qoriq-cpufreq.c 6.9 KB

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