drivers/cpufreq/ppc-corenet-cpufreq.c

   1 /*
   2  * Copyright 2013 Freescale Semiconductor, Inc.
   3  *
   4  * CPU Frequency Scaling driver for Freescale PowerPC corenet 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 <sysdev/fsl_soc.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 /**
  26  * struct cpu_data - per CPU data struct
  27  * @clk: the clk of CPU
  28  * @parent: the parent node of cpu clock
  29  * @table: frequency table
  30  */
  31 struct cpu_data {
  32         struct clk *clk;
  33         struct device_node *parent;
  34         struct cpufreq_frequency_table *table;
  35 };
  36
  37 /**
  38  * struct soc_data - SoC specific data
  39  * @freq_mask: mask the disallowed frequencies
  40  * @flag: unique flags
  41  */
  42 struct soc_data {
  43         u32 freq_mask[4];
  44         u32 flag;
  45 };
  46
  47 #define FREQ_MASK       1
  48 /* see hardware specification for the allowed frqeuencies */
  49 static const struct soc_data sdata[] = {
  50         { /* used by p2041 and p3041 */
  51                 .freq_mask = {0x8, 0x8, 0x2, 0x2},
  52                 .flag = FREQ_MASK,
  53         },
  54         { /* used by p5020 */
  55                 .freq_mask = {0x8, 0x2},
  56                 .flag = FREQ_MASK,
  57         },
  58         { /* used by p4080, p5040 */
  59                 .freq_mask = {0},
  60                 .flag = 0,
  61         },
  62 };
  63
  64 /*
  65  * the minimum allowed core frequency, in Hz
  66  * for chassis v1.0, >= platform frequency
  67  * for chassis v2.0, >= platform frequency / 2
  68  */
  69 static u32 min_cpufreq;
  70 static const u32 *fmask;
  71
  72 /* serialize frequency changes  */
  73 static DEFINE_MUTEX(cpufreq_lock);
  74 static DEFINE_PER_CPU(struct cpu_data *, cpu_data);
  75
  76 /* cpumask in a cluster */
  77 static DEFINE_PER_CPU(cpumask_var_t, cpu_mask);
  78
  79 #ifndef CONFIG_SMP
  80 static inline const struct cpumask *cpu_core_mask(int cpu)
  81 {
  82         return cpumask_of(0);
  83 }
  84 #endif
  85
  86 static unsigned int corenet_cpufreq_get_speed(unsigned int cpu)
  87 {
  88         struct cpu_data *data = per_cpu(cpu_data, cpu);
  89
  90         return clk_get_rate(data->clk) / 1000;
  91 }
  92
  93 /* reduce the duplicated frequencies in frequency table */
  94 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
  95                 int count)
  96 {
  97         int i, j;
  98
  99         for (i = 1; i < count; i++) {
 100                 for (j = 0; j < i; j++) {
 101                         if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
 102                                         freq_table[j].frequency !=
 103                                         freq_table[i].frequency)
 104                                 continue;
 105
 106                         freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
 107                         break;
 108                 }
 109         }
 110 }
 111
 112 /* sort the frequencies in frequency table in descenting order */
 113 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
 114                 int count)
 115 {
 116         int i, j, ind;
 117         unsigned int freq, max_freq;
 118         struct cpufreq_frequency_table table;
 119         for (i = 0; i < count - 1; i++) {
 120                 max_freq = freq_table[i].frequency;
 121                 ind = i;
 122                 for (j = i + 1; j < count; j++) {
 123                         freq = freq_table[j].frequency;
 124                         if (freq == CPUFREQ_ENTRY_INVALID ||
 125                                         freq <= max_freq)
 126                                 continue;
 127                         ind = j;
 128                         max_freq = freq;
 129                 }
 130
 131                 if (ind != i) {
 132                         /* exchange the frequencies */
 133                         table.driver_data = freq_table[i].driver_data;
 134                         table.frequency = freq_table[i].frequency;
 135                         freq_table[i].driver_data = freq_table[ind].driver_data;
 136                         freq_table[i].frequency = freq_table[ind].frequency;
 137                         freq_table[ind].driver_data = table.driver_data;
