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 */
78 COMPAT_SAMSUNG_EXYNOS_SPI, /* Exynos SPI */
79 COMPAT_SAMSUNG_EXYNOS_EHCI, /* Exynos EHCI controller */
80 COMPAT_SAMSUNG_EXYNOS_USB_PHY, /* Exynos phy controller for usb2.0 */
85 /* GPIOs are numbered from 0 */
87 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */
89 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
92 /* This is the state of a GPIO pin as defined by the fdt */
93 struct fdt_gpio_state {
94 const char *name; /* name of the fdt property defining this */
95 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
96 u8 flags; /* FDT_GPIO_... flags */
99 /* This tells us whether a fdt_gpio_state record is valid or not */
100 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
103 * Read the GPIO taking into account the polarity of the pin.
105 * @param gpio pointer to the decoded gpio
106 * @return value of the gpio if successful, < 0 if unsuccessful
108 int fdtdec_get_gpio(struct fdt_gpio_state *gpio);
111 * Write the GPIO taking into account the polarity of the pin.
113 * @param gpio pointer to the decoded gpio
114 * @return 0 if successful
116 int fdtdec_set_gpio(struct fdt_gpio_state *gpio, int val);
119 * Find the next numbered alias for a peripheral. This is used to enumerate
120 * all the peripherals of a certain type.
122 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
123 * this function will return a pointer to the node the alias points to, and
124 * then update *upto to 1. Next time you call this function, the next node
127 * All nodes returned will match the compatible ID, as it is assumed that
128 * all peripherals use the same driver.
130 * @param blob FDT blob to use
131 * @param name Root name of alias to search for
132 * @param id Compatible ID to look for
133 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
135 int fdtdec_next_alias(const void *blob, const char *name,
136 enum fdt_compat_id id, int *upto);
139 * Find the compatible ID for a given node.
141 * Generally each node has at least one compatible string attached to it.
142 * This function looks through our list of known compatible strings and
143 * returns the corresponding ID which matches the compatible string.
145 * @param blob FDT blob to use
146 * @param node Node containing compatible string to find
147 * @return compatible ID, or COMPAT_UNKNOWN if we cannot find a match
149 enum fdt_compat_id fdtdec_lookup(const void *blob, int node);
152 * Find the next compatible node for a peripheral.
154 * Do the first call with node = 0. This function will return a pointer to
155 * the next compatible node. Next time you call this function, pass the
156 * value returned, and the next node will be provided.
158 * @param blob FDT blob to use
159 * @param node Start node for search
160 * @param id Compatible ID to look for (enum fdt_compat_id)
161 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
163 int fdtdec_next_compatible(const void *blob, int node,
164 enum fdt_compat_id id);
167 * Find the next compatible subnode for a peripheral.
169 * Do the first call with node set to the parent and depth = 0. This
170 * function will return the offset of the next compatible node. Next time
171 * you call this function, pass the node value returned last time, with
172 * depth unchanged, and the next node will be provided.
174 * @param blob FDT blob to use
175 * @param node Start node for search
176 * @param id Compatible ID to look for (enum fdt_compat_id)
177 * @param depthp Current depth (set to 0 before first call)
178 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
180 int fdtdec_next_compatible_subnode(const void *blob, int node,
181 enum fdt_compat_id id, int *depthp);
184 * Look up an address property in a node and return it as an address.
185 * The property must hold either one address with no trailing data or
186 * one address with a length. This is only tested on 32-bit machines.
188 * @param blob FDT blob
189 * @param node node to examine
190 * @param prop_name name of property to find
191 * @return address, if found, or FDT_ADDR_T_NONE if not
193 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
194 const char *prop_name);
197 * Look up a 32-bit integer property in a node and return it. The property
198 * must have at least 4 bytes of data. The value of the first cell is
201 * @param blob FDT blob
202 * @param node node to examine
203 * @param prop_name name of property to find
204 * @param default_val default value to return if the property is not found
205 * @return integer value, if found, or default_val if not
207 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
211 * Look up a 64-bit integer property in a node and return it. The property
212 * must have at least 8 bytes of data (2 cells). The first two cells are
213 * concatenated to form a 8 bytes value, where the first cell is top half and
214 * the second cell is bottom half.
