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_NVIDIA_TEGRA20_SFLASH, /* Tegra 2 SPI flash controller */
74 COMPAT_SMSC_LAN9215, /* SMSC 10/100 Ethernet LAN9215 */
75 COMPAT_SAMSUNG_EXYNOS5_SROMC, /* Exynos5 SROMC */
76 COMPAT_SAMSUNG_S3C2440_I2C, /* Exynos I2C Controller */
77 COMPAT_SAMSUNG_EXYNOS5_SOUND, /* Exynos Sound */
78 COMPAT_WOLFSON_WM8994_CODEC, /* Wolfson WM8994 Sound Codec */
79 COMPAT_SAMSUNG_EXYNOS_SPI, /* Exynos SPI */
80 COMPAT_SAMSUNG_EXYNOS_EHCI, /* Exynos EHCI controller */
81 COMPAT_SAMSUNG_EXYNOS_USB_PHY, /* Exynos phy controller for usb2.0 */
82 COMPAT_MAXIM_MAX77686_PMIC, /* MAX77686 PMIC */
87 /* GPIOs are numbered from 0 */
89 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */
91 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
94 /* This is the state of a GPIO pin as defined by the fdt */
95 struct fdt_gpio_state {
96 const char *name; /* name of the fdt property defining this */
97 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
98 u8 flags; /* FDT_GPIO_... flags */
101 /* This tells us whether a fdt_gpio_state record is valid or not */
102 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
105 * Read the GPIO taking into account the polarity of the pin.
107 * @param gpio pointer to the decoded gpio
108 * @return value of the gpio if successful, < 0 if unsuccessful
110 int fdtdec_get_gpio(struct fdt_gpio_state *gpio);
113 * Write the GPIO taking into account the polarity of the pin.
115 * @param gpio pointer to the decoded gpio
116 * @return 0 if successful
118 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);
121 * Find the next numbered alias for a peripheral. This is used to enumerate
122 * all the peripherals of a certain type.
124 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
125 * this function will return a pointer to the node the alias points to, and
126 * then update *upto to 1. Next time you call this function, the next node
129 * All nodes returned will match the compatible ID, as it is assumed that
130 * all peripherals use the same driver.
132 * @param blob FDT blob to use
133 * @param name Root name of alias to search for
134 * @param id Compatible ID to look for
135 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
137 int fdtdec_next_alias(const void *blob, const char *name,
138 enum fdt_compat_id id, int *upto);
141 * Find the compatible ID for a given node.
143 * Generally each node has at least one compatible string attached to it.
144 * This function looks through our list of known compatible strings and
145 * returns the corresponding ID which matches the compatible string.
147 * @param blob FDT blob to use
148 * @param node Node containing compatible string to find
149 * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
151 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
154 * Find the next compatible node for a peripheral.
156 * Do the first call with node = 0. This function will return a pointer to
157 * the next compatible node. Next time you call this function, pass the
158 * value returned, and the next node will be provided.
160 * @param blob FDT blob to use
161 * @param node Start node for search
162 * @param id Compatible ID to look for (enum fdt_compat_id)
163 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
165 int fdtdec_next_compatible(const void *blob, int node,
166 enum fdt_compat_id id);
169 * Find the next compatible subnode for a peripheral.
171 * Do the first call with node set to the parent and depth = 0. This
172 * function will return the offset of the next compatible node. Next time
173 * you call this function, pass the node value returned last time, with
174 * depth unchanged, and the next node will be provided.
176 * @param blob FDT blob to use
177 * @param node Start node for search
178 * @param id Compatible ID to look for (enum fdt_compat_id)
179 * @param depthp Current depth (set to 0 before first call)
180 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
182 int fdtdec_next_compatible_subnode(const void *blob, int node,
183 enum fdt_compat_id id, int *depthp);
186 * Look up an address property in a node and return it as an address.
187 * The property must hold either one address with no trailing data or
188 * one address with a length. This is only tested on 32-bit machines.
190 * @param blob FDT blob
191 * @param node node to examine
192 * @param prop_name name of property to find
193 * @return address, if found, or FDT_ADDR_T_NONE if not
195 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
196 const char *prop_name);
199 * Look up a 32-bit integer property in a node and return it. The property
200 * must have at least 4 bytes of data. The value of the first cell is
203 * @param blob FDT blob
204 * @param node node to examine
205 * @param prop_name name of property to find
206 * @param default_val default value to return if the property is not found
207 * @return integer value, if found, or default_val if not
209 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
213 * Look up a 64-bit integer property in a node and return it. The property
214 * must have at least 8 bytes of data (2 cells). The first two cells are
215 * concatenated to form a 8 bytes value, where the first cell is top half and
216 * the second cell is bottom half.
