drivers/cpufreq/qoriq-cpufreq.c

   1 /*
   2  * Copyright 2013 Freescale Semiconductor, Inc.
   3  *
   4  * CPU Frequency Scaling driver for Freescale QorIQ 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/clk-provider.h>
  15 #include <linux/cpufreq.h>
  16 #include <linux/errno.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
  27  * @pclk: the parent clock of cpu
  28  * @table: frequency table
  29  */
  30 struct cpu_data {
  31         struct clk **pclk;
  32         struct cpufreq_frequency_table *table;
  33 };
  34
  35 /*
  36  * Don't use cpufreq on this SoC -- used when the SoC would have otherwise
  37  * matched a more generic compatible.
  38  */
  39 #define SOC_BLACKLIST           1
  40
  41 /**
  42  * struct soc_data - SoC specific data
  43  * @flags: SOC_xxx
  44  */
  45 struct soc_data {
  46         u32 flags;
  47 };
  48
  49 static u32 get_bus_freq(void)
  50 {
  51         struct device_node *soc;
  52         u32 sysfreq;
  53         struct clk *pltclk;
  54         int ret;
  55
  56         /* get platform freq by searching bus-frequency property */
  57         soc = of_find_node_by_type(NULL, "soc");
  58         if (soc) {
  59                 ret = of_property_read_u32(soc, "bus-frequency", &sysfreq);
  60                 of_node_put(soc);
  61                 if (!ret)
  62                         return sysfreq;
  63         }
  64
  65         /* get platform freq by its clock name */
  66         pltclk = clk_get(NULL, "cg-pll0-div1");
  67         if (IS_ERR(pltclk)) {
  68                 pr_err("%s: can't get bus frequency %ld\n",
  69                        __func__, PTR_ERR(pltclk));
  70                 return PTR_ERR(pltclk);
  71         }
  72
  73         return clk_get_rate(pltclk);
  74 }
  75
  76 static struct clk *cpu_to_clk(int cpu)
  77 {
  78         struct device_node *np;
  79         struct clk *clk;
  80
  81         if (!cpu_present(cpu))
  82                 return NULL;
  83
  84         np = of_get_cpu_node(cpu, NULL);
  85         if (!np)
  86                 return NULL;
  87
  88         clk = of_clk_get(np, 0);
  89         of_node_put(np);
  90         return clk;
  91 }
  92
  93 /* traverse cpu nodes to get cpu mask of sharing clock wire */
  94 static void set_affected_cpus(struct cpufreq_policy *policy)
  95 {
  96         struct cpumask *dstp = policy->cpus;
  97         struct clk *clk;
  98         int i;
  99
 100         for_each_present_cpu(i) {
 101                 clk = cpu_to_clk(i);
 102                 if (IS_ERR(clk)) {
 103                         pr_err("%s: no clock for cpu %d\n", __func__, i);
 104                         continue;
 105                 }
 106
 107                 if (clk_is_match(policy->clk, clk))
 108                         cpumask_set_cpu(i, dstp);
 109         }
 110 }
 111
 112 /* reduce the duplicated frequencies in frequency table */
 113 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
 114                 int count)
 115 {
 116         int i, j;
 117
 118         for (i = 1; i < count; i++) {
 119                 for (j = 0; j < i; j++) {
 120                         if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
 121                                         freq_table[j].frequency !=
 122                                         freq_table[i].frequency)
 123                                 continue;
 124
 125                         freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
 126                         break;
 127                 }
 128         }
 129 }
 130
 131 /* sort the frequencies in frequency table in descenting order */
 132 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
 133                 int count)
 134 {
 135         int i, j, ind;
 136         unsigned int freq, max_freq;
 137         struct cpufreq_frequency_table table;
 138
 139         for (i = 0; i < count - 1; i++) {
 140                 max_freq = freq_table[i].frequency;
 141                 ind = i;
 142                 for (j = i + 1; j < count; j++) {
 143                         freq = freq_table[j].frequency;
 144                         if (freq == CPUFREQ_ENTRY_INVALID ||
 145                                         freq <= max_freq)
 146                                 continue;
 147                         ind = j;
 148                         max_freq = freq;
 149                 }
 150
 151                 if (ind != i) {
 152                         /* exchange the frequencies */
 153                         table.driver_data = freq_table[i].driver_data;
 154                         table.frequency = freq_table[i].frequency;
 155                         freq_table[i].driver_data = freq_table[ind].driver_data;
 156                         freq_table[i].frequency = freq_table[ind].frequency;
 157                         freq_table[ind].driver_data = table.driver_data;
 158                         freq_table[ind].frequency = table.frequency;
 159                 }
 160         }
 161 }
 162
 163 static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
 164 {
 165         struct device_node *np;
 166         int i, count;
 167         u32 freq;
 168         struct clk *clk;
 169         const struct clk_hw *hwclk;
 170         struct cpufreq_frequency_table *table;
 171         struct cpu_data *data;
 172         unsigned int cpu = policy->cpu;
 173         u64 u64temp;
 174
 175         np = of_get_cpu_node(cpu, NULL);