216 * @param blob FDT blob
217 * @param node node to examine
218 * @param prop_name name of property to find
219 * @param default_val default value to return if the property is not found
220 * @return integer value, if found, or default_val if not
222 uint64_t fdtdec_get_uint64(const void *blob, int node, const char *prop_name,
223 uint64_t default_val);
226 * Checks whether a node is enabled.
227 * This looks for a 'status' property. If this exists, then returns 1 if
228 * the status is 'ok' and 0 otherwise. If there is no status property,
229 * it returns 1 on the assumption that anything mentioned should be enabled
232 * @param blob FDT blob
233 * @param node node to examine
234 * @return integer value 0 (not enabled) or 1 (enabled)
236 int fdtdec_get_is_enabled(const void *blob, int node);
239 * Make sure we have a valid fdt available to control U-Boot.
241 * If not, a message is printed to the console if the console is ready.
243 * @return 0 if all ok, -1 if not
245 int fdtdec_prepare_fdt(void);
248 * Checks that we have a valid fdt available to control U-Boot.
250 * However, if not then for the moment nothing is done, since this function
251 * is called too early to panic().
255 int fdtdec_check_fdt(void);
258 * Find the nodes for a peripheral and return a list of them in the correct
259 * order. This is used to enumerate all the peripherals of a certain type.
261 * To use this, optionally set up a /aliases node with alias properties for
262 * a peripheral. For example, for usb you could have:
265 * usb0 = "/ehci@c5008000";
266 * usb1 = "/ehci@c5000000";
269 * Pass "usb" as the name to this function and will return a list of two
270 * nodes offsets: /ehci@c5008000 and ehci@c5000000.
272 * All nodes returned will match the compatible ID, as it is assumed that
273 * all peripherals use the same driver.
275 * If no alias node is found, then the node list will be returned in the
276 * order found in the fdt. If the aliases mention a node which doesn't
277 * exist, then this will be ignored. If nodes are found with no aliases,
278 * they will be added in any order.
280 * If there is a gap in the aliases, then this function return a 0 node at
281 * that position. The return value will also count these gaps.
283 * This function checks node properties and will not return nodes which are
284 * marked disabled (status = "disabled").
286 * @param blob FDT blob to use
287 * @param name Root name of alias to search for
288 * @param id Compatible ID to look for
289 * @param node_list Place to put list of found nodes
290 * @param maxcount Maximum number of nodes to find
291 * @return number of nodes found on success, FTD_ERR_... on error
293 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
294 enum fdt_compat_id id, int *node_list, int maxcount);
297 * This function is similar to fdtdec_find_aliases_for_id() except that it
298 * adds to the node_list that is passed in. Any 0 elements are considered
299 * available for allocation - others are considered already used and are
302 * You can use this by calling fdtdec_find_aliases_for_id() with an
303 * uninitialised array, then setting the elements that are returned to -1,
304 * say, then calling this function, perhaps with a different compat id.
305 * Any elements you get back that are >0 are new nodes added by the call
308 * Note that if you have some nodes with aliases and some without, you are
309 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
310 * one compat_id may fill in positions for which you have aliases defined
311 * for another compat_id. When you later call *this* function with the second
312 * compat_id, the alias positions may already be used. A debug warning may
313 * be generated in this case, but it is safest to define aliases for all
314 * nodes when you care about the ordering.
316 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
317 enum fdt_compat_id id, int *node_list, int maxcount);
320 * Get the name for a compatible ID
322 * @param id Compatible ID to look for
323 * @return compatible string for that id
325 const char *fdtdec_get_compatible(enum fdt_compat_id id);
327 /* Look up a phandle and follow it to its node. Then return the offset
330 * @param blob FDT blob
331 * @param node node to examine
332 * @param prop_name name of property to find
333 * @return node offset if found, -ve error code on error
335 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
338 * Look up a property in a node and return its contents in an integer
339 * array of given length. The property must have at least enough data for
340 * the array (4*count bytes). It may have more, but this will be ignored.
342 * @param blob FDT blob
343 * @param node node to examine
344 * @param prop_name name of property to find
345 * @param array array to fill with data
346 * @param count number of array elements
347 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
348 * or -FDT_ERR_BADLAYOUT if not enough data
350 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
351 u32 *array, int count);
354 * Look up a property in a node and return a pointer to its contents as a
355 * unsigned int array of given length. The property must have at least enough
356 * data for the array ('count' cells). It may have more, but this will be
357 * ignored. The data is not copied.
