Add a basic assortment of functions to access the live device tree.
Signed-off-by: Simon Glass sjg@chromium.org ---
include/dm/of_access.h | 164 +++++++++++++++++++++++++ lib/Makefile | 1 + lib/of_access.c | 328 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 493 insertions(+) create mode 100644 include/dm/of_access.h create mode 100644 lib/of_access.c
diff --git a/include/dm/of_access.h b/include/dm/of_access.h new file mode 100644 index 00000000000..9a157d8a5b7 --- /dev/null +++ b/include/dm/of_access.h @@ -0,0 +1,164 @@ +/* + * Originally from Linux v4.9 + * Copyright (C) 1996-2005 Paul Mackerras. + * + * Updates for PPC64 by Peter Bergner & David Engebretsen, IBM Corp. + * Updates for SPARC64 by David S. Miller + * Derived from PowerPC and Sparc prom.h files by Stephen Rothwell, IBM Corp. + * + * Copyright (c) 2017 Google, Inc + * Written by Simon Glass sjg@chromium.org + * + * Modified for U-Boot + * Copyright (c) 2017 Google, Inc + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#ifndef _DM_OF_ACCESS_H +#define _DM_OF_ACCESS_H + +#include <dm/of.h> + +/** + * of_find_all_nodes - Get next node in global list + * @prev: Previous node or NULL to start iteration + * of_node_put() will be called on it + * + * Returns a node pointer with refcount incremented, use + * of_node_put() on it when done. + */ +struct device_node *of_find_all_nodes(struct device_node *prev); + +#define for_each_of_allnodes_from(from, dn) \ + for (dn = __of_find_all_nodes(from); dn; dn = __of_find_all_nodes(dn)) +#define for_each_of_allnodes(dn) for_each_of_allnodes_from(NULL, dn) + +/* Dummy functions to mirror Linux. These are not yet used in U-Boot */ +static inline struct device_node *of_node_get(struct device_node *node) +{ + return node; +} + +static inline void of_node_put(struct device_node *node) { } + +/** + * of_find_property() - find a property in a node + * + * @np: Pointer to device node holding property + * @name: Name of property + * @lenp: If non-NULL, returns length of property + * @return pointer to property, or NULL if not found + */ +struct property *of_find_property(const struct device_node *np, + const char *name, int *lenp); + +/* + * Find a property with a given name for a given node + * and return the value. + */ +const void *of_get_property(const struct device_node *np, const char *name, + int *lenp); + +/** + * of_device_is_available - check if a device is available for use + * + * @device: Node to check for availability, with locks already held + * + * Returns true if the status property is absent or set to "okay" or "ok", + * false otherwise + */ +bool of_device_is_available(const struct device_node *device); + +/** + * of_find_node_by_phandle - Find a node given a phandle + * @handle: phandle of the node to find + * + * Returns a node pointer with refcount incremented, use + * of_node_put() on it when done. + */ +struct device_node *of_find_node_by_phandle(phandle handle); + +/** + * of_parse_phandle - Resolve a phandle property to a device_node pointer + * @np: Pointer to device node holding phandle property + * @phandle_name: Name of property holding a phandle value + * @index: For properties holding a table of phandles, this is the index into + * the table + * + * Returns the device_node pointer with refcount incremented. Use + * of_node_put() on it when done. + */ +struct device_node *of_parse_phandle(const struct device_node *np, + const char *phandle_name, int index); + +/** + * of_parse_phandle_with_args() - Find a node pointed by phandle in a list + * @np: pointer to a device tree node containing a list + * @list_name: property name that contains a list + * @cells_name: property name that specifies phandles' arguments count + * @index: index of a phandle to parse out + * @out_args: optional pointer to output arguments structure (will be filled) + * + * This function is useful to parse lists of phandles and their arguments. + * Returns 0 on success and fills out_args, on error returns appropriate + * errno value. + * + * Caller is responsible to call of_node_put() on the returned out_args->np + * pointer. + * + * Example: + * + * phandle1: node1 { + * #list-cells = <2>; + * } + * + * phandle2: node2 { + * #list-cells = <1>; + * } + * + * node3 { + * list = <&phandle1 1 2 &phandle2 3>; + * } + * + * To get a device_node of the `node2' node you may call this: + * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args); + */ +int of_parse_phandle_with_args(const struct device_node *np, + const char *list_name, const char *cells_name, + int index, struct of_phandle_args *out_args); + +/** + * of_read_u32() - Find