| Message ID | 20181003143824.13059-6-ulf.hansson@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | PM / Domains: Support hierarchical CPU arrangement (PSCI/ARM) (a subset) | expand |
On Wed, Oct 03, 2018 at 04:38:18PM +0200, Ulf Hansson wrote: > The CPU's idle state nodes are currently parsed at the common cpuidle DT > library, but also when initializing back-end data for the arch specific CPU > operations, as in the PSCI driver case. > > To avoid open-coding, let's introduce of_get_cpu_state_node(), which takes > the device node for the CPU and the index to the requested idle state node, > as in-parameters. In case a corresponding idle state node is found, it > returns the node with the refcount incremented for it, else it returns > NULL. > > Moreover, for ARM, there are two generic methods, to describe the CPU's > idle states, either via the flattened description through the > "cpu-idle-states" binding [1] or via the hierarchical layout, using the > "power-domains" and the "domain-idle-states" bindings [2]. Hence, let's > take both options into account. > > [1] > Documentation/devicetree/bindings/arm/idle-states.txt > [2] > Documentation/devicetree/bindings/arm/psci.txt > > Cc: Rob Herring <robh+dt@kernel.org> > Cc: devicetree@vger.kernel.org > Cc: Lina Iyer <ilina@codeaurora.org> > Suggested-by: Sudeep Holla <sudeep.holla@arm.com> > Co-developed-by: Lina Iyer <lina.iyer@linaro.org> > Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> > Reviewed-by: Rob Herring <robh@kernel.org> > --- > drivers/of/base.c | 35 +++++++++++++++++++++++++++++++++++ > include/linux/of.h | 8 ++++++++ > 2 files changed, 43 insertions(+) > > diff --git a/drivers/of/base.c b/drivers/of/base.c > index 74eaedd5b860..bf1d5fa34899 100644 > --- a/drivers/of/base.c > +++ b/drivers/of/base.c > @@ -424,6 +424,41 @@ int of_cpu_node_to_id(struct device_node *cpu_node) > } > EXPORT_SYMBOL(of_cpu_node_to_id); > > +/** > + * of_get_cpu_state_node - Get CPU's idle state node at the given index > + * > + * @cpu_node: The device node for the CPU > + * @index: The index in the list of the idle states > + * > + * Two generic methods can be used to describe a CPU's idle states, either via > + * a flattened description through the "cpu-idle-states" binding or via the > + * hierarchical layout, using the "power-domains" and the "domain-idle-states" > + * bindings. This function check for both and returns the idle state node for > + * the requested index. > + * > + * In case and idle state node is found at index, the refcount incremented for > + * it, so call of_node_put() on it when done. Returns NULL if not found. > + */ > +struct device_node *of_get_cpu_state_node(struct device_node *cpu_node, No strong opinion but I am wondering if it makes sense to get cpu logical index and fetch the cpu of_node here to contain the refcount on it within this function while we are trying to consolidate. I do see that may not be so useful in psci.c but keeping refcount for cpu of_node here keeps the user free from that. I am fine as it is if there are reasons not to do that. -- Regards, Sudeep
diff --git a/drivers/of/base.c b/drivers/of/base.c index 74eaedd5b860..bf1d5fa34899 100644 --- a/drivers/of/base.c +++ b/drivers/of/base.c @@ -424,6 +424,41 @@ int of_cpu_node_to_id(struct device_node *cpu_node) } EXPORT_SYMBOL(of_cpu_node_to_id); +/** + * of_get_cpu_state_node - Get CPU's idle state node at the given index + * + * @cpu_node: The device node for the CPU + * @index: The index in the list of the idle states + * + * Two generic methods can be used to describe a CPU's idle states, either via + * a flattened description through the "cpu-idle-states" binding or via the + * hierarchical layout, using the "power-domains" and the "domain-idle-states" + * bindings. This function check for both and returns the idle state node for + * the requested index. + * + * In case and idle state node is found at index, the refcount incremented for + * it, so call of_node_put() on it when done. Returns NULL if not found. + */ +struct device_node *of_get_cpu_state_node(struct device_node *cpu_node, + int index) +{ + struct of_phandle_args args; + int err; + + err = of_parse_phandle_with_args(cpu_node, "power-domains", + "#power-domain-cells", 0, &args); + if (!err) { + struct device_node *state_node = + of_parse_phandle(args.np, "domain-idle-states", index); + + of_node_put(args.np); + return state_node; + } + + return of_parse_phandle(cpu_node, "cpu-idle-states", index); +} +EXPORT_SYMBOL(of_get_cpu_state_node); + /** * __of_device_is_compatible() - Check if the node matches given constraints * @device: pointer to node diff --git a/include/linux/of.h b/include/linux/of.h index 99b0ebf49632..42dae048674c 100644 --- a/include/linux/of.h +++ b/include/linux/of.h @@ -353,6 +353,8 @@ extern const void *of_get_property(const struct device_node *node, const char *name, int *lenp); extern struct device_node *of_get_cpu_node(int cpu, unsigned int *thread); +extern struct device_node *of_get_cpu_state_node(struct device_node *cpu_node, + int index); #define for_each_property_of_node(dn, pp) \ for (pp = dn->properties; pp != NULL; pp = pp->next) @@ -754,6 +756,12 @@ static inline struct device_node *of_get_cpu_node(int cpu, return NULL; } +static inline struct device_node *of_get_cpu_state_node(struct device_node *cpu_node, + int index) +{ + return NULL; +} + static inline int of_n_addr_cells(struct device_node *np) { return 0;