dell-smbios-wmi.c 6.7 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279
  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * WMI methods for use with dell-smbios
  4. *
  5. * Copyright (c) 2017 Dell Inc.
  6. */
  7. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  8. #include <linux/dmi.h>
  9. #include <linux/list.h>
  10. #include <linux/module.h>
  11. #include <linux/mutex.h>
  12. #include <linux/uaccess.h>
  13. #include <linux/wmi.h>
  14. #include "dell-smbios.h"
  15. #include "dell-wmi-descriptor.h"
  16. static DEFINE_MUTEX(call_mutex);
  17. static DEFINE_MUTEX(list_mutex);
  18. static int wmi_supported;
  19. struct misc_bios_flags_structure {
  20. struct dmi_header header;
  21. u16 flags0;
  22. } __packed;
  23. #define FLAG_HAS_ACPI_WMI 0x02
  24. #define DELL_WMI_SMBIOS_GUID "A80593CE-A997-11DA-B012-B622A1EF5492"
  25. struct wmi_smbios_priv {
  26. struct dell_wmi_smbios_buffer *buf;
  27. struct list_head list;
  28. struct wmi_device *wdev;
  29. struct device *child;
  30. u32 req_buf_size;
  31. };
  32. static LIST_HEAD(wmi_list);
  33. static inline struct wmi_smbios_priv *get_first_smbios_priv(void)
  34. {
  35. return list_first_entry_or_null(&wmi_list,
  36. struct wmi_smbios_priv,
  37. list);
  38. }
  39. static int run_smbios_call(struct wmi_device *wdev)
  40. {
  41. struct acpi_buffer output = {ACPI_ALLOCATE_BUFFER, NULL};
  42. struct wmi_smbios_priv *priv;
  43. struct acpi_buffer input;
  44. union acpi_object *obj;
  45. acpi_status status;
  46. priv = dev_get_drvdata(&wdev->dev);
  47. input.length = priv->req_buf_size - sizeof(u64);
  48. input.pointer = &priv->buf->std;
  49. dev_dbg(&wdev->dev, "evaluating: %u/%u [%x,%x,%x,%x]\n",
  50. priv->buf->std.cmd_class, priv->buf->std.cmd_select,
  51. priv->buf->std.input[0], priv->buf->std.input[1],
  52. priv->buf->std.input[2], priv->buf->std.input[3]);
  53. status = wmidev_evaluate_method(wdev, 0, 1, &input, &output);
  54. if (ACPI_FAILURE(status))
  55. return -EIO;
  56. obj = (union acpi_object *)output.pointer;
  57. if (obj->type != ACPI_TYPE_BUFFER) {
  58. dev_dbg(&wdev->dev, "received type: %d\n", obj->type);
  59. if (obj->type == ACPI_TYPE_INTEGER)
  60. dev_dbg(&wdev->dev, "SMBIOS call failed: %llu\n",
  61. obj->integer.value);
  62. kfree(output.pointer);
  63. return -EIO;
  64. }
  65. memcpy(&priv->buf->std, obj->buffer.pointer, obj->buffer.length);
  66. dev_dbg(&wdev->dev, "result: [%08x,%08x,%08x,%08x]\n",
  67. priv->buf->std.output[0], priv->buf->std.output[1],
  68. priv->buf->std.output[2], priv->buf->std.output[3]);
  69. kfree(output.pointer);
  70. return 0;
  71. }
  72. static int dell_smbios_wmi_call(struct calling_interface_buffer *buffer)
  73. {
  74. struct wmi_smbios_priv *priv;
  75. size_t difference;
  76. size_t size;
  77. int ret;
  78. mutex_lock(&call_mutex);
  79. priv = get_first_smbios_priv();
  80. if (!priv) {
  81. ret = -ENODEV;
  82. goto out_wmi_call;
  83. }
  84. size = sizeof(struct calling_interface_buffer);
  85. difference = priv->req_buf_size - sizeof(u64) - size;
  86. memset(&priv->buf->ext, 0, difference);
  87. memcpy(&priv->buf->std, buffer, size);
  88. ret = run_smbios_call(priv->wdev);
  89. memcpy(buffer, &priv->buf->std, size);
  90. out_wmi_call:
  91. mutex_unlock(&call_mutex);
  92. return ret;
  93. }
  94. static long dell_smbios_wmi_filter(struct wmi_device *wdev, unsigned int cmd,
  95. struct wmi_ioctl_buffer *arg)
  96. {
  97. struct wmi_smbios_priv *priv;
  98. int ret = 0;
  99. switch (cmd) {
  100. case DELL_WMI_SMBIOS_CMD:
  101. mutex_lock(&call_mutex);
  102. priv = dev_get_drvdata(&wdev->dev);
  103. if (!priv) {
  104. ret = -ENODEV;
  105. goto fail_smbios_cmd;
  106. }
  107. memcpy(priv->buf, arg, priv->req_buf_size);
  108. if (dell_smbios_call_filter(&wdev->dev, &priv->buf->std)) {
  109. dev_err(&wdev->dev, "Invalid call %d/%d:%8x\n",
  110. priv->buf->std.cmd_class,
  111. priv->buf->std.cmd_select,
  112. priv->buf->std.input[0]);
  113. ret = -EFAULT;
  114. goto fail_smbios_cmd;
  115. }
