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
64 /* GPIOs are numbered from 0 */
66 FDT_GPIO_NONE = -1U, /* an invalid GPIO used to end our list */
68 FDT_GPIO_ACTIVE_LOW = 1 << 0, /* input is active low (else high) */
71 /* This is the state of a GPIO pin as defined by the fdt */
72 struct fdt_gpio_state {
73 const char *name; /* name of the fdt property defining this */
74 uint gpio; /* GPIO number, or FDT_GPIO_NONE if none */
75 u8 flags; /* FDT_GPIO_... flags */
78 /* This tells us whether a fdt_gpio_state record is valid or not */
79 #define fdt_gpio_isvalid(x) ((x)->gpio != FDT_GPIO_NONE)
82 * Find the next numbered alias for a peripheral. This is used to enumerate
83 * all the peripherals of a certain type.
85 * Do the first call with *upto = 0. Assuming /aliases/<name>0 exists then
86 * this function will return a pointer to the node the alias points to, and
87 * then update *upto to 1. Next time you call this function, the next node
90 * All nodes returned will match the compatible ID, as it is assumed that
91 * all peripherals use the same driver.
93 * @param blob FDT blob to use
94 * @param name Root name of alias to search for
95 * @param id Compatible ID to look for
96 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
98 int fdtdec_next_alias(const void *blob, const char *name,
99 enum fdt_compat_id id, int *upto);
102 * Find the next compatible node for a peripheral.
104 * Do the first call with node = 0. This function will return a pointer to
105 * the next compatible node. Next time you call this function, pass the
106 * value returned, and the next node will be provided.
108 * @param blob FDT blob to use
109 * @param node Start node for search
110 * @param id Compatible ID to look for (enum fdt_compat_id)
111 * @return offset of next compatible node, or -FDT_ERR_NOTFOUND if no more
113 int fdtdec_next_compatible(const void *blob, int node,
114 enum fdt_compat_id id);
117 * Look up an address property in a node and return it as an address.
118 * The property must hold either one address with no trailing data or
119 * one address with a length. This is only tested on 32-bit machines.
121 * @param blob FDT blob
122 * @param node node to examine
123 * @param prop_name name of property to find
124 * @return address, if found, or FDT_ADDR_T_NONE if not
126 fdt_addr_t fdtdec_get_addr(const void *blob, int node,
127 const char *prop_name);
130 * Look up a 32-bit integer property in a node and return it. The property
131 * must have at least 4 bytes of data. The value of the first cell is
134 * @param blob FDT blob
135 * @param node node to examine
136 * @param prop_name name of property to find
137 * @param default_val default value to return if the property is not found
138 * @return integer value, if found, or default_val if not
140 s32 fdtdec_get_int(const void *blob, int node, const char *prop_name,
144 * Checks whether a node is enabled.
145 * This looks for a 'status' property. If this exists, then returns 1 if
146 * the status is 'ok' and 0 otherwise. If there is no status property,
147 * it returns 1 on the assumption that anything mentioned should be enabled
150 * @param blob FDT blob
151 * @param node node to examine
152 * @return integer value 0 (not enabled) or 1 (enabled)
154 int fdtdec_get_is_enabled(const void *blob, int node);
157 * Checks whether we have a valid fdt available to control U-Boot, and panic
160 int fdtdec_check_fdt(void);
163 * Find the nodes for a peripheral and return a list of them in the correct
164 * order. This is used to enumerate all the peripherals of a certain type.
166 * To use this, optionally set up a /aliases node with alias properties for
167 * a peripheral. For example, for usb you could have:
170 * usb0 = "/ehci@c5008000";
171 * usb1 = "/ehci@c5000000";
174 * Pass "usb" as the name to this function and will return a list of two
175 * nodes offsets: /ehci@c5008000 and ehci@c5000000.
177 * All nodes returned will match the compatible ID, as it is assumed that
178 * all peripherals use the same driver.
180 * If no alias node is found, then the node list will be returned in the
181 * order found in the fdt. If the aliases mention a node which doesn't
182 * exist, then this will be ignored. If nodes are found with no aliases,
183 * they will be added in any order.
185 * If there is a gap in the aliases, then this function return a 0 node at
186 * that position. The return value will also count these gaps.
188 * This function checks node properties and will not return nodes which are
189 * marked disabled (status = "disabled").
191 * @param blob FDT blob to use
192 * @param name Root name of alias to search for
193 * @param id Compatible ID to look for
194 * @param node_list Place to put list of found nodes
195 * @param maxcount Maximum number of nodes to find
196 * @return number of nodes found on success, FTD_ERR_... on error
198 int fdtdec_find_aliases_for_id(const void *blob, const char *name,
199 enum fdt_compat_id id, int *node_list, int maxcount);
202 * Get the name for a compatible ID
204 * @param id Compatible ID to look for
205 * @return compatible string for that id
207 const char *fdtdec_get_compatible(enum fdt_compat_id id);
209 /* Look up a phandle and follow it to its node. Then return the offset
212 * @param blob FDT blob
213 * @param node node to examine
214 * @param prop_name name of property to find
215 * @return node offset if found, -ve error code on error
217 int fdtdec_lookup_phandle(const void *blob, int node, const char *prop_name);
220 * Look up a property in a node and return its contents in an integer
221 * array of given length. The property must have at least enough data for
222 * the array (4*count bytes). It may have more, but this will be ignored.
224 * @param blob FDT blob
225 * @param node node to examine
226 * @param prop_name name of property to find
227 * @param array array to fill with data
228 * @param count number of array elements
229 * @return 0 if ok, or -FDT_ERR_NOTFOUND if the property is not found,
230 * or -FDT_ERR_BADLAYOUT if not enough data
232 int fdtdec_get_int_array(const void *blob, int node, const char *prop_name,
233 u32 *array, int count);
236 * Look up a boolean property in a node and return it.
238 * A boolean properly is true if present in the device tree and false if not
239 * present, regardless of its value.
241 * @param blob FDT blob
242 * @param node node to examine
243 * @param prop_name name of property to find
244 * @return 1 if the properly is present; 0 if it isn't present
246 int fdtdec_get_bool(const void *blob, int node, const char *prop_name);
249 * Decode a single GPIOs from an FDT.
251 * If the property is not found, then the GPIO structure will still be
252 * initialised, with gpio set to FDT_GPIO_NONE. This makes it easy to
253 * provide optional GPIOs.
255 * @param blob FDT blob to use
256 * @param node Node to look at
257 * @param prop_name Node property name
258 * @param gpio gpio elements to fill from FDT
259 * @return 0 if ok, -FDT_ERR_NOTFOUND if the property is missing.
261 int fdtdec_decode_gpio(const void *blob, int node, const char *prop_name,
262 struct fdt_gpio_state *gpio);
265 * Set up a GPIO pin according to the provided gpio information. At present this
266 * just requests the GPIO.
268 * If the gpio is FDT_GPIO_NONE, no action is taken. This makes it easy to
269 * deal with optional GPIOs.
271 * @param gpio GPIO info to use for set up
272 * @return 0 if all ok or gpio was FDT_GPIO_NONE; -1 on error
274 int fdtdec_setup_gpio(struct fdt_gpio_state *gpio);