| Message ID | 20201014145418.31838-2-rf@opensource.cirrus.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add dts for Rpi4 + Cirrus Lochnagar and codecs | expand |
On Wed, Oct 14, 2020 at 9:54 AM Richard Fitzgerald <rf@opensource.cirrus.com> wrote: > > Add an equivalent of of_count_phandle_with_args() for fixed argument > sets, to pair with of_parse_phandle_with_fixed_args(). > > Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> > --- > drivers/of/base.c | 42 ++++++++++++++++++++++++++++++++++++++++++ > include/linux/of.h | 9 +++++++++ > 2 files changed, 51 insertions(+) > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index ea44fea99813..45d8b0e65345 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -1772,6 +1772,48 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na > } > EXPORT_SYMBOL(of_count_phandle_with_args); > > +/** > + * of_count_phandle_with_fixed_args() - Find the number of phandles references in a property > + * @np: pointer to a device tree node containing a list > + * @list_name: property name that contains a list > + * @cell_count: number of argument cells following the phandle > + * > + * Returns the number of phandle + argument tuples within a property. It > + * is a typical pattern to encode a list of phandle and variable > + * arguments into a single property. > + */ > +int of_count_phandle_with_fixed_args(const struct device_node *np, > + const char *list_name, > + int cells_count) > +{ Looks to me like you can refactor of_count_phandle_with_args to handle both case and then make this and of_count_phandle_with_args simple wrapper functions. > + struct of_phandle_iterator it; > + int rc, cur_index = 0; > + > + if (!cells_count) { > + const __be32 *list; > + int size; > + > + list = of_get_property(np, list_name, &size); > + if (!list) > + return -ENOENT; > + > + return size / sizeof(*list); > + } > + > + rc = of_phandle_iterator_init(&it, np, list_name, NULL, cells_count); > + if (rc) > + return rc; > + > + while ((rc = of_phandle_iterator_next(&it)) == 0) > + cur_index += 1; > + > + if (rc != -ENOENT) > + return rc; > + > + return cur_index; > +} > +EXPORT_SYMBOL(of_count_phandle_with_fixed_args); > + > /** > * __of_add_property - Add a property to a node without lock operations > */ > diff --git a/include/linux/of.h b/include/linux/of.h > index 5cf7ae0465d1..9f315da4e9da 100644 > --- a/include/linux/of.h > +++ b/include/linux/of.h > @@ -377,6 +377,8 @@ extern int of_parse_phandle_with_fixed_args(const struct device_node *np, > struct of_phandle_args *out_args); > extern int of_count_phandle_with_args(const struct device_node *np, > const char *list_name, const char *cells_name); > +extern int of_count_phandle_with_fixed_args(const struct device_node *np, > + const char *list_name, int cells_count); > > /* phandle iterator functions */ > extern int of_phandle_iterator_init(struct of_phandle_iterator *it, > @@ -886,6 +888,13 @@ static inline int of_count_phandle_with_args(struct device_node *np, > return -ENOSYS; > } > > +static inline int of_count_phandle_with_fixed_args(const struct device_node *np, > + const char *list_name, > + int cells_count) > +{ > + return -ENOSYS; > +} > + > static inline int of_phandle_iterator_init(struct of_phandle_iterator *it, > const struct device_node *np, > const char *list_name, > -- > 2.20.1 >
On 2020-10-14 19:39, Rob Herring wrote: > On Wed, Oct 14, 2020 at 9:54 AM Richard Fitzgerald > <rf@opensource.cirrus.com> wrote: >> >> Add an equivalent of of_count_phandle_with_args() for fixed argument >> sets, to pair with of_parse_phandle_with_fixed_args(). >> >> Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> >> --- >> drivers/of/base.c | 42 ++++++++++++++++++++++++++++++++++++++++++ >> include/linux/of.h | 9 +++++++++ >> 2 files changed, 51 insertions(+) >> >> diff --git a/drivers/of/base.c b/drivers/of/base.c >> index ea44fea99813..45d8b0e65345 100644 >> --- a/drivers/of/base.c >> +++ b/drivers/of/base.c >> @@ -1772,6 +1772,48 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na >> } >> EXPORT_SYMBOL(of_count_phandle_with_args); >> >> +/** >> + * of_count_phandle_with_fixed_args() - Find the number of phandles references in a property >> + * @np: pointer to a device tree node containing a list >> + * @list_name: property name that contains a list >> + * @cell_count: number of argument cells following the phandle >> + * >> + * Returns the number of phandle + argument tuples within a property. It >> + * is a typical pattern to encode a list of phandle and variable >> + * arguments into a single property. >> + */ >> +int of_count_phandle_with_fixed_args(const struct device_node *np, >> + const char *list_name, >> + int cells_count) >> +{ > > Looks to me like you can refactor of_count_phandle_with_args to handle > both case and then make this and of_count_phandle_with_args simple > wrapper functions. Although for just counting the number of phandles each with n arguments that a property contains, isn't that simply a case of dividing the property length by n + 1? The phandles themselves will be validated by any subsequent of_parse_phandle*() call anyway, so there doesn't seem much point in doing more work then necessary here. >> + struct of_phandle_iterator it; >> + int rc, cur_index = 0; >> + >> + if (!cells_count) { >> + const __be32 *list; >> + int size; >> + >> + list = of_get_property(np, list_name, &size); >> + if (!list) >> + return -ENOENT; >> + >> + return size / sizeof(*list); Case in point - if it's OK to do exactly that for n == 0, then clearly we're *aren't* fussed about validating anything, so the n > 0 code below is nothing more than a massively expensive way to check for a nonzero remainder :/ Robin. >> + } >> + >> + rc = of_phandle_iterator_init(&it, np, list_name, NULL, cells_count); >> + if (rc) >> + return rc; >> + >> + while ((rc = of_phandle_iterator_next(&it)) == 0) >> + cur_index += 1; >> + >> + if (rc != -ENOENT) >> + return rc; >> + >> + return cur_index; >> +} >> +EXPORT_SYMBOL(of_count_phandle_with_fixed_args); >> + >> /** >> * __of_add_property - Add a property to a node without lock operations >> */ >> diff --git a/include/linux/of.h b/include/linux/of.h >> index 5cf7ae0465d1..9f315da4e9da 100644 >> --- a/include/linux/of.h >> +++ b/include/linux/of.h >> @@ -377,6 +377,8 @@ extern int of_parse_phandle_with_fixed_args(const struct device_node *np, >> struct of_phandle_args *out_args); >> extern int of_count_phandle_with_args(const struct device_node *np, >> const char *list_name, const char *cells_name); >> +extern int of_count_phandle_with_fixed_args(const struct device_node *np, >> + const char *list_name, int cells_count); >> >> /* phandle iterator functions */ >> extern int of_phandle_iterator_init(struct of_phandle_iterator *it, >> @@ -886,6 +888,13 @@ static inline int of_count_phandle_with_args(struct device_node *np, >> return -ENOSYS; >> } >> >> +static inline int of_count_phandle_with_fixed_args(const struct device_node *np, >> + const char *list_name, >> + int cells_count) >> +{ >> + return -ENOSYS; >> +} >> + >> static inline int of_phandle_iterator_init(struct of_phandle_iterator *it, >> const struct device_node *np, >> const char *list_name, >> -- >> 2.20.1 >> > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
On 15/10/2020 17:52, Robin Murphy wrote: > On 2020-10-14 19:39, Rob Herring wrote: >> On Wed, Oct 14, 2020 at 9:54 AM Richard Fitzgerald >> <rf@opensource.cirrus.com> wrote: >>> >>> Add an equivalent of of_count_phandle_with_args() for fixed argument >>> sets, to pair with of_parse_phandle_with_fixed_args(). >>> >>> Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> >>> --- >>> drivers/of/base.c | 42 ++++++++++++++++++++++++++++++++++++++++++ >>> include/linux/of.h | 9 +++++++++ >>> 2 files changed, 51 insertions(+) >>> >>> diff --git a/drivers/of/base.c b/drivers/of/base.c >>> index ea44fea99813..45d8b0e65345 100644 >>> --- a/drivers/of/base.c >>> +++ b/drivers/of/base.c >>> @@ -1772,6 +1772,48 @@ int of_count_phandle_with_args(const struct >>> device_node *np, const char *list_na >>> } >>> EXPORT_SYMBOL(of_count_phandle_with_args); >>> >>> +/** >>> + * of_count_phandle_with_fixed_args() - Find