On Wed, 11 Dec 2013 14:33:38 +0100, Hiroshi Doyu <hd...@nvidia.com> wrote:
> Hi Grant,
>
> Grant Likely <grant.lik...@linaro.org> wrote @ Wed, 11 Dec 2013 14:28:45
> +0100:
>
> > On Thu, 21 Nov 2013 11:57:00 -0700, Stephen Warren <swar...@wwwdotorg.org>
> > 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 <hd...@nvidia.com>
> > > > ---
> > > > 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 <hd...@nvidia.com>
> 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 <hd...@nvidia.com>
> Cc: Rob Herring <robherri...@gmail.com>
> ---
> 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 <hd...@nvidia.com>
> ---
> 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
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