218 * @param blob FDT blob
219 * @param node node to examine
220 * @param prop_name name of property to find
221 * @param default_val default value to return if the property is not found
222 * @return integer value, if found, or default_val if not
224 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
225 uint64_t default_val);
228 * Checks whether a node is enabled.
229 * This looks for a 'status' property. If this exists, then returns 1 if
230 * the status is 'ok' and 0 otherwise. If there is no status property,
231 * it returns 1 on the assumption that anything mentioned should be enabled
234 * @param blob FDT blob
235 * @param node node to examine
236 * @return integer value 0 (not enabled) or 1 (enabled)
238 int fdtdec_get_is_enabled(const void *blob, int node);
241 * Make sure we have a valid fdt available to control U-Boot.
243 * If not, a message is printed to the console if the console is ready.
245 * @return 0 if all ok, -1 if not
247 int fdtdec_prepare_fdt(void);
250 * Checks that we have a valid fdt available to control U-Boot.
252 * However, if not then for the moment nothing is done, since this function
253 * is called too early to panic().
257 int fdtdec_check_fdt(void);
260 * Find the nodes for a peripheral and return a list of them in the correct
261 * order. This is used to enumerate all the peripherals of a certain type.
263 * To use this, optionally set up a /aliases node with alias properties for
264 * a peripheral. For example, for usb you could have:
267 * usb0 = "/ehci@c5008000";
268 * usb1 = "/ehci@c5000000";
271 * Pass "usb" as the name to this function and will return a list of two
272 * nodes offsets: /ehci@c5008000 and ehci@c5000000.
274 * All nodes returned will match the compatible ID, as it is assumed that
275 * all peripherals use the same driver.
277 * If no alias node is found, then the node list will be returned in the
278 * order found in the fdt. If the aliases mention a node which doesn't
279 * exist, then this will be ignored. If nodes are found with no aliases,
280 * they will be added in any order.
282 * If there is a gap in the aliases, then this function return a 0 node at
283 * that position. The return value will also count these gaps.
285 * This function checks node properties and will not return nodes which are
286 * marked disabled (status = "disabled").
288 * @param blob FDT blob to use
289 * @param name Root name of alias to search for
290 * @param id Compatible ID to look for
291 * @param node_list Place to put list of found nodes
292 * @param maxcount Maximum number of nodes to find
293 * @return number of nodes found on success, FTD_ERR_... on error
295 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
296 enum fdt_compat_id id, int *node_list, int maxcount);
299 * This function is similar to fdtdec_find_aliases_for_id() except that it
300 * adds to the node_list that is passed in. Any 0 elements are considered
301 * available for allocation - others are considered already used and are
304 * You can use this by calling fdtdec_find_aliases_for_id() with an
305 * uninitialised array, then setting the elements that are returned to -1,
306 * say, then calling this function, perhaps with a different compat id.
307 * Any elements you get back that are >0 are new nodes added by the call
310 * Note that if you have some nodes with aliases and some without, you are
311 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
312 * one compat_id may fill in positions for which you have aliases defined
313 * for another compat_id. When you later call *this* function with the second
314 * compat_id, the alias positions may already be used. A debug warning may
315 * be generated in this case, but it is safest to define aliases for all
316 * nodes when you care about the ordering.
318 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
319 enum fdt_compat_id id, int *node_list, int maxcount);
322 * Get the name for a compatible ID
324 * @param id Compatible ID to look for
325 * @return compatible string for that id
327 const char *fdtdec_get_compatible(enum fdt_compat_id id);
329 /* Look up a phandle and follow it to its node. Then return the offset
332 * @param blob FDT blob
333 * @param node node to examine
334 * @param prop_name name of property to find
335 * @return node offset if found, -ve error code on error
337 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
340 * Look up a property in a node and return its contents in an integer
341 * array of given length. The property must have at least enough data for
342 * the array (4*count bytes). It may have more, but this will be ignored.
