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/cpufreq.h>
  15 #include <linux/cpu_cooling.h>
  16 #include <linux/errno.h>
  17 #include <linux/init.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/mutex.h>
  21 #include <linux/of.h>
  22 #include <linux/slab.h>
  23 #include <linux/smp.h>
  24
  25 #if !defined(CONFIG_ARM)
  26 #include <asm/smp.h>    /* for get_hard_smp_processor_id() in UP configs */
  27 #endif
  28
  29 /**
  30  * struct cpu_data
  31  * @pclk: the parent clock of cpu
  32  * @table: frequency table
  33  */
  34 struct cpu_data {
  35         struct clk **pclk;
  36         struct cpufreq_frequency_table *table;
  37         struct thermal_cooling_device *cdev;
  38 };
  39
  40 /**
  41  * struct soc_data - SoC specific data
  42  * @freq_mask: mask the disallowed frequencies
  43  * @flag: unique flags
  44  */
  45 struct soc_data {
  46         u32 freq_mask[4];
  47         u32 flag;
  48 };
  49
  50 #define FREQ_MASK       1
  51 /* see hardware specification for the allowed frqeuencies */
  52 static const struct soc_data sdata[] = {
  53         { /* used by p2041 and p3041 */
  54                 .freq_mask = {0x8, 0x8, 0x2, 0x2},
  55                 .flag = FREQ_MASK,
  56         },
  57         { /* used by p5020 */
  58                 .freq_mask = {0x8, 0x2},
  59                 .flag = FREQ_MASK,
  60         },
  61         { /* used by p4080, p5040 */
  62                 .freq_mask = {0},
  63                 .flag = 0,
  64         },
  65 };
  66
  67 /*
  68  * the minimum allowed core frequency, in Hz
  69  * for chassis v1.0, >= platform frequency
  70  * for chassis v2.0, >= platform frequency / 2
  71  */
  72 static u32 min_cpufreq;
  73 static const u32 *fmask;
  74
  75 #if defined(CONFIG_ARM)
  76 static int get_cpu_physical_id(int cpu)
  77 {
  78         return topology_core_id(cpu);
  79 }
  80 #else
  81 static int get_cpu_physical_id(int cpu)
  82 {
  83         return get_hard_smp_processor_id(cpu);
  84 }
  85 #endif
  86
  87 static u32 get_bus_freq(void)
  88 {
  89         struct device_node *soc;
  90         u32 sysfreq;
  91
  92         soc = of_find_node_by_type(NULL, "soc");
  93         if (!soc)
  94                 return 0;
  95
  96         if (of_property_read_u32(soc, "bus-frequency", &sysfreq))
  97                 sysfreq = 0;
  98
  99         of_node_put(soc);
 100
 101         return sysfreq;
 102 }
 103
 104 static struct device_node *cpu_to_clk_node(int cpu)
 105 {
 106         struct device_node *np, *clk_np;
 107
 108         if (!cpu_present(cpu))
 109                 return NULL;
 110
 111         np = of_get_cpu_node(cpu, NULL);
 112         if (!np)
 113                 return NULL;
 114
 115         clk_np = of_parse_phandle(np, "clocks", 0);
 116         if (!clk_np)
 117                 return NULL;
 118
 119         of_node_put(np);
 120
 121         return clk_np;
 122 }
 123
 124 /* traverse cpu nodes to get cpu mask of sharing clock wire */
 125 static void set_affected_cpus(struct cpufreq_policy *policy)
 126 {
 127         struct device_node *np, *clk_np;
 128         struct cpumask *dstp = policy->cpus;
 129         int i;
 130
 131         np = cpu_to_clk_node(policy->cpu);
 132         if (!np)
 133                 return;
 134
 135         for_each_present_cpu(i) {
 136                 clk_np = cpu_to_clk_node(i);
 137                 if (!clk_np)
 138                         continue;
 139
 140                 if (clk_np == np)
 141                         cpumask_set_cpu(i, dstp);
 142
 143                 of_node_put(clk_np);
 144         }
 145         of_node_put(np);
 146 }
 147
 148 /* reduce the duplicated frequencies in frequency table */
 149 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
 150                 int count)
 151 {
 152         int i, j;
 153
 154         for (i = 1; i < count; i++) {
 155                 for (j = 0; j < i; j++) {