the number of phandles >>> references in a property >>> + * @np: pointer to a device tree node containing a list >>> + * @list_name: property name that contains a list >>> + * @cell_count: number of argument cells following the phandle >>> + * >>> + * Returns the number of phandle + argument tuples within a >>> property. It >>> + * is a typical pattern to encode a list of phandle and variable >>> + * arguments into a single property. >>> + */ >>> +int of_count_phandle_with_fixed_args(const struct device_node *np, >>> + const char *list_name, >>> + int cells_count) >>> +{ >> >> Looks to me like you can refactor of_count_phandle_with_args to handle >> both case and then make this and of_count_phandle_with_args simple >> wrapper functions. > > Although for just counting the number of phandles each with n arguments > that a property contains, isn't that simply a case of dividing the > property length by n + 1? The phandles themselves will be validated by > any subsequent of_parse_phandle*() call anyway, so there doesn't seem > much point in doing more work then necessary here. > As I'm not a DT expert, I'm reluctant to change existing algorithms that could break everything just for the trivial case of adding a fixed arguments count. I have a re-worked patch as suggested by Rob that re-uses the existing counting function for both cases. >>> + struct of_phandle_iterator it; >>> + int rc, cur_index = 0; >>> + >>> + if (!cells_count) { >>> + const __be32 *list; >>> + int size; >>> + >>> + list = of_get_property(np, list_name, &size); >>> + if (!list) >>> + return -ENOENT; >>> + >>> + return size / sizeof(*list); > > Case in point - if it's OK to do exactly that for n == 0, then clearly > we're *aren't* fussed about validating anything, so the n > 0 code below > is nothing more than a massively expensive way to check for a nonzero > remainder :/ > > Robin. > >>> + } >>> + >>> + rc = of_phandle_iterator_init(&it, np, list_name, NULL, >>> cells_count); >>> + if (rc) >>> + return rc; >>> + >>> + while ((rc = of_phandle_iterator_next(&it)) == 0) >>> + cur_index += 1; >>> + >>> + if (rc != -ENOENT) >>> + return rc; >>> + >>> + return cur_index; >>> +} >>> +EXPORT_SYMBOL(of_count_phandle_with_fixed_args); >>> + >>> /** >>> * __of_add_property - Add a property to a node without lock >>> operations >>> */ >>> diff --git a/include/linux/of.h b/include/linux/of.h >>> index 5cf7ae0465d1..9f315da4e9da 100644 >>> --- a/include/linux/of.h >>> +++ b/include/linux/of.h >>> @@ -377,6 +377,8 @@ extern int of_parse_phandle_with_fixed_args(const >>> struct device_node *np, >>> struct of_phandle_args *out_args); >>> extern int of_count_phandle_with_args(const struct device_node *np, >>> const char *list_name, const char *cells_name); >>> +extern int of_count_phandle_with_fixed_args(const struct device_node >>> *np, >>> + const char *list_name, int cells_count); >>> >>> /* phandle iterator functions */ >>> extern int of_phandle_iterator_init(struct of_phandle_iterator *it, >>> @@ -886,6 +888,13 @@ static inline int >>> of_count_phandle_with_args(struct device_node *np, >>> return -ENOSYS; >>> } >>> >>> +static inline int of_count_phandle_with_fixed_args(const struct >>> device_node *np, >>> + const char >>> *list_name, >>> + int cells_count) >>> +{ >>> + return -ENOSYS; >>> +} >>> + >>> static inline int of_phandle_iterator_init(struct >>> of_phandle_iterator *it, >>> const struct device_node >>> *np, >>> const char *list_name, >>> -- >>> 2.20.1 >>> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >>
