Hiroshi Doyu <hdoyu@xxxxxxxxxx> wrote @ Thu, 28 Nov 2013 14:58:18 +0200 (EET): .... > > In other words, an implementation more along the lines of > > include/linux/of.h's: > > > > #define of_property_for_each_u32(np, propname, prop, p, u) \ > > for (prop = of_find_property(np, propname, NULL), \ > > p = of_prop_next_u32(prop, NULL, &u); \ > > p; \ > > p = of_prop_next_u32(prop, p, &u)) > > > > ... so you'd need functions like of_prop_first_specifier() and > > of_prop_next_specifier(), and perhaps some associated set of state > > variables, perhaps with all the state wrapped into a single struct for > > simplicity. > > Although I couldn't invent any struct to hold params and state here, > I'd like you to review the following interface is ok or not. Tried again to introduce a new struct to keep track of iteration state as below: ----8<---------8<---------8<---------8<---------8<---------8<-- From: Hiroshi Doyu <hdoyu@xxxxxxxxxx> Iterating over a property containing a list of phandles with arguments is a common operation for device drivers. This patch adds a new of_property_for_each_phandle_with_args() macro to make the iteration simpler. Introduced a new struct "of_phandle_iter" to keep the state when iterating over the list. Signed-off-by: Hiroshi Doyu <hdoyu@xxxxxxxxxx> --- v6+++: Introduced a new struct "of_phandle_iter" to keep the state when iterating over the list. v6++: Optimized to avoid O(n^2), suggested by Stephen Warren. http://lists.linuxfoundation.org/pipermail/iommu/2013-November/007066.html I didn't introduce any struct to hold params and state here. v6+: Use the description, which Grant Likely proposed, to be full enough that a future reader can figure out why a patch was written. v5: New patch for v5. Signed-off-by: Hiroshi Doyu <hdoyu@xxxxxxxxxx> --- drivers/of/base.c | 71 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/of.h | 45 ++++++++++++++++++++++++++++++++++ 2 files changed, 116 insertions(+) diff --git a/drivers/of/base.c b/drivers/of/base.c index f807d0e..16fb2d9 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -1201,6 +1201,77 @@ void of_print_phandle_args(const char *msg, const struct of_phandle_args *args) printk("\n"); } +void of_phandle_iter_next(struct of_phandle_iter *iter, + struct of_phandle_args *out_args) +{ + phandle phandle; + struct device_node *dn; + int i, count = iter->cell_count; + + iter->err = -EINVAL; + if (!iter->cells_name && !iter->cell_count) + return; + + phandle = be32_to_cpup(iter->cur++); + if (!phandle) + return; + + dn = of_find_node_by_phandle(phandle); + if (!dn) + return; + + if (iter->cells_name) + if (of_property_read_u32(dn, iter->cells_name, &count)) + return; + + out_args->np = dn; + out_args->args_count = count; + for (i = 0; i < count; i++) + out_args->args[i] = be32_to_cpup(iter->cur++); + + iter->err = 0; +} +EXPORT_SYMBOL_GPL(of_phandle_iter_next); + +static void __of_phandle_iter_set(struct of_phandle_iter *iter, + const struct device_node *np, + const char *list_name) +{ + size_t bytes; + const __be32 *prop; + + prop = of_get_property(np, list_name, &bytes); + if (!prop) { + iter->err = -EINVAL; + return; + } + + iter->cur = prop; + iter->end = prop + bytes / sizeof(*prop); + iter->err = 0; +} + +void of_phandle_iter_start(struct of_phandle_iter *iter, + const struct device_node *np, + const char *list_name, + const char *cells_name, + int cell_count, + struct of_phandle_args *out_args) +{ + iter->err = -EINVAL; + if (!cells_name && !cell_count) + return; + + iter->cells_name = cells_name; + iter->cell_count = cell_count; + __of_phandle_iter_set(iter, np, list_name); + if (iter->err) + return; + + of_phandle_iter_next(iter, out_args); +} +EXPORT_SYMBOL_GPL(of_phandle_iter_start); + static int __of_parse_phandle_with_args(const struct device_node *np, const char *list_name, const char *cells_name, diff --git a/include/linux/of.h b/include/linux/of.h index 276c546..1132b49 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -74,6 +74,18 @@ struct of_phandle_args { uint32_t args[MAX_PHANDLE_ARGS]; }; +/* + * keep the state at iterating a list of phandles with variable number + * of args + */ +struct of_phandle_iter { + int err; + const __be32 *cur; /* current phandle */ + const __be32 *end; /* end of the last phandle */ + const char *cells_name; + int cell_count; +}; + #ifdef CONFIG_OF_DYNAMIC extern struct device_node *of_node_get(struct device_node *node); extern void of_node_put(struct device_node *node); @@ -303,6 +315,16 @@ extern int of_parse_phandle_with_fixed_args(const struct device_node *np, extern int of_count_phandle_with_args(const struct device_node *np, const char *list_name, const char *cells_name); +extern void of_phandle_iter_start(struct of_phandle_iter *iter, + const struct device_node *np, + const char *list_name, + const char *cells_name, + int cell_count, + struct of_phandle_args *out_args); + +extern void of_phandle_iter_next(struct of_phandle_iter *iter, + struct of_phandle_args *out_args); + extern void of_alias_scan(void * (*dt_alloc)(u64 size, u64 align)); extern int of_alias_get_id(struct device_node *np, const char *stem); @@ -527,6 +549,22 @@ static inline int of_count_phandle_with_args(struct device_node *np, return -ENOSYS; } +static inline void of_phandle_iter_start(struct of_phandle_iter *iter, + const struct device_node *np, + const char *list_name, + const char *cells_name, + const int cell_count, + struct of_phandle_args *out_args) +{ + iter->err = -ENOSYS; +} + +static inline void of_phandle_iter_next(struct of_phandle_iter *iter, + struct of_phandle_args *out_args) +{ + iter->err = -ENOSYS; +} + static inline int of_alias_get_id(struct device_node *np, const char *stem) { return -ENOSYS; @@ -613,6 +651,13 @@ static inline int of_property_read_u32(const struct device_node *np, s; \ s = of_prop_next_string(prop, s)) +#define of_property_for_each_phandle_with_args(iter, node, list_name, \ + cells_name, cell_count, out_args) \ + for (of_phandle_iter_start(&iter, node, list_name, \ + cells_name, cell_count, &out_args); \ + !iter.err && iter.end - iter.cur >= 0 ; \ + of_phandle_iter_next(&iter, &out_args)) + #if defined(CONFIG_PROC_FS) && defined(CONFIG_PROC_DEVICETREE) extern void proc_device_tree_add_node(struct device_node *, struct proc_dir_entry *); extern void proc_device_tree_add_prop(struct proc_dir_entry *pde, struct property *prop); -- 1.8.1.5 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
