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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         .vco_min        = ICST525_VCO_MIN,
  38         .vd_min         = 8,
  39         .vd_max         = 132,
  40         .rd_min         = 24,
  41         .rd_max         = 24,
  42 };
  43
  44 static const struct icst_params cclk_params = {
  45         .ref            = 24000000,
  46         .vco_max        = ICST525_VCO_MAX_5V,
  47         .vco_min        = ICST525_VCO_MIN,
  48         .vd_min         = 12,
  49         .vd_max         = 160,
  50         .rd_min         = 24,
  51         .rd_max         = 24,
  52 };
  53
  54 /*
  55  * Validate the speed policy.
  56  */
  57 static int integrator_verify_policy(struct cpufreq_policy *policy)
  58 {
  59         struct icst_vco vco;
  60
  61         cpufreq_verify_within_limits(policy,
  62                                      policy->cpuinfo.min_freq,
  63                                      policy->cpuinfo.max_freq);
  64
  65         vco = icst525_hz_to_vco(&cclk_params, policy->max * 1000);
  66         policy->max = icst525_hz(&cclk_params, vco) / 1000;
  67
  68         vco = icst525_hz_to_vco(&cclk_params, policy->min * 1000);
  69         policy->min = icst525_hz(&cclk_params, vco) / 1000;
  70
  71         cpufreq_verify_within_limits(policy,
  72                                      policy->cpuinfo.min_freq,
  73                                      policy->cpuinfo.max_freq);
  74
  75         return 0;
  76 }
  77
  78
  79 static int integrator_set_target(struct cpufreq_policy *policy,
  80                                  unsigned int target_freq,
  81                                  unsigned int relation)
  82 {
  83         cpumask_t cpus_allowed;
  84         int cpu = policy->cpu;
  85         struct icst_vco vco;
  86         struct cpufreq_freqs freqs;
  87         u_int cm_osc;
  88
  89         /*
  90          * Save this threads cpus_allowed mask.
  91          */
  92         cpus_allowed = current->cpus_allowed;
  93
  94         /*
  95          * Bind to the specified CPU.  When this call returns,
  96          * we should be running on the right CPU.
  97          */
  98         set_cpus_allowed(current, cpumask_of_cpu(cpu));
  99         BUG_ON(cpu != smp_processor_id());
 100
 101         /* get current setting */
 102         cm_osc = __raw_readl(CM_OSC);
 103
 104         if (machine_is_integrator()) {
 105                 vco.s = (cm_osc >> 8) & 7;
 106         } else if (machine_is_cintegrator()) {
 107                 vco.s = 1;
 108         }
 109         vco.v = cm_osc & 255;
 110         vco.r = 22;
 111         freqs.old = icst525_hz(&cclk_params, vco) / 1000;
 112
 113         /* icst525_hz_to_vco rounds down -- so we need the next
 114          * larger freq in case of CPUFREQ_RELATION_L.
 115          */
 116         if (relation == CPUFREQ_RELATION_L)
 117                 target_freq += 999;
 118         if (target_freq > policy->max)
 119                 target_freq = policy->max;
 120         vco = icst525_hz_to_vco(&cclk_params, target_freq * 1000);
 121         freqs.new = icst525_hz(&cclk_params, vco) / 1000;
 122
 123         freqs.cpu = policy->cpu;
 124
 125         if (freqs.old == freqs.new) {
 126                 set_cpus_allowed(current, cpus_allowed);
 127                 return 0;
 128         }
 129
 130         cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
 131
 132         cm_osc = __raw_readl(CM_OSC);
 133
 134         if (machine_is_integrator()) {
 135                 cm_osc &= 0xfffff800;
 136                 cm_osc |= vco.s << 8;
 137         } else if (machine_is_cintegrator()) {
 138                 cm_osc &= 0xffffff00;
 139         }
 140         cm_osc |= vco.v;
 141
 142         __raw_writel(0xa05f, CM_LOCK);
 143         __raw_writel(cm_osc, CM_OSC);
 144         __raw_writel(0, CM_LOCK);
 145
 146         /*
 147          * Restore the CPUs allowed mask.
 148          */
 149         set_cpus_allowed(current, cpus_allowed);
 150
 151         cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
 152
 153         return 0;
 154 }
 155
 156 static unsigned int integrator_get(unsigned int cpu)
 157 {
 158         cpumask_t cpus_allowed;
 159         unsigned int current_freq;
 160         u_int cm_osc;
 161         struct icst_vco vco;
 162
 163         cpus_allowed = current->cpus_allowed;
 164
 165         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 166         BUG_ON(cpu != smp_processor_id());
 167
 168         /* detect memory etc. */
 169         cm_osc = __raw_readl(CM_OSC);
 170
 171         if (machine_is_integrator()) {
 172                 vco.s = (cm_osc >> 8) & 7;
 173         } else if (machine_is_cintegrator()) {
 174                 vco.s = 1;
 175         }
 176         vco.v = cm_osc & 255;
 177         vco.r = 22;
 178
 179         current_freq = icst525_hz(&cclk_params, vco) / 1000; /* current freq */
 180
 181         set_cpus_allowed(current, cpus_allowed);
 182
 183         return current_freq;
 184 }
 185
 186 static int integrator_cpufreq_init(struct cpufreq_policy *policy)
 187 {
 188
 189         /* set default policy and cpuinfo */
 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);