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 /**
  27  * struct cpu_data
  28  * @pclk: the parent clock of cpu
  29  * @table: frequency table
  30  */
  31 struct cpu_data {
  32         struct clk **pclk;
  33         struct cpufreq_frequency_table *table;
  34         struct thermal_cooling_device *cdev;
  35 };
  36
  37 /*
  38  * Don't use cpufreq on this SoC -- used when the SoC would have otherwise
  39  * matched a more generic compatible.
  40  */
  41 #define SOC_BLACKLIST           1
  42
  43 /**
  44  * struct soc_data - SoC specific data
  45  * @flags: SOC_xxx
  46  */
  47 struct soc_data {
  48         u32 flags;
  49 };
  50
  51 static u32 get_bus_freq(void)
  52 {
  53         struct device_node *soc;
  54         u32 sysfreq;
  55         struct clk *pltclk;
  56         int ret;
  57
  58         /* get platform freq by searching bus-frequency property */
  59         soc = of_find_node_by_type(NULL, "soc");
  60         if (soc) {
  61                 ret = of_property_read_u32(soc, "bus-frequency", &sysfreq);
  62                 of_node_put(soc);
  63                 if (!ret)
  64                         return sysfreq;
  65         }
  66
  67         /* get platform freq by its clock name */
  68         pltclk = clk_get(NULL, "cg-pll0-div1");
  69         if (IS_ERR(pltclk)) {
  70                 pr_err("%s: can't get bus frequency %ld\n",
  71                        __func__, PTR_ERR(pltclk));
  72                 return PTR_ERR(pltclk);
  73         }
  74
  75         return clk_get_rate(pltclk);
  76 }
  77
  78 static struct clk *cpu_to_clk(int cpu)
  79 {
  80         struct device_node *np;
  81         struct clk *clk;
  82
  83         if (!cpu_present(cpu))
  84                 return NULL;
  85
  86         np = of_get_cpu_node(cpu, NULL);
  87         if (!np)
  88                 return NULL;
  89
  90         clk = of_clk_get(np, 0);
  91         of_node_put(np);
  92         return clk;
  93 }
  94
  95 /* traverse cpu nodes to get cpu mask of sharing clock wire */
  96 static void set_affected_cpus(struct cpufreq_policy *policy)
  97 {
  98         struct cpumask *dstp = policy->cpus;
  99         struct clk *clk;
 100         int i;
 101
 102         for_each_present_cpu(i) {
 103                 clk = cpu_to_clk(i);
 104                 if (IS_ERR(clk)) {
 105                         pr_err("%s: no clock for cpu %d\n", __func__, i);
 106                         continue;
 107                 }
 108
 109                 if (clk_is_match(policy->clk, clk))
 110                         cpumask_set_cpu(i, dstp);
 111         }
 112 }
 113
 114 /* reduce the duplicated frequencies in frequency table */
 115 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
 116                 int count)
 117 {
 118         int i, j;
 119
 120         for (i = 1; i < count; i++) {
 121                 for (j = 0; j < i; j++) {
 122                         if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
 123                                         freq_table[j].frequency !=
 124                                         freq_table[i].frequency)
 125                                 continue;
 126
 127                         freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
 128                         break;
 129                 }
 130         }
 131 }
 132
 133 /* sort the frequencies in frequency table in descenting order */
 134 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
 135                 int count)
 136 {
 137         int i, j, ind;
 138         unsigned int freq, max_freq;
 139         struct cpufreq_frequency_table table;
 140
 141         for (i = 0; i < count - 1; i++) {
 142                 max_freq = freq_table[i].frequency;
 143                 ind = i;
 144                 for (j = i + 1; j < count; j++) {
 145                         freq = freq_table[j].frequency;
 146                         if (freq == CPUFREQ_ENTRY_INVALID ||
 147                                         freq <= max_freq)
 148                                 continue;
 149                         ind = j;
 150                         max_freq = freq;
 151                 }
 152
 153                 if (ind != i) {
 154                         /* exchange the frequencies */
 155                         table.driver_data = freq_table[i].driver_data;
 156                         table.frequency = freq_table[i].frequency;
 157                         freq_table[i].driver_data = freq_table[ind].driver_data;
 158                         freq_table[i].frequency = freq_table[ind].frequency;
 159                         freq_table[ind].driver_data = table.driver_data;
 160                         freq_table[ind].frequency = table.frequency;
 161                 }
 162         }
 163 }
 164
 165 static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
 166 {
 167         struct device_node *np;
 168         int i, count;
 169         u32 freq;
 170         struct clk *clk;
 171         const struct clk_hw *hwclk;
 172         struct cpufreq_frequency_table *table;
 173         struct cpu_data *data;
 174         unsigned int cpu = policy->cpu;
 175         u64 u64temp;
 176
 177         np = of_get_cpu_node(cpu, NULL);
 178         if (!np)
 179                 return -ENODEV;
 180
 181         data = kzalloc(sizeof(*data), GFP_KERNEL);
 182         if (!data)
 183                 goto err_np;
