| Message ID | 20180731161340.13000-9-georgi.djakov@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Introduce on-chip interconnect API | expand |
On 2018-07-31 09:13, Georgi Djakov wrote: > Currently we support only platform data for specifying the interconnect > endpoints. As now the endpoints are hard-coded into the consumer driver > this may lead to complications when a single driver is used by multiple > SoCs, which may have different interconnect topology. > To avoid cluttering the consumer drivers, introduce a translation > function > to help us get the board specific interconnect data from device-tree. > > Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> > --- > drivers/interconnect/core.c | 62 ++++++++++++++++++++++++++++++++++++ > include/linux/interconnect.h | 7 ++++ > 2 files changed, 69 insertions(+) > > diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c > index 9fef180cf77e..d1b6adff0a3d 100644 > --- a/drivers/interconnect/core.c > +++ b/drivers/interconnect/core.c > @@ -16,6 +16,7 @@ > #include <linux/module.h> > #include <linux/mutex.h> > #include <linux/slab.h> > +#include <linux/of.h> > #include <linux/overflow.h> > #include <linux/uaccess.h> > > @@ -251,6 +252,67 @@ static int apply_constraints(struct icc_path > *path) > return ret; > } > > +struct icc_path *of_icc_get(struct device *dev, const char *name) > +{ > + struct device_node *np = NULL; > + struct of_phandle_args src_args, dst_args; > + u32 src_id, dst_id; > + int idx = 0; > + int ret; > + > + if (!dev || !dev->of_node) > + return ERR_PTR(-ENODEV); > + > + np = dev->of_node; > + > + /* > + * When the consumer DT node do not have "interconnects" property > + * return a NULL path to skip setting constraints. > + */ > + if (!of_find_property(np, "interconnects", NULL)) > + return NULL; > + > + /* > + * We use a combination of phandle and specifier for endpoint. For > now > + * lets support only global ids and extend this is the future if > needed > + * without breaking DT compatibility. > + */ > + if (name) { > + idx = of_property_match_string(np, "interconnect-names", name); > + if (idx < 0) > + return ERR_PTR(idx); > + } > + > + ret = of_parse_phandle_with_args(np, "interconnects", > + "#interconnect-cells", idx * 2, > + &src_args); > + if (ret) > + return ERR_PTR(ret); > + > + of_node_put(src_args.np); > + > + if (!src_args.args_count || src_args.args_count > 1) > + return ERR_PTR(-EINVAL); > + > + src_id = src_args.args[0]; > + > + ret = of_parse_phandle_with_args(np, "interconnects", > + "#interconnect-cells", idx * 2 + 1, > + &dst_args); > + if (ret) > + return ERR_PTR(ret); > + > + of_node_put(dst_args.np); > + > + if (!dst_args.args_count || dst_args.args_count > 1) > + return ERR_PTR(-EINVAL); > + > + dst_id = dst_args.args[0]; > + > + return icc_get(dev, src_id, dst_id); > +} > +EXPORT_SYMBOL_GPL(of_icc_get); > + > /** > * icc_set() - set constraints on an interconnect path between two > endpoints > * @path: reference to the path returned by icc_get() > diff --git a/include/linux/interconnect.h > b/include/linux/interconnect.h > index 593215371fd6..ae6744da9bc2 100644 > --- a/include/linux/interconnect.h > +++ b/include/linux/interconnect.h > @@ -17,6 +17,7 @@ struct device; > > struct icc_path *icc_get(struct device *dev, const int src_id, > const int dst_id); > +struct icc_path *of_icc_get(struct device *dev, const char *name); > void icc_put(struct icc_path *path); > int icc_set(struct icc_path *path, u32 avg_bw, u32 peak_bw); > > @@ -28,6 +29,12 @@ static inline struct icc_path *icc_get(struct > device *dev, const int src_id, > return NULL; > } > > +static inline struct icc_path *of_icc_get(struct device *dev, > + const char *name) > +{ > + return NULL; > +} > + Might want to return PTR(-ENODEV) or some error code so that client doesn't have to do NULL check AND an error check? -Saravana
