On 23/11/15 14:28, Juri Lelli wrote: > With the introduction of cpu capacity bindings, CPU capacities can now be > extracted from DT. Add parsing of such information at boot time. Also, > store such information using per CPU variables, as we do for arm. > > Cc: Catalin Marinas <catalin.marinas@xxxxxxx> > Cc: Will Deacon <will.deacon@xxxxxxx> > Cc: Mark Brown <broonie@xxxxxxxxxx> > Cc: Sudeep Holla <sudeep.holla@xxxxxxx> > Signed-off-by: Juri Lelli <juri.lelli@xxxxxxx> > --- > arch/arm64/kernel/topology.c | 46 ++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 46 insertions(+) A lot of code disappears if you get rid of capacity-scale. > > diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c > index 694f6de..4423cc5 100644 > --- a/arch/arm64/kernel/topology.c > +++ b/arch/arm64/kernel/topology.c > @@ -23,6 +23,45 @@ > #include <asm/cputype.h> > #include <asm/topology.h> > > +static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; > + > +unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) > +{ > + return per_cpu(cpu_scale, cpu); > +} > + > +static void set_capacity_scale(unsigned int cpu, unsigned long capacity) > +{ > + per_cpu(cpu_scale, cpu) = capacity; > +} > + > +static u32 capacity_scale = SCHED_CAPACITY_SCALE; > + > +static void __init parse_cpu_capacity(struct device_node *cpu_node, int cpu) > +{ > + int ret; > + u32 cpu_capacity; > + > + ret = of_property_read_u32(cpu_node, > + "capacity", > + &cpu_capacity); > + if (!ret) { > + u64 capacity; > + > + /* > + * Enforce capacity <= capacity-scale. > + */ > + cpu_capacity = cpu_capacity <= capacity_scale ? cpu_capacity : > + capacity_scale; > + capacity = (cpu_capacity << SCHED_CAPACITY_SHIFT) / > + capacity_scale; > + > + set_capacity_scale(cpu, capacity); > + pr_info("CPU%d: DT cpu_capacity %lu\n", > + cpu, arch_scale_cpu_capacity(NULL, cpu)); > + } > +} > + > static int __init get_cpu_for_node(struct device_node *node) > { > struct device_node *cpu_node; > @@ -34,6 +73,7 @@ static int __init get_cpu_for_node(struct device_node *node) > > for_each_possible_cpu(cpu) { > if (of_get_cpu_node(cpu, NULL) == cpu_node) { > + parse_cpu_capacity(cpu_node, cpu); > of_node_put(cpu_node); > return cpu; > } > @@ -173,6 +213,12 @@ static int __init parse_dt_topology(void) > return 0; > } > > + if (!of_property_read_u32(cn, "capacity-scale", &capacity_scale)) > + pr_info("DT cpus capacity-scale %u\n", capacity_scale); > + else > + pr_debug("DT cpus capacity-scale not found: assuming %u\n", > + capacity_scale); > + > /* > * When topology is provided cpu-map is essentially a root > * cluster with restricted subnodes. > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html