 156                         if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
 157                                         freq_table[j].frequency !=
 158                                         freq_table[i].frequency)
 159                                 continue;
 160
 161                         freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
 162                         break;
 163                 }
 164         }
 165 }
 166
 167 /* sort the frequencies in frequency table in descenting order */
 168 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
 169                 int count)
 170 {
 171         int i, j, ind;
 172         unsigned int freq, max_freq;
 173         struct cpufreq_frequency_table table;
 174
 175         for (i = 0; i < count - 1; i++) {
 176                 max_freq = freq_table[i].frequency;
 177                 ind = i;
 178                 for (j = i + 1; j < count; j++) {
 179                         freq = freq_table[j].frequency;
 180                         if (freq == CPUFREQ_ENTRY_INVALID ||
 181                                         freq <= max_freq)
 182                                 continue;
 183                         ind = j;
 184                         max_freq = freq;
 185                 }
 186
 187                 if (ind != i) {
 188                         /* exchange the frequencies */
 189                         table.driver_data = freq_table[i].driver_data;
 190                         table.frequency = freq_table[i].frequency;
 191                         freq_table[i].driver_data = freq_table[ind].driver_data;
 192                         freq_table[i].frequency = freq_table[ind].frequency;
 193                         freq_table[ind].driver_data = table.driver_data;
 194                         freq_table[ind].frequency = table.frequency;
 195                 }
 196         }
 197 }
 198
 199 static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
 200 {
 201         struct device_node *np, *pnode;
 202         int i, count, ret;
 203         u32 freq, mask;
 204         struct clk *clk;
 205         struct cpufreq_frequency_table *table;
 206         struct cpu_data *data;
 207         unsigned int cpu = policy->cpu;
 208         u64 u64temp;
 209
 210         np = of_get_cpu_node(cpu, NULL);
 211         if (!np)
 212                 return -ENODEV;
 213
 214         data = kzalloc(sizeof(*data), GFP_KERNEL);
 215         if (!data)
 216                 goto err_np;
 217
 218         policy->clk = of_clk_get(np, 0);
 219         if (IS_ERR(policy->clk)) {
 220                 pr_err("%s: no clock information\n", __func__);
 221                 goto err_nomem2;
 222         }
 223
 224         pnode = of_parse_phandle(np, "clocks", 0);
 225         if (!pnode) {
 226                 pr_err("%s: could not get clock information\n", __func__);
 227                 goto err_nomem2;
 228         }
 229
 230         count = of_property_count_strings(pnode, "clock-names");
 231         data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
 232         if (!data->pclk) {
 233                 pr_err("%s: no memory\n", __func__);
 234                 goto err_node;
 235         }
 236
 237         table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
 238         if (!table) {
 239                 pr_err("%s: no memory\n", __func__);
 240                 goto err_pclk;
 241         }
 242
 243         if (fmask)
 244                 mask = fmask[get_cpu_physical_id(cpu)];
 245         else
 246                 mask = 0x0;
 247
 248         for (i = 0; i < count; i++) {
 249                 clk = of_clk_get(pnode, i);
 250                 data->pclk[i] = clk;
 251                 freq = clk_get_rate(clk);
 252                 /*
 253                  * the clock is valid if its frequency is not masked
 254                  * and large than minimum allowed frequency.
