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 static DEFINE_PER_CPU(struct cpu_data *, cpu_data);
  73
  74 /* cpumask in a cluster */
  75 static DEFINE_PER_CPU(cpumask_var_t, cpu_mask);
  76
  77 #ifndef CONFIG_SMP
  78 static inline const struct cpumask *cpu_core_mask(int cpu)
  79 {
  80         return cpumask_of(0);
  81 }
  82 #endif
  83
  84 static unsigned int corenet_cpufreq_get_speed(unsigned int cpu)
  85 {
  86         struct cpu_data *data = per_cpu(cpu_data, cpu);
  87
  88         return clk_get_rate(data->clk) / 1000;
  89 }
  90
  91 /* reduce the duplicated frequencies in frequency table */
  92 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
  93                 int count)
  94 {
  95         int i, j;
  96
  97         for (i = 1; i < count; i++) {
  98                 for (j = 0; j < i; j++) {
  99                         if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
 100                                         freq_table[j].frequency !=
 101                                         freq_table[i].frequency)
 102                                 continue;
 103
 104                         freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
 105                         break;
 106                 }
 107         }
 108 }
 109
 110 /* sort the frequencies in frequency table in descenting order */
 111 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
 112                 int count)
 113 {
 114         int i, j, ind;
 115         unsigned int freq, max_freq;
 116         struct cpufreq_frequency_table table;
 117         for (i = 0; i < count - 1; i++) {
 118                 max_freq = freq_table[i].frequency;
 119                 ind = i;
 120                 for (j = i + 1; j < count; j++) {
 121                         freq = freq_table[j].frequency;
 122                         if (freq == CPUFREQ_ENTRY_INVALID ||
 123                                         freq <= max_freq)
 124                                 continue;
 125                         ind = j;
 126                         max_freq = freq;
 127                 }
 128
 129                 if (ind != i) {
 130                         /* exchange the frequencies */
 131                         table.driver_data = freq_table[i].driver_data;
 132                         table.frequency = freq_table[i].frequency;
 133                         freq_table[i].driver_data = freq_table[ind].driver_data;
 134                         freq_table[i].frequency = freq_table[ind].frequency;
 135                         freq_table[ind].driver_data = table.driver_data;
 136                         freq_table[ind].frequency = table.frequency;
 137                 }
 138         }
 139 }
 140
 141 static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
 142 {
 143         struct device_node *np;
 144         int i, count, ret;
 145         u32 freq, mask;
 146         struct clk *clk;
 147         struct cpufreq_frequency_table *table;
 148         struct cpu_data *data;
 149         unsigned int cpu = policy->cpu;
 150
 151         np = of_get_cpu_node(cpu, NULL);
 152         if (!np)
 153                 return -ENODEV;
 154
 155         data = kzalloc(sizeof(*data), GFP_KERNEL);
 156         if (!data) {
 157                 pr_err("%s: no memory\n", __func__);
 158                 goto err_np;
 159         }
 160
 161         data->clk = of_clk_get(np, 0);
 162         if (IS_ERR(data->clk)) {
 163                 pr_err("%s: no clock information\n", __func__);
 164                 goto err_nomem2;
 165         }
 166
 167         data->parent = of_parse_phandle(np, "clocks", 0);
 168         if (!data->parent) {
 169                 pr_err("%s: could not get clock information\n", __func__);
 170                 goto err_nomem2;
 171         }
 172
 173         count = of_property_count_strings(data->parent, "clock-names");
 174         table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
 175         if (!table) {
 176                 pr_err("%s: no memory\n", __func__);
 177                 goto err_node;
 178         }
 179
 180         if (fmask)
 181                 mask = fmask[get_hard_smp_processor_id(cpu)];
 182         else
 183                 mask = 0x0;
 184
 185         for (i = 0; i < count; i++) {
 186                 clk = of_clk_get(data->parent, i);
 187                 freq = clk_get_rate(clk);
 188                 /*
 189                  * the clock is valid if its frequency is not masked
 190                  * and large than minimum allowed frequency.
