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 */
22 #ifndef __fdtdec_h
23 #define __fdtdec_h
25 /*
26 * This file contains convenience functions for decoding useful and
27 * enlightening information from FDTs. It is intended to be used by device
28 * drivers and board-specific code within U-Boot. It aims to reduce the
29 * amount of FDT munging required within U-Boot itself, so that driver code
30 * changes to support FDT are minimized.
31 */
33 #include <libfdt.h>
35 /*
36 * A typedef for a physical address. Note that fdt data is always big
37 * endian even on a litle endian machine.
38 */
39 #ifdef CONFIG_PHYS_64BIT
40 typedef u64 fdt_addr_t;
41 #define FDT_ADDR_T_NONE (-1ULL)
42 #define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
43 #define fdt_size_to_cpu(reg) be64_to_cpu(reg)
44 #else
45 typedef u32 fdt_addr_t;
46 #define FDT_ADDR_T_NONE (-1U)
47 #define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
48 #define fdt_size_to_cpu(reg) be32_to_cpu(reg)
49 #endif
51 /* Information obtained about memory from the FDT */
52 struct fdt_memory {
53 fdt_addr_t start;
54 fdt_addr_t end;
55 };
57 /**
58 * Compat types that we know about and for which we might have drivers.
59 * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
60 * within drivers.
61 */
62 enum fdt_compat_id {
63 COMPAT_UNKNOWN,
64 COMPAT_NVIDIA_TEGRA20_USB, /* Tegra20 USB port */
65 COMPAT_NVIDIA_TEGRA20_I2C, /* Tegra20 i2c */
66 COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra20 dvc (really just i2c) */
67 COMPAT_NVIDIA_TEGRA20_EMC, /* Tegra20 memory controller */
68 COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */
69 COMPAT_NVIDIA_TEGRA20_KBC, /* Tegra20 Keyboard */
70 COMPAT_NVIDIA_TEGRA20_NAND, /* Tegra2 NAND controller */
71 COMPAT_NVIDIA_TEGRA20_PWM, /* Tegra 2 PWM controller */
72 COMPAT_NVIDIA_TEGRA20_DC, /* Tegra 2 Display controller */
73 COMPAT_NVIDIA_TEGRA20_SFLASH, /* Tegra 2 SPI flash controller */
74 COMPAT_NVIDIA_TEGRA20_SLINK, /* Tegra 2 SPI SLINK controller */
75 COMPAT_SMSC_LAN9215, /* SMSC 10/100 Ethernet LAN9215 */
76 COMPAT_SAMSUNG_EXYNOS5_SROMC, /* Exynos5 SROMC */
77 COMPAT_SAMSUNG_S3C2440_I2C, /* Exynos I2C Controller */
78 COMPAT_SAMSUNG_EXYNOS5_SOUND, /* Exynos Sound */
79 COMPAT_WOLFSON_WM8994_CODEC, /* Wolfson WM8994 Sound Codec */
80 COMPAT_SAMSUNG_EXYNOS_SPI, /* Exynos SPI */
81 COMPAT_SAMSUNG_EXYNOS_EHCI, /* Exynos EHCI controller */
82 COMPAT_SAMSUNG_EXYNOS_USB_PHY, /* Exynos phy controller for usb2.0 */
83 COMPAT_MAXIM_MAX77686_PMIC, /* MAX77686 PMIC */
85 COMPAT_COUNT,
86 };
88 /* GPIOs are numbered from 0 */
89 enum {
90 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */
92 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
93 };
95 /* This is the state of a GPIO pin as defined by the fdt */
96 struct fdt_gpio_state {
97 const char *name; /* name of the fdt property defining this */
98 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
99 u8 flags; /* FDT_GPIO_... flags */
100 };
102 /* This tells us whether a fdt_gpio_state record is valid or not */
103 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
105 /**
106 * Read the GPIO taking into account the polarity of the pin.
107 *
108 * @param gpio pointer to the decoded gpio
109 * @return value of the gpio if successful, < 0 if unsuccessful
110 */
111 int fdtdec_get_gpio(struct fdt_gpio_state *gpio);
113 /**
114 * Write the GPIO taking into account the polarity of the pin.
