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 */
79 /* GPIOs are numbered from 0 */
81 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */
83 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
86 /* This is the state of a GPIO pin as defined by the fdt */
87 struct fdt_gpio_state {
88 const char *name; /* name of the fdt property defining this */
89 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
90 u8 flags; /* FDT_GPIO_... flags */
93 /* This tells us whether a fdt_gpio_state record is valid or not */
94 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
97 * Read the GPIO taking into account the polarity of the pin.
99 * @param gpio pointer to the decoded gpio
100 * @return value of the gpio if successful, < 0 if unsuccessful
102 int fdtdec_get_gpio(struct fdt_gpio_state *gpio);
105 * Write the GPIO taking into account the polarity of the pin.
107 * @param gpio pointer to the decoded gpio
108 * @return 0 if successful
110 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);
113 * Find the next numbered alias for a peripheral. This is used to enumerate
114 * all the peripherals of a certain type.
116 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
117 * this function will return a pointer to the node the alias points to, and
118 * then update *upto to 1. Next time you call this function, the next node
121 * All nodes returned will match the compatible ID, as it is assumed that
122 * all peripherals use the same driver.
124 * @param blob FDT blob to use
125 * @param name Root name of alias to search for
126 * @param id Compatible ID to look for
127 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
129 int fdtdec_next_alias(const void *blob, const char *name,
130 enum fdt_compat_id id, int *upto);
133 * Find the compatible ID for a given node.
135 * Generally each node has at least one compatible string attached to it.
136 * This function looks through our list of known compatible strings and
137 * returns the corresponding ID which matches the compatible string.
139 * @param blob FDT blob to use
140 * @param node Node containing compatible string to find
141 * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
143 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
146 * Find the next compatible node for a peripheral.
148 * Do the first call with node = 0. This function will return a pointer to
149 * the next compatible node. Next time you call this function, pass the
150 * value returned, and the next node will be provided.
152 * @param blob FDT blob to use
153 * @param node Start node for search
154 * @param id Compatible ID to look for (enum fdt_compat_id)
155 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
157 int fdtdec_next_compatible(const void *blob, int node,
158 enum fdt_compat_id id);
161 * Find the next compatible subnode for a peripheral.
163 * Do the first call with node set to the parent and depth = 0. This
164 * function will return the offset of the next compatible node. Next time
165 * you call this function, pass the node value returned last time, with
166 * depth unchanged, and the next node will be provided.
168 * @param blob FDT blob to use
169 * @param node Start node for search
170 * @param id Compatible ID to look for (enum fdt_compat_id)
171 * @param depthp Current depth (set to 0 before first call)
172 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
174 int fdtdec_next_compatible_subnode(const void *blob, int node,
175 enum fdt_compat_id id, int *depthp);
178 * Look up an address property in a node and return it as an address.
179 * The property must hold either one address with no trailing data or
180 * one address with a length. This is only tested on 32-bit machines.
182 * @param blob FDT blob
183 * @param node node to examine
184 * @param prop_name name of property to find
185 * @return address, if found, or FDT_ADDR_T_NONE if not
187 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
188 const char *prop_name);
191 * Look up a 32-bit integer property in a node and return it. The property
192 * must have at least 4 bytes of data. The value of the first cell is
195 * @param blob FDT blob
196 * @param node node to examine
197 * @param prop_name name of property to find
198 * @param default_val default value to return if the property is not found
199 * @return integer value, if found, or default_val if not
201 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
205 * Look up a 64-bit integer property in a node and return it. The property
206 * must have at least 8 bytes of data (2 cells). The first two cells are
207 * concatenated to form a 8 bytes value, where the first cell is top half and
208 * the second cell is bottom half.
210 * @param blob FDT blob
211 * @param node node to examine
212 * @param prop_name name of property to find
213 * @param default_val default value to return if the property is not found
214 * @return integer value, if found, or default_val if not
216 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
217 uint64_t default_val);
220 * Checks whether a node is enabled.
