fdtdec.h 14 KB

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  1. /*
  2. * Copyright (c) 2011 The Chromium OS Authors.
  3. * See file CREDITS for list of people who contributed to this
  4. * project.
  5. *
  6. * This program is free software; you can redistribute it and/or
  7. * modify it under the terms of the GNU General Public License as
  8. * published by the Free Software Foundation; either version 2 of
  9. * the License, or (at your option) any later version.
  10. *
  11. * This program is distributed in the hope that it will be useful,
  12. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14. * GNU General Public License for more details.
  15. *
  16. * You should have received a copy of the GNU General Public License
  17. * along with this program; if not, write to the Free Software
  18. * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  19. * MA 02111-1307 USA
  20. */
  21. /*
  22. * This file contains convenience functions for decoding useful and
  23. * enlightening information from FDTs. It is intended to be used by device
  24. * drivers and board-specific code within U-Boot. It aims to reduce the
  25. * amount of FDT munging required within U-Boot itself, so that driver code
  26. * changes to support FDT are minimized.
  27. */
  28. #include <libfdt.h>
  29. /*
  30. * A typedef for a physical address. Note that fdt data is always big
  31. * endian even on a litle endian machine.
  32. */
  33. #ifdef CONFIG_PHYS_64BIT
  34. typedef u64 fdt_addr_t;
  35. #define FDT_ADDR_T_NONE (-1ULL)
  36. #define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
  37. #else
  38. typedef u32 fdt_addr_t;
  39. #define FDT_ADDR_T_NONE (-1U)
  40. #define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
  41. #endif
  42. /* Information obtained about memory from the FDT */
  43. struct fdt_memory {
  44. fdt_addr_t start;
  45. fdt_addr_t end;
  46. };
  47. /**
  48. * Compat types that we know about and for which we might have drivers.
  49. * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
  50. * within drivers.
  51. */
  52. enum fdt_compat_id {
  53. COMPAT_UNKNOWN,
  54. COMPAT_NVIDIA_TEGRA20_USB, /* Tegra2 USB port */
  55. COMPAT_NVIDIA_TEGRA20_I2C, /* Tegra2 i2c */
  56. COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra2 dvc (really just i2c) */
  57. COMPAT_NVIDIA_TEGRA20_EMC, /* Tegra2 memory controller */
  58. COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra2 memory timing table */
  59. COMPAT_NVIDIA_TEGRA20_KBC, /* Tegra2 Keyboard */
  60. COMPAT_COUNT,
  61. };
  62. /* GPIOs are numbered from 0 */
  63. enum {
  64. FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */
  65. FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
  66. };
  67. /* This is the state of a GPIO pin as defined by the fdt */
  68. struct fdt_gpio_state {
  69. const char *name; /* name of the fdt property defining this */
  70. uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
  71. u8 flags; /* FDT_GPIO_... flags */
  72. };
  73. /* This tells us whether a fdt_gpio_state record is valid or not */
  74. #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
  75. /**
  76. * Find the next numbered alias for a peripheral. This is used to enumerate
  77. * all the peripherals of a certain type.
  78. *
  79. * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
  80. * this function will return a pointer to the node the alias points to, and
  81. * then update *upto to 1. Next time you call this function, the next node
  82. * will be returned.
  83. *
  84. * All nodes returned will match the compatible ID, as it is assumed that
  85. * all peripherals use the same driver.
  86. *
  87. * @param blob FDT blob to use
  88. * @param name Root name of alias to search for
  89. * @param id Compatible ID to look for
  90. * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
  91. */
  92. int fdtdec_next_alias(const void *blob, const char *name,
  93. enum fdt_compat_id id, int *upto);
  94. /**
  95. * Find the next compatible node for a peripheral.
  96. *
  97. * Do the first call with node = 0. This function will return a pointer to
  98. * the next compatible node. Next time you call this function, pass the
  99. * value returned, and the next node will be provided.
  100. *
  101. * @param blob FDT blob to use
  102. * @param node Start node for search
  103. * @param id Compatible ID to look for (enum fdt_compat_id)
  104. * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
  105. */
  106. int fdtdec_next_compatible(const void *blob, int node,
  107. enum fdt_compat_id id);
  108. /**
  109. * Find the next compatible subnode for a peripheral.
  110. *
  111. * Do the first call with node set to the parent and depth = 0. This
  112. * function will return the offset of the next compatible node. Next time
  113. * you call this function, pass the node value returned last time, with
  114. * depth unchanged, and the next node will be provided.