115 *
116 * @param gpio pointer to the decoded gpio
117 * @return 0 if successful
118 */
119 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);
121 /**
122 * Find the next numbered alias for a peripheral. This is used to enumerate
123 * all the peripherals of a certain type.
124 *
125 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
126 * this function will return a pointer to the node the alias points to, and
127 * then update *upto to 1. Next time you call this function, the next node
128 * will be returned.
129 *
130 * All nodes returned will match the compatible ID, as it is assumed that
131 * all peripherals use the same driver.
132 *
133 * @param blob FDT blob to use
134 * @param name Root name of alias to search for
135 * @param id Compatible ID to look for
136 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
137 */
138 int fdtdec_next_alias(const void *blob, const char *name,
139 enum fdt_compat_id id, int *upto);
141 /**
142 * Find the compatible ID for a given node.
143 *
144 * Generally each node has at least one compatible string attached to it.
145 * This function looks through our list of known compatible strings and
146 * returns the corresponding ID which matches the compatible string.
147 *
148 * @param blob FDT blob to use
149 * @param node Node containing compatible string to find
150 * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
151 */
152 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
154 /**
155 * Find the next compatible node for a peripheral.
156 *
157 * Do the first call with node = 0. This function will return a pointer to
158 * the next compatible node. Next time you call this function, pass the
159 * value returned, and the next node will be provided.
160 *
161 * @param blob FDT blob to use
162 * @param node Start node for search
163 * @param id Compatible ID to look for (enum fdt_compat_id)
164 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
165 */
166 int fdtdec_next_compatible(const void *blob, int node,
167 enum fdt_compat_id id);
169 /**
170 * Find the next compatible subnode for a peripheral.
171 *
172 * Do the first call with node set to the parent and depth = 0. This
173 * function will return the offset of the next compatible node. Next time
174 * you call this function, pass the node value returned last time, with
175 * depth unchanged, and the next node will be provided.
176 *
177 * @param blob FDT blob to use
178 * @param node Start node for search
179 * @param id Compatible ID to look for (enum fdt_compat_id)
180 * @param depthp Current depth (set to 0 before first call)
181 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
182 */
183 int fdtdec_next_compatible_subnode(const void *blob, int node,
184 enum fdt_compat_id id, int *depthp);
186 /**
187 * Look up an address property in a node and return it as an address.
188 * The property must hold either one address with no trailing data or
189 * one address with a length. This is only tested on 32-bit machines.
190 *
191 * @param blob FDT blob
192 * @param node node to examine
193 * @param prop_name name of property to find
194 * @return address, if found, or FDT_ADDR_T_NONE if not
195 */
196 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
197 const char *prop_name);
199 /**
200 * Look up a 32-bit integer property in a node and return it. The property
201 * must have at least 4 bytes of data. The value of the first cell is
202 * returned.
203 *
204 * @param blob FDT blob
205 * @param node node to examine
206 * @param prop_name name of property to find
207 * @param default_val default value to return if the property is not found
208 * @return integer value, if found, or default_val if not
209 */
210 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
211 s32 default_val);
213 /**
214 * Look up a 64-bit integer property in a node and return it. The property
215 * must have at least 8 bytes of data (2 cells). The first two cells are
216 * concatenated to form a 8 bytes value, where the first cell is top half and
217 * the second cell is bottom half.
218 *
219 * @param blob FDT blob
220 * @param node node to examine
221 * @param prop_name name of property to find
222 * @param default_val default value to return if the property is not found
223 * @return integer value, if found, or default_val if not
224 */
225 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
226 uint64_t default_val);
228 /**
229 * Checks whether a node is enabled.
230 * This looks for a 'status' property. If this exists, then returns 1 if
231 * the status is 'ok' and 0 otherwise. If there is no status property,
232 * it returns 1 on the assumption that anything mentioned should be enabled
233 * by default.
234 *
235 * @param blob FDT blob
236 * @param node node to examine
237 * @return integer value 0 (not enabled) or 1 (enabled)
238 */
239 int fdtdec_get_is_enabled(const void *blob, int node);
241 /**
242 * Make sure we have a valid fdt available to control U-Boot.
243 *
244 * If not, a message is printed to the console if the console is ready.
