2 * Copyright (c) 2011 The Chromium OS Authors.
3 * See file CREDITS for list of people who contributed to this
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.
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.
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,
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.
36 * A typedef for a physical address. Note that fdt data is always big
37 * endian even on a litle endian machine.
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)
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)
51 /* Information obtained about memory from the FDT */
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
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_SMSC_LAN9215, /* SMSC 10/100 Ethernet LAN9215 */
74 COMPAT_SAMSUNG_EXYNOS5_SROMC, /* Exynos5 SROMC */
75 COMPAT_SAMSUNG_S3C2440_I2C, /* Exynos I2C Controller */
76 COMPAT_SAMSUNG_EXYNOS5_SOUND, /* Exynos Sound */
77 COMPAT_WOLFSON_WM8994_CODEC, /* Wolfson WM8994 Sound Codec */
82 /* GPIOs are numbered from 0 */
84 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */
86 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
89 /* This is the state of a GPIO pin as defined by the fdt */
90 struct fdt_gpio_state {
91 const char *name; /* name of the fdt property defining this */
92 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
93 u8 flags; /* FDT_GPIO_... flags */
96 /* This tells us whether a fdt_gpio_state record is valid or not */
97 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
100 * Read the GPIO taking into account the polarity of the pin.
102 * @param gpio pointer to the decoded gpio
103 * @return value of the gpio if successful, < 0 if unsuccessful
105 int fdtdec_get_gpio(struct fdt_gpio_state *gpio);
108 * Write the GPIO taking into account the polarity of the pin.
110 * @param gpio pointer to the decoded gpio
111 * @return 0 if successful
113 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);
116 * Find the next numbered alias for a peripheral. This is used to enumerate
117 * all the peripherals of a certain type.
119 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
120 * this function will return a pointer to the node the alias points to, and
121 * then update *upto to 1. Next time you call this function, the next node
124 * All nodes returned will match the compatible ID, as it is assumed that
125 * all peripherals use the same driver.
127 * @param blob FDT blob to use
128 * @param name Root name of alias to search for
129 * @param id Compatible ID to look for
130 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
132 int fdtdec_next_alias(const void *blob, const char *name,
133 enum fdt_compat_id id, int *upto);
136 * Find the compatible ID for a given node.
138 * Generally each node has at least one compatible string attached to it.
139 * This function looks through our list of known compatible strings and
140 * returns the corresponding ID which matches the compatible string.
142 * @param blob FDT blob to use
143 * @param node Node containing compatible string to find
144 * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
146 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
149 * Find the next compatible node for a peripheral.
151 * Do the first call with node = 0. This function will return a pointer to
152 * the next compatible node. Next time you call this function, pass the
153 * value returned, and the next node will be provided.
155 * @param blob FDT blob to use
156 * @param node Start node for search
157 * @param id Compatible ID to look for (enum fdt_compat_id)
158 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
160 int fdtdec_next_compatible(const void *blob, int node,
161 enum fdt_compat_id id);
164 * Find the next compatible subnode for a peripheral.
166 * Do the first call with node set to the parent and depth = 0. This
167 * function will return the offset of the next compatible node. Next time
168 * you call this function, pass the node value returned last time, with
169 * depth unchanged, and the next node will be provided.
171 * @param blob FDT blob to use
172 * @param node Start node for search
173 * @param id Compatible ID to look for (enum fdt_compat_id)
174 * @param depthp Current depth (set to 0 before first call)
175 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
177 int fdtdec_next_compatible_subnode(const void *blob, int node,
178 enum fdt_compat_id id, int *depthp);
181 * Look up an address property in a node and return it as an address.
182 * The property must hold either one address with no trailing data or
183 * one address with a length. This is only tested on 32-bit machines.
185 * @param blob FDT blob
186 * @param node node to examine
187 * @param prop_name name of property to find
188 * @return address, if found, or FDT_ADDR_T_NONE if not
190 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
191 const char *prop_name);
194 * Look up a 32-bit integer property in a node and return it. The property
195 * must have at least 4 bytes of data. The value of the first cell is
198 * @param blob FDT blob
199 * @param node node to examine
200 * @param prop_name name of property to find
201 * @param default_val default value to return if the property is not found
202 * @return integer value, if found, or default_val if not
204 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
208 * Look up a 64-bit integer property in a node and return it. The property
209 * must have at least 8 bytes of data (2 cells). The first two cells are
210 * concatenated to form a 8 bytes value, where the first cell is top half and
211 * the second cell is bottom half.
