Add a sysfs cpu_capacity attribute with which it is possible to read and write (thus over-writing default values) CPUs capacity. This might be useful in situation where there is no way to get proper default values at boot time. The new attribute shows up as: /sys/devices/system/cpu/cpu*/cpu_capacity Cc: Russell King <linux@xxxxxxxxxxxxxxxx> Signed-off-by: Juri Lelli <juri.lelli@xxxxxxx> --- arch/arm/kernel/topology.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 68 insertions(+) diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index ecbff03..a226761 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -52,6 +52,74 @@ static void set_capacity_scale(unsigned int cpu, unsigned long capacity) per_cpu(cpu_scale, cpu) = capacity; } +#ifdef CONFIG_PROC_SYSCTL +#include <asm/cpu.h> +#include <linux/string.h> +static ssize_t show_cpu_capacity(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + struct cpu *cpu = container_of(dev, struct cpu, dev); + ssize_t rc; + int cpunum = cpu->dev.id; + unsigned long capacity = arch_scale_cpu_capacity(NULL, cpunum); + + rc = sprintf(buf, "%lu\n", capacity); + + return rc; +} + +static ssize_t store_cpu_capacity(struct device *dev, + struct device_attribute *attr, + const char *buf, + size_t count) +{ + struct cpu *cpu = container_of(dev, struct cpu, dev); + int this_cpu = cpu->dev.id, i; + unsigned long new_capacity; + ssize_t ret; + + if (count) { + char *p = (char *) buf; + + ret = kstrtoul(p, 0, &new_capacity); + if (ret) + return ret; + if (new_capacity > SCHED_CAPACITY_SCALE) + return -EINVAL; + + for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) + set_capacity_scale(i, new_capacity); + } + + return count; +} + +static DEVICE_ATTR(cpu_capacity, + 0644, + show_cpu_capacity, + store_cpu_capacity); + +static int register_cpu_capacity_sysctl(void) +{ + int i; + struct device *cpu; + + for_each_possible_cpu(i) { + cpu = get_cpu_device(i); + if (!cpu) { + pr_err("%s: too early to get CPU%d device!\n", + __func__, i); + continue; + } + device_create_file(cpu, &dev_attr_cpu_capacity); + } + + return 0; +} +late_initcall(register_cpu_capacity_sysctl); +#endif + #ifdef CONFIG_OF struct cpu_efficiency { const char *compatible; -- 2.2.2 -- 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