bt1-l2-ctl.c 7.3 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
  4. *
  5. * Authors:
  6. * Serge Semin <Sergey.Semin@baikalelectronics.ru>
  7. *
  8. * Baikal-T1 CM2 L2-cache Control Block driver.
  9. */
  10. #include <linux/kernel.h>
  11. #include <linux/module.h>
  12. #include <linux/bitfield.h>
  13. #include <linux/types.h>
  14. #include <linux/device.h>
  15. #include <linux/platform_device.h>
  16. #include <linux/regmap.h>
  17. #include <linux/mfd/syscon.h>
  18. #include <linux/sysfs.h>
  19. #include <linux/of.h>
  20. #define L2_CTL_REG 0x028
  21. #define L2_CTL_DATA_STALL_FLD 0
  22. #define L2_CTL_DATA_STALL_MASK GENMASK(1, L2_CTL_DATA_STALL_FLD)
  23. #define L2_CTL_TAG_STALL_FLD 2
  24. #define L2_CTL_TAG_STALL_MASK GENMASK(3, L2_CTL_TAG_STALL_FLD)
  25. #define L2_CTL_WS_STALL_FLD 4
  26. #define L2_CTL_WS_STALL_MASK GENMASK(5, L2_CTL_WS_STALL_FLD)
  27. #define L2_CTL_SET_CLKRATIO BIT(13)
  28. #define L2_CTL_CLKRATIO_LOCK BIT(31)
  29. #define L2_CTL_STALL_MIN 0
  30. #define L2_CTL_STALL_MAX 3
  31. #define L2_CTL_STALL_SET_DELAY_US 1
  32. #define L2_CTL_STALL_SET_TOUT_US 1000
  33. /*
  34. * struct l2_ctl - Baikal-T1 L2 Control block private data.
  35. * @dev: Pointer to the device structure.
  36. * @sys_regs: Baikal-T1 System Controller registers map.
  37. */
  38. struct l2_ctl {
  39. struct device *dev;
  40. struct regmap *sys_regs;
  41. };
  42. /*
  43. * enum l2_ctl_stall - Baikal-T1 L2-cache-RAM stall identifier.
  44. * @L2_WSSTALL: Way-select latency.
  45. * @L2_TAGSTALL: Tag latency.
  46. * @L2_DATASTALL: Data latency.
  47. */
  48. enum l2_ctl_stall {
  49. L2_WS_STALL,
  50. L2_TAG_STALL,
  51. L2_DATA_STALL
  52. };
  53. /*
  54. * struct l2_ctl_device_attribute - Baikal-T1 L2-cache device attribute.
  55. * @dev_attr: Actual sysfs device attribute.
  56. * @id: L2-cache stall field identifier.
  57. */
  58. struct l2_ctl_device_attribute {
  59. struct device_attribute dev_attr;
  60. enum l2_ctl_stall id;
  61. };
  62. #define to_l2_ctl_dev_attr(_dev_attr) \
  63. container_of(_dev_attr, struct l2_ctl_device_attribute, dev_attr)
  64. #define L2_CTL_ATTR_RW(_name, _prefix, _id) \
  65. struct l2_ctl_device_attribute l2_ctl_attr_##_name = \
  66. { __ATTR(_name, 0644, _prefix##_show, _prefix##_store), _id }
  67. static int l2_ctl_get_latency(struct l2_ctl *l2, enum l2_ctl_stall id, u32 *val)
  68. {
  69. u32 data = 0;
  70. int ret;
  71. ret = regmap_read(l2->sys_regs, L2_CTL_REG, &data);
  72. if (ret)
  73. return ret;
  74. switch (id) {
  75. case L2_WS_STALL:
  76. *val = FIELD_GET(L2_CTL_WS_STALL_MASK, data);
  77. break;
  78. case L2_TAG_STALL:
  79. *val = FIELD_GET(L2_CTL_TAG_STALL_MASK, data);
  80. break;
  81. case L2_DATA_STALL:
  82. *val = FIELD_GET(L2_CTL_DATA_STALL_MASK, data);
  83. break;
  84. default:
  85. return -EINVAL;
  86. }
  87. return 0;
  88. }