  116. ret = run_smbios_call(priv->wdev);
  117. if (ret)
  118. goto fail_smbios_cmd;
  119. memcpy(arg, priv->buf, priv->req_buf_size);
  120. fail_smbios_cmd:
  121. mutex_unlock(&call_mutex);
  122. break;
  123. default:
  124. ret = -ENOIOCTLCMD;
  125. }
  126. return ret;
  127. }
  128. static int dell_smbios_wmi_probe(struct wmi_device *wdev, const void *context)
  129. {
  130. struct wmi_driver *wdriver =
  131. container_of(wdev->dev.driver, struct wmi_driver, driver);
  132. struct wmi_smbios_priv *priv;
  133. u32 hotfix;
  134. int count;
  135. int ret;
  136. ret = dell_wmi_get_descriptor_valid();
  137. if (ret)
  138. return ret;
  139. priv = devm_kzalloc(&wdev->dev, sizeof(struct wmi_smbios_priv),
  140. GFP_KERNEL);
  141. if (!priv)
  142. return -ENOMEM;
  143. /* WMI buffer size will be either 4k or 32k depending on machine */
  144. if (!dell_wmi_get_size(&priv->req_buf_size))
  145. return -EPROBE_DEFER;
  146. /* some SMBIOS calls fail unless BIOS contains hotfix */
  147. if (!dell_wmi_get_hotfix(&hotfix))
  148. return -EPROBE_DEFER;
  149. if (!hotfix) {
  150. dev_warn(&wdev->dev,
  151. "WMI SMBIOS userspace interface not supported(%u), try upgrading to a newer BIOS\n",
  152. hotfix);
  153. wdriver->filter_callback = NULL;
  154. }
  155. /* add in the length object we will use internally with ioctl */
  156. priv->req_buf_size += sizeof(u64);
  157. ret = set_required_buffer_size(wdev, priv->req_buf_size);
  158. if (ret)
  159. return ret;
  160. count = get_order(priv->req_buf_size);
  161. priv->buf = (void *)__get_free_pages(GFP_KERNEL, count);
  162. if (!priv->buf)
  163. return -ENOMEM;
  164. /* ID is used by dell-smbios to set priority of drivers */
  165. wdev->dev.id = 1;
  166. ret = dell_smbios_register_device(&wdev->dev, &dell_smbios_wmi_call);
  167. if (ret)
  168. goto fail_register;
  169. priv->wdev = wdev;
  170. dev_set_drvdata(&wdev->dev, priv);
  171. mutex_lock(&list_mutex);
  172. list_add_tail(&priv->list, &wmi_list);
  173. mutex_unlock(&list_mutex);
  174. return 0;
  175. fail_register:
  176. free_pages((unsigned long)priv->buf, count);
  177. return ret;
  178. }
  179. static int dell_smbios_wmi_remove(struct wmi_device *wdev)
  180. {
  181. struct wmi_smbios_priv *priv = dev_get_drvdata(&wdev->dev);
  182. int count;
  183. mutex_lock(&call_mutex);
  184. mutex_lock(&list_mutex);
  185. list_del(&priv->list);
  186. mutex_unlock(&list_mutex);
  187. dell_smbios_unregister_device(&wdev->dev);
  188. count = get_order(priv->req_buf_size);
  189. free_pages((unsigned long)priv->buf, count);
  190. mutex_unlock(&call_mutex);
  191. return 0;
  192. }
  193. static const struct wmi_device_id dell_smbios_wmi_id_table[] = {
  194. { .guid_string = DELL_WMI_SMBIOS_GUID },
  195. { },
  196. };
  197. static void parse_b1_table(const struct dmi_header *dm)
  198. {
  199. struct misc_bios_flags_structure *flags =
  200. container_of(dm, struct misc_bios_flags_structure, header);
  201. /* 4 bytes header, 8 bytes flags */
  202. if (dm->length < 12)
  203. return;
  204. if (dm->handle != 0xb100)
  205. return;
  206. if ((flags->flags0 & FLAG_HAS_ACPI_WMI))
  207. wmi_supported = 1;
  208. }
  209. static void find_b1(const struct dmi_header *dm, void *dummy)
  210. {
  211. switch (dm->type) {
  212. case 0xb1: /* misc bios flags */
  213. parse_b1_table(dm);
  214. break;
  215. }
  216. }
  217. static struct wmi_driver dell_smbios_wmi_driver = {
  218. .driver = {
  219. .name = "dell-smbios",
  220. },
  221. .probe = dell_smbios_wmi_probe,
  222. .remove = dell_smbios_wmi_remove,
  223. .id_table = dell_smbios_wmi_id_table,
  224. .filter_callback = dell_smbios_wmi_filter,
  225. };
  226. int init_dell_smbios_wmi(void)
  227. {
  228. dmi_walk(find_b1, NULL);
  229. if (!wmi_supported)
  230. return -ENODEV;
  231. return wmi_driver_register(&dell_smbios_wmi_driver);
  232. }
  233. void exit_dell_smbios_wmi(void)
  234. {
  235. if (wmi_supported)
  236. wmi_driver_unregister(&dell_smbios_wmi_driver);
  237. }
  238. MODULE_DEVICE_TABLE(wmi, dell_smbios_wmi_id_table);