245 *
246 * @return 0 if all ok, -1 if not
247 */
248 int fdtdec_prepare_fdt(void);
250 /**
251 * Checks that we have a valid fdt available to control U-Boot.
253 * However, if not then for the moment nothing is done, since this function
254 * is called too early to panic().
255 *
256 * @returns 0
257 */
258 int fdtdec_check_fdt(void);
260 /**
261 * Find the nodes for a peripheral and return a list of them in the correct
262 * order. This is used to enumerate all the peripherals of a certain type.
263 *
264 * To use this, optionally set up a /aliases node with alias properties for
265 * a peripheral. For example, for usb you could have:
266 *
267 * aliases {
268 * usb0 = "/ehci@c5008000";
269 * usb1 = "/ehci@c5000000";
270 * };
271 *
272 * Pass "usb" as the name to this function and will return a list of two
273 * nodes offsets: /ehci@c5008000 and ehci@c5000000.
274 *
275 * All nodes returned will match the compatible ID, as it is assumed that
276 * all peripherals use the same driver.
277 *
278 * If no alias node is found, then the node list will be returned in the
279 * order found in the fdt. If the aliases mention a node which doesn't
280 * exist, then this will be ignored. If nodes are found with no aliases,
281 * they will be added in any order.
282 *
283 * If there is a gap in the aliases, then this function return a 0 node at
284 * that position. The return value will also count these gaps.
285 *
286 * This function checks node properties and will not return nodes which are
287 * marked disabled (status = "disabled").
288 *
289 * @param blob FDT blob to use
290 * @param name Root name of alias to search for
291 * @param id Compatible ID to look for
292 * @param node_list Place to put list of found nodes
293 * @param maxcount Maximum number of nodes to find
294 * @return number of nodes found on success, FTD_ERR_... on error
295 */
296 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
297 enum fdt_compat_id id, int *node_list, int maxcount);
299 /*
300 * This function is similar to fdtdec_find_aliases_for_id() except that it
301 * adds to the node_list that is passed in. Any 0 elements are considered
302 * available for allocation - others are considered already used and are
303 * skipped.
304 *
305 * You can use this by calling fdtdec_find_aliases_for_id() with an
306 * uninitialised array, then setting the elements that are returned to -1,
307 * say, then calling this function, perhaps with a different compat id.
308 * Any elements you get back that are >0 are new nodes added by the call
309 * to this function.
310 *
311 * Note that if you have some nodes with aliases and some without, you are
312 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
313 * one compat_id may fill in positions for which you have aliases defined
314 * for another compat_id. When you later call *this* function with the second
315 * compat_id, the alias positions may already be used. A debug warning may
316 * be generated in this case, but it is safest to define aliases for all
317 * nodes when you care about the ordering.
318 */
319 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
320 enum fdt_compat_id id, int *node_list, int maxcount);
322 /*
323 * Get the name for a compatible ID
324 *
325 * @param id Compatible ID to look for
326 * @return compatible string for that id
327 */
328 const char *fdtdec_get_compatible(enum fdt_compat_id id);
330 /* Look up a phandle and follow it to its node. Then return the offset
331 * of that node.
332 *
333 * @param blob FDT blob
334 * @param node node to examine
335 * @param prop_name name of property to find
336 * @return node offset if found, -ve error code on error
337 */
338 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
340 /**
341 * Look up a property in a node and return its contents in an integer
342 * array of given length. The property must have at least enough data for
343 * the array (4*count bytes). It may have more, but this will be ignored.
344 *
345 * @param blob FDT blob
346 * @param node node to examine
347 * @param prop_name name of property to find
348 * @param array array to fill with data
349 * @param count number of array elements
350 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
351 * or -FDT_ERR_BADLAYOUT if not enough data
352 */
353 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
354 u32 *array, int count);
356 /**
357 * Look up a property in a node and return a pointer to its contents as a
358 * unsigned int array of given length. The property must have at least enough
359 * data for the array ('count' cells). It may have more, but this will be
360 * ignored. The data is not copied.
361 *
362 * Note that you must access elements of the array with fdt32_to_cpu(),
363 * since the elements will be big endian even on a little endian machine.