359 * Note that you must access elements of the array with fdt32_to_cpu(),
360 * since the elements will be big endian even on a little endian machine.
362 * @param blob FDT blob
363 * @param node node to examine
364 * @param prop_name name of property to find
365 * @param count number of array elements
366 * @return pointer to array if found, or NULL if the property is not
367 * found or there is not enough data
369 const u32 *fdtdec_locate_array(const void *blob, int node,
370 const char *prop_name, int count);
373 * Look up a boolean property in a node and return it.
375 * A boolean properly is true if present in the device tree and false if not
376 * present, regardless of its value.
378 * @param blob FDT blob
379 * @param node node to examine
380 * @param prop_name name of property to find
381 * @return 1 if the properly is present; 0 if it isn't present
383 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
386 * Decode a single GPIOs from an FDT.
388 * If the property is not found, then the GPIO structure will still be
389 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
390 * provide optional GPIOs.
392 * @param blob FDT blob to use
393 * @param node Node to look at
394 * @param prop_name Node property name
395 * @param gpio gpio elements to fill from FDT
396 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
398 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
399 struct fdt_gpio_state *gpio);
402 * Decode a list of GPIOs from an FDT. This creates a list of GPIOs with no
405 * @param blob FDT blob to use
406 * @param node Node to look at
407 * @param prop_name Node property name
408 * @param gpio Array of gpio elements to fill from FDT. This will be
409 * untouched if either 0 or an error is returned
410 * @param max_count Maximum number of elements allowed
411 * @return number of GPIOs read if ok, -FDT_ERR_BADLAYOUT if max_count would
412 * be exceeded, or -FDT_ERR_NOTFOUND if the property is missing.
414 int fdtdec_decode_gpios(const void *blob, int node, const char *prop_name,
415 struct fdt_gpio_state *gpio, int max_count);
418 * Set up a GPIO pin according to the provided gpio information. At present this
419 * just requests the GPIO.
421 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
422 * deal with optional GPIOs.
424 * @param gpio GPIO info to use for set up
425 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
427 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
430 * Look in the FDT for a config item with the given name and return its value
431 * as a 32-bit integer. The property must have at least 4 bytes of data. The
432 * value of the first cell is returned.
434 * @param blob FDT blob to use
435 * @param prop_name Node property name
436 * @param default_val default value to return if the property is not found
437 * @return integer value, if found, or default_val if not
439 int fdtdec_get_config_int(const void *blob, const char *prop_name,
443 * Look in the FDT for a config item with the given name
444 * and return whether it exists.
446 * @param blob FDT blob
447 * @param prop_name property name to look up
448 * @return 1, if it exists, or 0 if not
450 int fdtdec_get_config_bool(const void *blob, const char *prop_name);
453 * Look in the FDT for a config item with the given name and return its value
456 * @param blob FDT blob
457 * @param prop_name property name to look up
458 * @returns property string, NULL on error.
460 char *fdtdec_get_config_string(const void *blob, const char *prop_name);
463 * Look up a property in a node and return its contents in a byte
464 * array of given length. The property must have at least enough data for
465 * the array (count bytes). It may have more, but this will be ignored.
467 * @param blob FDT blob
468 * @param node node to examine
469 * @param prop_name name of property to find
470 * @param array array to fill with data
471 * @param count number of array elements
472 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
473 * or -FDT_ERR_BADLAYOUT if not enough data
475 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
476 u8 *array, int count);
479 * Look up a property in a node and return a pointer to its contents as a
480 * byte array of given length. The property must have at least enough data
481 * for the array (count bytes). It may have more, but this will be ignored.
482 * The data is not copied.
484 * @param blob FDT blob
485 * @param node node to examine
486 * @param prop_name name of property to find
487 * @param count number of array elements
488 * @return pointer to byte array if found, or NULL if the property is not
489 * found or there is not enough data
491 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
492 const char *prop_name, int count);
495 * Look up a property in a node which contains a memory region address and
496 * size. Then return a pointer to this address.
498 * The property must hold one address with a length. This is only tested on
501 * @param blob FDT blob
502 * @param node node to examine
503 * @param prop_name name of property to find
504 * @param ptrp returns pointer to region, or NULL if no address
505 * @param size returns size of region
506 * @return 0 if ok, -1 on error (propery not found)
508 int fdtdec_decode_region(const void *blob, int node,
509 const char *prop_name, void **ptrp, size_t *size);