213 * @param blob FDT blob
214 * @param node node to examine
215 * @param prop_name name of property to find
216 * @param default_val default value to return if the property is not found
217 * @return integer value, if found, or default_val if not
219 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
220 uint64_t default_val);
223 * Checks whether a node is enabled.
224 * This looks for a 'status' property. If this exists, then returns 1 if
225 * the status is 'ok' and 0 otherwise. If there is no status property,
226 * it returns 1 on the assumption that anything mentioned should be enabled
229 * @param blob FDT blob
230 * @param node node to examine
231 * @return integer value 0 (not enabled) or 1 (enabled)
233 int fdtdec_get_is_enabled(const void *blob, int node);
236 * Make sure we have a valid fdt available to control U-Boot.
238 * If not, a message is printed to the console if the console is ready.
240 * @return 0 if all ok, -1 if not
242 int fdtdec_prepare_fdt(void);
245 * Checks that we have a valid fdt available to control U-Boot.
247 * However, if not then for the moment nothing is done, since this function
248 * is called too early to panic().
252 int fdtdec_check_fdt(void);
255 * Find the nodes for a peripheral and return a list of them in the correct
256 * order. This is used to enumerate all the peripherals of a certain type.
258 * To use this, optionally set up a /aliases node with alias properties for
259 * a peripheral. For example, for usb you could have:
262 * usb0 = "/ehci@c5008000";
263 * usb1 = "/ehci@c5000000";
266 * Pass "usb" as the name to this function and will return a list of two
267 * nodes offsets: /ehci@c5008000 and ehci@c5000000.
269 * All nodes returned will match the compatible ID, as it is assumed that
270 * all peripherals use the same driver.
272 * If no alias node is found, then the node list will be returned in the
273 * order found in the fdt. If the aliases mention a node which doesn't
274 * exist, then this will be ignored. If nodes are found with no aliases,
275 * they will be added in any order.
277 * If there is a gap in the aliases, then this function return a 0 node at
278 * that position. The return value will also count these gaps.
280 * This function checks node properties and will not return nodes which are
281 * marked disabled (status = "disabled").
283 * @param blob FDT blob to use
284 * @param name Root name of alias to search for
285 * @param id Compatible ID to look for
286 * @param node_list Place to put list of found nodes
287 * @param maxcount Maximum number of nodes to find
288 * @return number of nodes found on success, FTD_ERR_... on error
290 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
291 enum fdt_compat_id id, int *node_list, int maxcount);
294 * This function is similar to fdtdec_find_aliases_for_id() except that it
295 * adds to the node_list that is passed in. Any 0 elements are considered
296 * available for allocation - others are considered already used and are
299 * You can use this by calling fdtdec_find_aliases_for_id() with an
300 * uninitialised array, then setting the elements that are returned to -1,
301 * say, then calling this function, perhaps with a different compat id.
302 * Any elements you get back that are >0 are new nodes added by the call
305 * Note that if you have some nodes with aliases and some without, you are
306 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
307 * one compat_id may fill in positions for which you have aliases defined
308 * for another compat_id. When you later call *this* function with the second
309 * compat_id, the alias positions may already be used. A debug warning may
310 * be generated in this case, but it is safest to define aliases for all
311 * nodes when you care about the ordering.
313 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
314 enum fdt_compat_id id, int *node_list, int maxcount);
317 * Get the name for a compatible ID
319 * @param id Compatible ID to look for
320 * @return compatible string for that id
322 const char *fdtdec_get_compatible(enum fdt_compat_id id);
324 /* Look up a phandle and follow it to its node. Then return the offset
327 * @param blob FDT blob
328 * @param node node to examine
329 * @param prop_name name of property to find
330 * @return node offset if found, -ve error code on error
332 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
335 * Look up a property in a node and return its contents in an integer
336 * array of given length. The property must have at least enough data for
337 * the array (4*count bytes). It may have more, but this will be ignored.