 191                  */
 192                 if (freq < min_cpufreq || (mask & (1 << i)))
 193                         table[i].frequency = CPUFREQ_ENTRY_INVALID;
 194                 else
 195                         table[i].frequency = freq / 1000;
 196                 table[i].driver_data = i;
 197         }
 198         freq_table_redup(table, count);
 199         freq_table_sort(table, count);
 200         table[i].frequency = CPUFREQ_TABLE_END;
 201
 202         /* set the min and max frequency properly */
 203         ret = cpufreq_table_validate_and_show(policy, table);
 204         if (ret) {
 205                 pr_err("invalid frequency table: %d\n", ret);
 206                 goto err_nomem1;
 207         }
 208
 209         data->table = table;
 210         per_cpu(cpu_data, cpu) = data;
 211
 212         /* update ->cpus if we have cluster, no harm if not */
 213         cpumask_copy(policy->cpus, per_cpu(cpu_mask, cpu));
 214         for_each_cpu(i, per_cpu(cpu_mask, cpu))
 215                 per_cpu(cpu_data, i) = data;
 216
 217         policy->cpuinfo.transition_latency = CPUFREQ_ETERNAL;
 218         of_node_put(np);
 219
 220         return 0;
 221
 222 err_nomem1:
 223         kfree(table);
 224 err_node:
 225         of_node_put(data->parent);
 226 err_nomem2:
 227         per_cpu(cpu_data, cpu) = NULL;
 228         kfree(data);
 229 err_np:
 230         of_node_put(np);
 231
 232         return -ENODEV;
 233 }
 234
 235 static int __exit corenet_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 236 {
 237         struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
 238         unsigned int cpu;
 239
 240         cpufreq_frequency_table_put_attr(policy->cpu);
 241         of_node_put(data->parent);
 242         kfree(data->table);
 243         kfree(data);
 244
 245         for_each_cpu(cpu, per_cpu(cpu_mask, policy->cpu))
 246                 per_cpu(cpu_data, cpu) = NULL;
 247
 248         return 0;
 249 }
 250
 251 static int corenet_cpufreq_target(struct cpufreq_policy *policy,
 252                 unsigned int index)
 253 {
 254         struct clk *parent;
 255         struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
 256
 257         parent = of_clk_get(data->parent, data->table[index].driver_data);
 258         return clk_set_parent(data->clk, parent);
 259 }
 260
 261 static struct cpufreq_driver ppc_corenet_cpufreq_driver = {
 262         .name           = "ppc_cpufreq",
 263         .flags          = CPUFREQ_CONST_LOOPS,
 264         .init           = corenet_cpufreq_cpu_init,
 265         .exit           = __exit_p(corenet_cpufreq_cpu_exit),
 266         .verify         = cpufreq_generic_frequency_table_verify,
 267         .target_index   = corenet_cpufreq_target,
 268         .get            = corenet_cpufreq_get_speed,
 269         .attr           = cpufreq_generic_attr,
 270 };
 271
 272 static const struct of_device_id node_matches[] __initdata = {
 273         { .compatible = "fsl,p2041-clockgen", .data = &sdata[0], },
 274         { .compatible = "fsl,p3041-clockgen", .data = &sdata[0], },
 275         { .compatible = "fsl,p5020-clockgen", .data = &sdata[1], },
 276         { .compatible = "fsl,p4080-clockgen", .data = &sdata[2], },
 277         { .compatible = "fsl,p5040-clockgen", .data = &sdata[2], },
 278         { .compatible = "fsl,qoriq-clockgen-2.0", },
 279         {}
 280 };
 281
 282 static int __init ppc_corenet_cpufreq_init(void)
 283 {
 284         int ret;
 285         struct device_node  *np;
 286         const struct of_device_id *match;
 287         const struct soc_data *data;
 288         unsigned int cpu;
 289
 290         np = of_find_matching_node(NULL, node_matches);
 291         if (!np)
 292                 return -ENODEV;
 293
 294         for_each_possible_cpu(cpu) {
 295                 if (!alloc_cpumask_var(&per_cpu(cpu_mask, cpu), GFP_KERNEL))
 296                         goto err_mask;
 297                 cpumask_copy(per_cpu(cpu_mask, cpu), cpu_core_mask(cpu));
 298         }
 299
 300         match = of_match_node(node_matches, np);
 301         data = match->data;
 302         if (data) {
 303                 if (data->flag)
 304                         fmask = data->freq_mask;
 305                 min_cpufreq = fsl_get_sys_freq();
 306         } else {
 307                 min_cpufreq = fsl_get_sys_freq() / 2;
 308         }
 309
 310         of_node_put(np);
 311
 312         ret = cpufreq_register_driver(&ppc_corenet_cpufreq_driver);
 313         if (!ret)
 314                 pr_info("Freescale PowerPC corenet CPU frequency scaling driver\n");
 315
 316         return ret;
 317
 318 err_mask:
 319         for_each_possible_cpu(cpu)
 320                 free_cpumask_var(per_cpu(cpu_mask, cpu));
 321
 322         return -ENOMEM;
 323 }
 324 module_init(ppc_corenet_cpufreq_init);
 325
 326 static void __exit ppc_corenet_cpufreq_exit(void)
 327 {
 328         unsigned int cpu;
 329
 330         for_each_possible_cpu(cpu)
 331                 free_cpumask_var(per_cpu(cpu_mask, cpu));
 332
 333         cpufreq_unregister_driver(&ppc_corenet_cpufreq_driver);
 334 }
 335 module_exit(ppc_corenet_cpufreq_exit);
 336
 337 MODULE_LICENSE("GPL");
 338 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
 339 MODULE_DESCRIPTION("cpufreq driver for Freescale e500mc series SoCs");