 184
 185         policy->clk = of_clk_get(np, 0);
 186         if (IS_ERR(policy->clk)) {
 187                 pr_err("%s: no clock information\n", __func__);
 188                 goto err_nomem2;
 189         }
 190
 191         hwclk = __clk_get_hw(policy->clk);
 192         count = clk_hw_get_num_parents(hwclk);
 193
 194         data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
 195         if (!data->pclk)
 196                 goto err_nomem2;
 197
 198         table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
 199         if (!table)
 200                 goto err_pclk;
 201
 202         for (i = 0; i < count; i++) {
 203                 clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
 204                 data->pclk[i] = clk;
 205                 freq = clk_get_rate(clk);
 206                 table[i].frequency = freq / 1000;
 207                 table[i].driver_data = i;
 208         }
 209         freq_table_redup(table, count);
 210         freq_table_sort(table, count);
 211         table[i].frequency = CPUFREQ_TABLE_END;
 212         policy->freq_table = table;
 213         data->table = table;
 214
 215         /* update ->cpus if we have cluster, no harm if not */
 216         set_affected_cpus(policy);
 217         policy->driver_data = data;
 218
 219         /* Minimum transition latency is 12 platform clocks */
 220         u64temp = 12ULL * NSEC_PER_SEC;
 221         do_div(u64temp, get_bus_freq());
 222         policy->cpuinfo.transition_latency = u64temp + 1;
 223
 224         of_node_put(np);
 225
 226         return 0;
 227
 228 err_pclk:
 229         kfree(data->pclk);
 230 err_nomem2:
 231         kfree(data);
 232 err_np:
 233         of_node_put(np);
 234
 235         return -ENODEV;
 236 }
 237
 238 static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 239 {
 240         struct cpu_data *data = policy->driver_data;
 241
 242         cpufreq_cooling_unregister(data->cdev);
 243         kfree(data->pclk);
 244         kfree(data->table);
 245         kfree(data);
 246         policy->driver_data = NULL;
 247
 248         return 0;
 249 }
 250
 251 static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
 252                 unsigned int index)
 253 {
 254         struct clk *parent;
 255         struct cpu_data *data = policy->driver_data;
 256
 257         parent = data->pclk[data->table[index].driver_data];
 258         return clk_set_parent(policy->clk, parent);
 259 }
 260
 261
 262 static void qoriq_cpufreq_ready(struct cpufreq_policy *policy)
 263 {
 264         struct cpu_data *cpud = policy->driver_data;
 265
 266         cpud->cdev = of_cpufreq_cooling_register(policy);
 267 }
 268
 269 static struct cpufreq_driver qoriq_cpufreq_driver = {
 270         .name           = "qoriq_cpufreq",
 271         .flags          = CPUFREQ_CONST_LOOPS,
 272         .init           = qoriq_cpufreq_cpu_init,
 273         .exit           = qoriq_cpufreq_cpu_exit,
 274         .verify         = cpufreq_generic_frequency_table_verify,
 275         .target_index   = qoriq_cpufreq_target,
 276         .get            = cpufreq_generic_get,
 277         .ready          = qoriq_cpufreq_ready,
 278         .attr           = cpufreq_generic_attr,
 279 };
 280
 281 static const struct soc_data blacklist = {
 282         .flags = SOC_BLACKLIST,
 283 };
 284
 285 static const struct of_device_id node_matches[] __initconst = {
 286         /* e6500 cannot use cpufreq due to erratum A-008083 */
 287         { .compatible = "fsl,b4420-clockgen", &blacklist },
 288         { .compatible = "fsl,b4860-clockgen", &blacklist },
 289         { .compatible = "fsl,t2080-clockgen", &blacklist },
 290         { .compatible = "fsl,t4240-clockgen", &blacklist },
 291
 292         { .compatible = "fsl,ls1012a-clockgen", },
 293         { .compatible = "fsl,ls1021a-clockgen", },
 294         { .compatible = "fsl,ls1043a-clockgen", },
 295         { .compatible = "fsl,ls1046a-clockgen", },
 296         { .compatible = "fsl,ls1088a-clockgen", },
 297         { .compatible = "fsl,ls2080a-clockgen", },
 298         { .compatible = "fsl,p4080-clockgen", },
 299         { .compatible = "fsl,qoriq-clockgen-1.0", },
 300         { .compatible = "fsl,qoriq-clockgen-2.0", },
 301         {}
 302 };
 303
 304 static int __init qoriq_cpufreq_init(void)
 305 {
 306         int ret;
 307         struct device_node  *np;
 308         const struct of_device_id *match;
 309         const struct soc_data *data;
 310
 311         np = of_find_matching_node(NULL, node_matches);
 312         if (!np)
 313                 return -ENODEV;
 314
 315         match = of_match_node(node_matches, np);
 316         data = match->data;
 317
 318         of_node_put(np);
 319
 320         if (data && data->flags & SOC_BLACKLIST)
 321                 return -ENODEV;
 322
 323         ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
 324         if (!ret)
 325                 pr_info("Freescale QorIQ CPU frequency scaling driver\n");
 326
 327         return ret;
 328 }
 329 module_init(qoriq_cpufreq_init);
 330
 331 static void __exit qoriq_cpufreq_exit(void)
 332 {
 333         cpufreq_unregister_driver(&qoriq_cpufreq_driver);
 334 }
 335 module_exit(qoriq_cpufreq_exit);
 336
 337 MODULE_LICENSE("GPL");
 338 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
 339 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");