and read a 32-bit integer from a property + * @np: device node from which the property value is to be read. + * @propname: name of the property to be searched. + * @outp: pointer to return value, modified only if return value is 0. + * + * Search for a property in a device node and read a 32-bit value from + * it. Returns 0 on success, -EINVAL if the property does not exist, + * -ENODATA if property does not have a value, and -EOVERFLOW if the + * property data isn't large enough. + * + * The out_value is modified only if a valid u64 value can be decoded. + */ +int of_read_u32(const struct device_node *np, const char *propname, u32 *outp); + +/** + * of_read_u32_array() - Find and read an array of 32 bit integers + * + * @np: device node from which the property value is to be read. + * @propname: name of the property to be searched. + * @out_values: pointer to return value, modified only if return value is 0. + * @sz: number of array elements to read + * @return 0 on success, -EINVAL if the property does not exist, -ENODATA + * if property does not have a value, and -EOVERFLOW is longer than sz. + * + * Search for a property in a device node and read 32-bit value(s) from + * it. + * + * The out_values is modified only if a valid u32 value can be decoded. + */ +int of_read_u32_array(const struct device_node *np, const char *propname, + u32 *out_values, size_t sz); + +#endif diff --git a/lib/Makefile b/lib/Makefile index 23e9f1ef11d..d07a062483a 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -15,6 +15,7 @@ obj-$(CONFIG_ZLIB) += zlib/ obj-$(CONFIG_BZIP2) += bzip2/ obj-$(CONFIG_TIZEN) += tizen/ obj-$(CONFIG_FIT) += libfdt/ +obj-$(CONFIG_OF_LIVE) += of_access.o obj-$(CONFIG_CMD_DHRYSTONE) += dhry/
obj-$(CONFIG_AES) += aes.o diff --git a/lib/of_access.c b/lib/of_access.c new file mode 100644 index 00000000000..e3ffb21dc8a --- /dev/null +++ b/lib/of_access.c @@ -0,0 +1,328 @@ +/* + * Originally from Linux v4.9 + * Paul Mackerras August 1996. + * Copyright (C) 1996-2005 Paul Mackerras. + * + * Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner. + * {engebret|bergner}@us.ibm.com + * + * Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net + * + * Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and + * Grant Likely. + * + * Modified for U-Boot + * Copyright (c) 2017 Google, Inc + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <common.h> +#include <libfdt.h> +#include <dm/of_access.h> +#include <linux/err.h> + +DECLARE_GLOBAL_DATA_PTR; + +static inline int np_to_offset(const struct device_node *np) +{ + return (ulong)np - (ulong)gd->fdt_blob; +} + +struct property *of_find_property(const struct device_node *np, + const char *name, int *lenp) +{ + struct property *pp; + + if (!np) + return NULL; + + for (pp = np->properties; pp; pp = pp->next) { + if (strcmp(pp->name, name) == 0) { + if (lenp) + *lenp = pp->length; + break; + } + } + + return pp; +} + +struct device_node *__of_find_all_nodes(struct device_node *prev) +{ + struct device_node *np; + if (!prev) { + np = gd->of_root; + } else if (prev->child) { + np = prev->child; + } else { + /* + * Walk back up looking for a sibling, or the end of the + * structure + */ + np = prev; + while (np->parent && !np->sibling) + np = np->parent; + np = np->sibling; /* Might be null at the end of the tree */ + } + return np; +} + +struct device_node *of_find_all_nodes(struct device_node *prev) +{ + struct device_node *np; + + np = __of_find_all_nodes(prev); + of_node_get(np); + of_node_put(prev); + return np; +} + +/** + * of_find_property_value_of_size + * + * Search for a property in a device node and valid the requested size. + * + * @np: device node from which the property value is to be read. + * @propname: name of the property to be searched. + * @len: requested length of property value + * + * @returns the property value on success, -EINVAL if the property does not + * exist, -ENODATA if property does not have a value, and -EOVERFLOW if the + * property data isn't large enough. + */ +static void *of_find_property_value_of_size(const struct device_node *np, + const char *propname, u32 len) +{ + struct property *prop = of_find_property(np, propname, NULL); + + if (!prop) + return ERR_PTR(-EINVAL); + if (!prop->value) + return ERR_PTR(-ENODATA); + if (len > prop->length) + return ERR_PTR(-EOVERFLOW); + + return prop->value; +} + +const void *of_get_property(const struct device_node *np, const char *name, + int *lenp) +{ + struct property *pp = of_find_property(np, name, lenp); + + return pp ? pp->value : NULL; +} + +bool of_device_is_available(const struct device_node *device) +{ + const char *status; + int statlen; + + if (!device) + return false; + + status = of_get_property(device, "status", &statlen); + if (status == NULL) + return true; + + if (statlen > 0) { + if (!strcmp(status, "okay") || !strcmp(status, "ok")) + return true; + } + + return false; +} + +struct device_node *of_find_node_by_phandle(phandle handle) +{ + struct device_node *np; + + if (!handle) + return NULL; + + for_each_of_allnodes(np) + if (np->phandle == handle) + break; + of_node_get(np); + return np; +} + +int of_read_u32(const struct device_node *np, const char *propname, u32 *outp) +{ + const __be32 *val; + + debug("%s: %s: ", __func__, propname); + if (!np) + return -EINVAL; + val = of_find_property_value_of_size(np, propname, sizeof(*outp)); + if (IS_ERR(val)) { + debug("(not found)\n"); + return PTR_ERR(val); + } + + *outp = be32_to_cpup(val); + debug("%#x (%d)\n", *outp, *outp); + + return 0; +} + +static int __of_parse_phandle_with_args(const struct device_node *np, + const char *list_name, + const char *cells_name, + int cell_count, int index, + struct of_phandle_args *out_args) +{ + const __be32 *list, *list_end; + int rc = 0, size, cur_index = 0; + uint32_t count = 0; + struct device_node *node = NULL; + phandle phandle; + + /* Retrieve the phandle list property */ + list = of_get_property(np, list_name, &size); + if (!list) + return -ENOENT; + list_end = list + size / sizeof(*list); + + /* Loop over the phandles until all the requested entry is found */ + while (list < list_end) { + rc = -EINVAL; + count = 0; + + /* + * If phandle is 0, then it is an empty entry with no + * arguments. Skip forward to the next entry. + */ + phandle = be32_to_cpup(list++); + if (phandle) { + /* + * Find the provider node and parse the #*-cells + * property to determine the argument length. + * + * This is not needed if the cell count is hard-coded + * (i.e. cells_name not set, but cell_count is set), + * except when we're going to return the found node + * below. + */ + if (cells_name || cur_index == index) { + node = of_find_node_by_phandle(phandle); + if (!node) { + debug("%s: could not find phandle\n", + np->full_name); + goto err; + } + } + + if (cells_name) { + if (of_read_u32(node, cells_name, &count)) { + debug("%s: could not get %s for %s\n", + np->full_name, cells_name, + node->full_name); + goto err; + } + } else { + count = cell_count; + } + + /* + * Make sure that the arguments actually fit in the + * remaining property data length + */ + if (list + count > list_end) { + debug("%s: arguments longer than property\n", + np->full_name); + goto err; + } + } + + /* + * All of the error cases above bail out of the loop, so at + * this point, the parsing is successful. If the requested + * index matches, then fill the out_args structure and return, + * or return -ENOENT for an empty entry. + */ + rc = -ENOENT; + if (cur_index == index) { + if (!phandle) + goto err; + + if (out_args) { + int i; + if (WARN_ON(count > OF_MAX_PHANDLE_ARGS)) + count = OF_MAX_PHANDLE_ARGS; + out_args->np = node; + out_args->args_count = count; + for (i = 0; i < count; i++) + out_args->args[i] = + be32_to_cpup(list++); + } else { + of_node_put(node); + } + + /* Found it! return success */ + return 0; + } + + of_node_put(node); + node = NULL; + list += count; + cur_index++; + } + + /* + * Unlock node before returning result; will be one of: + * -ENOENT : index is for empty phandle + * -EINVAL : parsing error on data + * [1..n] : Number of phandle (count mode; when index = -1) + */ + rc = index < 0 ? cur_index : -ENOENT; + err: + if (node) + of_node_put(node); + return rc; +} + +struct device_node *of_parse_phandle(const struct device_node *np, + const char *phandle_name, int index) +{ + struct of_phandle_args args; + + if (index < 0) + return NULL; + + if (__of_parse_phandle_with_args(np, phandle_name, NULL, 0, + index, &args)) + return NULL; + + return args.np; +} + +int of_parse_phandle_with_args(const struct device_node *np, + const char *list_name, const char *cells_name, + int index, struct of_phandle_args *out_args) +{ + if (index < 0) + return -EINVAL; + return __of_parse_phandle_with_args(np, list_name, cells_name, 0, + index, out_args); +} + +int of_read_u32_array(const struct device_node *np, const char *propname, + u32 *out_values, size_t sz) +{ + const __be32 *val; + + debug("%s: %s: ", __func__, propname); + val = of_find_property_value_of_size(np, propname, + sz * sizeof(*out_values)); + + if (IS_ERR(val)) + return PTR_ERR(val); + + debug("size %zd\n", sz); + while (sz--) + *out_values++ = be32_to_cpup(val++); + + return 0; +}