221 * This looks for a 'status' property. If this exists, then returns 1 if
222 * the status is 'ok' and 0 otherwise. If there is no status property,
223 * it returns 1 on the assumption that anything mentioned should be enabled
226 * @param blob FDT blob
227 * @param node node to examine
228 * @return integer value 0 (not enabled) or 1 (enabled)
230 int fdtdec_get_is_enabled(const void *blob, int node);
233 * Make sure we have a valid fdt available to control U-Boot.
235 * If not, a message is printed to the console if the console is ready.
237 * @return 0 if all ok, -1 if not
239 int fdtdec_prepare_fdt(void);
242 * Checks that we have a valid fdt available to control U-Boot.
244 * However, if not then for the moment nothing is done, since this function
245 * is called too early to panic().
249 int fdtdec_check_fdt(void);
252 * Find the nodes for a peripheral and return a list of them in the correct
253 * order. This is used to enumerate all the peripherals of a certain type.
255 * To use this, optionally set up a /aliases node with alias properties for
256 * a peripheral. For example, for usb you could have:
259 * usb0 = "/ehci@c5008000";
260 * usb1 = "/ehci@c5000000";
263 * Pass "usb" as the name to this function and will return a list of two
264 * nodes offsets: /ehci@c5008000 and ehci@c5000000.
266 * All nodes returned will match the compatible ID, as it is assumed that
267 * all peripherals use the same driver.
269 * If no alias node is found, then the node list will be returned in the
270 * order found in the fdt. If the aliases mention a node which doesn't
271 * exist, then this will be ignored. If nodes are found with no aliases,
272 * they will be added in any order.
274 * If there is a gap in the aliases, then this function return a 0 node at
275 * that position. The return value will also count these gaps.
277 * This function checks node properties and will not return nodes which are
278 * marked disabled (status = "disabled").
280 * @param blob FDT blob to use
281 * @param name Root name of alias to search for
282 * @param id Compatible ID to look for
283 * @param node_list Place to put list of found nodes
284 * @param maxcount Maximum number of nodes to find
285 * @return number of nodes found on success, FTD_ERR_... on error
287 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
288 enum fdt_compat_id id, int *node_list, int maxcount);
291 * This function is similar to fdtdec_find_aliases_for_id() except that it
292 * adds to the node_list that is passed in. Any 0 elements are considered
293 * available for allocation - others are considered already used and are
296 * You can use this by calling fdtdec_find_aliases_for_id() with an
297 * uninitialised array, then setting the elements that are returned to -1,
298 * say, then calling this function, perhaps with a different compat id.
299 * Any elements you get back that are >0 are new nodes added by the call
302 * Note that if you have some nodes with aliases and some without, you are
303 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
304 * one compat_id may fill in positions for which you have aliases defined
305 * for another compat_id. When you later call *this* function with the second
306 * compat_id, the alias positions may already be used. A debug warning may
307 * be generated in this case, but it is safest to define aliases for all
308 * nodes when you care about the ordering.
310 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
311 enum fdt_compat_id id, int *node_list, int maxcount);
314 * Get the name for a compatible ID
316 * @param id Compatible ID to look for
317 * @return compatible string for that id
319 const char *fdtdec_get_compatible(enum fdt_compat_id id);
321 /* Look up a phandle and follow it to its node. Then return the offset
324 * @param blob FDT blob
325 * @param node node to examine
326 * @param prop_name name of property to find
327 * @return node offset if found, -ve error code on error
329 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
332 * Look up a property in a node and return its contents in an integer
333 * array of given length. The property must have at least enough data for
334 * the array (4*count bytes). It may have more, but this will be ignored.
336 * @param blob FDT blob
337 * @param node node to examine
338 * @param prop_name name of property to find
339 * @param array array to fill with data
340 * @param count number of array elements
341 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
342 * or -FDT_ERR_BADLAYOUT if not enough data
344 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
345 u32 *array, int count);
348 * Look up a property in a node and return a pointer to its contents as a
349 * unsigned int array of given length. The property must have at least enough
350 * data for the array ('count' cells). It may have more, but this will be
351 * ignored. The data is not copied.
