/*
 * drivers/base/cpu.c - basic CPU class support
 */

#include <linux/sysdev.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/sched.h>
#include <linux/cpu.h>
#include <linux/topology.h>
#include <linux/device.h>
#include <linux/node.h>

#include "base.h"

struct sysdev_class cpu_sysdev_class = {
        .name = "cpu",
};
EXPORT_SYMBOL(cpu_sysdev_class);

static DEFINE_PER_CPU(struct sys_device *, cpu_sys_devices);

#ifdef CONFIG_HOTPLUG_CPU
static ssize_t show_online(struct sys_device *dev, struct sysdev_attribute *attr,
                           char *buf)
{
        struct cpu *cpu = container_of(dev, struct cpu, sysdev);

        return sprintf(buf, "%u\n", !!cpu_online(cpu->sysdev.id));
}

static ssize_t __ref store_online(struct sys_device *dev, struct sysdev_attribute *attr,
                                 const char *buf, size_t count)
{
        struct cpu *cpu = container_of(dev, struct cpu, sysdev);
        ssize_t ret;

        switch (buf[0]) {
        case '0':
                ret = cpu_down(cpu->sysdev.id);
                if (!ret)
                        kobject_uevent(&dev->kobj, KOBJ_OFFLINE);
                break;
        case '1':
                ret = cpu_up(cpu->sysdev.id);
                if (!ret)
                        kobject_uevent(&dev->kobj, KOBJ_ONLINE);
                break;
        default:
                ret = -EINVAL;
        }

        if (ret >= 0)
                ret = count;
        return ret;
}
static SYSDEV_ATTR(online, 0644, show_online, store_online);

static void __cpuinit register_cpu_control(struct cpu *cpu)
{
        sysdev_create_file(&cpu->sysdev, &attr_online);
}
void unregister_cpu(struct cpu *cpu)
{
        int logical_cpu = cpu->sysdev.id;

        unregister_cpu_under_node(logical_cpu, cpu_to_node(logical_cpu));

        sysdev_remove_file(&cpu->sysdev, &attr_online);

        sysdev_unregister(&cpu->sysdev);
        per_cpu(cpu_sys_devices, logical_cpu) = NULL;
        return;
}
#else /* ... !CONFIG_HOTPLUG_CPU */
static inline void register_cpu_control(struct cpu *cpu)
{
}
#endif /* CONFIG_HOTPLUG_CPU */

#ifdef CONFIG_KEXEC
#include <linux/kexec.h>

static ssize_t show_crash_notes(struct sys_device *dev, struct sysdev_attribute *attr,
                                char *buf)
{
        struct cpu *cpu = container_of(dev, struct cpu, sysdev);
        ssize_t rc;
        unsigned long long addr;
        int cpunum;

        cpunum = cpu->sysdev.id;

        /*
         * Might be reading other cpu's data based on which cpu read thread
         * has been scheduled. But cpu data (memory) is allocated once during
         * boot up and this data does not change there after. Hence this
         * operation should be safe. No locking required.
         */
        addr = __pa(per_cpu_ptr(crash_notes, cpunum));
        rc = sprintf(buf, "%Lx\n", addr);
        return rc;
}
static SYSDEV_ATTR(crash_notes, 0400, show_crash_notes, NULL);
#endif

/*
 * Print cpu online, possible, present, and system maps
 */
static ssize_t print_cpus_map(char *buf, const struct cpumask *map)
{
        int n = cpulist_scnprintf(buf, PAGE_SIZE-2, map);

        buf[n++] = '\n';
        buf[n] = '\0';
        return n;
}

#define print_cpus_func(type) \
static ssize_t print_cpus_##type(struct sysdev_class *class, char *buf) \
{                                                                       \
        return print_cpus_map(buf, cpu_##type##_mask);                  \
}                                                                       \
static struct sysdev_class_attribute attr_##type##_map =                \
        _SYSDEV_CLASS_ATTR(type, 0444, print_cpus_##type, NULL)

print_cpus_func(online);
print_cpus_func(possible);
print_cpus_func(present);