Hi Saravana, On 08/02/2018 01:57 AM, skannan@codeaurora.org wrote: > On 2018-07-31 09:13, Georgi Djakov wrote: >> Currently we support only platform data for specifying the interconnect >> endpoints. As now the endpoints are hard-coded into the consumer driver >> this may lead to complications when a single driver is used by multiple >> SoCs, which may have different interconnect topology. >> To avoid cluttering the consumer drivers, introduce a translation >> function >> to help us get the board specific interconnect data from device-tree. >> >> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> >> --- >> drivers/interconnect/core.c | 62 ++++++++++++++++++++++++++++++++++++ >> include/linux/interconnect.h | 7 ++++ >> 2 files changed, 69 insertions(+) >> >> diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c >> index 9fef180cf77e..d1b6adff0a3d 100644 >> --- a/drivers/interconnect/core.c >> +++ b/drivers/interconnect/core.c [..] >> --- a/include/linux/interconnect.h >> +++ b/include/linux/interconnect.h >> @@ -17,6 +17,7 @@ struct device; >> >> struct icc_path *icc_get(struct device *dev, const int src_id, >> const int dst_id); >> +struct icc_path *of_icc_get(struct device *dev, const char *name); >> void icc_put(struct icc_path *path); >> int icc_set(struct icc_path *path, u32 avg_bw, u32 peak_bw); >> >> @@ -28,6 +29,12 @@ static inline struct icc_path *icc_get(struct >> device *dev, const int src_id, >> return NULL; >> } >> >> +static inline struct icc_path *of_icc_get(struct device *dev, >> + const char *name) >> +{ >> + return NULL; >> +} >> + > > Might want to return PTR(-ENODEV) or some error code so that client > doesn't have to do NULL check AND an error check? > > -Saravana NULL is returned when CONFIG_INTERCONNECT=n. Configuration of interconnects by consumer drivers could be optional and that's why null is returned instead of an error. The consumer drivers decide how to proceed in this case and if there is a hard requirement for interconnect support, then i would suggest to express it as a dependency in Kconfig. Thanks, Georgi
On 2018-08-02 05:07, Georgi Djakov wrote: > Hi Saravana, > > On 08/02/2018 01:57 AM, skannan@codeaurora.org wrote: >> On 2018-07-31 09:13, Georgi Djakov wrote: >>> Currently we support only platform data for specifying the >>> interconnect >>> endpoints. As now the endpoints are hard-coded into the consumer >>> driver >>> this may lead to complications when a single driver is used by >>> multiple >>> SoCs, which may have different interconnect topology. >>> To avoid cluttering the consumer drivers, introduce a translation >>> function >>> to help us get the board specific interconnect data from device-tree. >>> >>> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> >>> --- >>> drivers/interconnect/core.c | 62 >>> ++++++++++++++++++++++++++++++++++++ >>> include/linux/interconnect.h | 7 ++++ >>> 2 files changed, 69 insertions(+) >>> >>> diff --git a/drivers/interconnect/core.c >>> b/drivers/interconnect/core.c >>> index 9fef180cf77e..d1b6adff0a3d 100644 >>> --- a/drivers/interconnect/core.c >>> +++ b/drivers/interconnect/core.c > [..] >>> --- a/include/linux/interconnect.h >>> +++ b/include/linux/interconnect.h >>> @@ -17,6 +17,7 @@ struct device; >>> >>> struct icc_path *icc_get(struct device *dev, const int src_id, >>> const int dst_id); >>> +struct icc_path *of_icc_get(struct device *dev, const char *name); >>> void icc_put(struct icc_path *path); >>> int icc_set(struct icc_path *path, u32 avg_bw, u32 peak_bw); >>> >>> @@ -28,6 +29,12 @@ static inline struct icc_path *icc_get(struct >>> device *dev, const int src_id, >>> return NULL; >>> } >>> >>> +static inline struct icc_path *of_icc_get(struct device *dev, >>> + const char *name) >>> +{ >>> + return NULL; >>> +} >>> + >> >> Might want to return PTR(-ENODEV) or some error code so that client >> doesn't have to do NULL check AND an error check? >> >> -Saravana > > NULL is returned when CONFIG_INTERCONNECT=n. Configuration of > interconnects by consumer drivers could be optional and that's why null > is returned instead of an error. The consumer drivers decide how to > proceed in this case and if there is a hard requirement for > interconnect > support, then i would suggest to express it as a dependency in Kconfig. Ehh... you could make the same argument with an error. If it's not mandatory for functioning, they can ignore a specific error and continue? At a minimum, these stub functions returning NULL doesn't match with the documentation that says these APIs will only ever return ERR_PTR(). -Saravana
