drivers/cpufreq/qoriq-cpufreq.c

   1 /*
   2  * Copyright 2013 Freescale Semiconductor, Inc.
   3  *
   4  * CPU Frequency Scaling driver for Freescale QorIQ SoCs.
   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
  11 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
  12
  13 #include <linux/clk.h>
  14 #include <linux/clk-provider.h>
  15 #include <linux/cpufreq.h>
  16 #include <linux/cpu_cooling.h>
  17 #include <linux/errno.h>
  18 #include <linux/init.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/mutex.h>
  22 #include <linux/of.h>
  23 #include <linux/slab.h>
  24 #include <linux/smp.h>
  25
  26 #if !defined(CONFIG_ARM)
  27 #include <asm/smp.h>    /* for get_hard_smp_processor_id() in UP configs */
  28 #endif
  29
  30 /**
  31  * struct cpu_data
  32  * @pclk: the parent clock of cpu
  33  * @table: frequency table
  34  */
  35 struct cpu_data {
  36         struct clk **pclk;
  37         struct cpufreq_frequency_table *table;
  38         struct thermal_cooling_device *cdev;
  39 };
  40
  41 /*
  42  * Don't use cpufreq on this SoC -- used when the SoC would have otherwise
  43  * matched a more generic compatible.
  44  */
  45 #define SOC_BLACKLIST           1
  46
  47 /**
  48  * struct soc_data - SoC specific data
  49  * @flags: SOC_xxx
  50  */
  51 struct soc_data {
  52         u32 flags;
  53 };
  54
  55 static u32 get_bus_freq(void)
  56 {
  57         struct device_node *soc;
  58         u32 sysfreq;
  59
  60         soc = of_find_node_by_type(NULL, "soc");
  61         if (!soc)
  62                 return 0;
  63
  64         if (of_property_read_u32(soc, "bus-frequency", &sysfreq))
  65                 sysfreq = 0;
  66
  67         of_node_put(soc);
  68
  69         return sysfreq;
  70 }
  71
  72 static struct clk *cpu_to_clk(int cpu)
  73 {
  74         struct device_node *np;
  75         struct clk *clk;
  76
  77         if (!cpu_present(cpu))
  78                 return NULL;
  79
  80         np = of_get_cpu_node(cpu, NULL);
  81         if (!np)
  82                 return NULL;
  83
  84         clk = of_clk_get(np, 0);
  85         of_node_put(np);
  86         return clk;
  87 }
  88
  89 /* traverse cpu nodes to get cpu mask of sharing clock wire */
  90 static void set_affected_cpus(struct cpufreq_policy *policy)
  91 {
  92         struct cpumask *dstp = policy->cpus;
  93         struct clk *clk;
  94         int i;
  95
  96         for_each_present_cpu(i) {
  97                 clk = cpu_to_clk(i);
  98                 if (IS_ERR(clk)) {
  99                         pr_err("%s: no clock for cpu %d\n", __func__, i);
 100                         continue;
 101                 }
 102
 103                 if (clk_is_match(policy->clk, clk))
 104                         cpumask_set_cpu(i, dstp);
 105         }
 106 }
 107
 108 /* reduce the duplicated frequencies in frequency table */
 109 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
 110                 int count)
 111 {
 112         int i, j;
 113
 114         for (i = 1; i < count; i++) {
 115                 for (j = 0; j < i; j++) {
 116                         if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
 117                                         freq_table[j].frequency !=
 118                                         freq_table[i].frequency)
 119                                 continue;
 120
 121                         freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
 122                         break;
 123                 }
 124         }
 125 }
 126
 127 /* sort the frequencies in frequency table in descenting order */
 128 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
 129                 int count)
 130 {
 131         int i, j, ind;
 132         unsigned int freq, max_freq;
 133         struct cpufreq_frequency_table table;
 134
 135         for (i = 0; i < count - 1; i++) {
 136                 max_freq = freq_table[i].frequency;
 137                 ind = i;
 138                 for (j = i + 1; j < count; j++) {
