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 */
80 /* GPIOs are numbered from 0 */
82 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */
84 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
87 /* This is the state of a GPIO pin as defined by the fdt */
88 struct fdt_gpio_state {
89 const char *name; /* name of the fdt property defining this */
90 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
91 u8 flags; /* FDT_GPIO_... flags */
94 /* This tells us whether a fdt_gpio_state record is valid or not */
95 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
98 * Read the GPIO taking into account the polarity of the pin.
100 * @param gpio pointer to the decoded gpio
101 * @return value of the gpio if successful, < 0 if unsuccessful
103 int fdtdec_get_gpio(struct fdt_gpio_state *gpio);
106 * Write the GPIO taking into account the polarity of the pin.
108 * @param gpio pointer to the decoded gpio
109 * @return 0 if successful
111 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);
114 * Find the next numbered alias for a peripheral. This is used to enumerate
115 * all the peripherals of a certain type.
117 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
118 * this function will return a pointer to the node the alias points to, and
119 * then update *upto to 1. Next time you call this function, the next node
122 * All nodes returned will match the compatible ID, as it is assumed that
123 * all peripherals use the same driver.
125 * @param blob FDT blob to use
126 * @param name Root name of alias to search for
127 * @param id Compatible ID to look for
128 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
130 int fdtdec_next_alias(const void *blob, const char *name,
131 enum fdt_compat_id id, int *upto);
134 * Find the compatible ID for a given node.
136 * Generally each node has at least one compatible string attached to it.
137 * This function looks through our list of known compatible strings and
138 * returns the corresponding ID which matches the compatible string.
140 * @param blob FDT blob to use
141 * @param node Node containing compatible string to find
142 * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
144 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
147 * Find the next compatible node for a peripheral.
149 * Do the first call with node = 0. This function will return a pointer to
150 * the next compatible node. Next time you call this function, pass the
151 * value returned, and the next node will be provided.
153 * @param blob FDT blob to use
154 * @param node Start node for search
155 * @param id Compatible ID to look for (enum fdt_compat_id)
156 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
158 int fdtdec_next_compatible(const void *blob, int node,
159 enum fdt_compat_id id);
162 * Find the next compatible subnode for a peripheral.
164 * Do the first call with node set to the parent and depth = 0. This
165 * function will return the offset of the next compatible node. Next time
166 * you call this function, pass the node value returned last time, with
167 * depth unchanged, and the next node will be provided.
169 * @param blob FDT blob to use
170 * @param node Start node for search
171 * @param id Compatible ID to look for (enum fdt_compat_id)
172 * @param depthp Current depth (set to 0 before first call)
173 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
175 int fdtdec_next_compatible_subnode(const void *blob, int node,
176 enum fdt_compat_id id, int *depthp);
179 * Look up an address property in a node and return it as an address.
180 * The property must hold either one address with no trailing data or
181 * one address with a length. This is only tested on 32-bit machines.
183 * @param blob FDT blob
184 * @param node node to examine
185 * @param prop_name name of property to find
186 * @return address, if found, or FDT_ADDR_T_NONE if not
188 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
189 const char *prop_name);
192 * Look up a 32-bit integer property in a node and return it. The property
193 * must have at least 4 bytes of data. The value of the first cell is
196 * @param blob FDT blob
197 * @param node node to examine
198 * @param prop_name name of property to find
199 * @param default_val default value to return if the property is not found
200 * @return integer value, if found, or default_val if not
202 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
206 * Look up a 64-bit integer property in a node and return it. The property
207 * must have at least 8 bytes of data (2 cells). The first two cells are
208 * concatenated to form a 8 bytes value, where the first cell is top half and
209 * the second cell is bottom half.
211 * @param blob FDT blob
212 * @param node node to examine
213 * @param prop_name name of property to find
214 * @param default_val default value to return if the property is not found
215 * @return integer value, if found, or default_val if not
217 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
218 uint64_t default_val);
221 * Checks whether a node is enabled.
