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 <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 #include <sysdev/fsl_soc.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         u64 u64temp;
 142
 143         np = of_get_cpu_node(cpu, NULL);
 144         if (!np)
 145                 return -ENODEV;
 146
 147         data = kzalloc(sizeof(*data), GFP_KERNEL);
 148         if (!data) {
 149                 pr_err("%s: no memory\n", __func__);
 150                 goto err_np;
 151         }
 152
 153         policy->clk = of_clk_get(np, 0);
 154         if (IS_ERR(policy->clk)) {
 155                 pr_err("%s: no clock information\n", __func__);
 156                 goto err_nomem2;
 157         }
 158
 159         data->parent = of_parse_phandle(np, "clocks", 0);
 160         if (!data->parent) {
 161                 pr_err("%s: could not get clock information\n", __func__);
 162                 goto err_nomem2;
 163         }
 164
 165         count = of_property_count_strings(data->parent, "clock-names");
 166         table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
 167         if (!table) {
 168                 pr_err("%s: no memory\n", __func__);
 169                 goto err_node;
 170         }
 171
 172         if (fmask)
 173                 mask = fmask[get_hard_smp_processor_id(cpu)];
 174         else
 175                 mask = 0x0;
 176
 177         for (i = 0; i < count; i++) {
 178                 clk = of_clk_get(data->parent, i);
 179                 freq = clk_get_rate(clk);
 180                 /*
 181                  * the clock is valid if its frequency is not masked
 182                  * and large than minimum allowed frequency.
 183                  */
 184                 if (freq < min_cpufreq || (mask & (1 << i)))
 185                         table[i].frequency = CPUFREQ_ENTRY_INVALID;
 186                 else
 187                         table[i].frequency = freq / 1000;
 188                 table[i].driver_data = i;
 189         }
 190         freq_table_redup(table, count);
 191         freq_table_sort(table, count);
 192         table[i].frequency = CPUFREQ_TABLE_END;
 193
 194         /* set the min and max frequency properly */
 195         ret = cpufreq_table_validate_and_show(policy, table);
 196         if (ret) {
 197                 pr_err("invalid frequency table: %d\n", ret);
 198                 goto err_nomem1;
 199         }
 200
 201         data->table = table;
 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         /* Minimum transition latency is 12 platform clocks */
 209         u64temp = 12ULL * NSEC_PER_SEC;
 210         do_div(u64temp, fsl_get_sys_freq());
 211         policy->cpuinfo.transition_latency = u64temp + 1;
 212
 213         of_node_put(np);
 214
 215         return 0;
 216
 217 err_nomem1:
 218         kfree(table);
 219 err_node:
 220         of_node_put(data->parent);
 221 err_nomem2:
 222         per_cpu(cpu_data, cpu) = NULL;
 223         kfree(data);
 224 err_np:
 225         of_node_put(np);
 226
 227         return -ENODEV;
 228 }
 229
 230 static int __exit corenet_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 231 {
 232         struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
 233         unsigned int cpu;
 234
 235         of_node_put(data->parent);
 236         kfree(data->table);
 237         kfree(data);
 238
 239         for_each_cpu(cpu, per_cpu(cpu_mask, policy->cpu))
 240                 per_cpu(cpu_data, cpu) = NULL;
 241
 242         return 0;
 243 }
 244
 245 static int corenet_cpufreq_target(struct cpufreq_policy *policy,
 246                 unsigned int index)
 247 {
 248         struct clk *parent;
 249         struct cpu_data *data = per_cpu(cpu_data, policy->cpu);
 250
 251         parent = of_clk_get(data->parent, data->table[index].driver_data);
 252         return clk_set_parent(policy->clk, parent);
 253 }
 254
 255 static struct cpufreq_driver ppc_corenet_cpufreq_driver = {
 256         .name           = "ppc_cpufreq",
 257         .flags          = CPUFREQ_CONST_LOOPS,
 258         .init           = corenet_cpufreq_cpu_init,
 259         .exit           = __exit_p(corenet_cpufreq_cpu_exit),
 260         .verify         = cpufreq_generic_frequency_table_verify,
 261         .target_index   = corenet_cpufreq_target,
 262         .get            = cpufreq_generic_get,
 263         .attr           = cpufreq_generic_attr,
 264 };
 265
 266 static const struct of_device_id node_matches[] __initdata = {
 267         { .compatible = "fsl,p2041-clockgen", .data = &sdata[0], },
 268         { .compatible = "fsl,p3041-clockgen", .data = &sdata[0], },
 269         { .compatible = "fsl,p5020-clockgen", .data = &sdata[1], },
 270         { .compatible = "fsl,p4080-clockgen", .data = &sdata[2], },
 271         { .compatible = "fsl,p5040-clockgen", .data = &sdata[2], },
 272         { .compatible = "fsl,qoriq-clockgen-2.0", },
 273         {}
 274 };
 275
 276 static int __init ppc_corenet_cpufreq_init(void)
 277 {
 278         int ret;
 279         struct device_node  *np;
 280         const struct of_device_id *match;
 281         const struct soc_data *data;
 282         unsigned int cpu;
 283
 284         np = of_find_matching_node(NULL, node_matches);
 285         if (!np)
 286                 return -ENODEV;
 287
 288         for_each_possible_cpu(cpu) {
 289                 if (!alloc_cpumask_var(&per_cpu(cpu_mask, cpu), GFP_KERNEL))
 290                         goto err_mask;
 291                 cpumask_copy(per_cpu(cpu_mask, cpu), cpu_core_mask(cpu));
 292         }
 293
 294         match = of_match_node(node_matches, np);
 295         data = match->data;
 296         if (data) {
 297                 if (data->flag)
 298                         fmask = data->freq_mask;
 299                 min_cpufreq = fsl_get_sys_freq();
 300         } else {
 301                 min_cpufreq = fsl_get_sys_freq() / 2;
 302         }
 303
 304         of_node_put(np);
 305
 306         ret = cpufreq_register_driver(&ppc_corenet_cpufreq_driver);
 307         if (!ret)
 308                 pr_info("Freescale PowerPC corenet CPU frequency scaling driver\n");
 309
 310         return ret;
 311
 312 err_mask:
 313         for_each_possible_cpu(cpu)
 314                 free_cpumask_var(per_cpu(cpu_mask, cpu));
 315
 316         return -ENOMEM;
 317 }
 318 module_init(ppc_corenet_cpufreq_init);
 319
 320 static void __exit ppc_corenet_cpufreq_exit(void)
 321 {
 322         unsigned int cpu;
 323
 324         for_each_possible_cpu(cpu)
 325                 free_cpumask_var(per_cpu(cpu_mask, cpu));
 326
 327         cpufreq_unregister_driver(&ppc_corenet_cpufreq_driver);
 328 }
 329 module_exit(ppc_corenet_cpufreq_exit);
 330
 331 MODULE_LICENSE("GPL");
 332 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
 333 MODULE_DESCRIPTION("cpufreq driver for Freescale e500mc series SoCs");