On Wed, 11 Dec 2013 14:33:38 +0100, Hiroshi Doyu <hdoyu@xxxxxxxxxx> wrote: > Hi Grant, > > Grant Likely <grant.likely@xxxxxxxxxx> wrote @ Wed, 11 Dec 2013 14:28:45 +0100: > > > On Thu, 21 Nov 2013 11:57:00 -0700, Stephen Warren <swarren@xxxxxxxxxxxxx> wrote: > > > On 11/21/2013 10:17 AM, Hiroshi Doyu wrote: > > > > 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 <hdoyu@xxxxxxxxxx> > > > > --- > > > > v6+: > > > > Use the description, which Grant Likely proposed, to be full enough > > > > that a future reader can figure out why a patch was written. > > > > http://lists.linuxfoundation.org/pipermail/iommu/2013-November/007062.html > ... > > > That's right, I forgot I said that. Yes please fix the implementation. > > Here's the latest. I'll include this with the next v7 series. > > Can I get your Acked-by with this? > > --8<---- > > From 8f7c0404aa68f0e8dbe0babc240590f6528ecc1f Mon Sep 17 00:00:00 2001 > From: Hiroshi Doyu <hdoyu@xxxxxxxxxx> > Date: Fri, 15 Nov 2013 10:52:53 +0200 > Subject: [PATCH] of: introduce of_property_for_each_phandle_with_args() > > 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 <hdoyu@xxxxxxxxxx> > Cc: Rob Herring <robherring2@xxxxxxxxx> > --- > v7: > Fixed some minors pointed by Rob and Stephen. > > 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 <hdoyu@xxxxxxxxxx> > --- > drivers/of/base.c | 46 ++++++++++++++++++++++++++++++++++++++++++++++ > include/linux/of.h | 32 ++++++++++++++++++++++++++++++++ > 2 files changed, 78 insertions(+) > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index f807d0e..cd4ab05 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -1201,6 +1201,52 @@ 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) Having to pass in cells_name, cell_count, cur and end each time seems a little odd. Can a state structure be used instead? struct of_phandle_iter_state { const char *cells_name; int cells_count; const __be32 *cur; const __be32 *end; struct of_phandle_args out_args; } Make the caller provide one of those and fill it in with the init function. > +{ > + struct device_node *dn; > + int i; > + > + if (!cells_name && !cell_count) > + return NULL; > + > + if (!cur || (cur >= end)) > + return NULL; > + > + dn = of_find_node_by_phandle(be32_to_cpup(cur++)); > + 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); > + *end = cur; > + if (bytes) > + *end += 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..4345582 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 +535,22 @@ 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 __be32 **end) > +{ > + 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 +637,14 @@ 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); \ The above construct is a little odd. Why wouldn't the initializer provide the first element (or NULL if empty) right at the start. That in combination with the suggestion I made above would change the macro to be: #define of_property_for_each_phandle_with_args(node, list_name, cells_name, \ cell_count, &iter_state) \ for (cur = of_phandle_iter_init(node, list_name, cells_name, \ cells_count, &iter_state); \ cur; cur = of_phandle_iter_next(&iter_state)) \ Simpler, right? It also means whatever the user passed in for cells_name, cell_count won't get evaluated every time through the loop. g. > + 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 -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