339 * @param blob FDT blob
340 * @param node node to examine
341 * @param prop_name name of property to find
342 * @param array array to fill with data
343 * @param count number of array elements
344 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
345 * or -FDT_ERR_BADLAYOUT if not enough data
347 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
348 u32 *array, int count);
351 * Look up a property in a node and return a pointer to its contents as a
352 * unsigned int array of given length. The property must have at least enough
353 * data for the array ('count' cells). It may have more, but this will be
354 * ignored. The data is not copied.
356 * Note that you must access elements of the array with fdt32_to_cpu(),
357 * since the elements will be big endian even on a little endian machine.
359 * @param blob FDT blob
360 * @param node node to examine
361 * @param prop_name name of property to find
362 * @param count number of array elements
363 * @return pointer to array if found, or NULL if the property is not
364 * found or there is not enough data
366 const u32 *fdtdec_locate_array(const void *blob, int node,
367 const char *prop_name, int count);
370 * Look up a boolean property in a node and return it.
372 * A boolean properly is true if present in the device tree and false if not
373 * present, regardless of its value.
375 * @param blob FDT blob
376 * @param node node to examine
377 * @param prop_name name of property to find
378 * @return 1 if the properly is present; 0 if it isn't present
380 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
383 * Decode a single GPIOs from an FDT.
385 * If the property is not found, then the GPIO structure will still be
386 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
387 * provide optional GPIOs.
389 * @param blob FDT blob to use
390 * @param node Node to look at
391 * @param prop_name Node property name
392 * @param gpio gpio elements to fill from FDT
393 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
395 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
396 struct fdt_gpio_state *gpio);
399 * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
402 * @param blob FDT blob to use
403 * @param node Node to look at
404 * @param prop_name Node property name
405 * @param gpio Array of gpio elements to fill from FDT. This will be
406 * untouched if either 0 or an error is returned
407 * @param max_count Maximum number of elements allowed
408 * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
409 * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
411 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name,
412 struct fdt_gpio_state *gpio, int max_count);
415 * Set up a GPIO pin according to the provided gpio information. At present this
416 * just requests the GPIO.
418 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
419 * deal with optional GPIOs.
421 * @param gpio GPIO info to use for set up
422 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
424 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
427 * Look in the FDT for a config item with the given name and return its value
428 * as a 32-bit integer. The property must have at least 4 bytes of data. The
429 * value of the first cell is returned.
431 * @param blob FDT blob to use
432 * @param prop_name Node property name
433 * @param default_val default value to return if the property is not found
434 * @return integer value, if found, or default_val if not
436 int fdtdec_get_config_int(const void *blob, const char *prop_name,
440 * Look in the FDT for a config item with the given name
441 * and return whether it exists.
443 * @param blob FDT blob
444 * @param prop_name property name to look up
445 * @return 1, if it exists, or 0 if not
447 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
450 * Look in the FDT for a config item with the given name and return its value
453 * @param blob FDT blob
454 * @param prop_name property name to look up
455 * @returns property string, NULL on error.
457 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
460 * Look up a property in a node and return its contents in a byte
461 * array of given length. The property must have at least enough data for
462 * the array (count bytes). It may have more, but this will be ignored.
464 * @param blob FDT blob
465 * @param node node to examine
466 * @param prop_name name of property to find
467 * @param array array to fill with data
468 * @param count number of array elements
469 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
470 * or -FDT_ERR_BADLAYOUT if not enough data
472 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
473 u8 *array, int count);
476 * Look up a property in a node and return a pointer to its contents as a
477 * byte array of given length. The property must have at least enough data
478 * for the array (count bytes). It may have more, but this will be ignored.
479 * The data is not copied.
481 * @param blob FDT blob
482 * @param node node to examine
483 * @param prop_name name of property to find
484 * @param count number of array elements
485 * @return pointer to byte array if found, or NULL if the property is not
486 * found or there is not enough data
488 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
489 const char *prop_name, int count);
492 * Look up a property in a node which contains a memory region address and
493 * size. Then return a pointer to this address.
495 * The property must hold one address with a length. This is only tested on
498 * @param blob FDT blob
499 * @param node node to examine
500 * @param prop_name name of property to find
501 * @param ptrp returns pointer to region, or NULL if no address
502 * @param size returns size of region
503 * @return 0 if ok, -1 on error (propery not found)
505 int fdtdec_decode_region(const void *blob, int node,
506 const char *prop_name, void **ptrp, size_t *size);