drivers/cpufreq/qoriq-cpufreq.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright 2013 Freescale Semiconductor, Inc.
   4  *
   5  * CPU Frequency Scaling driver for Freescale QorIQ SoCs.
   6  */
   7
   8 #define pr_fmt(fmt)     KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/clk.h>
  11 #include <linux/clk-provider.h>
  12 #include <linux/cpufreq.h>
  13 #include <linux/errno.h>
  14 #include <linux/init.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/mutex.h>
  18 #include <linux/of.h>
  19 #include <linux/slab.h>
  20 #include <linux/smp.h>
  21 #include <linux/platform_device.h>
  22
  23 /**
  24  * struct cpu_data
  25  * @pclk: the parent clock of cpu
  26  * @table: frequency table
  27  */
  28 struct cpu_data {
  29         struct clk **pclk;
  30         struct cpufreq_frequency_table *table;
  31 };
  32
  33 /**
  34  * struct soc_data - SoC specific data
  35  * @flags: SOC_xxx
  36  */
  37 struct soc_data {
  38         u32 flags;
  39 };
  40
  41 static u32 get_bus_freq(void)
  42 {
  43         struct device_node *soc;
  44         u32 sysfreq;
  45         struct clk *pltclk;
  46         int ret;
  47
  48         /* get platform freq by searching bus-frequency property */
  49         soc = of_find_node_by_type(NULL, "soc");
  50         if (soc) {
  51                 ret = of_property_read_u32(soc, "bus-frequency", &sysfreq);
  52                 of_node_put(soc);
  53                 if (!ret)
  54                         return sysfreq;
  55         }
  56
  57         /* get platform freq by its clock name */
  58         pltclk = clk_get(NULL, "cg-pll0-div1");
  59         if (IS_ERR(pltclk)) {
  60                 pr_err("%s: can't get bus frequency %ld\n",
  61                        __func__, PTR_ERR(pltclk));
  62                 return PTR_ERR(pltclk);
  63         }
  64
  65         return clk_get_rate(pltclk);
  66 }
  67
  68 static struct clk *cpu_to_clk(int cpu)
  69 {
  70         struct device_node *np;
  71         struct clk *clk;
  72
  73         if (!cpu_present(cpu))
  74                 return NULL;
  75
  76         np = of_get_cpu_node(cpu, NULL);
  77         if (!np)
  78                 return NULL;
  79
  80         clk = of_clk_get(np, 0);
  81         of_node_put(np);
  82         return clk;
  83 }
  84
  85 /* traverse cpu nodes to get cpu mask of sharing clock wire */
  86 static void set_affected_cpus(struct cpufreq_policy *policy)
  87 {
  88         struct cpumask *dstp = policy->cpus;
  89         struct clk *clk;
  90         int i;
  91
  92         for_each_present_cpu(i) {
  93                 clk = cpu_to_clk(i);
  94                 if (IS_ERR(clk)) {
  95                         pr_err("%s: no clock for cpu %d\n", __func__, i);
  96                         continue;
  97                 }
  98
  99                 if (clk_is_match(policy->clk, clk))
 100                         cpumask_set_cpu(i, dstp);
 101         }
 102 }
 103
 104 /* reduce the duplicated frequencies in frequency table */
 105 static void freq_table_redup(struct cpufreq_frequency_table *freq_table,
 106                 int count)
 107 {
 108         int i, j;
 109
 110         for (i = 1; i < count; i++) {
 111                 for (j = 0; j < i; j++) {
 112                         if (freq_table[j].frequency == CPUFREQ_ENTRY_INVALID ||
 113                                         freq_table[j].frequency !=
 114                                         freq_table[i].frequency)
 115                                 continue;
 116
 117                         freq_table[i].frequency = CPUFREQ_ENTRY_INVALID;
 118                         break;
 119                 }
 120         }
 121 }
 122
 123 /* sort the frequencies in frequency table in descenting order */
 124 static void freq_table_sort(struct cpufreq_frequency_table *freq_table,
 125                 int count)
 126 {
 127         int i, j, ind;
 128         unsigned int freq, max_freq;
 129         struct cpufreq_frequency_table table;
 130
 131         for (i = 0; i < count - 1; i++) {
 132                 max_freq = freq_table[i].frequency;
 133                 ind = i;
 134                 for (j = i + 1; j < count; j++) {
 135                         freq = freq_table[j].frequency;
 136                         if (freq == CPUFREQ_ENTRY_INVALID ||
 137                                         freq <= max_freq)
 138                                 continue;
 139                         ind = j;
 140                         max_freq = freq;
 141                 }
 142
 143                 if (ind != i) {
 144                         /* exchange the frequencies */
 145                         table.driver_data = freq_table[i].driver_data;
 146                         table.frequency = freq_table[i].frequency;
 147                         freq_table[i].driver_data = freq_table[ind].driver_data;
 148                         freq_table[i].frequency = freq_table[ind].frequency;
 149                         freq_table[ind].driver_data = table.driver_data;
 150                         freq_table[ind].frequency = table.frequency;
 151                 }
 152         }
 153 }
 154
 155 static int qoriq_cpufreq_cpu_init(struct cpufreq_policy *policy)