 139                         freq = freq_table[j].frequency;
 140                         if (freq == CPUFREQ_ENTRY_INVALID ||
 141                                         freq <= max_freq)
 142                                 continue;
 143                         ind = j;
 144                         max_freq = freq;
 145                 }
 146
 147                 if (ind != i) {
 148                         /* exchange the frequencies */
 149                         table.driver_data = freq_table[i].driver_data;
 150                         table.frequency = freq_table[i].frequency;
 151                         freq_table[i].driver_data = freq_table[ind].driver_data;
 152                         freq_table[i].frequency = freq_table[ind].frequency;
 153                         freq_table[ind].driver_data = table.driver_data;
 154                         freq_table[ind].frequency = table.frequency;
 155                 }
 156         }
 157 }
 158
 159 static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
 160 {
 161         struct device_node *np;
 162         int i, count, ret;
 163         u32 freq;
 164         struct clk *clk;
 165         const struct clk_hw *hwclk;
 166         struct cpufreq_frequency_table *table;
 167         struct cpu_data *data;
 168         unsigned int cpu = policy->cpu;
 169         u64 u64temp;
 170
 171         np = of_get_cpu_node(cpu, NULL);
 172         if (!np)
 173                 return -ENODEV;
 174
 175         data = kzalloc(sizeof(*data), GFP_KERNEL);
 176         if (!data)
 177                 goto err_np;
 178
 179         policy->clk = of_clk_get(np, 0);
 180         if (IS_ERR(policy->clk)) {
 181                 pr_err("%s: no clock information\n", __func__);
 182                 goto err_nomem2;
 183         }
 184
 185         hwclk = __clk_get_hw(policy->clk);
 186         count = clk_hw_get_num_parents(hwclk);
 187
 188         data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
 189         if (!data->pclk) {
 190                 pr_err("%s: no memory\n", __func__);
 191                 goto err_nomem2;
 192         }
 193
 194         table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
 195         if (!table) {
 196                 pr_err("%s: no memory\n", __func__);
 197                 goto err_pclk;
 198         }
 199
 200         for (i = 0; i < count; i++) {
 201                 clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
 202                 data->pclk[i] = clk;
 203                 freq = clk_get_rate(clk);
 204                 table[i].frequency = freq / 1000;
 205                 table[i].driver_data = i;
 206         }
 207         freq_table_redup(table, count);
 208         freq_table_sort(table, count);
 209         table[i].frequency = CPUFREQ_TABLE_END;
 210
 211         /* set the min and max frequency properly */
 212         ret = cpufreq_table_validate_and_show(policy, table);
 213         if (ret) {
 214                 pr_err("invalid frequency table: %d\n", ret);
 215                 goto err_nomem1;
 216         }
 217
 218         data->table = table;
 219
 220         /* update ->cpus if we have cluster, no harm if not */
 221         set_affected_cpus(policy);
 222         policy->driver_data = data;
 223
 224         /* Minimum transition latency is 12 platform clocks */
 225         u64temp = 12ULL * NSEC_PER_SEC;
 226         do_div(u64temp, get_bus_freq());
 227         policy->cpuinfo.transition_latency = u64temp + 1;
 228
 229         of_node_put(np);
 230
 231         return 0;
 232
 233 err_nomem1:
 234         kfree(table);
 235 err_pclk:
 236         kfree(data->pclk);
 237 err_nomem2:
 238         kfree(data);
 239 err_np:
 240         of_node_put(np);
 241
 242         return -ENODEV;
 243 }
 244
 245 static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 246 {
 247         struct cpu_data *data = policy->driver_data;
 248
 249         cpufreq_cooling_unregister(data->cdev);
 250         kfree(data->pclk);