  89. static int l2_ctl_set_latency(struct l2_ctl *l2, enum l2_ctl_stall id, u32 val)
  90. {
  91. u32 mask = 0, data = 0;
  92. int ret;
  93. val = clamp_val(val, L2_CTL_STALL_MIN, L2_CTL_STALL_MAX);
  94. switch (id) {
  95. case L2_WS_STALL:
  96. data = FIELD_PREP(L2_CTL_WS_STALL_MASK, val);
  97. mask = L2_CTL_WS_STALL_MASK;
  98. break;
  99. case L2_TAG_STALL:
  100. data = FIELD_PREP(L2_CTL_TAG_STALL_MASK, val);
  101. mask = L2_CTL_TAG_STALL_MASK;
  102. break;
  103. case L2_DATA_STALL:
  104. data = FIELD_PREP(L2_CTL_DATA_STALL_MASK, val);
  105. mask = L2_CTL_DATA_STALL_MASK;
  106. break;
  107. default:
  108. return -EINVAL;
  109. }
  110. data |= L2_CTL_SET_CLKRATIO;
  111. mask |= L2_CTL_SET_CLKRATIO;
  112. ret = regmap_update_bits(l2->sys_regs, L2_CTL_REG, mask, data);
  113. if (ret)
  114. return ret;
  115. return regmap_read_poll_timeout(l2->sys_regs, L2_CTL_REG, data,
  116. data & L2_CTL_CLKRATIO_LOCK,
  117. L2_CTL_STALL_SET_DELAY_US,
  118. L2_CTL_STALL_SET_TOUT_US);
  119. }
  120. static void l2_ctl_clear_data(void *data)
  121. {
  122. struct l2_ctl *l2 = data;
  123. struct platform_device *pdev = to_platform_device(l2->dev);
  124. platform_set_drvdata(pdev, NULL);
  125. }
  126. static struct l2_ctl *l2_ctl_create_data(struct platform_device *pdev)
  127. {
  128. struct device *dev = &pdev->dev;
  129. struct l2_ctl *l2;
  130. int ret;
  131. l2 = devm_kzalloc(dev, sizeof(*l2), GFP_KERNEL);
  132. if (!l2)
  133. return ERR_PTR(-ENOMEM);
  134. ret = devm_add_action(dev, l2_ctl_clear_data, l2);
  135. if (ret) {
  136. dev_err(dev, "Can't add L2 CTL data clear action\n");
  137. return ERR_PTR(ret);
  138. }
  139. l2->dev = dev;
  140. platform_set_drvdata(pdev, l2);
  141. return l2;
  142. }
  143. static int l2_ctl_find_sys_regs(struct l2_ctl *l2)
  144. {
  145. l2->sys_regs = syscon_node_to_regmap(l2->dev->of_node->parent);
  146. if (IS_ERR(l2->sys_regs)) {
  147. dev_err(l2->dev, "Couldn't get L2 CTL register map\n");
  148. return PTR_ERR(l2->sys_regs);
  149. }
  150. return 0;
  151. }
  152. static int l2_ctl_of_parse_property(struct l2_ctl *l2, enum l2_ctl_stall id,
  153. const char *propname)
  154. {
  155. int ret = 0;
  156. u32 data;
  157. if (!of_property_read_u32(l2->dev->of_node, propname, &data)) {
  158. ret = l2_ctl_set_latency(l2, id, data);
  159. if (ret)
  160. dev_err(l2->dev, "Invalid value of '%s'\n", propname);
  161. }
  162. return ret;
  163. }
  164. static int l2_ctl_of_parse(struct l2_ctl *l2)
  165. {
  166. int ret;
  167. ret = l2_ctl_of_parse_property(l2, L2_WS_STALL, "baikal,l2-ws-latency");
  168. if (ret)
  169. return ret;
  170. ret = l2_ctl_of_parse_property(l2, L2_TAG_STALL, "baikal,l2-tag-latency");
  171. if (ret)
  172. return ret;
  173. return l2_ctl_of_parse_property(l2, L2_DATA_STALL,
  174. "baikal,l2-data-latency");
  175. }
  176. static ssize_t l2_ctl_latency_show(struct device *dev,
  177. struct device_attribute *attr,
