ia64-acpi-cpufreq.c 7.6 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * This file provides the ACPI based P-state support. This
  4. * module works with generic cpufreq infrastructure. Most of
  5. * the code is based on i386 version
  6. * (arch/i386/kernel/cpu/cpufreq/acpi-cpufreq.c)
  7. *
  8. * Copyright (C) 2005 Intel Corp
  9. * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
  10. */
  11. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  12. #include <linux/kernel.h>
  13. #include <linux/slab.h>
  14. #include <linux/module.h>
  15. #include <linux/init.h>
  16. #include <linux/cpufreq.h>
  17. #include <linux/proc_fs.h>
  18. #include <asm/io.h>
  19. #include <linux/uaccess.h>
  20. #include <asm/pal.h>
  21. #include <linux/acpi.h>
  22. #include <acpi/processor.h>
  23. MODULE_AUTHOR("Venkatesh Pallipadi");
  24. MODULE_DESCRIPTION("ACPI Processor P-States Driver");
  25. MODULE_LICENSE("GPL");
  26. struct cpufreq_acpi_io {
  27. struct acpi_processor_performance acpi_data;
  28. unsigned int resume;
  29. };
  30. struct cpufreq_acpi_req {
  31. unsigned int cpu;
  32. unsigned int state;
  33. };
  34. static struct cpufreq_acpi_io *acpi_io_data[NR_CPUS];
  35. static struct cpufreq_driver acpi_cpufreq_driver;
  36. static int
  37. processor_set_pstate (
  38. u32 value)
  39. {
  40. s64 retval;
  41. pr_debug("processor_set_pstate\n");
  42. retval = ia64_pal_set_pstate((u64)value);
  43. if (retval) {
  44. pr_debug("Failed to set freq to 0x%x, with error 0x%lx\n",
  45. value, retval);
  46. return -ENODEV;
  47. }
  48. return (int)retval;
  49. }
  50. static int
  51. processor_get_pstate (
  52. u32 *value)
  53. {
  54. u64 pstate_index = 0;
  55. s64 retval;
  56. pr_debug("processor_get_pstate\n");
  57. retval = ia64_pal_get_pstate(&pstate_index,
  58. PAL_GET_PSTATE_TYPE_INSTANT);
  59. *value = (u32) pstate_index;
  60. if (retval)
  61. pr_debug("Failed to get current freq with "
  62. "error 0x%lx, idx 0x%x\n", retval, *value);
  63. return (int)retval;
  64. }
  65. /* To be used only after data->acpi_data is initialized */
  66. static unsigned
  67. extract_clock (
  68. struct cpufreq_acpi_io *data,
  69. unsigned value)
  70. {
  71. unsigned long i;
  72. pr_debug("extract_clock\n");
  73. for (i = 0; i < data->acpi_data.state_count; i++) {
  74. if (value == data->acpi_data.states[i].status)
  75. return data->acpi_data.states[i].core_frequency;
  76. }
  77. return data->acpi_data.states[i-1].core_frequency;
  78. }
  79. static long
  80. processor_get_freq (
  81. void *arg)
  82. {
  83. struct cpufreq_acpi_req *req = arg;
  84. unsigned int cpu = req->cpu;
  85. struct cpufreq_acpi_io *data = acpi_io_data[cpu];
  86. u32 value;
  87. int ret;
  88. pr_debug("processor_get_freq\n");
  89. if (smp_processor_id() != cpu)
  90. return -EAGAIN;
  91. /* processor_get_pstate gets the instantaneous frequency */
  92. ret = processor_get_pstate(&value);
  93. if (ret) {
  94. pr_warn("get performance failed with error %d\n", ret);
  95. return ret;
  96. }
  97. return 1000 * extract_clock(data, value);
  98. }
  99. static long
  100. processor_set_freq (
  101. void *arg)
  102. {
  103. struct cpufreq_acpi_req *req = arg;
  104. unsigned int cpu = req->cpu;
  105. struct cpufreq_acpi_io *data = acpi_io_data[cpu];
  106. int ret, state = req->state;
  107. u32 value;
  108. pr_debug("processor_set_freq\n");
  109. if (smp_processor_id() != cpu)
  110. return -EAGAIN;
  111. if (state == data->acpi_data.state) {
  112. if (unlikely(data->resume)) {
  113. pr_debug("Called after resume, resetting to P%d\n", state);
  114. data->resume = 0;
  115. } else {
  116. pr_debug("Already at target state (P%d)\n", state);
  117. return 0;
  118. }
  119. }
  120. pr_debug("Transitioning from P%d to P%d\n",
  121. data->acpi_data.state, state);
  122. /*
  123. * First we write the target state's 'control' value to the
  124. * control_register.