 156 {
 157         struct device_node *np;
 158         int i, count;
 159         u32 freq;
 160         struct clk *clk;
 161         const struct clk_hw *hwclk;
 162         struct cpufreq_frequency_table *table;
 163         struct cpu_data *data;
 164         unsigned int cpu = policy->cpu;
 165         u64 u64temp;
 166
 167         np = of_get_cpu_node(cpu, NULL);
 168         if (!np)
 169                 return -ENODEV;
 170
 171         data = kzalloc(sizeof(*data), GFP_KERNEL);
 172         if (!data)
 173                 goto err_np;
 174
 175         policy->clk = of_clk_get(np, 0);
 176         if (IS_ERR(policy->clk)) {
 177                 pr_err("%s: no clock information\n", __func__);
 178                 goto err_nomem2;
 179         }
 180
 181         hwclk = __clk_get_hw(policy->clk);
 182         count = clk_hw_get_num_parents(hwclk);
 183
 184         data->pclk = kcalloc(count, sizeof(struct clk *), GFP_KERNEL);
 185         if (!data->pclk)
 186                 goto err_nomem2;
 187
 188         table = kcalloc(count + 1, sizeof(*table), GFP_KERNEL);
 189         if (!table)
 190                 goto err_pclk;
 191
 192         for (i = 0; i < count; i++) {
 193                 clk = clk_hw_get_parent_by_index(hwclk, i)->clk;
 194                 data->pclk[i] = clk;
 195                 freq = clk_get_rate(clk);
 196                 table[i].frequency = freq / 1000;
 197                 table[i].driver_data = i;
 198         }
 199         freq_table_redup(table, count);
 200         freq_table_sort(table, count);
 201         table[i].frequency = CPUFREQ_TABLE_END;
 202         policy->freq_table = table;
 203         data->table = table;
 204
 205         /* update ->cpus if we have cluster, no harm if not */
 206         set_affected_cpus(policy);
 207         policy->driver_data = data;
 208
 209         /* Minimum transition latency is 12 platform clocks */
 210         u64temp = 12ULL * NSEC_PER_SEC;
 211         do_div(u64temp, get_bus_freq());
 212         policy->cpuinfo.transition_latency = u64temp + 1;
 213
 214         of_node_put(np);
 215
 216         return 0;
 217
 218 err_pclk:
 219         kfree(data->pclk);
 220 err_nomem2:
 221         kfree(data);
 222 err_np:
 223         of_node_put(np);
 224
 225         return -ENODEV;
 226 }
 227
 228 static int qoriq_cpufreq_cpu_exit(struct cpufreq_policy *policy)
 229 {
 230         struct cpu_data *data = policy->driver_data;
 231
 232         kfree(data->pclk);
 233         kfree(data->table);
 234         kfree(data);
 235         policy->driver_data = NULL;
 236
 237         return 0;
 238 }
 239
 240 static int qoriq_cpufreq_target(struct cpufreq_policy *policy,
 241                 unsigned int index)
 242 {
 243         struct clk *parent;
 244         struct cpu_data *data = policy->driver_data;
 245
 246         parent = data->pclk[data->table[index].driver_data];
 247         return clk_set_parent(policy->clk, parent);
 248 }
 249
 250 static struct cpufreq_driver qoriq_cpufreq_driver = {
 251         .name           = "qoriq_cpufreq",
 252         .flags          = CPUFREQ_CONST_LOOPS |
 253                           CPUFREQ_IS_COOLING_DEV,
 254         .init           = qoriq_cpufreq_cpu_init,
 255         .exit           = qoriq_cpufreq_cpu_exit,
 256         .verify         = cpufreq_generic_frequency_table_verify,
 257         .target_index   = qoriq_cpufreq_target,
 258         .get            = cpufreq_generic_get,
 259         .attr           = cpufreq_generic_attr,
 260 };
 261
 262 static const struct of_device_id qoriq_cpufreq_blacklist[] = {
 263         /* e6500 cannot use cpufreq due to erratum A-008083 */
 264         { .compatible = "fsl,b4420-clockgen", },
 265         { .compatible = "fsl,b4860-clockgen", },
 266         { .compatible = "fsl,t2080-clockgen", },
 267         { .compatible = "fsl,t4240-clockgen", },
 268         {}
 269 };
 270
 271 static int qoriq_cpufreq_probe(struct platform_device *pdev)
 272 {
 273         int ret;
 274         struct device_node *np;
 275
 276         np = of_find_matching_node(NULL, qoriq_cpufreq_blacklist);
 277         if (np) {
 278                 dev_info(&pdev->dev, "Disabling due to erratum A-008083");
 279                 return -ENODEV;
 280         }
 281
 282         ret = cpufreq_register_driver(&qoriq_cpufreq_driver);
 283         if (ret)
 284                 return ret;
 285
 286         dev_info(&pdev->dev, "Freescale QorIQ CPU frequency scaling driver\n");
 287         return 0;
 288 }
 289
 290 static int qoriq_cpufreq_remove(struct platform_device *pdev)
 291 {
 292         cpufreq_unregister_driver(&qoriq_cpufreq_driver);
 293
 294         return 0;
 295 }
 296
 297 static struct platform_driver qoriq_cpufreq_platform_driver = {
 298         .driver = {
 299                 .name = "qoriq-cpufreq",
 300         },
 301         .probe = qoriq_cpufreq_probe,
 302         .remove = qoriq_cpufreq_remove,
 303 };
 304 module_platform_driver(qoriq_cpufreq_platform_driver);
 305
 306 MODULE_ALIAS("platform:qoriq-cpufreq");
 307 MODULE_LICENSE("GPL");
 308 MODULE_AUTHOR("Tang Yuantian <Yuantian.Tang@freescale.com>");
 309 MODULE_DESCRIPTION("cpufreq driver for Freescale QorIQ series SoCs");