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