[RFC][PATCHv6+++ 01/13] of: introduce of_property_for_earch_phandle_with_args()
From: Hiroshi Doyu <hidden>
Date: 2013-12-02 11:02:53
Also in:
linux-devicetree, linux-iommu, linux-tegra, lkml
Subsystem:
open firmware and flattened device tree, the rest · Maintainers:
Rob Herring, Saravana Kannan, Linus Torvalds
Stephen Warren [off-list ref] wrote @ Sun, 1 Dec 2013 20:00:09 +0100:
On 11/29/2013 04:46 AM, Hiroshi Doyu wrote: ...quoted
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 <redacted> --- v6+++:Surely that's v9; "+++" is rather unusual.
My intention was to put this into the next v7 series after I get this reviewed as RFC. ...
Together with removing:quoted
+ const char *cells_name; + int cell_count;... then you'd only be left with cur/end, so I think you could get away without a struct at all, but simply "cur" as the iterator variable, plus "end" as the one temp variable.
Although the above proposal would be alsmot same as "[RFC][PATCHv6++ 01/13]"(*1) where I use *list(cur) and rem as remaining count, here's the update. I'll put this into v7 series. ---8<------8<------8<------8<------8<------8<------8<------8<------8<--- From: Hiroshi Doyu <redacted> 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. Signed-off-by: Hiroshi Doyu <redacted> --- v6++++: Iterate without intrducing a new struct. 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 <redacted> --- drivers/of/base.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++++++ include/linux/of.h | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 87 insertions(+)
diff --git a/drivers/of/base.c b/drivers/of/base.c
index f807d0e..7501f24 100644
--- a/drivers/of/base.c
+++ b/drivers/of/base.c@@ -1201,6 +1201,59 @@ void of_print_phandle_args(const char *msg, const struct of_phandle_args *args) printk("\n"); } +const __be32 *of_phandle_iter_next(const char *cells_name, int cell_count, + const __be32 *cur, const __be32 *end, + struct of_phandle_args *out_args) +{ + phandle phandle; + struct device_node *dn; + int i; + + if (!cells_name && !cell_count) + return NULL; + + if (!cur) + return NULL; + + if (end - cur <= 0) + return NULL; + + phandle = be32_to_cpup(cur++); + if (!phandle) + return NULL; + + dn = of_find_node_by_phandle(phandle); + if (!dn) + return NULL; + + if (cells_name) + if (of_property_read_u32(dn, cells_name, &cell_count)) + return NULL; + + out_args->np = dn; + out_args->args_count = cell_count; + for (i = 0; i < cell_count; i++) + out_args->args[i] = be32_to_cpup(cur++); + + return cur; +} +EXPORT_SYMBOL_GPL(of_phandle_iter_next); + +const __be32 *of_phandle_iter_init(const struct device_node *np, + const char *list_name, + const __be32 **end) +{ + size_t bytes; + const __be32 *cur; + + cur = of_get_property(np, list_name, &bytes); + if (bytes) + *end = cur + bytes / sizeof(*cur); + + return cur; +} +EXPORT_SYMBOL_GPL(of_phandle_iter_init); + 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..c23710b 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h@@ -303,6 +303,14 @@ 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 const __be32 *of_phandle_iter_init(const struct device_node *np, + const char *list_name, + const __be32 **end); +extern const __be32 *of_phandle_iter_next(const char *cells_name, + int cell_count, + const __be32 *cur, const __be32 *end, + 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 +535,24 @@ static inline int of_count_phandle_with_args(struct device_node *np, return -ENOSYS; } +static inline const __be32 *of_phandle_iter_init(const struct device_node *np, + const char *list_name, + const char *cells_name, + const int cell_count, + struct of_phandle_args *out_args) +{ + return NULL; +} + +static inline const __be32 *of_phandle_iter_next(const char *cells_name, + int cell_count, + const __be32 *cur, + const __be32 *end, + struct of_phandle_args *out_args); +{ + return NULL; +} + static inline int of_alias_get_id(struct device_node *np, const char *stem) { return -ENOSYS;
@@ -613,6 +639,14 @@ 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(node, list_name, cells_name, \ + cell_count, out_args, cur, end) \ + for (cur = of_phandle_iter_init(node, list_name, &end), \ + cur = of_phandle_iter_next(cells_name, cell_count, \ + cur, end, &out_args); \ + cur; \ + cur = of_phandle_iter_next(cells_name, cell_count, cur, end, &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
*1:
http://lists.linuxfoundation.org/pipermail/iommu/2013-November/007086.html