222 * This looks for a 'status' property. If this exists, then returns 1 if
223 * the status is 'ok' and 0 otherwise. If there is no status property,
224 * it returns 1 on the assumption that anything mentioned should be enabled
227 * @param blob FDT blob
228 * @param node node to examine
229 * @return integer value 0 (not enabled) or 1 (enabled)
231 int fdtdec_get_is_enabled(const void *blob, int node);
234 * Make sure we have a valid fdt available to control U-Boot.
236 * If not, a message is printed to the console if the console is ready.
238 * @return 0 if all ok, -1 if not
240 int fdtdec_prepare_fdt(void);
243 * Checks that we have a valid fdt available to control U-Boot.
245 * However, if not then for the moment nothing is done, since this function
246 * is called too early to panic().
250 int fdtdec_check_fdt(void);
253 * Find the nodes for a peripheral and return a list of them in the correct
254 * order. This is used to enumerate all the peripherals of a certain type.
256 * To use this, optionally set up a /aliases node with alias properties for
257 * a peripheral. For example, for usb you could have:
260 * usb0 = "/ehci@c5008000";
261 * usb1 = "/ehci@c5000000";
264 * Pass "usb" as the name to this function and will return a list of two
265 * nodes offsets: /ehci@c5008000 and ehci@c5000000.
267 * All nodes returned will match the compatible ID, as it is assumed that
268 * all peripherals use the same driver.
270 * If no alias node is found, then the node list will be returned in the
271 * order found in the fdt. If the aliases mention a node which doesn't
272 * exist, then this will be ignored. If nodes are found with no aliases,
273 * they will be added in any order.
275 * If there is a gap in the aliases, then this function return a 0 node at
276 * that position. The return value will also count these gaps.
278 * This function checks node properties and will not return nodes which are
279 * marked disabled (status = "disabled").
281 * @param blob FDT blob to use
282 * @param name Root name of alias to search for
283 * @param id Compatible ID to look for
284 * @param node_list Place to put list of found nodes
285 * @param maxcount Maximum number of nodes to find
286 * @return number of nodes found on success, FTD_ERR_... on error
288 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
289 enum fdt_compat_id id, int *node_list, int maxcount);
292 * This function is similar to fdtdec_find_aliases_for_id() except that it
293 * adds to the node_list that is passed in. Any 0 elements are considered
294 * available for allocation - others are considered already used and are
297 * You can use this by calling fdtdec_find_aliases_for_id() with an
298 * uninitialised array, then setting the elements that are returned to -1,
299 * say, then calling this function, perhaps with a different compat id.
300 * Any elements you get back that are >0 are new nodes added by the call
303 * Note that if you have some nodes with aliases and some without, you are
304 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
305 * one compat_id may fill in positions for which you have aliases defined
306 * for another compat_id. When you later call *this* function with the second
307 * compat_id, the alias positions may already be used. A debug warning may
308 * be generated in this case, but it is safest to define aliases for all
309 * nodes when you care about the ordering.
311 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
312 enum fdt_compat_id id, int *node_list, int maxcount);
315 * Get the name for a compatible ID
317 * @param id Compatible ID to look for
318 * @return compatible string for that id
320 const char *fdtdec_get_compatible(enum fdt_compat_id id);
322 /* Look up a phandle and follow it to its node. Then return the offset
325 * @param blob FDT blob
326 * @param node node to examine
327 * @param prop_name name of property to find
328 * @return node offset if found, -ve error code on error
330 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
333 * Look up a property in a node and return its contents in an integer
334 * array of given length. The property must have at least enough data for
335 * the array (4*count bytes). It may have more, but this will be ignored.
337 * @param blob FDT blob
338 * @param node node to examine
339 * @param prop_name name of property to find
340 * @param array array to fill with data
341 * @param count number of array elements
342 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
343 * or -FDT_ERR_BADLAYOUT if not enough data
345 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
346 u32 *array, int count);
349 * Look up a property in a node and return a pointer to its contents as a
350 * unsigned int array of given length. The property must have at least enough
351 * data for the array ('count' cells). It may have more, but this will be
352 * ignored. The data is not copied.
