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