| Message ID | 20131202.130220.1404999403649937134.hdoyu@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Mon, Dec 2, 2013 at 5:02 AM, Hiroshi Doyu <hdoyu@nvidia.com> wrote: > Stephen Warren <swarren@wwwdotorg.org> wrote @ Sun, 1 Dec 2013 20:00:09 +0100: > >> On 11/29/2013 04:46 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. >> > >> > Introduced a new struct "of_phandle_iter" to keep the state when >> > iterating over the list. >> > >> > Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com> >> > --- >> > 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: >> >> > + 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 <hdoyu@nvidia.com> > > 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@nvidia.com> > --- > 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@nvidia.com> > --- > 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) These 2 if's can be combined: if (!cur || (end - cur <= 0)) > + return NULL; > + > + phandle = be32_to_cpup(cur++); > + if (!phandle) > + return NULL; Won't of_find_node_by_phandle do this check? > + > + 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) Need to update the arguments. > +{ > + 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, \ Some extra whitespace here. > + 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
On Mon, 2 Dec 2013 15:39:25 +0100 Rob Herring <robherring2@gmail.com> wrote: > On Mon, Dec 2, 2013 at 5:02 AM, Hiroshi Doyu <hdoyu@nvidia.com> wrote: > > Stephen Warren <swarren@wwwdotorg.org> wrote @ Sun, 1 Dec 2013 20:00:09 +0100: > > > >> On 11/29/2013 04:46 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. > >> > > >> > Introduced a new struct "of_phandle_iter" to keep the state when > >> > iterating over the list. > >> > > >> > Signed-off-by: Hiroshi Doyu <hdoyu@nvidia.com> .... Rob, thank you for review. I'll fix them and put this one into the next v7 series.
On 12/02/2013 04:02 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. > diff --git a/drivers/of/base.c b/drivers/of/base.c > +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; > +} "bytes" doesn't seem like the correct thing to check in that if statement. The property might exist but be zero length. Perhaps if (cur) would be better, or just initializing *end in all cases (the value won't be used if (!cur), so setting *end to a bogus value in that case won't matter). > +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) ... > + if (!cur) > + return NULL; > + > + if (end - cur <= 0) > + return NULL; Related, don't you want if (cur >= end) there; just compare the pointers directly rather than explicitly calculating and testing the difference?
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);