353 * Note that you must access elements of the array with fdt32_to_cpu(),
354 * since the elements will be big endian even on a little endian machine.
356 * @param blob FDT blob
357 * @param node node to examine
358 * @param prop_name name of property to find
359 * @param count number of array elements
360 * @return pointer to array if found, or NULL if the property is not
361 * found or there is not enough data
363 const u32 *fdtdec_locate_array(const void *blob, int node,
364 const char *prop_name, int count);
367 * Look up a boolean property in a node and return it.
369 * A boolean properly is true if present in the device tree and false if not
370 * present, regardless of its value.
372 * @param blob FDT blob
373 * @param node node to examine
374 * @param prop_name name of property to find
375 * @return 1 if the properly is present; 0 if it isn't present
377 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
380 * Decode a single GPIOs from an FDT.
382 * If the property is not found, then the GPIO structure will still be
383 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
384 * provide optional GPIOs.
386 * @param blob FDT blob to use
387 * @param node Node to look at
388 * @param prop_name Node property name
389 * @param gpio gpio elements to fill from FDT
390 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
392 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
393 struct fdt_gpio_state *gpio);
396 * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
399 * @param blob FDT blob to use
400 * @param node Node to look at
401 * @param prop_name Node property name
402 * @param gpio Array of gpio elements to fill from FDT. This will be
403 * untouched if either 0 or an error is returned
404 * @param max_count Maximum number of elements allowed
405 * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
406 * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
408 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name,
409 struct fdt_gpio_state *gpio, int max_count);
412 * Set up a GPIO pin according to the provided gpio information. At present this
413 * just requests the GPIO.
415 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
416 * deal with optional GPIOs.
418 * @param gpio GPIO info to use for set up
419 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
421 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
424 * Look in the FDT for a config item with the given name and return its value
425 * as a 32-bit integer. The property must have at least 4 bytes of data. The
426 * value of the first cell is returned.
428 * @param blob FDT blob to use
429 * @param prop_name Node property name
430 * @param default_val default value to return if the property is not found
431 * @return integer value, if found, or default_val if not
433 int fdtdec_get_config_int(const void *blob, const char *prop_name,
437 * Look in the FDT for a config item with the given name
438 * and return whether it exists.
440 * @param blob FDT blob
441 * @param prop_name property name to look up
442 * @return 1, if it exists, or 0 if not
444 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
447 * Look in the FDT for a config item with the given name and return its value
450 * @param blob FDT blob
451 * @param prop_name property name to look up
452 * @returns property string, NULL on error.
454 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
457 * Look up a property in a node and return its contents in a byte
458 * array of given length. The property must have at least enough data for
459 * the array (count bytes). It may have more, but this will be ignored.
461 * @param blob FDT blob
462 * @param node node to examine
463 * @param prop_name name of property to find
464 * @param array array to fill with data
465 * @param count number of array elements
466 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
467 * or -FDT_ERR_BADLAYOUT if not enough data
469 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
470 u8 *array, int count);
473 * Look up a property in a node and return a pointer to its contents as a
474 * byte array of given length. The property must have at least enough data
475 * for the array (count bytes). It may have more, but this will be ignored.
476 * The data is not copied.
478 * @param blob FDT blob
479 * @param node node to examine
480 * @param prop_name name of property to find
481 * @param count number of array elements
482 * @return pointer to byte array if found, or NULL if the property is not
483 * found or there is not enough data
485 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
486 const char *prop_name, int count);
489 * Look up a property in a node which contains a memory region address and
490 * size. Then return a pointer to this address.
492 * The property must hold one address with a length. This is only tested on
495 * @param blob FDT blob
496 * @param node node to examine
497 * @param prop_name name of property to find
498 * @param ptrp returns pointer to region, or NULL if no address
499 * @param size returns size of region
500 * @return 0 if ok, -1 on error (propery not found)
502 int fdtdec_decode_region(const void *blob, int node,
503 const char *prop_name, void **ptrp, size_t *size);