 138                         freq_table[ind].frequency = table.frequency;
 139                 }
 140         }
 141 }
 142
 143 static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
 144 {
 145         struct device_node *np;
 146         int i, count, ret;
 147         u32 freq, mask;
 148         struct clk *clk;
 149         struct cpufreq_frequency_table *table;
 150         struct cpu_data *data;
 151         unsigned int cpu = policy->cpu;
 152
 153         np = of_get_cpu_node(cpu, NULL);
 154         if (!np)
 155                 return -ENODEV;
 156
 157         data = kzalloc(sizeof(*data), GFP_KERNEL);
 158         if (!data) {
 159                 pr_err("%s: no memory\n", __func__);
 160                 goto err_np;
 161         }
 162
 163         data->clk = of_clk_get(np, 0);
 164         if (IS_ERR(data->clk)) {
 165                 pr_err("%s: no clock information\n", __func__);
 166                 goto err_nomem2;
 167         }
 168
 169         data->parent = of_parse_phandle(np, "clocks", 0);
 170         if (!data->parent) {
 171                 pr_err("%s: could not get clock information\n", __func__);
 172                 goto err_nomem2;
 173         }
 174
 175         count = of_property_count_strings(data->parent, "clock-names");
 176         table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
 177         if (!table) {
 178                 pr_err("%s: no memory\n", __func__);
 179                 goto err_node;
 180         }
 181
 182         if (fmask)
 183                 mask = fmask[get_hard_smp_processor_id(cpu)];
 184         else
 185                 mask = 0x0;
 186
 187         for (i = 0; i < count; i++) {
 188                 clk = of_clk_get(data->parent, i);
 189                 freq = clk_get_rate(clk);
 190                 /*
 191                  * the clock is valid if its frequency is not masked
 192                  * and large than minimum allowed frequency.
 193                  */
 194                 if (freq < min_cpufreq || (mask & (1 << i)))
 195                         table[i].frequency = CPUFREQ_ENTRY_INVALID;
 196                 else
 197                         table[i].frequency = freq / 1000;
 198                 table[i].driver_data = i;
 199         }
 200         freq_table_redup(table, count);
 201         freq_table_sort(table, count);
 202         table[i].frequency = CPUFREQ_TABLE_END;
 203
 204         /* set the min and max frequency properly */
 205         ret = cpufreq_frequency_table_cpuinfo(policy, table);
 206         if (ret) {
 207                 pr_err("invalid frequency table: %d\n", ret);
 208                 goto err_nomem1;
 209         }
 210
 211         data->table = table;
 212         per_cpu(cpu_data, cpu) = data;
 213
 214         /* update ->cpus if we have cluster, no harm if not */
 215         cpumask_copy(policy->cpus, per_cpu(cpu_mask, cpu));
 216         for_each_cpu(i, per_cpu(cpu_mask, cpu))
 217                 per_cpu(cpu_data, i) = data;
 218
 219         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 220         policy->cur = corenet_cpufreq_get_speed(policy->cpu);
 221
 222         cpufreq_frequency_table_get_attr(table, cpu);
 223         of_node_put(np);
 224
 225         return 0;
 226
 227 err_nomem1:
 228         kfree(table);
 229 err_node:
 230         of_node_put(data->parent);
 231 err_nomem2:
 232         per_cpu(cpu_data, cpu) = NULL;
 233         kfree(data);
 234 err_np:
 235         of_node_put(np);
 236
 237         return -ENODEV;
 238 }
 239
 240 static int __exit corenet_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 241 {
 242         struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
 243         unsigned int cpu;
 244
 245         cpufreq_frequency_table_put_attr(policy->cpu);
 246         of_node_put(data->parent);
 247         kfree(data->table);
 248         kfree(data);
 249
 250         for_each_cpu(cpu, per_cpu(cpu_mask, policy->cpu))
 251                 per_cpu(cpu_data, cpu) = NULL;
 252
 253         return 0;
 254 }
 255
 256 static int corenet_cpufreq_verify(struct cpufreq_policy *policy)
 257 {
 258         struct cpufreq_frequency_table *table =
 259                 per_cpu(cpu_data, policy->cpu)->table;
 260
 261         return cpufreq_frequency_table_verify(policy, table);
 262 }
 263