344 * @param blob FDT blob
345 * @param node node to examine
346 * @param prop_name name of property to find
347 * @param array array to fill with data
348 * @param count number of array elements
349 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
350 * or -FDT_ERR_BADLAYOUT if not enough data
352 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
353 u32 *array, int count);
356 * Look up a property in a node and return a pointer to its contents as a
357 * unsigned int array of given length. The property must have at least enough
358 * data for the array ('count' cells). It may have more, but this will be
359 * ignored. The data is not copied.
361 * Note that you must access elements of the array with fdt32_to_cpu(),
362 * since the elements will be big endian even on a little endian machine.
364 * @param blob FDT blob
365 * @param node node to examine
366 * @param prop_name name of property to find
367 * @param count number of array elements
368 * @return pointer to array if found, or NULL if the property is not
369 * found or there is not enough data
371 const u32 *fdtdec_locate_array(const void *blob, int node,
372 const char *prop_name, int count);
375 * Look up a boolean property in a node and return it.
377 * A boolean properly is true if present in the device tree and false if not
378 * present, regardless of its value.
380 * @param blob FDT blob
381 * @param node node to examine
382 * @param prop_name name of property to find
383 * @return 1 if the properly is present; 0 if it isn't present
385 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
388 * Decode a single GPIOs from an FDT.
390 * If the property is not found, then the GPIO structure will still be
391 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
392 * provide optional GPIOs.
394 * @param blob FDT blob to use
395 * @param node Node to look at
396 * @param prop_name Node property name
397 * @param gpio gpio elements to fill from FDT
398 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
400 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
401 struct fdt_gpio_state *gpio);
404 * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
407 * @param blob FDT blob to use
408 * @param node Node to look at
409 * @param prop_name Node property name
410 * @param gpio Array of gpio elements to fill from FDT. This will be
411 * untouched if either 0 or an error is returned
412 * @param max_count Maximum number of elements allowed
413 * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
414 * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
416 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name,
417 struct fdt_gpio_state *gpio, int max_count);
420 * Set up a GPIO pin according to the provided gpio information. At present this
421 * just requests the GPIO.
423 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
424 * deal with optional GPIOs.
426 * @param gpio GPIO info to use for set up
427 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
429 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
432 * Look in the FDT for a config item with the given name and return its value
433 * as a 32-bit integer. The property must have at least 4 bytes of data. The
434 * value of the first cell is returned.
436 * @param blob FDT blob to use
437 * @param prop_name Node property name
438 * @param default_val default value to return if the property is not found
439 * @return integer value, if found, or default_val if not
441 int fdtdec_get_config_int(const void *blob, const char *prop_name,
445 * Look in the FDT for a config item with the given name
446 * and return whether it exists.
448 * @param blob FDT blob
449 * @param prop_name property name to look up
450 * @return 1, if it exists, or 0 if not
452 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
455 * Look in the FDT for a config item with the given name and return its value
458 * @param blob FDT blob
459 * @param prop_name property name to look up
460 * @returns property string, NULL on error.
462 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
465 * Look up a property in a node and return its contents in a byte
466 * array of given length. The property must have at least enough data for
467 * the array (count bytes). It may have more, but this will be ignored.
469 * @param blob FDT blob
470 * @param node node to examine
471 * @param prop_name name of property to find
472 * @param array array to fill with data
473 * @param count number of array elements
474 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
475 * or -FDT_ERR_BADLAYOUT if not enough data
477 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
478 u8 *array, int count);
481 * Look up a property in a node and return a pointer to its contents as a
482 * byte array of given length. The property must have at least enough data
483 * for the array (count bytes). It may have more, but this will be ignored.
484 * The data is not copied.
486 * @param blob FDT blob
487 * @param node node to examine
488 * @param prop_name name of property to find
489 * @param count number of array elements
490 * @return pointer to byte array if found, or NULL if the property is not
491 * found or there is not enough data
493 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
494 const char *prop_name, int count);
497 * Look up a property in a node which contains a memory region address and
498 * size. Then return a pointer to this address.
500 * The property must hold one address with a length. This is only tested on
503 * @param blob FDT blob
504 * @param node node to examine
505 * @param prop_name name of property to find
506 * @param ptrp returns pointer to region, or NULL if no address
507 * @param size returns size of region
508 * @return 0 if ok, -1 on error (propery not found)
510 int fdtdec_decode_region(const void *blob, int node,
511 const char *prop_name, void **ptrp, size_t *size);