| Message ID | 3781679.27UF2dWtKL@phil (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Thu, Jan 16, 2014 at 12:04 PM, Heiko Stübner <heiko@sntech.de> wrote: > The need to know the number of array elements in a property is > a common pattern. To prevent duplication of open-coded implementations > add a helper function that also centralises strict sanity checking > and DTB format details. > > Suggested-by: Mark Rutland <mark.rutland@arm.com> > Signed-off-by: Heiko Stuebner <heiko@sntech.de> > --- > Hi Mark, > did you mean it like this? I've tested it with the sram-reserve change and > it made the part of the determining the number elements a lot nicer :-) > > drivers/of/base.c | 32 ++++++++++++++++++++++++++++++++ > include/linux/of.h | 8 ++++++++ > 2 files changed, 40 insertions(+) > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index f807d0e..0f40ea5 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -920,6 +920,38 @@ int of_property_read_u32_index(const struct device_node *np, > EXPORT_SYMBOL_GPL(of_property_read_u32_index); > > /** > + * of_property_count_u32_elems - Count the number of u32 values in a property > + * > + * @np: device node from which the property value is to be read. > + * @propname: name of the property to be searched. > + * > + * Search for a property in a device node and count the number of u32 elements > + * in it. Returns number of elements on sucess, -EINVAL if the property does > + * not exist or its length does not match a multiple of u32 and -ENODATA if the > + * property does not have a value. > + */ > +int of_property_count_u32_elems(const struct device_node *np, > + const char *propname) > +{ > + int elem_size = sizeof(u32); This should be a parameter, so functions for different sized properties can be a simple wrapper function. > + int len; > + struct property *prop = of_find_property(np, propname, &len); > + > + if (!prop) > + return -EINVAL; > + if (!prop->value) > + return -ENODATA; > + > + if (prop->length % elem_size != 0) { > + pr_err("size of %s is not a multiple of u32\n", propname); The node name would be useful here too. > + return -EINVAL; > + } > + > + return len / elem_size; > +} > +EXPORT_SYMBOL_GPL(of_property_count_u32_elems); > + > +/** > * of_property_read_u8_array - Find and read an array of u8 from a property. > * > * @np: device node from which the property value is to be read. > diff --git a/include/linux/of.h b/include/linux/of.h > index 276c546..5794942 100644 > --- a/include/linux/of.h > +++ b/include/linux/of.h > @@ -253,6 +253,8 @@ extern struct property *of_find_property(const struct device_node *np, > extern int of_property_read_u32_index(const struct device_node *np, > const char *propname, > u32 index, u32 *out_value); > +extern int of_property_count_u32_elems(const struct device_node *np, > + const char *propname); > extern int of_property_read_u8_array(const struct device_node *np, > const char *propname, u8 *out_values, size_t sz); > extern int of_property_read_u16_array(const struct device_node *np, > @@ -432,6 +434,12 @@ static inline int of_property_read_u32_index(const struct device_node *np, > return -ENOSYS; > } > > +static inline int of_property_count_u32_elems(const struct device_node *np, > + const char *propname) > +{ > + return -ENOSYS; > +} > + > static inline int of_property_read_u8_array(const struct device_node *np, > const char *propname, u8 *out_values, size_t sz) > { > -- > 1.7.10.4 > >
On Thu, Jan 16, 2014 at 06:04:42PM +0000, Heiko Stübner wrote: > The need to know the number of array elements in a property is > a common pattern. To prevent duplication of open-coded implementations > add a helper function that also centralises strict sanity checking > and DTB format details. > > Suggested-by: Mark Rutland <mark.rutland@arm.com> > Signed-off-by: Heiko Stuebner <heiko@sntech.de> > --- > Hi Mark, > did you mean it like this? I've tested it with the sram-reserve change and > it made the part of the determining the number elements a lot nicer :-) Yes! This looks pretty nice! :) > > drivers/of/base.c | 32 ++++++++++++++++++++++++++++++++ > include/linux/of.h | 8 ++++++++ > 2 files changed, 40 insertions(+) > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index f807d0e..0f40ea5 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -920,6 +920,38 @@ int of_property_read_u32_index(const