linux/drivers/cpufreq/ppc-corenet-cpufreq.c
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   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 */
  31struct 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 */
  42struct 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 */
  49static 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 */
  69static u32 min_cpufreq;
  70static const u32 *fmask;
  71
  72/* serialize frequency changes  */
  73static DEFINE_MUTEX(cpufreq_lock);
  74static DEFINE_PER_CPU(struct cpu_data *, cpu_data);
  75
  76/* cpumask in a cluster */
  77static DEFINE_PER_CPU(cpumask_var_t, cpu_mask);
  78
  79#ifndef CONFIG_SMP
  80static inline const struct cpumask *cpu_core_mask(int cpu)
  81{
  82        return cpumask_of(0);
  83}
  84#endif
  85
  86static 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 */
  94static 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 */
 113static 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
 143static 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
 227err_nomem1:
 228        kfree(table);
 229err_node:
 230        of_node_put(data->parent);
 231err_nomem2:
 232        per_cpu(cpu_data, cpu) = NULL;
 233        kfree(data);
 234err_np:
 235        of_node_put(np);
 236
 237        return -ENODEV;
 238}
 239
 240static 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
 256static 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
 264static 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
 296static struct freq_attr *corenet_cpufreq_attr[] = {
 297        &cpufreq_freq_attr_scaling_available_freqs,
 298        NULL,
 299};
 300
 301static struct cpufreq_driver ppc_corenet_cpufreq_driver = {
 302        .name           = "ppc_cpufreq",
 303        .flags          = CPUFREQ_CONST_LOOPS,
 304        .init           = corenet_cpufreq_cpu_init,
 305        .exit           = __exit_p(corenet_cpufreq_cpu_exit),
 306        .verify         = corenet_cpufreq_verify,
 307        .target         = corenet_cpufreq_target,
 308        .get            = corenet_cpufreq_get_speed,
 309        .attr           = corenet_cpufreq_attr,
 310};
 311
 312static const struct of_device_id node_matches[] __initdata = {
 313        { .compatible = "fsl,p2041-clockgen", .data = &sdata[0], },
 314        { .compatible = "fsl,p3041-clockgen", .data = &sdata[0], },
 315        { .compatible = "fsl,p5020-clockgen", .data = &sdata[1], },
 316        { .compatible = "fsl,p4080-clockgen", .data = &sdata[2], },
 317        { .compatible = "fsl,p5040-clockgen", .data = &sdata[2], },
 318        { .compatible = "fsl,qoriq-clockgen-2.0", },
 319        {}
 320};
 321
 322static int __init ppc_corenet_cpufreq_init(void)
 323{
 324        int ret;
 325        struct device_node  *np;
 326        const struct of_device_id *match;
 327        const struct soc_data *data;
 328        unsigned int cpu;
 329
 330        np = of_find_matching_node(NULL, node_matches);
 331        if (!np)
 332                return -ENODEV;
 333
 334        for_each_possible_cpu(cpu) {
 335                if (!alloc_cpumask_var(&per_cpu(cpu_mask, cpu), GFP_KERNEL))
 336                        goto err_mask;
 337                cpumask_copy(per_cpu(cpu_mask, cpu), cpu_core_mask(cpu));
 338        }
 339
 340        match = of_match_node(node_matches, np);
 341        data = match->data;
 342        if (data) {
 343                if (data->flag)
 344                        fmask = data->freq_mask;
 345                min_cpufreq = fsl_get_sys_freq();
 346        } else {
 347                min_cpufreq = fsl_get_sys_freq() / 2;
 348        }
 349
 350        of_node_put(np);
 351
 352        ret = cpufreq_register_driver(&ppc_corenet_cpufreq_driver);
 353        if (!ret)
 354                pr_info("Freescale PowerPC corenet CPU frequency scaling driver\n");
 355
 356        return ret;
 357
 358err_mask:
 359        for_each_possible_cpu(cpu)
 360                free_cpumask_var(per_cpu(cpu_mask, cpu));
 361
 362        return -ENOMEM;
 363}
 364module_init(ppc_corenet_cpufreq_init);
 365
 366static void __exit ppc_corenet_cpufreq_exit(void)
 367{
 368        unsigned int cpu;
 369
 370        for_each_possible_cpu(cpu)
 371                free_cpumask_var(per_cpu(cpu_mask, cpu));
 372
 373        cpufreq_unregister_driver(&ppc_corenet_cpufreq_driver);
 374}
 375module_exit(ppc_corenet_cpufreq_exit);
 376
 377MODULE_LICENSE("GPL");
 378MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
 379MODULE_DESCRIPTION("cpufreq driver for Freescale e500mc series SoCs");
 380
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