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,
24 * This file contains convenience functions for decoding useful and
25 * enlightening information from FDTs. It is intended to be used by device
26 * drivers and board-specific code within U-Boot. It aims to reduce the
27 * amount of FDT munging required within U-Boot itself, so that driver code
28 * changes to support FDT are minimized.
34 * A typedef for a physical address. Note that fdt data is always big
35 * endian even on a litle endian machine.
37 #ifdef CONFIG_PHYS_64BIT
38 typedef u64 fdt_addr_t;
39 #define FDT_ADDR_T_NONE (-1ULL)
40 #define fdt_addr_to_cpu(reg) be64_to_cpu(reg)
42 typedef u32 fdt_addr_t;
43 #define FDT_ADDR_T_NONE (-1U)
44 #define fdt_addr_to_cpu(reg) be32_to_cpu(reg)
47 /* Information obtained about memory from the FDT */
54 * Compat types that we know about and for which we might have drivers.
55 * Each is named COMPAT_<dir>_<filename> where <dir> is the directory
60 COMPAT_NVIDIA_TEGRA20_USB, /* Tegra2 USB port */
61 COMPAT_NVIDIA_TEGRA20_I2C, /* Tegra2 i2c */
62 COMPAT_NVIDIA_TEGRA20_DVC, /* Tegra2 dvc (really just i2c) */
63 COMPAT_NVIDIA_TEGRA20_EMC, /* Tegra2 memory controller */
64 COMPAT_NVIDIA_TEGRA20_EMC_TABLE, /* Tegra2 memory timing table */
69 /* GPIOs are numbered from 0 */
71 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */
73 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
76 /* This is the state of a GPIO pin as defined by the fdt */
77 struct fdt_gpio_state {
78 const char *name; /* name of the fdt property defining this */
79 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
80 u8 flags; /* FDT_GPIO_... flags */
83 /* This tells us whether a fdt_gpio_state record is valid or not */
84 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
87 * Find the next numbered alias for a peripheral. This is used to enumerate
88 * all the peripherals of a certain type.
90 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
91 * this function will return a pointer to the node the alias points to, and
92 * then update *upto to 1. Next time you call this function, the next node
95 * All nodes returned will match the compatible ID, as it is assumed that
96 * all peripherals use the same driver.
98 * @param blob FDT blob to use
99 * @param name Root name of alias to search for
100 * @param id Compatible ID to look for
101 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
103 int fdtdec_next_alias(const void *blob, const char *name,
104 enum fdt_compat_id id, int *upto);
107 * Find the next compatible node for a peripheral.
109 * Do the first call with node = 0. This function will return a pointer to
110 * the next compatible node. Next time you call this function, pass the
111 * value returned, and the next node will be provided.
113 * @param blob FDT blob to use
114 * @param node Start node for search
115 * @param id Compatible ID to look for (enum fdt_compat_id)
116 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
118 int fdtdec_next_compatible(const void *blob, int node,
119 enum fdt_compat_id id);
122 * Find the next compatible subnode for a peripheral.
124 * Do the first call with node set to the parent and depth = 0. This
125 * function will return the offset of the next compatible node. Next time
126 * you call this function, pass the node value returned last time, with
127 * depth unchanged, and the next node will be provided.
129 * @param blob FDT blob to use
130 * @param node Start node for search
131 * @param id Compatible ID to look for (enum fdt_compat_id)
132 * @param depthp Current depth (set to 0 before first call)
133 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
135 int fdtdec_next_compatible_subnode(const void *blob, int node,
136 enum fdt_compat_id id, int *depthp);
139 * Look up an address property in a node and return it as an address.
140 * The property must hold either one address with no trailing data or
141 * one address with a length. This is only tested on 32-bit machines.
143 * @param blob FDT blob
144 * @param node node to examine
145 * @param prop_name name of property to find
146 * @return address, if found, or FDT_ADDR_T_NONE if not
148 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
149 const char *prop_name);
152 * Look up a 32-bit integer property in a node and return it. The property
153 * must have at least 4 bytes of data. The value of the first cell is
156 * @param blob FDT blob
157 * @param node node to examine
158 * @param prop_name name of property to find
159 * @param default_val default value to return if the property is not found
160 * @return integer value, if found, or default_val if not
162 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
166 * Checks whether a node is enabled.
167 * This looks for a 'status' property. If this exists, then returns 1 if
168 * the status is 'ok' and 0 otherwise. If there is no status property,
169 * it returns 1 on the assumption that anything mentioned should be enabled
172 * @param blob FDT blob
173 * @param node node to examine
174 * @return integer value 0 (not enabled) or 1 (enabled)
176 int fdtdec_get_is_enabled(const void *blob, int node);
179 * Make sure we have a valid fdt available to control U-Boot.
181 * If not, a message is printed to the console if the console is ready.
183 * @return 0 if all ok, -1 if not
185 int fdtdec_prepare_fdt(void);
188 * Checks that we have a valid fdt available to control U-Boot.
