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@xxxxxxxxxx> > Cc: devicetree@xxxxxxxxxxxxxxx > Cc: Lina Iyer <ilina@xxxxxxxxxxxxxx> > Suggested-by: Sudeep Holla <sudeep.holla@xxxxxxx> > Co-developed-by: Lina Iyer <lina.iyer@xxxxxxxxxx> > Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx> > Reviewed-by: Rob Herring <robh@xxxxxxxxxx> > --- > 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
