
 171         } else if (machine_is_cintegrator()) {
 172                 vco.s = 1;
 173         }
 174         vco.v = cm_osc & 255;
 175         vco.r = 22;
 176
 177         current_freq = icst525_hz(&cclk_params, vco) / 1000; /* current freq */
 178
 179         set_cpus_allowed(current, cpus_allowed);
 180
 181         return current_freq;
 182 }
 183
 184 static int integrator_cpufreq_init(struct cpufreq_policy *policy)
 185 {
 186
 187         /* set default policy and cpuinfo */
 188         policy->cpuinfo.max_freq = 160000;
 189         policy->cpuinfo.min_freq = 12000;
 190         policy->cpuinfo.transition_latency = 1000000; /* 1 ms, assumed */
 191         policy->cur = policy->min = policy->max = integrator_get(policy->cpu);
 192
 193         return 0;
 194 }
 195
 196 static struct cpufreq_driver integrator_driver = {
 197         .verify         = integrator_verify_policy,
 198         .target         = integrator_set_target,
 199         .get            = integrator_get,
 200         .init           = integrator_cpufreq_init,
 201         .name           = "integrator",
 202 };
 203
 204 static int __init integrator_cpu_init(void)
 205 {
 206         return cpufreq_register_driver(&integrator_driver);
 207 }
 208
 209 static void __exit integrator_cpu_exit(void)
 210 {
 211         cpufreq_unregister_driver(&integrator_driver);
 212 }
 213
 214 MODULE_AUTHOR ("Russell M. King");
 215 MODULE_DESCRIPTION ("cpufreq driver for ARM Integrator CPUs");
 216 MODULE_LICENSE ("GPL");
 217
 218 module_init(integrator_cpu_init);
 219 module_exit(integrator_cpu_exit);