On Tue, Jul 31, 2018 at 9:13 AM Georgi Djakov <georgi.djakov@linaro.org> wrote: > > Currently we support only platform data for specifying the interconnect > endpoints. As now the endpoints are hard-coded into the consumer driver > this may lead to complications when a single driver is used by multiple > SoCs, which may have different interconnect topology. > To avoid cluttering the consumer drivers, introduce a translation function > to help us get the board specific interconnect data from device-tree. > > Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> > --- > drivers/interconnect/core.c | 62 ++++++++++++++++++++++++++++++++++++ > include/linux/interconnect.h | 7 ++++ > 2 files changed, 69 insertions(+) > FWIW I don't have any strong opinions on whether of_icc_get returns an error or NULL, other than to suggest following suit with what other frameworks have chosen to do. Though perhaps most other frameworks are not quite as optional for a particular driver. Reviewed-by: Evan Green <evgreen@chromium.org>
Hi Saravana, On 08/02/2018 10:12 PM, skannan@codeaurora.org wrote: > On 2018-08-02 05:07, Georgi Djakov wrote: >> Hi Saravana, >> >> On 08/02/2018 01:57 AM, skannan@codeaurora.org wrote: >>> On 2018-07-31 09:13, Georgi Djakov wrote: >>>> Currently we support only platform data for specifying the interconnect >>>> endpoints. As now the endpoints are hard-coded into the consumer driver >>>> this may lead to complications when a single driver is used by multiple >>>> SoCs, which may have different interconnect topology. >>>> To avoid cluttering the consumer drivers, introduce a translation >>>> function >>>> to help us get the board specific interconnect data from device-tree. >>>> >>>> Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> >>>> --- >>>> drivers/interconnect/core.c | 62 ++++++++++++++++++++++++++++++++++++ >>>> include/linux/interconnect.h | 7 ++++ >>>> 2 files changed, 69 insertions(+) >>>> >>>> diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c >>>> index 9fef180cf77e..d1b6adff0a3d 100644 >>>> --- a/drivers/interconnect/core.c >>>> +++ b/drivers/interconnect/core.c >> [..] >>>> --- a/include/linux/interconnect.h >>>> +++ b/include/linux/interconnect.h >>>> @@ -17,6 +17,7 @@ struct device; >>>> >>>> struct icc_path *icc_get(struct device *dev, const int src_id, >>>> const int dst_id); >>>> +struct icc_path *of_icc_get(struct device *dev, const char *name); >>>> void icc_put(struct icc_path *path); >>>> int icc_set(struct icc_path *path, u32 avg_bw, u32 peak_bw); >>>> >>>> @@ -28,6 +29,12 @@ static inline struct icc_path *icc_get(struct >>>> device *dev, const int src_id, >>>> return NULL; >>>> } >>>> >>>> +static inline struct icc_path *of_icc_get(struct device *dev, >>>> + const char *name) >>>> +{ >>>> + return NULL; >>>> +} >>>> + >>> >>> Might want to return PTR(-ENODEV) or some error code so that client >>> doesn't have to do NULL check AND an error check? >>> >>> -Saravana >> >> NULL is returned when CONFIG_INTERCONNECT=n. Configuration of >> interconnects by consumer drivers could be optional and that's why null >> is returned instead of an error. The consumer drivers decide how to >> proceed in this case and if there is a hard requirement for interconnect >> support, then i would suggest to express it as a dependency in Kconfig. > > Ehh... you could make the same argument with an error. If it's not > mandatory for functioning, they can ignore a specific error and > continue? At a minimum, these stub functions returning NULL doesn't > match with the documentation that says these APIs will only ever return > ERR_PTR(). > > -Saravana Here i am trying to align with other frameworks, which provide some resources to consumers. The regulator/clock/reset frameworks return NULL, so i prefer to do the same here. Drivers are free to handle NULL specifically, but they don't have to. This NULL may also mean that interconnects have been already configured by bootloader or firmware. Of course i accept the comment to update the documentation to mention this. Thanks, Georgi
diff --git a/drivers/interconnect/core.c b/drivers/interconnect/core.c index 9fef180cf77e..d1b6adff0a3d 100644 --- a/drivers/interconnect/core.c +++ b/drivers/interconnect/core.c @@ -16,6 +16,7 @@ #include <linux/module.h> #include <linux/mutex.h> #include <linux/slab.h> +#include <linux/of.h> #include <linux/overflow.h> #include <linux/uaccess.h> @@ -251,6 +252,67 @@ static int apply_constraints(struct icc_path *path) return ret; } +struct icc_path *of_icc_get(struct device *dev, const char *name) +{ + struct device_node *np = NULL; + struct of_phandle_args src_args, dst_args; + u32 src_id, dst_id; + int idx = 0; + int ret; + + if (!dev || !dev->of_node) + return ERR_PTR(-ENODEV); + + np = dev->of_node; + + /* + * When the consumer DT node do not have "interconnects" property + * return a NULL path to skip setting constraints. + */ + if (!of_find_property(np, "interconnects", NULL)) + return NULL; + + /* + * We use a combination of phandle and specifier for endpoint. For now + * lets support only global ids and extend this is the future if needed + * without breaking DT compatibility. + */ + if (name) { + idx = of_property_match_string(np, "interconnect-names", name); + if (idx < 0) + return ERR_PTR(idx); + } + + ret = of_parse_phandle_with_args(np, "interconnects", + "#interconnect-cells", idx * 2, + &src_args); + if (ret) + return ERR_PTR(ret); + + of_node_put(src_args.np); + + if (!src_args.args_count || src_args.args_count > 1) + return ERR_PTR(-EINVAL); + + src_id = src_args.args[0]; + + ret = of_parse_phandle_with_args(np, "interconnects", + "#interconnect-cells", idx * 2 + 1, + &dst_args); + if (ret) + return ERR_PTR(ret); + + of_node_put(dst_args.np); + + if (!dst_args.args_count || dst_args.args_count > 1) + return ERR_PTR(-EINVAL); + + dst_id = dst_args.args[0]; + + return icc_get(dev, src_id, dst_id); +} +EXPORT_SYMBOL_GPL(of_icc_get); + /** * icc_set() - set constraints on an interconnect path between two endpoints * @path: reference to the path returned by icc_get() diff --git a/include/linux/interconnect.h b/include/linux/interconnect.h index 593215371fd6..ae6744da9bc2 100644 --- a/include/linux/interconnect.h +++ b/include/linux/interconnect.h @@ -17,6 +17,7 @@ struct device; struct icc_path *icc_get(struct device *dev, const int src_id, const int dst_id); +struct icc_path *of_icc_get(struct device *dev, const char *name); void icc_put(struct icc_path *path); int icc_set(struct icc_path *path, u32 avg_bw, u32 peak_bw); @@ -28,6 +29,12 @@ static inline struct icc_path *icc_get(struct device *dev, const int src_id, return NULL; } +static inline struct icc_path *of_icc_get(struct device *dev, + const char *name) +{ + return NULL; +} + static inline void icc_put(struct icc_path *path) { }
Currently we support only platform data for specifying the interconnect endpoints. As now the endpoints are hard-coded into the consumer driver this may lead to complications when a single driver is used by multiple SoCs, which may have different interconnect topology. To avoid cluttering the consumer drivers, introduce a translation function to help us get the board specific interconnect data from device-tree. Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org> --- drivers/interconnect/core.c | 62 ++++++++++++++++++++++++++++++++++++ include/linux/interconnect.h | 7 ++++ 2 files changed, 69 insertions(+)