  115. *
  116. * @param blob FDT blob to use
  117. * @param node Start node for search
  118. * @param id Compatible ID to look for (enum fdt_compat_id)
  119. * @param depthp Current depth (set to 0 before first call)
  120. * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
  121. */
  122. int fdtdec_next_compatible_subnode(const void *blob, int node,
  123. enum fdt_compat_id id, int *depthp);
  124. /**
  125. * Look up an address property in a node and return it as an address.
  126. * The property must hold either one address with no trailing data or
  127. * one address with a length. This is only tested on 32-bit machines.
  128. *
  129. * @param blob FDT blob
  130. * @param node node to examine
  131. * @param prop_name name of property to find
  132. * @return address, if found, or FDT_ADDR_T_NONE if not
  133. */
  134. fdt_addr_t fdtdec_get_addr(const void *blob, int node,
  135. const char *prop_name);
  136. /**
  137. * Look up a 32-bit integer property in a node and return it. The property
  138. * must have at least 4 bytes of data. The value of the first cell is
  139. * returned.
  140. *
  141. * @param blob FDT blob
  142. * @param node node to examine
  143. * @param prop_name name of property to find
  144. * @param default_val default value to return if the property is not found
  145. * @return integer value, if found, or default_val if not
  146. */
  147. s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
  148. s32 default_val);
  149. /**
  150. * Checks whether a node is enabled.
  151. * This looks for a 'status' property. If this exists, then returns 1 if
  152. * the status is 'ok' and 0 otherwise. If there is no status property,
  153. * it returns 1 on the assumption that anything mentioned should be enabled
  154. * by default.
  155. *
  156. * @param blob FDT blob
  157. * @param node node to examine
  158. * @return integer value 0 (not enabled) or 1 (enabled)
  159. */
  160. int fdtdec_get_is_enabled(const void *blob, int node);
  161. /**
  162. * Make sure we have a valid fdt available to control U-Boot.
  163. *
  164. * If not, a message is printed to the console if the console is ready.
  165. *
  166. * @return 0 if all ok, -1 if not
  167. */
  168. int fdtdec_prepare_fdt(void);
  169. /**
  170. * Checks that we have a valid fdt available to control U-Boot.
  171. * However, if not then for the moment nothing is done, since this function
  172. * is called too early to panic().
  173. *
  174. * @returns 0
  175. */
  176. int fdtdec_check_fdt(void);
  177. /**
  178. * Find the nodes for a peripheral and return a list of them in the correct
  179. * order. This is used to enumerate all the peripherals of a certain type.
  180. *
  181. * To use this, optionally set up a /aliases node with alias properties for
  182. * a peripheral. For example, for usb you could have:
  183. *
  184. * aliases {
  185. * usb0 = "/ehci@c5008000";
  186. * usb1 = "/ehci@c5000000";
  187. * };
  188. *
  189. * Pass "usb" as the name to this function and will return a list of two
  190. * nodes offsets: /ehci@c5008000 and ehci@c5000000.
  191. *
  192. * All nodes returned will match the compatible ID, as it is assumed that
  193. * all peripherals use the same driver.
  194. *
  195. * If no alias node is found, then the node list will be returned in the
  196. * order found in the fdt. If the aliases mention a node which doesn't
  197. * exist, then this will be ignored. If nodes are found with no aliases,
  198. * they will be added in any order.
  199. *
  200. * If there is a gap in the aliases, then this function return a 0 node at
  201. * that position. The return value will also count these gaps.
  202. *
  203. * This function checks node properties and will not return nodes which are
  204. * marked disabled (status = "disabled").
  205. *
  206. * @param blob FDT blob to use
  207. * @param name Root name of alias to search for
  208. * @param id Compatible ID to look for
  209. * @param node_list Place to put list of found nodes
  210. * @param maxcount Maximum number of nodes to find
  211. * @return number of nodes found on success, FTD_ERR_... on error
  212. */
  213. int fdtdec_find_aliases_for_id(const void *blob, const char *name,
  214. enum fdt_compat_id id, int *node_list, int maxcount);
  215. /*
  216. * This function is similar to fdtdec_find_aliases_for_id() except that it
  217. * adds to the node_list that is passed in. Any 0 elements are considered
  218. * available for allocation - others are considered already used and are
  219. * skipped.
  220. *
  221. * You can use this by calling fdtdec_find_aliases_for_id() with an
  222. * uninitialised array, then setting the elements that are returned to -1,
  223. * say, then calling this function, perhaps with a different compat id.
  224. * Any elements you get back that are >0 are new nodes added by the call
  225. * to this function.