 251         kfree(data->table);
 252         kfree(data);
 253         policy->driver_data = NULL;
 254
 255         return 0;
 256 }
 257
 258 static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
 259                 unsigned int index)
 260 {
 261         struct clk *parent;
 262         struct cpu_data *data = policy->driver_data;
 263
 264         parent = data->pclk[data->table[index].driver_data];
 265         return clk_set_parent(policy->clk, parent);
 266 }
 267
 268
 269 static void qoriq_cpufreq_ready(struct cpufreq_policy *policy)
 270 {
 271         struct cpu_data *cpud = policy->driver_data;
 272         struct device_node *np = of_get_cpu_node(policy->cpu, NULL);
 273
 274         if (of_find_property(np, "#cooling-cells", NULL)) {
 275                 cpud->cdev = of_cpufreq_cooling_register(np,
 276                                                          policy->related_cpus);
 277
 278                 if (IS_ERR(cpud->cdev) && PTR_ERR(cpud->cdev) != -ENOSYS) {
 279                         pr_err("cpu%d is not running as cooling device: %ld\n",
 280                                         policy->cpu, PTR_ERR(cpud->cdev));
 281
 282                         cpud->cdev = NULL;
 283                 }
 284         }
 285
 286         of_node_put(np);
 287 }
 288
 289 static struct cpufreq_driver qoriq_cpufreq_driver = {
 290         .name           = "qoriq_cpufreq",
 291         .flags          = CPUFREQ_CONST_LOOPS,
 292         .init           = qoriq_cpufreq_cpu_init,
 293         .exit           = qoriq_cpufreq_cpu_exit,
 294         .verify         = cpufreq_generic_frequency_table_verify,
 295         .target_index   = qoriq_cpufreq_target,
 296         .get            = cpufreq_generic_get,
 297         .ready          = qoriq_cpufreq_ready,
 298         .attr           = cpufreq_generic_attr,
 299 };
 300
 301 static const struct soc_data blacklist = {
 302         .flags = SOC_BLACKLIST,
 303 };
 304
 305 static const struct of_device_id node_matches[] __initconst = {
 306         /* e6500 cannot use cpufreq due to erratum A-008083 */
 307         { .compatible = "fsl,b4420-clockgen", &blacklist },
 308         { .compatible = "fsl,b4860-clockgen", &blacklist },
 309         { .compatible = "fsl,t2080-clockgen", &blacklist },
 310         { .compatible = "fsl,t4240-clockgen", &blacklist },
 311
 312         { .compatible = "fsl,ls1012a-clockgen", },
 313         { .compatible = "fsl,ls1021a-clockgen", },
 314         { .compatible = "fsl,ls1043a-clockgen", },
 315         { .compatible = "fsl,ls1046a-clockgen", },
 316         { .compatible = "fsl,ls1088a-clockgen", },
 317         { .compatible = "fsl,ls2080a-clockgen", },
 318         { .compatible = "fsl,p4080-clockgen", },
 319         { .compatible = "fsl,qoriq-clockgen-1.0", },
 320         { .compatible = "fsl,qoriq-clockgen-2.0", },
 321         {}
 322 };
 323
 324 static int __init qoriq_cpufreq_init(void)
 325 {
 326         int ret;
 327         struct device_node  *np;
 328         const struct of_device_id *match;
 329         const struct soc_data *data;
 330
 331         np = of_find_matching_node(NULL, node_matches);
 332         if (!np)
 333                 return -ENODEV;
 334
 335         match = of_match_node(node_matches, np);
 336         data = match->data;
 337
 338         of_node_put(np);
 339
 340         if (data && data->flags & SOC_BLACKLIST)
 341                 return -ENODEV;
 342
 343         ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
 344         if (!ret)
 345                 pr_info("Freescale QorIQ CPU frequency scaling driver\n");
 346
 347         return ret;
 348 }
 349 module_init(qoriq_cpufreq_init);
 350
 351 static void __exit qoriq_cpufreq_exit(void)
 352 {
 353         cpufreq_unregister_driver(&qoriq_cpufreq_driver);
 354 }
 355 module_exit(qoriq_cpufreq_exit);
 356
 357 MODULE_LICENSE("GPL");
 358 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
 359 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");