364 *
365 * @param blob FDT blob
366 * @param node node to examine
367 * @param prop_name name of property to find
368 * @param count number of array elements
369 * @return pointer to array if found, or NULL if the property is not
370 * found or there is not enough data
371 */
372 const u32 *fdtdec_locate_array(const void *blob, int node,
373 const char *prop_name, int count);
375 /**
376 * Look up a boolean property in a node and return it.
377 *
378 * A boolean properly is true if present in the device tree and false if not
379 * present, regardless of its value.
380 *
381 * @param blob FDT blob
382 * @param node node to examine
383 * @param prop_name name of property to find
384 * @return 1 if the properly is present; 0 if it isn't present
385 */
386 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
388 /**
389 * Decode a single GPIOs from an FDT.
390 *
391 * If the property is not found, then the GPIO structure will still be
392 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
393 * provide optional GPIOs.
394 *
395 * @param blob FDT blob to use
396 * @param node Node to look at
397 * @param prop_name Node property name
398 * @param gpio gpio elements to fill from FDT
399 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
400 */
401 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
402 struct fdt_gpio_state *gpio);
404 /**
405 * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
406 * terminating item.
407 *
408 * @param blob FDT blob to use
409 * @param node Node to look at
410 * @param prop_name Node property name
411 * @param gpio Array of gpio elements to fill from FDT. This will be
412 * untouched if either 0 or an error is returned
413 * @param max_count Maximum number of elements allowed
414 * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
415 * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
416 */
417 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name,
418 struct fdt_gpio_state *gpio, int max_count);
420 /**
421 * Set up a GPIO pin according to the provided gpio information. At present this
422 * just requests the GPIO.
423 *
424 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
425 * deal with optional GPIOs.
426 *
427 * @param gpio GPIO info to use for set up
428 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
429 */
430 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
432 /**
433 * Look in the FDT for a config item with the given name and return its value
434 * as a 32-bit integer. The property must have at least 4 bytes of data. The
435 * value of the first cell is returned.
436 *
437 * @param blob FDT blob to use
438 * @param prop_name Node property name
439 * @param default_val default value to return if the property is not found
440 * @return integer value, if found, or default_val if not
441 */
442 int fdtdec_get_config_int(const void *blob, const char *prop_name,
443 int default_val);
445 /**
446 * Look in the FDT for a config item with the given name
447 * and return whether it exists.
448 *
449 * @param blob FDT blob
450 * @param prop_name property name to look up
451 * @return 1, if it exists, or 0 if not
452 */
453 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
455 /**
456 * Look in the FDT for a config item with the given name and return its value
457 * as a string.
458 *
459 * @param blob FDT blob
460 * @param prop_name property name to look up
461 * @returns property string, NULL on error.
462 */
463 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
465 /*
466 * Look up a property in a node and return its contents in a byte
467 * array of given length. The property must have at least enough data for
468 * the array (count bytes). It may have more, but this will be ignored.
469 *
470 * @param blob FDT blob
471 * @param node node to examine
472 * @param prop_name name of property to find
473 * @param array array to fill with data
474 * @param count number of array elements
475 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
476 * or -FDT_ERR_BADLAYOUT if not enough data
477 */
478 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
479 u8 *array, int count);
481 /**
482 * Look up a property in a node and return a pointer to its contents as a
483 * byte array of given length. The property must have at least enough data
484 * for the array (count bytes). It may have more, but this will be ignored.
485 * The data is not copied.
486 *
487 * @param blob FDT blob
488 * @param node node to examine
489 * @param prop_name name of property to find
490 * @param count number of array elements
491 * @return pointer to byte array if found, or NULL if the property is not
492 * found or there is not enough data
493 */
494 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
495 const char *prop_name, int count);
497 /**
498 * Look up a property in a node which contains a memory region address and
499 * size. Then return a pointer to this address.
500 *
501 * The property must hold one address with a length. This is only tested on
502 * 32-bit machines.
503 *
504 * @param blob FDT blob
505 * @param node node to examine
506 * @param prop_name name of property to find
507 * @param ptrp returns pointer to region, or NULL if no address
508 * @param size returns size of region
509 * @return 0 if ok, -1 on error (propery not found)
510 */
511 int fdtdec_decode_region(const void *blob, int node,
512 const char *prop_name, void **ptrp, size_t *size);
513 #endif