  178. char *buf)
  179. {
  180. struct l2_ctl_device_attribute *devattr = to_l2_ctl_dev_attr(attr);
  181. struct l2_ctl *l2 = dev_get_drvdata(dev);
  182. u32 data;
  183. int ret;
  184. ret = l2_ctl_get_latency(l2, devattr->id, &data);
  185. if (ret)
  186. return ret;
  187. return scnprintf(buf, PAGE_SIZE, "%u\n", data);
  188. }
  189. static ssize_t l2_ctl_latency_store(struct device *dev,
  190. struct device_attribute *attr,
  191. const char *buf, size_t count)
  192. {
  193. struct l2_ctl_device_attribute *devattr = to_l2_ctl_dev_attr(attr);
  194. struct l2_ctl *l2 = dev_get_drvdata(dev);
  195. u32 data;
  196. int ret;
  197. if (kstrtouint(buf, 0, &data) < 0)
  198. return -EINVAL;
  199. ret = l2_ctl_set_latency(l2, devattr->id, data);
  200. if (ret)
  201. return ret;
  202. return count;
  203. }
  204. static L2_CTL_ATTR_RW(l2_ws_latency, l2_ctl_latency, L2_WS_STALL);
  205. static L2_CTL_ATTR_RW(l2_tag_latency, l2_ctl_latency, L2_TAG_STALL);
  206. static L2_CTL_ATTR_RW(l2_data_latency, l2_ctl_latency, L2_DATA_STALL);
  207. static struct attribute *l2_ctl_sysfs_attrs[] = {
  208. &l2_ctl_attr_l2_ws_latency.dev_attr.attr,
  209. &l2_ctl_attr_l2_tag_latency.dev_attr.attr,
  210. &l2_ctl_attr_l2_data_latency.dev_attr.attr,
  211. NULL
  212. };
  213. ATTRIBUTE_GROUPS(l2_ctl_sysfs);
  214. static void l2_ctl_remove_sysfs(void *data)
  215. {
  216. struct l2_ctl *l2 = data;
  217. device_remove_groups(l2->dev, l2_ctl_sysfs_groups);
  218. }
  219. static int l2_ctl_init_sysfs(struct l2_ctl *l2)
  220. {
  221. int ret;
  222. ret = device_add_groups(l2->dev, l2_ctl_sysfs_groups);
  223. if (ret) {
  224. dev_err(l2->dev, "Failed to create L2 CTL sysfs nodes\n");
  225. return ret;
  226. }
  227. ret = devm_add_action_or_reset(l2->dev, l2_ctl_remove_sysfs, l2);
  228. if (ret)
  229. dev_err(l2->dev, "Can't add L2 CTL sysfs remove action\n");
  230. return ret;
  231. }
  232. static int l2_ctl_probe(struct platform_device *pdev)
  233. {
  234. struct l2_ctl *l2;
  235. int ret;
  236. l2 = l2_ctl_create_data(pdev);
  237. if (IS_ERR(l2))
  238. return PTR_ERR(l2);
  239. ret = l2_ctl_find_sys_regs(l2);
  240. if (ret)
  241. return ret;
  242. ret = l2_ctl_of_parse(l2);
  243. if (ret)
  244. return ret;
  245. ret = l2_ctl_init_sysfs(l2);
  246. if (ret)
  247. return ret;
  248. return 0;
  249. }
  250. static const struct of_device_id l2_ctl_of_match[] = {
  251. { .compatible = "baikal,bt1-l2-ctl" },
  252. { }
  253. };
  254. MODULE_DEVICE_TABLE(of, l2_ctl_of_match);
  255. static struct platform_driver l2_ctl_driver = {
  256. .probe = l2_ctl_probe,
  257. .driver = {
  258. .name = "bt1-l2-ctl",
  259. .of_match_table = l2_ctl_of_match
  260. }
  261. };
  262. module_platform_driver(l2_ctl_driver);
  263. MODULE_AUTHOR("Serge Semin <Sergey.Semin@baikalelectronics.ru>");
  264. MODULE_DESCRIPTION("Baikal-T1 L2-cache driver");
  265. MODULE_LICENSE("GPL v2");