struct device_node *np, > EXPORT_SYMBOL_GPL(of_property_read_u32_index); > > /** > + * of_property_count_u32_elems - Count the number of u32 values in a property > + * > + * @np: device node from which the property value is to be read. > + * @propname: name of the property to be searched. > + * > + * Search for a property in a device node and count the number of u32 elements > + * in it. Returns number of elements on sucess, -EINVAL if the property does > + * not exist or its length does not match a multiple of u32 and -ENODATA if the > + * property does not have a value. > + */ > +int of_property_count_u32_elems(const struct device_node *np, > + const char *propname) > +{ > + int elem_size = sizeof(u32); > + int len; > + struct property *prop = of_find_property(np, propname, &len); > + > + if (!prop) > + return -EINVAL; > + if (!prop->value) > + return -ENODATA; > + > + if (prop->length % elem_size != 0) { > + pr_err("size of %s is not a multiple of u32\n", propname); > + return -EINVAL; > + } > + > + return len / elem_size; > +} > +EXPORT_SYMBOL_GPL(of_property_count_u32_elems); As Rob said in his reply, it would be nice to split this into a static helper that took elem size as a parameter, so we can have the full suite of of_property_count_{u8,u16,u32,u64}_elems. Also, I think you can get rid of len and always use prop->length, as other helpers seem to do. Cheers for putting this together! Mark.
diff --git a/drivers/of/base.c b/drivers/of/base.c index f807d0e..0f40ea5 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -920,6 +920,38 @@ int of_property_read_u32_index(const struct device_node *np, EXPORT_SYMBOL_GPL(of_property_read_u32_index); /** + * of_property_count_u32_elems - Count the number of u32 values in a property + * + * @np: device node from which the property value is to be read. + * @propname: name of the property to be searched. + * + * Search for a property in a device node and count the number of u32 elements + * in it. Returns number of elements on sucess, -EINVAL if the property does + * not exist or its length does not match a multiple of u32 and -ENODATA if the + * property does not have a value. + */ +int of_property_count_u32_elems(const struct device_node *np, + const char *propname) +{ + int elem_size = sizeof(u32); + int len; + struct property *prop = of_find_property(np, propname, &len); + + if (!prop) + return -EINVAL; + if (!prop->value) + return -ENODATA; + + if (prop->length % elem_size != 0) { + pr_err("size of %s is not a multiple of u32\n", propname); + return -EINVAL; + } + + return len / elem_size; +} +EXPORT_SYMBOL_GPL(of_property_count_u32_elems); + +/** * of_property_read_u8_array - Find and read an array of u8 from a property. * * @np: device node from which the property value is to be read. diff --git a/include/linux/of.h b/include/linux/of.h index 276c546..5794942 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -253,6 +253,8 @@ extern struct property *of_find_property(const struct device_node *np, extern int of_property_read_u32_index(const struct device_node *np, const char *propname, u32 index, u32 *out_value); +extern int of_property_count_u32_elems(const struct device_node *np, + const char *propname); extern int of_property_read_u8_array(const struct device_node *np, const char *propname, u8 *out_values, size_t sz); extern int of_property_read_u16_array(const struct device_node *np, @@ -432,6 +434,12 @@ static inline int of_property_read_u32_index(const struct device_node *np, return -ENOSYS; } +static inline int of_property_count_u32_elems(const struct device_node *np, + const char *propname) +{ + return -ENOSYS; +} + static inline int of_property_read_u8_array(const struct device_node *np, const char *propname, u8 *out_values, size_t sz) {
The need to know the number of array elements in a property is a common pattern. To prevent duplication of open-coded implementations add a helper function that also centralises strict sanity checking and DTB format details. Suggested-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Heiko Stuebner <heiko@sntech.de> --- Hi Mark, did you mean it like this? I've tested it with the sram-reserve change and it made the part of the determining the number elements a lot nicer :-) drivers/of/base.c | 32 ++++++++++++++++++++++++++++++++ include/linux/of.h | 8 ++++++++ 2 files changed, 40 insertions(+)