  226. *
  227. * Note that if you have some nodes with aliases and some without, you are
  228. * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
  229. * one compat_id may fill in positions for which you have aliases defined
  230. * for another compat_id. When you later call *this* function with the second
  231. * compat_id, the alias positions may already be used. A debug warning may
  232. * be generated in this case, but it is safest to define aliases for all
  233. * nodes when you care about the ordering.
  234. */
  235. int fdtdec_add_aliases_for_id(const void *blob, const char *name,
  236. enum fdt_compat_id id, int *node_list, int maxcount);
  237. /*
  238. * Get the name for a compatible ID
  239. *
  240. * @param id Compatible ID to look for
  241. * @return compatible string for that id
  242. */
  243. const char *fdtdec_get_compatible(enum fdt_compat_id id);
  244. /* Look up a phandle and follow it to its node. Then return the offset
  245. * of that node.
  246. *
  247. * @param blob FDT blob
  248. * @param node node to examine
  249. * @param prop_name name of property to find
  250. * @return node offset if found, -ve error code on error
  251. */
  252. int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
  253. /**
  254. * Look up a property in a node and return its contents in an integer
  255. * array of given length. The property must have at least enough data for
  256. * the array (4*count bytes). It may have more, but this will be ignored.
  257. *
  258. * @param blob FDT blob
  259. * @param node node to examine
  260. * @param prop_name name of property to find
  261. * @param array array to fill with data
  262. * @param count number of array elements
  263. * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
  264. * or -FDT_ERR_BADLAYOUT if not enough data
  265. */
  266. int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
  267. u32 *array, int count);
  268. /**
  269. * Look up a property in a node and return a pointer to its contents as a
  270. * unsigned int array of given length. The property must have at least enough
  271. * data for the array ('count' cells). It may have more, but this will be
  272. * ignored. The data is not copied.
  273. *
  274. * Note that you must access elements of the array with fdt32_to_cpu(),
  275. * since the elements will be big endian even on a little endian machine.
  276. *
  277. * @param blob FDT blob
  278. * @param node node to examine
  279. * @param prop_name name of property to find
  280. * @param count number of array elements
  281. * @return pointer to array if found, or NULL if the property is not
  282. * found or there is not enough data
  283. */
  284. const u32 *fdtdec_locate_array(const void *blob, int node,
  285. const char *prop_name, int count);
  286. /**
  287. * Look up a boolean property in a node and return it.
  288. *
  289. * A boolean properly is true if present in the device tree and false if not
  290. * present, regardless of its value.
  291. *
  292. * @param blob FDT blob
  293. * @param node node to examine
  294. * @param prop_name name of property to find
  295. * @return 1 if the properly is present; 0 if it isn't present
  296. */
  297. int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
  298. /**
  299. * Decode a single GPIOs from an FDT.
  300. *
  301. * If the property is not found, then the GPIO structure will still be
  302. * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
  303. * provide optional GPIOs.
  304. *
  305. * @param blob FDT blob to use
  306. * @param node Node to look at
  307. * @param prop_name Node property name
  308. * @param gpio gpio elements to fill from FDT
  309. * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
  310. */
  311. int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
  312. struct fdt_gpio_state *gpio);
  313. /**
  314. * Set up a GPIO pin according to the provided gpio information. At present this
  315. * just requests the GPIO.
  316. *
  317. * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
  318. * deal with optional GPIOs.
  319. *
  320. * @param gpio GPIO info to use for set up
  321. * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
  322. */
  323. int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
  324. /*
  325. * Look up a property in a node and return its contents in a byte
  326. * array of given length. The property must have at least enough data for
  327. * the array (count bytes). It may have more, but this will be ignored.
  328. *
  329. * @param blob FDT blob
  330. * @param node node to examine
  331. * @param prop_name name of property to find
  332. * @param array array to fill with data
  333. * @param count number of array elements
  334. * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
  335. * or -FDT_ERR_BADLAYOUT if not enough data
  336. */
  337. int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
  338. u8 *array, int count);
  339. /**
  340. * Look up a property in a node and return a pointer to its contents as a
  341. * byte array of given length. The property must have at least enough data
  342. * for the array (count bytes). It may have more, but this will be ignored.
  343. * The data is not copied.
  344. *
  345. * @param blob FDT blob
  346. * @param node node to examine
  347. * @param prop_name name of property to find
  348. * @param count number of array elements
  349. * @return pointer to byte array if found, or NULL if the property is not
  350. * found or there is not enough data
  351. */
  352. const u8 *fdtdec_locate_byte_array(const void *blob, int node,
  353. const char *prop_name, int count);