 176         if (!np)
 177                 return -ENODEV;
 178
 179         data = kzalloc(sizeof(*data), GFP_KERNEL);
 180         if (!data)
 181                 goto err_np;
 182
 183         policy->clk = of_clk_get(np, 0);
 184         if (IS_ERR(policy->clk)) {
 185                 pr_err("%s: no clock information\n", __func__);
 186                 goto err_nomem2;
 187         }
 188
 189         hwclk = __clk_get_hw(policy->clk);
 190         count = clk_hw_get_num_parents(hwclk);
 191
 192         data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
 193         if (!data->pclk)
 194                 goto err_nomem2;
 195
 196         table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
 197         if (!table)
 198                 goto err_pclk;
 199
 200         for (i = 0; i < count; i++) {
 201                 clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
 202                 data->pclk[i] = clk;
 203                 freq = clk_get_rate(clk);
 204                 table[i].frequency = freq / 1000;
 205                 table[i].driver_data = i;
 206         }
 207         freq_table_redup(table, count);
 208         freq_table_sort(table, count);
 209         table[i].frequency = CPUFREQ_TABLE_END;
 210         policy->freq_table = table;
 211         data->table = table;
 212
 213         /* update ->cpus if we have cluster, no harm if not */
 214         set_affected_cpus(policy);
 215         policy->driver_data = data;
 216
 217         /* Minimum transition latency is 12 platform clocks */
 218         u64temp = 12ULL * NSEC_PER_SEC;
 219         do_div(u64temp, get_bus_freq());
 220         policy->cpuinfo.transition_latency = u64temp + 1;
 221
 222         of_node_put(np);
 223
 224         return 0;
 225
 226 err_pclk:
 227         kfree(data->pclk);
 228 err_nomem2:
 229         kfree(data);
 230 err_np:
 231         of_node_put(np);
 232
 233         return -ENODEV;
 234 }
 235
 236 static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 237 {
 238         struct cpu_data *data = policy->driver_data;
 239
 240         kfree(data->pclk);
 241         kfree(data->table);
 242         kfree(data);
 243         policy->driver_data = NULL;
 244
 245         return 0;
 246 }
 247
 248 static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
 249                 unsigned int index)
 250 {
 251         struct clk *parent;
 252         struct cpu_data *data = policy->driver_data;
 253
 254         parent = data->pclk[data->table[index].driver_data];
 255         return clk_set_parent(policy->clk, parent);
 256 }
 257
 258 static struct cpufreq_driver qoriq_cpufreq_driver = {
 259         .name           = "qoriq_cpufreq",
 260         .flags          = CPUFREQ_CONST_LOOPS |
 261                           CPUFREQ_IS_COOLING_DEV,
 262         .init           = qoriq_cpufreq_cpu_init,
 263         .exit           = qoriq_cpufreq_cpu_exit,
 264         .verify         = cpufreq_generic_frequency_table_verify,
 265         .target_index   = qoriq_cpufreq_target,
 266         .get            = cpufreq_generic_get,
 267         .attr           = cpufreq_generic_attr,
 268 };
 269
 270 static const struct soc_data blacklist = {
 271         .flags = SOC_BLACKLIST,
 272 };
 273
 274 static const struct of_device_id node_matches[] __initconst = {
 275         /* e6500 cannot use cpufreq due to erratum A-008083 */
 276         { .compatible = "fsl,b4420-clockgen", &blacklist },
 277         { .compatible = "fsl,b4860-clockgen", &blacklist },
 278         { .compatible = "fsl,t2080-clockgen", &blacklist },
 279         { .compatible = "fsl,t4240-clockgen", &blacklist },
 280
 281         { .compatible = "fsl,ls1012a-clockgen", },
 282         { .compatible = "fsl,ls1021a-clockgen", },
 283         { .compatible = "fsl,ls1028a-clockgen", },
 284         { .compatible = "fsl,ls1043a-clockgen", },
 285         { .compatible = "fsl,ls1046a-clockgen", },
 286         { .compatible = "fsl,ls1088a-clockgen", },
 287         { .compatible = "fsl,ls2080a-clockgen", },
 288         { .compatible = "fsl,lx2160a-clockgen", },
 289         { .compatible = "fsl,p4080-clockgen", },
 290         { .compatible = "fsl,qoriq-clockgen-1.0", },
 291         { .compatible = "fsl,qoriq-clockgen-2.0", },
 292         {}
 293 };
 294
 295 static int __init qoriq_cpufreq_init(void)
 296 {
 297         int ret;
 298         struct device_node  *np;
 299         const struct of_device_id *match;
 300         const struct soc_data *data;
 301
 302         np = of_find_matching_node(NULL, node_matches);
 303         if (!np)
 304                 return -ENODEV;
 305
 306         match = of_match_node(node_matches, np);
 307         data = match->data;
 308
 309         of_node_put(np);
 310
 311         if (data && data->flags & SOC_BLACKLIST)
 312                 return -ENODEV;
 313
 314         ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
 315         if (!ret)
 316                 pr_info("Freescale QorIQ CPU frequency scaling driver\n");
 317
 318         return ret;
 319 }
 320 module_init(qoriq_cpufreq_init);
 321
 322 static void __exit qoriq_cpufreq_exit(void)
 323 {
 324         cpufreq_unregister_driver(&qoriq_cpufreq_driver);
 325 }
 326 module_exit(qoriq_cpufreq_exit);
 327
 328 MODULE_LICENSE("GPL");
 329 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
 330 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");