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)
44 typedef u32 fdt_addr_t;
45 #define FDT_ADDR_T_NONE (-1U)
46 #define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
49 /* Information obtained about memory from the FDT */
56 * Compat types that we know about and for which we might have drivers.
57 * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
62 COMPAT_NVIDIA_TEGRA20_USB, /* Tegra20 USB port */
63 COMPAT_NVIDIA_TEGRA20_I2C, /* Tegra20 i2c */
64 COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra20 dvc (really just i2c) */
65 COMPAT_NVIDIA_TEGRA20_EMC, /* Tegra20 memory controller */
66 COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra20 memory timing table */
67 COMPAT_NVIDIA_TEGRA20_KBC, /* Tegra20 Keyboard */
72 /* GPIOs are numbered from 0 */
74 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */
76 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
79 /* This is the state of a GPIO pin as defined by the fdt */
80 struct fdt_gpio_state {
81 const char *name; /* name of the fdt property defining this */
82 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
83 u8 flags; /* FDT_GPIO_... flags */
86 /* This tells us whether a fdt_gpio_state record is valid or not */
87 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
90 * Find the next numbered alias for a peripheral. This is used to enumerate
91 * all the peripherals of a certain type.
93 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
94 * this function will return a pointer to the node the alias points to, and
95 * then update *upto to 1. Next time you call this function, the next node
98 * All nodes returned will match the compatible ID, as it is assumed that
99 * all peripherals use the same driver.
101 * @param blob FDT blob to use
102 * @param name Root name of alias to search for
103 * @param id Compatible ID to look for
104 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
106 int fdtdec_next_alias(const void *blob, const char *name,
107 enum fdt_compat_id id, int *upto);
110 * Find the next compatible node for a peripheral.
112 * Do the first call with node = 0. This function will return a pointer to
113 * the next compatible node. Next time you call this function, pass the
114 * value returned, and the next node will be provided.
116 * @param blob FDT blob to use
117 * @param node Start node for search
118 * @param id Compatible ID to look for (enum fdt_compat_id)
119 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
121 int fdtdec_next_compatible(const void *blob, int node,
122 enum fdt_compat_id id);
125 * Find the next compatible subnode for a peripheral.
127 * Do the first call with node set to the parent and depth = 0. This
128 * function will return the offset of the next compatible node. Next time
129 * you call this function, pass the node value returned last time, with
130 * depth unchanged, and the next node will be provided.
132 * @param blob FDT blob to use
133 * @param node Start node for search
134 * @param id Compatible ID to look for (enum fdt_compat_id)
135 * @param depthp Current depth (set to 0 before first call)
136 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
138 int fdtdec_next_compatible_subnode(const void *blob, int node,
139 enum fdt_compat_id id, int *depthp);
142 * Look up an address property in a node and return it as an address.
143 * The property must hold either one address with no trailing data or
144 * one address with a length. This is only tested on 32-bit machines.
146 * @param blob FDT blob
147 * @param node node to examine
148 * @param prop_name name of property to find
149 * @return address, if found, or FDT_ADDR_T_NONE if not
151 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
152 const char *prop_name);
155 * Look up a 32-bit integer property in a node and return it. The property
156 * must have at least 4 bytes of data. The value of the first cell is
159 * @param blob FDT blob
160 * @param node node to examine
161 * @param prop_name name of property to find
162 * @param default_val default value to return if the property is not found
163 * @return integer value, if found, or default_val if not
165 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
169 * Checks whether a node is enabled.
170 * This looks for a 'status' property. If this exists, then returns 1 if
171 * the status is 'ok' and 0 otherwise. If there is no status property,
172 * it returns 1 on the assumption that anything mentioned should be enabled
175 * @param blob FDT blob
176 * @param node node to examine
177 * @return integer value 0 (not enabled) or 1 (enabled)
179 int fdtdec_get_is_enabled(const void *blob, int node);
182 * Make sure we have a valid fdt available to control U-Boot.
184 * If not, a message is printed to the console if the console is ready.
186 * @return 0 if all ok, -1 if not
188 int fdtdec_prepare_fdt(void);
191 * Checks that we have a valid fdt available to control U-Boot.
193 * However, if not then for the moment nothing is done, since this function
194 * is called too early to panic().
198 int fdtdec_check_fdt(void);
201 * Find the nodes for a peripheral and return a list of them in the correct
202 * order. This is used to enumerate all the peripherals of a certain type.
204 * To use this, optionally set up a /aliases node with alias properties for
205 * a peripheral. For example, for usb you could have:
208 * usb0 = "/ehci@c5008000";
209 * usb1 = "/ehci@c5000000";
212 * Pass "usb" as the name to this function and will return a list of two
213 * nodes offsets: /ehci@c5008000 and ehci@c5000000.
215 * All nodes returned will match the compatible ID, as it is assumed that
216 * all peripherals use the same driver.
218 * If no alias node is found, then the node list will be returned in the
219 * order found in the fdt. If the aliases mention a node which doesn't
220 * exist, then this will be ignored. If nodes are found with no aliases,
221 * they will be added in any order.