 255                  */
 256                 if (freq < min_cpufreq || (mask & (1 << i)))
 257                         table[i].frequency = CPUFREQ_ENTRY_INVALID;
 258                 else
 259                         table[i].frequency = freq / 1000;
 260                 table[i].driver_data = i;
 261         }
 262         freq_table_redup(table, count);
 263         freq_table_sort(table, count);
 264         table[i].frequency = CPUFREQ_TABLE_END;
 265
 266         /* set the min and max frequency properly */
 267         ret = cpufreq_table_validate_and_show(policy, table);
 268         if (ret) {
 269                 pr_err("invalid frequency table: %d\n", ret);
 270                 goto err_nomem1;
 271         }
 272
 273         data->table = table;
 274
 275         /* update ->cpus if we have cluster, no harm if not */
 276         set_affected_cpus(policy);
 277         policy->driver_data = data;
 278
 279         /* Minimum transition latency is 12 platform clocks */
 280         u64temp = 12ULL * NSEC_PER_SEC;
 281         do_div(u64temp, get_bus_freq());
 282         policy->cpuinfo.transition_latency = u64temp + 1;
 283
 284         of_node_put(np);
 285         of_node_put(pnode);
 286
 287         return 0;
 288
 289 err_nomem1:
 290         kfree(table);
 291 err_pclk:
 292         kfree(data->pclk);
 293 err_node:
 294         of_node_put(pnode);
 295 err_nomem2:
 296         policy->driver_data = NULL;
 297         kfree(data);
 298 err_np:
 299         of_node_put(np);
 300
 301         return -ENODEV;
 302 }
 303
 304 static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 305 {
 306         struct cpu_data *data = policy->driver_data;
 307
 308         cpufreq_cooling_unregister(data->cdev);
 309         kfree(data->pclk);
 310         kfree(data->table);
 311         kfree(data);
 312         policy->driver_data = NULL;
 313
 314         return 0;
 315 }
 316
 317 static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
 318                 unsigned int index)
 319 {
 320         struct clk *parent;
 321         struct cpu_data *data = policy->driver_data;
 322
 323         parent = data->pclk[data->table[index].driver_data];
 324         return clk_set_parent(policy->clk, parent);
 325 }
 326
 327
 328 static void qoriq_cpufreq_ready(struct cpufreq_policy *policy)
 329 {
 330         struct cpu_data *cpud = policy->driver_data;
 331         struct device_node *np = of_get_cpu_node(policy->cpu, NULL);
 332
 333         if (of_find_property(np, "#cooling-cells", NULL)) {
 334                 cpud->cdev = of_cpufreq_cooling_register(np,
 335                                                          policy->related_cpus);
 336
 337                 if (IS_ERR(cpud->cdev) && PTR_ERR(cpud->cdev) != -ENOSYS) {
 338                         pr_err("cpu%d is not running as cooling device: %ld\n",
 339                                         policy->cpu, PTR_ERR(cpud->cdev));
 340
 341                         cpud->cdev = NULL;
 342                 }
 343         }
 344
 345         of_node_put(np);
 346 }
 347
 348 static struct cpufreq_driver qoriq_cpufreq_driver = {
 349         .name           = "qoriq_cpufreq",
 350         .flags          = CPUFREQ_CONST_LOOPS,
 351         .init           = qoriq_cpufreq_cpu_init,
 352         .exit           = qoriq_cpufreq_cpu_exit,
 353         .verify         = cpufreq_generic_frequency_table_verify,
 354         .target_index   = qoriq_cpufreq_target,
 355         .get            = cpufreq_generic_get,
 356         .ready          = qoriq_cpufreq_ready,
 357         .attr           = cpufreq_generic_attr,
 358 };
 359
 360 static const struct of_device_id node_matches[] __initconst = {
 361         { .compatible = "fsl,p2041-clockgen", .data = &sdata[0], },
 362         { .compatible = "fsl,p3041-clockgen", .data = &sdata[0], },
 363         { .compatible = "fsl,p5020-clockgen", .data = &sdata[1], },
 364         { .compatible = "fsl,p4080-clockgen", .data = &sdata[2], },
 365         { .compatible = "fsl,p5040-clockgen", .data = &sdata[2], },
 366         { .compatible = "fsl,qoriq-clockgen-2.0", },
 367         {}
 368 };
 369
 370 static int __init qoriq_cpufreq_init(void)
 371 {
 372         int ret;
 373         struct device_node  *np;
 374         const struct of_device_id *match;
 375         const struct soc_data *data;
 376
 377         np = of_find_matching_node(NULL, node_matches);
 378         if (!np)
 379                 return -ENODEV;
 380
 381         match = of_match_node(node_matches, np);
 382         data = match->data;
 383         if (data) {
 384                 if (data->flag)
 385                         fmask = data->freq_mask;
 386                 min_cpufreq = get_bus_freq();
 387         } else {
 388                 min_cpufreq = get_bus_freq() / 2;
 389         }
 390
 391         of_node_put(np);
 392
 393         ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
 394         if (!ret)
 395                 pr_info("Freescale QorIQ CPU frequency scaling driver\n");
 396
 397         return ret;
 398 }
 399 module_init(qoriq_cpufreq_init);
 400
 401 static void __exit qoriq_cpufreq_exit(void)
 402 {
 403         cpufreq_unregister_driver(&qoriq_cpufreq_driver);
 404 }
 405 module_exit(qoriq_cpufreq_exit);
 406
 407 MODULE_LICENSE("GPL");
 408 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
 409 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");