On Thu, Oct 15, 2020 at 11:52 AM Robin Murphy <robin.murphy@arm.com> wrote: > > On 2020-10-14 19:39, Rob Herring wrote: > > On Wed, Oct 14, 2020 at 9:54 AM Richard Fitzgerald > > <rf@opensource.cirrus.com> wrote: > >> > >> Add an equivalent of of_count_phandle_with_args() for fixed argument > >> sets, to pair with of_parse_phandle_with_fixed_args(). > >> > >> Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> > >> --- > >> drivers/of/base.c | 42 ++++++++++++++++++++++++++++++++++++++++++ > >> include/linux/of.h | 9 +++++++++ > >> 2 files changed, 51 insertions(+) > >> > >> diff --git a/drivers/of/base.c b/drivers/of/base.c > >> index ea44fea99813..45d8b0e65345 100644 > >> --- a/drivers/of/base.c > >> +++ b/drivers/of/base.c > >> @@ -1772,6 +1772,48 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na > >> } > >> EXPORT_SYMBOL(of_count_phandle_with_args); > >> > >> +/** > >> + * of_count_phandle_with_fixed_args() - Find the number of phandles references in a property > >> + * @np: pointer to a device tree node containing a list > >> + * @list_name: property name that contains a list > >> + * @cell_count: number of argument cells following the phandle > >> + * > >> + * Returns the number of phandle + argument tuples within a property. It > >> + * is a typical pattern to encode a list of phandle and variable > >> + * arguments into a single property. > >> + */ > >> +int of_count_phandle_with_fixed_args(const struct device_node *np, > >> + const char *list_name, > >> + int cells_count) > >> +{ > > > > Looks to me like you can refactor of_count_phandle_with_args to handle > > both case and then make this and of_count_phandle_with_args simple > > wrapper functions. > > Although for just counting the number of phandles each with n arguments > that a property contains, isn't that simply a case of dividing the > property length by n + 1? The phandles themselves will be validated by > any subsequent of_parse_phandle*() call anyway, so there doesn't seem > much point in doing more work then necessary here. > > >> + struct of_phandle_iterator it; > >> + int rc, cur_index = 0; > >> + > >> + if (!cells_count) { > >> + const __be32 *list; > >> + int size; > >> + > >> + list = of_get_property(np, list_name, &size); > >> + if (!list) > >> + return -ENOENT; > >> + > >> + return size / sizeof(*list); > > Case in point - if it's OK to do exactly that for n == 0, then clearly > we're *aren't* fussed about validating anything, so the n > 0 code below > is nothing more than a massively expensive way to check for a nonzero > remainder :/ Indeed. We should just generalize this. It can still be refactored to shared code. It's probably worthwhile to check for a remainder here IMO. Rob
On 16/10/2020 14:31, Rob Herring wrote: > On Thu, Oct 15, 2020 at 11:52 AM Robin Murphy <robin.murphy@arm.com> wrote: >> >> On 2020-10-14 19:39, Rob Herring wrote: >>> On Wed, Oct 14, 2020 at 9:54 AM Richard Fitzgerald >>> <rf@opensource.cirrus.com> wrote: >>>> >>>> Add an equivalent of of_count_phandle_with_args() for fixed argument >>>> sets, to pair with of_parse_phandle_with_fixed_args(). >>>> >>>> Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> >>>> --- >>>> drivers/of/base.c | 42 ++++++++++++++++++++++++++++++++++++++++++ >>>> include/linux/of.h | 9 +++++++++ >>>> 2 files changed, 51 insertions(+) >>>> >>>> diff --git a/drivers/of/base.c b/drivers/of/base.c >>>> index ea44fea99813..45d8b0e65345 100644 >>>> --- a/drivers/of/base.c >>>> +++ b/drivers/of/base.c >>>> @@ -1772,6 +1772,48 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na >>>> } >>>> EXPORT_SYMBOL(of_count_phandle_with_args); >>>> >>>> +/** >>>> + * of_count_phandle_with_fixed_args() - Find the number of phandles references in a property >>>> + * @np: pointer to a device tree node containing a list >>>> + * @list_name: property name that contains a list >>>> + * @cell_count: number of argument cells following the phandle >>>> + * >>>> + * Returns the number of phandle + argument tuples within a property. It >>>> + * is a typical pattern to encode a list of phandle and variable >>>> + * arguments into a single property. >>>> + */ >>>> +int of_count_phandle_with_fixed_args(const struct device_node *np, >>>> + const char *list_name, >>>> + int cells_count) >>>> +{ >>> >>> Looks to me like you can refactor of_count_phandle_with_args to handle >>> both case and then make this and of_count_phandle_with_args simple >>> wrapper functions. >> >> Although for just counting the number of phandles each with n arguments >> that a property contains, isn't that simply a case of dividing the >> property length by n + 1? The phandles