From 15c9a0acc3f7873db4b7d35d016729b2dc229b49 Mon Sep 17 00:00:00 2001 From: Grant Likely Date: Mon, 12 Dec 2011 09:25:57 -0700 Subject: of: create of_phandle_args to simplify return of phandle parsing data of_parse_phandle_with_args() needs to return quite a bit of data. Rather than making each datum a separate **out_ argument, this patch creates struct of_phandle_args to contain all the returned data and reworks the user of the function. This patch also enables of_parse_phandle_with_args() to return the device node pointer for the phandle node. This patch also ends up being fairly major surgery to of_parse_handle_with_args(). The existing structure didn't work well when extending to use of_phandle_args, and I discovered bugs during testing. I also took the opportunity to rename the function to be like the existing of_parse_phandle(). v2: - moved declaration of of_phandle_args to fix compile on non-DT builds - fixed incorrect index in example usage - fixed incorrect return code handling for empty entries Reviewed-by: Shawn Guo Signed-off-by: Grant Likely --- drivers/of/base.c | 146 ++++++++++++++++++++++++++++-------------------------- 1 file changed, 75 insertions(+), 71 deletions(-) (limited to 'drivers/of/base.c') diff --git a/drivers/of/base.c b/drivers/of/base.c index 9b6588ef0673..c6db9ab9046e 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -824,17 +824,19 @@ of_parse_phandle(struct device_node *np, const char *phandle_name, int index) EXPORT_SYMBOL(of_parse_phandle); /** - * of_parse_phandles_with_args - Find a node pointed by phandle in a list + * 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_node: optional pointer to device_node struct pointer (will be filled) - * @out_args: optional pointer to arguments pointer (will be filled) + * @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_node and out_args, on error returns - * appropriate errno value. + * 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->node + * pointer. * * Example: * @@ -851,94 +853,96 @@ EXPORT_SYMBOL(of_parse_phandle); * } * * To get a device_node of the `node2' node you may call this: - * of_parse_phandles_with_args(node3, "list", "#list-cells", 2, &node2, &args); + * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args); */ -int of_parse_phandles_with_args(struct device_node *np, const char *list_name, +int of_parse_phandle_with_args(struct device_node *np, const char *list_name, const char *cells_name, int index, - struct device_node **out_node, - const void **out_args) + struct of_phandle_args *out_args) { - int ret = -EINVAL; - const __be32 *list; - const __be32 *list_end; - int size; - int cur_index = 0; + const __be32 *list, *list_end; + int size, cur_index = 0; + uint32_t count = 0; struct device_node *node = NULL; - const void *args = NULL; + phandle phandle; + /* Retrieve the phandle list property */ list = of_get_property(np, list_name, &size); - if (!list) { - ret = -ENOENT; - goto err0; - } + if (!list) + return -EINVAL; list_end = list + size / sizeof(*list); + /* Loop over the phandles until all the requested entry is found */ while (list < list_end) { - const __be32 *cells; - phandle phandle; + 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++); - args = list; - - /* one cell hole in the list = <>; */ - if (!phandle) - goto next; - - node = of_find_node_by_phandle(phandle); - if (!node) { - pr_debug("%s: could not find phandle\n", - np->full_name); - goto err0; - } + if (phandle) { + /* + * Find the provider node and parse the #*-cells + * property to determine the argument length + */ + node = of_find_node_by_phandle(phandle); + if (!node) { + pr_err("%s: could not find phandle\n", + np->full_name); + break; + } + if (of_property_read_u32(node, cells_name, &count)) { + pr_err("%s: could not get %s for %s\n", + np->full_name, cells_name, + node->full_name); + break; + } - cells = of_get_property(node, cells_name, &size); - if (!cells || size != sizeof(*cells)) { - pr_debug("%s: could not get %s for %s\n", - np->full_name, cells_name, node->full_name); - goto err1; + /* + * Make sure that the arguments actually fit in the + * remaining property data length + */ + if (list + count > list_end) { + pr_err("%s: arguments longer than property\n", + np->full_name); + break; + } } - list += be32_to_cpup(cells); - if (list > list_end) { - pr_debug("%s: insufficient arguments length\n", - np->full_name); - goto err1; + /* + * 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. + */ + if (cur_index == index) { + if (!phandle) + return -ENOENT; + + if (out_args) { + int i; + if (WARN_ON(count > MAX_PHANDLE_ARGS)) + count = 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++); + } + return 0; } -next: - if (cur_index == index) - break; of_node_put(node); node = NULL; - args = NULL; + list += count; cur_index++; } - if (!node) { - /* - * args w/o node indicates that the loop above has stopped at - * the 'hole' cell. Report this differently. - */ - if (args) - ret = -EEXIST; - else - ret = -ENOENT; - goto err0; - } - - if (out_node) - *out_node = node; - if (out_args) - *out_args = args; - - return 0; -err1: - of_node_put(node); -err0: - pr_debug("%s failed with status %d\n", __func__, ret); - return ret; + /* Loop exited without finding a valid entry; return an error */ + if (node) + of_node_put(node); + return -EINVAL; } -EXPORT_SYMBOL(of_parse_phandles_with_args); +EXPORT_SYMBOL(of_parse_phandle_with_args); /** * prom_add_property - Add a property to a node -- cgit v1.2.3