 264 static int corenet_cpufreq_target(struct cpufreq_policy *policy,
 265                 unsigned int target_freq, unsigned int relation)
 266 {
 267         struct cpufreq_freqs freqs;
 268         unsigned int new;
 269         struct clk *parent;
 270         int ret;
 271         struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
 272
 273         cpufreq_frequency_table_target(policy, data->table,
 274                         target_freq, relation, &new);
 275
 276         if (policy->cur == data->table[new].frequency)
 277                 return 0;
 278
 279         freqs.old = policy->cur;
 280         freqs.new = data->table[new].frequency;
 281
 282         mutex_lock(&cpufreq_lock);
 283         cpufreq_notify_transition(policy, &freqs, CPUFREQ_PRECHANGE);
 284
 285         parent = of_clk_get(data->parent, data->table[new].driver_data);
 286         ret = clk_set_parent(data->clk, parent);
 287         if (ret)
 288                 freqs.new = freqs.old;
 289
 290         cpufreq_notify_transition(policy, &freqs, CPUFREQ_POSTCHANGE);
 291         mutex_unlock(&cpufreq_lock);
 292
 293         return ret;
 294 }
 295
 296 static struct freq_attr *corenet_cpufreq_attr[] = {
 297         &cpufreq_freq_attr_scaling_available_freqs,
 298         NULL,
 299 };
 300
 301 static struct cpufreq_driver ppc_corenet_cpufreq_driver = {
 302         .name           = "ppc_cpufreq",
 303         .owner          = THIS_MODULE,
 304         .flags          = CPUFREQ_CONST_LOOPS,
 305         .init           = corenet_cpufreq_cpu_init,
 306         .exit           = __exit_p(corenet_cpufreq_cpu_exit),
 307         .verify         = corenet_cpufreq_verify,
 308         .target         = corenet_cpufreq_target,
 309         .get            = corenet_cpufreq_get_speed,
 310         .attr           = corenet_cpufreq_attr,
 311 };
 312
 313 static const struct of_device_id node_matches[] __initdata = {
 314         { .compatible = "fsl,p2041-clockgen", .data = &sdata[0], },
 315         { .compatible = "fsl,p3041-clockgen", .data = &sdata[0], },
 316         { .compatible = "fsl,p5020-clockgen", .data = &sdata[1], },
 317         { .compatible = "fsl,p4080-clockgen", .data = &sdata[2], },
 318         { .compatible = "fsl,p5040-clockgen", .data = &sdata[2], },
 319         { .compatible = "fsl,qoriq-clockgen-2.0", },
 320         {}
 321 };
 322
 323 static int __init ppc_corenet_cpufreq_init(void)
 324 {
 325         int ret;
 326         struct device_node  *np;
 327         const struct of_device_id *match;
 328         const struct soc_data *data;
 329         unsigned int cpu;
 330
 331         np = of_find_matching_node(NULL, node_matches);
 332         if (!np)
 333                 return -ENODEV;
 334
 335         for_each_possible_cpu(cpu) {
 336                 if (!alloc_cpumask_var(&per_cpu(cpu_mask, cpu), GFP_KERNEL))
 337                         goto err_mask;
 338                 cpumask_copy(per_cpu(cpu_mask, cpu), cpu_core_mask(cpu));
 339         }
 340
 341         match = of_match_node(node_matches, np);
 342         data = match->data;
 343         if (data) {
 344                 if (data->flag)
 345                         fmask = data->freq_mask;
 346                 min_cpufreq = fsl_get_sys_freq();
 347         } else {
 348                 min_cpufreq = fsl_get_sys_freq() / 2;
 349         }
 350
 351         of_node_put(np);
 352
 353         ret = cpufreq_register_driver(&ppc_corenet_cpufreq_driver);
 354         if (!ret)
 355                 pr_info("Freescale PowerPC corenet CPU frequency scaling driver\n");
 356
 357         return ret;
 358
 359 err_mask:
 360         for_each_possible_cpu(cpu)
 361                 free_cpumask_var(per_cpu(cpu_mask, cpu));
 362
 363         return -ENOMEM;
 364 }
 365 module_init(ppc_corenet_cpufreq_init);
 366
 367 static void __exit ppc_corenet_cpufreq_exit(void)
 368 {
 369         unsigned int cpu;
 370
 371         for_each_possible_cpu(cpu)
 372                 free_cpumask_var(per_cpu(cpu_mask, cpu));
 373
 374         cpufreq_unregister_driver(&ppc_corenet_cpufreq_driver);
 375 }
 376 module_exit(ppc_corenet_cpufreq_exit);
 377
 378 MODULE_LICENSE("GPL");
 379 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
 380 MODULE_DESCRIPTION("cpufreq driver for Freescale e500mc series SoCs");