190 * However, if not then for the moment nothing is done, since this function
191 * is called too early to panic().
195 int fdtdec_check_fdt(void);
198 * Find the nodes for a peripheral and return a list of them in the correct
199 * order. This is used to enumerate all the peripherals of a certain type.
201 * To use this, optionally set up a /aliases node with alias properties for
202 * a peripheral. For example, for usb you could have:
205 * usb0 = "/ehci@c5008000";
206 * usb1 = "/ehci@c5000000";
209 * Pass "usb" as the name to this function and will return a list of two
210 * nodes offsets: /ehci@c5008000 and ehci@c5000000.
212 * All nodes returned will match the compatible ID, as it is assumed that
213 * all peripherals use the same driver.
215 * If no alias node is found, then the node list will be returned in the
216 * order found in the fdt. If the aliases mention a node which doesn't
217 * exist, then this will be ignored. If nodes are found with no aliases,
218 * they will be added in any order.
220 * If there is a gap in the aliases, then this function return a 0 node at
221 * that position. The return value will also count these gaps.
223 * This function checks node properties and will not return nodes which are
224 * marked disabled (status = "disabled").
226 * @param blob FDT blob to use
227 * @param name Root name of alias to search for
228 * @param id Compatible ID to look for
229 * @param node_list Place to put list of found nodes
230 * @param maxcount Maximum number of nodes to find
231 * @return number of nodes found on success, FTD_ERR_... on error
233 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
234 enum fdt_compat_id id, int *node_list, int maxcount);
237 * This function is similar to fdtdec_find_aliases_for_id() except that it
238 * adds to the node_list that is passed in. Any 0 elements are considered
239 * available for allocation - others are considered already used and are
242 * You can use this by calling fdtdec_find_aliases_for_id() with an
243 * uninitialised array, then setting the elements that are returned to -1,
244 * say, then calling this function, perhaps with a different compat id.
245 * Any elements you get back that are >0 are new nodes added by the call
248 * Note that if you have some nodes with aliases and some without, you are
249 * sailing close to the wind. The call to fdtdec_find_aliases_for_id() with
250 * one compat_id may fill in positions for which you have aliases defined
251 * for another compat_id. When you later call *this* function with the second
252 * compat_id, the alias positions may already be used. A debug warning may
253 * be generated in this case, but it is safest to define aliases for all
254 * nodes when you care about the ordering.
256 int fdtdec_add_aliases_for_id(const void *blob, const char *name,
257 enum fdt_compat_id id, int *node_list, int maxcount);
260 * Get the name for a compatible ID
262 * @param id Compatible ID to look for
263 * @return compatible string for that id
265 const char *fdtdec_get_compatible(enum fdt_compat_id id);
267 /* Look up a phandle and follow it to its node. Then return the offset
270 * @param blob FDT blob
271 * @param node node to examine
272 * @param prop_name name of property to find
273 * @return node offset if found, -ve error code on error
275 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
278 * Look up a property in a node and return its contents in an integer
279 * array of given length. The property must have at least enough data for
280 * the array (4*count bytes). It may have more, but this will be ignored.
282 * @param blob FDT blob
283 * @param node node to examine
284 * @param prop_name name of property to find
285 * @param array array to fill with data
286 * @param count number of array elements
287 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
288 * or -FDT_ERR_BADLAYOUT if not enough data
290 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
291 u32 *array, int count);
294 * Look up a property in a node and return a pointer to its contents as a
295 * unsigned int array of given length. The property must have at least enough
296 * data for the array ('count' cells). It may have more, but this will be
297 * ignored. The data is not copied.
299 * Note that you must access elements of the array with fdt32_to_cpu(),
300 * since the elements will be big endian even on a little endian machine.
302 * @param blob FDT blob
303 * @param node node to examine
304 * @param prop_name name of property to find
305 * @param count number of array elements
306 * @return pointer to array if found, or NULL if the property is not
307 * found or there is not enough data
309 const u32 *fdtdec_locate_array(const void *blob, int node,
310 const char *prop_name, int count);
313 * Look up a boolean property in a node and return it.
315 * A boolean properly is true if present in the device tree and false if not
316 * present, regardless of its value.
318 * @param blob FDT blob
319 * @param node node to examine
320 * @param prop_name name of property to find
321 * @return 1 if the properly is present; 0 if it isn't present
323 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
326 * Decode a single GPIOs from an FDT.
328 * If the property is not found, then the GPIO structure will still be
329 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
330 * provide optional GPIOs.
332 * @param blob FDT blob to use
333 * @param node Node to look at
334 * @param prop_name Node property name
335 * @param gpio gpio elements to fill from FDT
336 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
338 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
339 struct fdt_gpio_state *gpio);
342 * Set up a GPIO pin according to the provided gpio information. At present this
343 * just requests the GPIO.
345 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
346 * deal with optional GPIOs.
348 * @param gpio GPIO info to use for set up
349 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
351 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);