223 * If there is a gap in the aliases, then this function return a 0 node at
224 * that position. The return value will also count these gaps.
226 * This function checks node properties and will not return nodes which are
227 * marked disabled (status = "disabled").
229 * @param blob FDT blob to use
230 * @param name Root name of alias to search for
231 * @param id Compatible ID to look for
232 * @param node_list Place to put list of found nodes
233 * @param maxcount Maximum number of nodes to find
234 * @return number of nodes found on success, FTD_ERR_... on error
236 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
237 enum fdt_compat_id id, int *node_list, int maxcount);
240 * This function is similar to fdtdec_find_aliases_for_id() except that it
241 * adds to the node_list that is passed in. Any 0 elements are considered
242 * available for allocation - others are considered already used and are
245 * You can use this by calling fdtdec_find_aliases_for_id() with an
246 * uninitialised array, then setting the elements that are returned to -1,
247 * say, then calling this function, perhaps with a different compat id.
248 * Any elements you get back that are >0 are new nodes added by the call
251 * Note that if you have some nodes with aliases and some without, you are
252 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
253 * one compat_id may fill in positions for which you have aliases defined
254 * for another compat_id. When you later call *this* function with the second
255 * compat_id, the alias positions may already be used. A debug warning may
256 * be generated in this case, but it is safest to define aliases for all
257 * nodes when you care about the ordering.
259 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
260 enum fdt_compat_id id, int *node_list, int maxcount);
263 * Get the name for a compatible ID
265 * @param id Compatible ID to look for
266 * @return compatible string for that id
268 const char *fdtdec_get_compatible(enum fdt_compat_id id);
270 /* Look up a phandle and follow it to its node. Then return the offset
273 * @param blob FDT blob
274 * @param node node to examine
275 * @param prop_name name of property to find
276 * @return node offset if found, -ve error code on error
278 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
281 * Look up a property in a node and return its contents in an integer
282 * array of given length. The property must have at least enough data for
283 * the array (4*count bytes). It may have more, but this will be ignored.
285 * @param blob FDT blob
286 * @param node node to examine
287 * @param prop_name name of property to find
288 * @param array array to fill with data
289 * @param count number of array elements
290 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
291 * or -FDT_ERR_BADLAYOUT if not enough data
293 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
294 u32 *array, int count);
297 * Look up a property in a node and return a pointer to its contents as a
298 * unsigned int array of given length. The property must have at least enough
299 * data for the array ('count' cells). It may have more, but this will be
300 * ignored. The data is not copied.
302 * Note that you must access elements of the array with fdt32_to_cpu(),
303 * since the elements will be big endian even on a little endian machine.
305 * @param blob FDT blob
306 * @param node node to examine
307 * @param prop_name name of property to find
308 * @param count number of array elements
309 * @return pointer to array if found, or NULL if the property is not
310 * found or there is not enough data
312 const u32 *fdtdec_locate_array(const void *blob, int node,
313 const char *prop_name, int count);
316 * Look up a boolean property in a node and return it.
318 * A boolean properly is true if present in the device tree and false if not
319 * present, regardless of its value.
321 * @param blob FDT blob
322 * @param node node to examine
323 * @param prop_name name of property to find
324 * @return 1 if the properly is present; 0 if it isn't present
326 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
329 * Decode a single GPIOs from an FDT.
331 * If the property is not found, then the GPIO structure will still be
332 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
333 * provide optional GPIOs.
335 * @param blob FDT blob to use
336 * @param node Node to look at
337 * @param prop_name Node property name
338 * @param gpio gpio elements to fill from FDT
339 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
341 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
342 struct fdt_gpio_state *gpio);
345 * Set up a GPIO pin according to the provided gpio information. At present this
346 * just requests the GPIO.
348 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
349 * deal with optional GPIOs.
351 * @param gpio GPIO info to use for set up
352 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
354 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);
357 * Look up a property in a node and return its contents in a byte
358 * array of given length. The property must have at least enough data for
359 * the array (count bytes). It may have more, but this will be ignored.
361 * @param blob FDT blob
362 * @param node node to examine
363 * @param prop_name name of property to find
364 * @param array array to fill with data
365 * @param count number of array elements
366 * @return 0 if ok, or -FDT_ERR_MISSING if the property is not found,
367 * or -FDT_ERR_BADLAYOUT if not enough data
369 int fdtdec_get_byte_array(const void *blob, int node, const char *prop_name,
370 u8 *array, int count);
373 * Look up a property in a node and return a pointer to its contents as a
374 * byte array of given length. The property must have at least enough data
375 * for the array (count bytes). It may have more, but this will be ignored.
376 * The data is not copied.
378 * @param blob FDT blob
379 * @param node node to examine
380 * @param prop_name name of property to find
381 * @param count number of array elements
382 * @return pointer to byte array if found, or NULL if the property is not
383 * found or there is not enough data
385 const u8 *fdtdec_locate_byte_array(const void *blob, int node,
386 const char *prop_name, int count);