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