  125. */
  126. value = (u32) data->acpi_data.states[state].control;
  127. pr_debug("Transitioning to state: 0x%08x\n", value);
  128. ret = processor_set_pstate(value);
  129. if (ret) {
  130. pr_warn("Transition failed with error %d\n", ret);
  131. return -ENODEV;
  132. }
  133. data->acpi_data.state = state;
  134. return 0;
  135. }
  136. static unsigned int
  137. acpi_cpufreq_get (
  138. unsigned int cpu)
  139. {
  140. struct cpufreq_acpi_req req;
  141. long ret;
  142. req.cpu = cpu;
  143. ret = work_on_cpu(cpu, processor_get_freq, &req);
  144. return ret > 0 ? (unsigned int) ret : 0;
  145. }
  146. static int
  147. acpi_cpufreq_target (
  148. struct cpufreq_policy *policy,
  149. unsigned int index)
  150. {
  151. struct cpufreq_acpi_req req;
  152. req.cpu = policy->cpu;
  153. req.state = index;
  154. return work_on_cpu(req.cpu, processor_set_freq, &req);
  155. }
  156. static int
  157. acpi_cpufreq_cpu_init (
  158. struct cpufreq_policy *policy)
  159. {
  160. unsigned int i;
  161. unsigned int cpu = policy->cpu;
  162. struct cpufreq_acpi_io *data;
  163. unsigned int result = 0;
  164. struct cpufreq_frequency_table *freq_table;
  165. pr_debug("acpi_cpufreq_cpu_init\n");
  166. data = kzalloc(sizeof(*data), GFP_KERNEL);
  167. if (!data)
  168. return (-ENOMEM);
  169. acpi_io_data[cpu] = data;
  170. result = acpi_processor_register_performance(&data->acpi_data, cpu);
  171. if (result)
  172. goto err_free;
  173. /* capability check */
  174. if (data->acpi_data.state_count <= 1) {
  175. pr_debug("No P-States\n");
  176. result = -ENODEV;
  177. goto err_unreg;
  178. }
  179. if ((data->acpi_data.control_register.space_id !=
  180. ACPI_ADR_SPACE_FIXED_HARDWARE) ||
  181. (data->acpi_data.status_register.space_id !=
  182. ACPI_ADR_SPACE_FIXED_HARDWARE)) {
  183. pr_debug("Unsupported address space [%d, %d]\n",
  184. (u32) (data->acpi_data.control_register.space_id),
  185. (u32) (data->acpi_data.status_register.space_id));
  186. result = -ENODEV;
  187. goto err_unreg;
  188. }
  189. /* alloc freq_table */
  190. freq_table = kcalloc(data->acpi_data.state_count + 1,
  191. sizeof(*freq_table),
  192. GFP_KERNEL);
  193. if (!freq_table) {
  194. result = -ENOMEM;
  195. goto err_unreg;
  196. }
  197. /* detect transition latency */
  198. policy->cpuinfo.transition_latency = 0;
  199. for (i=0; i<data->acpi_data.state_count; i++) {
  200. if ((data->acpi_data.states[i].transition_latency * 1000) >
  201. policy->cpuinfo.transition_latency) {
  202. policy->cpuinfo.transition_latency =
  203. data->acpi_data.states[i].transition_latency * 1000;
  204. }
  205. }
  206. /* table init */
  207. for (i = 0; i <= data->acpi_data.state_count; i++)
  208. {
  209. if (i < data->acpi_data.state_count) {
  210. freq_table[i].frequency =
  211. data->acpi_data.states[i].core_frequency * 1000;
  212. } else {
  213. freq_table[i].frequency = CPUFREQ_TABLE_END;
  214. }
  215. }
  216. policy->freq_table = freq_table;
  217. /* notify BIOS that we exist */
  218. acpi_processor_notify_smm(THIS_MODULE);
  219. pr_info("CPU%u - ACPI performance management activated\n", cpu);
  220. for (i = 0; i < data->acpi_data.state_count; i++)
  221. pr_debug(" %cP%d: %d MHz, %d mW, %d uS, %d uS, 0x%x 0x%x\n",
  222. (i == data->acpi_data.state?'*':' '), i,
  223. (u32) data->acpi_data.states[i].core_frequency,
  224. (u32) data->acpi_data.states[i].power,
  225. (u32) data->acpi_data.states[i].transition_latency,
  226. (u32) data->acpi_data.states[i].bus_master_latency,
  227. (u32) data->acpi_data.states[i].status,
  228. (u32) data->acpi_data.states[i].control);
  229. /* the first call to ->target() should result in us actually
  230. * writing something to the appropriate registers. */
  231. data->resume = 1;
  232. return (result);
  233. err_unreg:
  234. acpi_processor_unregister_performance(cpu);
  235. err_free:
  236. kfree(data);
  237. acpi_io_data[cpu] = NULL;
  238. return (result);
  239. }
  240. static int
  241. acpi_cpufreq_cpu_exit (
  242. struct cpufreq_policy *policy)
  243. {
  244. struct cpufreq_acpi_io *data = acpi_io_data[policy->cpu];
  245. pr_debug("acpi_cpufreq_cpu_exit\n");
  246. if (data) {
  247. acpi_io_data[policy->cpu] = NULL;
  248. acpi_processor_unregister_performance(policy->cpu);
  249. kfree(policy->freq_table);
  250. kfree(data);
  251. }
  252. return (0);
  253. }
  254. static struct cpufreq_driver acpi_cpufreq_driver = {
  255. .verify = cpufreq_generic_frequency_table_verify,
  256. .target_index = acpi_cpufreq_target,
  257. .get = acpi_cpufreq_get,
  258. .init = acpi_cpufreq_cpu_init,
  259. .exit = acpi_cpufreq_cpu_exit,
  260. .name = "acpi-cpufreq",
  261. .attr = cpufreq_generic_attr,
  262. };
  263. static int __init
  264. acpi_cpufreq_init (void)
  265. {
  266. pr_debug("acpi_cpufreq_init\n");
  267. return cpufreq_register_driver(&acpi_cpufreq_driver);
  268. }
  269. static void __exit
  270. acpi_cpufreq_exit (void)
  271. {
  272. pr_debug("acpi_cpufreq_exit\n");
  273. cpufreq_unregister_driver(&acpi_cpufreq_driver);
  274. }
  275. late_initcall(acpi_cpufreq_init);
  276. module_exit(acpi_cpufreq_exit);