354 * Note that you must access elements of the array with fdt32_to_cpu(),
355 * since the elements will be big endian even on a little endian machine.
357 * @param blob FDT blob
358 * @param node node to examine
359 * @param prop_name name of property to find
360 * @param count number of array elements
361 * @return pointer to array if found, or NULL if the property is not
362 * found or there is not enough data
364 const u32 *fdtdec_locate_array(const void *blob, int node,
365 const char *prop_name, int count);
368 * Look up a boolean property in a node and return it.
370 * A boolean properly is true if present in the device tree and false if not
371 * present, regardless of its value.
373 * @param blob FDT blob
374 * @param node node to examine
375 * @param prop_name name of property to find
376 * @return 1 if the properly is present; 0 if it isn't present
378 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
381 * Decode a single GPIOs from an FDT.
383 * If the property is not found, then the GPIO structure will still be
384 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
385 * provide optional GPIOs.
387 * @param blob FDT blob to use
388 * @param node Node to look at
389 * @param prop_name Node property name
390 * @param gpio gpio elements to fill from FDT
391 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
393 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
394 struct fdt_gpio_state *gpio);
397 * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
400 * @param blob FDT blob to use
401 * @param node Node to look at
402 * @param prop_name Node property name
403 * @param gpio Array of gpio elements to fill from FDT. This will be
404 * untouched if either 0 or an error is returned
405 * @param max_count Maximum number of elements allowed
406 * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
407 * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
409 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name,
410 struct fdt_gpio_state *gpio, int max_count);
413 * Set up a GPIO pin according to the provided gpio information. At present this
414 * just requests the GPIO.
416 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
417 * deal with optional GPIOs.
419 * @param gpio GPIO info to use for set up
420 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
422 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
425 * Look in the FDT for a config item with the given name and return its value
426 * as a 32-bit integer. The property must have at least 4 bytes of data. The
427 * value of the first cell is returned.
429 * @param blob FDT blob to use
430 * @param prop_name Node property name
431 * @param default_val default value to return if the property is not found
432 * @return integer value, if found, or default_val if not
434 int fdtdec_get_config_int(const void *blob, const char *prop_name,
438 * Look in the FDT for a config item with the given name
439 * and return whether it exists.
441 * @param blob FDT blob
442 * @param prop_name property name to look up
443 * @return 1, if it exists, or 0 if not
445 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
448 * Look in the FDT for a config item with the given name and return its value
451 * @param blob FDT blob
452 * @param prop_name property name to look up
453 * @returns property string, NULL on error.
455 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
458 * Look up a property in a node and return its contents in a byte
459 * array of given length. The property must have at least enough data for
460 * the array (count bytes). It may have more, but this will be ignored.
462 * @param blob FDT blob
463 * @param node node to examine
464 * @param prop_name name of property to find
465 * @param array array to fill with data
466 * @param count number of array elements
467 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
468 * or -FDT_ERR_BADLAYOUT if not enough data
470 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
471 u8 *array, int count);
474 * Look up a property in a node and return a pointer to its contents as a
475 * byte array of given length. The property must have at least enough data
476 * for the array (count bytes). It may have more, but this will be ignored.
477 * The data is not copied.
479 * @param blob FDT blob
480 * @param node node to examine
481 * @param prop_name name of property to find
482 * @param count number of array elements
483 * @return pointer to byte array if found, or NULL if the property is not
484 * found or there is not enough data
486 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
487 const char *prop_name, int count);
490 * Look up a property in a node which contains a memory region address and
491 * size. Then return a pointer to this address.
493 * The property must hold one address with a length. This is only tested on
496 * @param blob FDT blob
497 * @param node node to examine
498 * @param prop_name name of property to find
499 * @param ptrp returns pointer to region, or NULL if no address
500 * @param size returns size of region
501 * @return 0 if ok, -1 on error (propery not found)
503 int fdtdec_decode_region(const void *blob, int node,
504 const char *prop_name, void **ptrp, size_t *size);