drivers/cpufreq/integrator-cpufreq.c

   1 /*
   2  *  Copyright (C) 2001-2002 Deep Blue Solutions Ltd.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * CPU support functions
   9  */
  10 #include <linux/module.h>
  11 #include <linux/types.h>
  12 #include <linux/kernel.h>
  13 #include <linux/cpufreq.h>
  14 #include <linux/sched.h>
  15 #include <linux/smp.h>
  16 #include <linux/init.h>
  17 #include <linux/io.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/of.h>
  20 #include <linux/of_address.h>
  21
  22 #include <asm/mach-types.h>
  23 #include <asm/hardware/icst.h>
  24
  25 static void __iomem *cm_base;
  26 /* The cpufreq driver only use the OSC register */
  27 #define INTEGRATOR_HDR_OSC_OFFSET       0x08
  28 #define INTEGRATOR_HDR_LOCK_OFFSET      0x14
  29
  30 static struct cpufreq_driver integrator_driver;
  31
  32 static const struct icst_params lclk_params = {
  33         .ref            = 24000000,
  34         .vco_max        = ICST525_VCO_MAX_5V,
  35         .vco_min        = ICST525_VCO_MIN,
  36         .vd_min         = 8,
  37         .vd_max         = 132,
  38         .rd_min         = 24,
  39         .rd_max         = 24,
  40         .s2div          = icst525_s2div,
  41         .idx2s          = icst525_idx2s,
  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         .s2div          = icst525_s2div,
  53         .idx2s          = icst525_idx2s,
  54 };
  55
  56 /*
  57  * Validate the speed policy.
  58  */
  59 static int integrator_verify_policy(struct cpufreq_policy *policy)
  60 {
  61         struct icst_vco vco;
  62
  63         cpufreq_verify_within_limits(policy,
  64                                      policy->cpuinfo.min_freq,
  65                                      policy->cpuinfo.max_freq);
  66
  67         vco = icst_hz_to_vco(&cclk_params, policy->max * 1000);
  68         policy->max = icst_hz(&cclk_params, vco) / 1000;
  69
  70         vco = icst_hz_to_vco(&cclk_params, policy->min * 1000);
  71         policy->min = icst_hz(&cclk_params, vco) / 1000;
  72
  73         cpufreq_verify_within_limits(policy,
  74                                      policy->cpuinfo.min_freq,
  75                                      policy->cpuinfo.max_freq);
  76
  77         return 0;
  78 }
  79
  80
  81 static int integrator_set_target(struct cpufreq_policy *policy,
  82                                  unsigned int target_freq,
  83                                  unsigned int relation)
  84 {
  85         cpumask_t cpus_allowed;
  86         int cpu = policy->cpu;
  87         struct icst_vco vco;
  88         struct cpufreq_freqs freqs;
  89         u_int cm_osc;
  90
  91         /*
  92          * Save this threads cpus_allowed mask.
  93          */
  94         cpus_allowed = current->cpus_allowed;
  95
  96         /*
  97          * Bind to the specified CPU.  When this call returns,
  98          * we should be running on the right CPU.
  99          */
 100         set_cpus_allowed(current, cpumask_of_cpu(cpu));
 101         BUG_ON(cpu != smp_processor_id());
 102
 103         /* get current setting */
 104         cm_osc = __raw_readl(cm_base + INTEGRATOR_HDR_OSC_OFFSET);
 105
 106         if (machine_is_integrator()) {
 107                 vco.s = (cm_osc >> 8) & 7;
 108         } else if (machine_is_cintegrator()) {
 109                 vco.s = 1;
 110         }
 111         vco.v = cm_osc & 255;
 112         vco.r = 22;
 113         freqs.old = icst_hz(&cclk_params, vco) / 1000;
 114
 115         /* icst_hz_to_vco rounds down -- so we need the next
 116          * larger freq in case of CPUFREQ_RELATION_L.
 117          */
 118         if (relation == CPUFREQ_RELATION_L)
 119                 target_freq += 999;
 120         if (target_freq > policy->max)
 121                 target_freq = policy->max;
 122         vco = icst_hz_to_vco(&cclk_params, target_freq * 1000);
 123         freqs.new = icst_hz(&cclk_params, vco) / 1000;
 124
 125         if (freqs.old == freqs.new) {
 126                 set_cpus_allowed(current, cpus_allowed);
 127                 return 0;
 128         }
 129
 130         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 131
 132         cm_osc = __raw_readl(cm_base + INTEGRATOR_HDR_OSC_OFFSET);
 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_base + INTEGRATOR_HDR_LOCK_OFFSET);
 143         __raw_writel(cm_osc, cm_base + INTEGRATOR_HDR_OSC_OFFSET);
 144         __raw_writel(0, cm_base + INTEGRATOR_HDR_LOCK_OFFSET);
 145
 146         /*
 147          * Restore the CPUs allowed mask.
 148          */
 149         set_cpus_allowed(current, cpus_allowed);
 150
 151         cpufreq_notify_transition(policy, &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_base + INTEGRATOR_HDR_OSC_OFFSET);
 170
 171         if (machine_is_integrator()) {
 172                 vco.s = (cm_osc >> 8) & 7;
 173         } else {
 174                 vco.s = 1;
 175         }
 176         vco.v = cm_osc & 255;
 177         vco.r = 22;
 178
 179         current_freq = icst_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_cpufreq_probe(struct platform_device *pdev)
 207 {
 208         struct resource *res;
 209
 210         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 211         if (!res)
 212                 return -ENODEV;
 213
 214         cm_base = devm_ioremap(&pdev->dev, res->start, resource_size(res));
 215         if (!cm_base)
 216                 return -ENODEV;
 217
 218         return cpufreq_register_driver(&integrator_driver);
 219 }
 220
 221 static void __exit integrator_cpufreq_remove(struct platform_device *pdev)
 222 {
 223         cpufreq_unregister_driver(&integrator_driver);
 224 }
 225
 226 static const struct of_device_id integrator_cpufreq_match[] = {
 227         { .compatible = "arm,core-module-integrator"},
 228         { },
 229 };
 230
 231 static struct platform_driver integrator_cpufreq_driver = {
 232         .driver = {
 233                 .name = "integrator-cpufreq",
 234                 .owner = THIS_MODULE,
 235                 .of_match_table = integrator_cpufreq_match,
 236         },
 237         .remove = __exit_p(integrator_cpufreq_remove),
 238 };
 239
 240 module_platform_driver_probe(integrator_cpufreq_driver,
 241                              integrator_cpufreq_probe);
 242
 243 MODULE_AUTHOR ("Russell M. King");
 244 MODULE_DESCRIPTION ("cpufreq driver for ARM Integrator CPUs");
 245 MODULE_LICENSE ("GPL");