themselves will be validated by >> any subsequent of_parse_phandle*() call anyway, so there doesn't seem >> much point in doing more work then necessary here. >> >>>> + struct of_phandle_iterator it; >>>> + int rc, cur_index = 0; >>>> + >>>> + if (!cells_count) { >>>> + const __be32 *list; >>>> + int size; >>>> + >>>> + list = of_get_property(np, list_name, &size); >>>> + if (!list) >>>> + return -ENOENT; >>>> + >>>> + return size / sizeof(*list); >> >> Case in point - if it's OK to do exactly that for n == 0, then clearly >> we're *aren't* fussed about validating anything, so the n > 0 code below >> is nothing more than a massively expensive way to check for a nonzero >> remainder :/ > > Indeed. We should just generalize this. It can still be refactored to > shared code. > > It's probably worthwhile to check for a remainder here IMO. > Ok, I looked at the implementation of of_phandle_iterator_next() and it is in fact simply incrementing by 'count' 32-bit words. So as Robin said the count_phandle_with_x_args()functions could simply divide the length by count+1. However, may I suggest that should be done in a separate patch after my patch to add count_phandle_with_fixed_args()? That way, if replacing the iteration with the simple length divide causes any unforeseen problems the patch can just be reverted. > Rob >
diff --git a/drivers/of/base.c b/drivers/of/base.c index ea44fea99813..45d8b0e65345 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -1772,6 +1772,48 @@ int of_count_phandle_with_args(const struct device_node *np, const char *list_na } EXPORT_SYMBOL(of_count_phandle_with_args); +/** + * of_count_phandle_with_fixed_args() - Find the number of phandles references in a property + * @np: pointer to a device tree node containing a list + * @list_name: property name that contains a list + * @cell_count: number of argument cells following the phandle + * + * Returns the number of phandle + argument tuples within a property. It + * is a typical pattern to encode a list of phandle and variable + * arguments into a single property. + */ +int of_count_phandle_with_fixed_args(const struct device_node *np, + const char *list_name, + int cells_count) +{ + struct of_phandle_iterator it; + int rc, cur_index = 0; + + if (!cells_count) { + const __be32 *list; + int size; + + list = of_get_property(np, list_name, &size); + if (!list) + return -ENOENT; + + return size / sizeof(*list); + } + + rc = of_phandle_iterator_init(&it, np, list_name, NULL, cells_count); + if (rc) + return rc; + + while ((rc = of_phandle_iterator_next(&it)) == 0) + cur_index += 1; + + if (rc != -ENOENT) + return rc; + + return cur_index; +} +EXPORT_SYMBOL(of_count_phandle_with_fixed_args); + /** * __of_add_property - Add a property to a node without lock operations */ diff --git a/include/linux/of.h b/include/linux/of.h index 5cf7ae0465d1..9f315da4e9da 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -377,6 +377,8 @@ extern int of_parse_phandle_with_fixed_args(const struct device_node *np, struct of_phandle_args *out_args); extern int of_count_phandle_with_args(const struct device_node *np, const char *list_name, const char *cells_name); +extern int of_count_phandle_with_fixed_args(const struct device_node *np, + const char *list_name, int cells_count); /* phandle iterator functions */ extern int of_phandle_iterator_init(struct of_phandle_iterator *it, @@ -886,6 +888,13 @@ static inline int of_count_phandle_with_args(struct device_node *np, return -ENOSYS; } +static inline int of_count_phandle_with_fixed_args(const struct device_node *np, + const char *list_name, + int cells_count) +{ + return -ENOSYS; +} + static inline int of_phandle_iterator_init(struct of_phandle_iterator *it, const struct device_node *np, const char *list_name,
Add an equivalent of of_count_phandle_with_args() for fixed argument sets, to pair with of_parse_phandle_with_fixed_args(). Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com> --- drivers/of/base.c | 42 ++++++++++++++++++++++++++++++++++++++++++ include/linux/of.h | 9 +++++++++ 2 files changed, 51 insertions(+)