/*
 * Print values for NR_CPUS and offlined cpus
 */
static ssize_t print_cpus_kernel_max(struct sysdev_class *class, char *buf)
{
        int n = snprintf(buf, PAGE_SIZE-2, "%d\n", NR_CPUS - 1);
        return n;
}
static SYSDEV_CLASS_ATTR(kernel_max, 0444, print_cpus_kernel_max, NULL);

/* arch-optional setting to enable display of offline cpus >= nr_cpu_ids */
unsigned int total_cpus;

static ssize_t print_cpus_offline(struct sysdev_class *class, char *buf)
{
        int n = 0, len = PAGE_SIZE-2;
        cpumask_var_t offline;

        /* display offline cpus < nr_cpu_ids */
        if (!alloc_cpumask_var(&offline, GFP_KERNEL))
                return -ENOMEM;
        cpumask_complement(offline, cpu_online_mask);
        n = cpulist_scnprintf(buf, len, offline);
        free_cpumask_var(offline);

        /* display offline cpus >= nr_cpu_ids */
        if (total_cpus && nr_cpu_ids < total_cpus) {
                if (n && n < len)
                        buf[n++] = ',';

                if (nr_cpu_ids == total_cpus-1)
                        n += snprintf(&buf[n], len - n, "%d", nr_cpu_ids);
                else
                        n += snprintf(&buf[n], len - n, "%d-%d",
                                                      nr_cpu_ids, total_cpus-1);
        }

        n += snprintf(&buf[n], len - n, "\n");
        return n;
}
static SYSDEV_CLASS_ATTR(offline, 0444, print_cpus_offline, NULL);

static struct sysdev_class_attribute *cpu_state_attr[] = {
        &attr_online_map,
        &attr_possible_map,
        &attr_present_map,
        &attr_kernel_max,
        &attr_offline,
};

static int cpu_states_init(void)
{
        int i;
        int err = 0;

        for (i = 0;  i < ARRAY_SIZE(cpu_state_attr); i++) {
                int ret;
                ret = sysdev_class_create_file(&cpu_sysdev_class,
                                                cpu_state_attr[i]);
                if (!err)
                        err = ret;
        }
        return err;
}

/*
 * register_cpu - Setup a sysfs device for a CPU.
 * @cpu - cpu->hotpluggable field set to 1 will generate a control file in
 *        sysfs for this CPU.
 * @num - CPU number to use when creating the device.
 *
 * Initialize and register the CPU device.
 */
int __cpuinit register_cpu(struct cpu *cpu, int num)
{
        int error;
        cpu->node_id = cpu_to_node(num);
        cpu->sysdev.id = num;
        cpu->sysdev.cls = &cpu_sysdev_class;

        error = sysdev_register(&cpu->sysdev);

        if (!error && cpu->hotpluggable)
                register_cpu_control(cpu);
        if (!error)
                per_cpu(cpu_sys_devices, num) = &cpu->sysdev;
        if (!error)
                register_cpu_under_node(num, cpu_to_node(num));

#ifdef CONFIG_KEXEC
        if (!error)
                error = sysdev_create_file(&cpu->sysdev, &attr_crash_notes);
#endif
        return error;
}

struct sys_device *get_cpu_sysdev(unsigned cpu)
{
        if (cpu < nr_cpu_ids && cpu_possible(cpu))
                return per_cpu(cpu_sys_devices, cpu);
        else
                return NULL;
}
EXPORT_SYMBOL_GPL(get_cpu_sysdev);

int __init cpu_dev_init(void)
{
        int err;

        err = sysdev_class_register(&cpu_sysdev_class);
        if (!err)
                err = cpu_states_init();

#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)
        if (!err)
                err = sched_create_sysfs_power_savings_entries(&cpu_sysdev_class);
#endif

        return err;
}