cregit-Linux how code gets into the kernel

Release 4.7 drivers/powercap/powercap_sys.c

Directory: drivers/powercap
/*
 * Power capping class
 * Copyright (c) 2013, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc.
 *
 */

#include <linux/module.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/powercap.h>


#define to_powercap_zone(n) container_of(n, struct powercap_zone, dev)

#define to_powercap_control_type(n) \
			container_of(n, struct powercap_control_type, dev)

/* Power zone show function */

#define define_power_zone_show(_attr)		\
static ssize_t _attr##_show(struct device *dev, \
                                        struct device_attribute *dev_attr,\
                                        char *buf) \
{ \
        u64 value; \
        ssize_t len = -EINVAL; \
        struct powercap_zone *power_zone = to_powercap_zone(dev); \
        \
        if (power_zone->ops->get_##_attr) { \
                if (!power_zone->ops->get_##_attr(power_zone, &value)) \
                        len = sprintf(buf, "%lld\n", value); \
        } \
        \
        return len; \
}

/* The only meaningful input is 0 (reset), others are silently ignored */

#define define_power_zone_store(_attr)		\
static ssize_t _attr##_store(struct device *dev,\
                                struct device_attribute *dev_attr, \
                                const char *buf, size_t count) \
{ \
        int err; \
        struct powercap_zone *power_zone = to_powercap_zone(dev); \
        u64 value; \
        \
        err = kstrtoull(buf, 10, &value); \
        if (err) \
                return -EINVAL; \
        if (value) \
                return count; \
        if (power_zone->ops->reset_##_attr) { \
                if (!power_zone->ops->reset_##_attr(power_zone)) \
                        return count; \
        } \
        \
        return -EINVAL; \
}

/* Power zone constraint show function */

#define define_power_zone_constraint_show(_attr) \
static ssize_t show_constraint_##_attr(struct device *dev, \
                                struct device_attribute *dev_attr,\
                                char *buf) \
{ \
        u64 value; \
        ssize_t len = -ENODATA; \
        struct powercap_zone *power_zone = to_powercap_zone(dev); \
        int id; \
        struct powercap_zone_constraint *pconst;\
        \
        if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
                return -EINVAL; \
        if (id >= power_zone->const_id_cnt)     \
                return -EINVAL; \
        pconst = &power_zone->constraints[id]; \
        if (pconst && pconst->ops && pconst->ops->get_##_attr) { \
                if (!pconst->ops->get_##_attr(power_zone, id, &value)) \
                        len = sprintf(buf, "%lld\n", value); \
        } \
        \
        return len; \
}

/* Power zone constraint store function */

#define define_power_zone_constraint_store(_attr) \
static ssize_t store_constraint_##_attr(struct device *dev,\
                                struct device_attribute *dev_attr, \
                                const char *buf, size_t count) \
{ \
        int err; \
        u64 value; \
        struct powercap_zone *power_zone = to_powercap_zone(dev); \
        int id; \
        struct powercap_zone_constraint *pconst;\
        \
        if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) \
                return -EINVAL; \
        if (id >= power_zone->const_id_cnt)     \
                return -EINVAL; \
        pconst = &power_zone->constraints[id]; \
        err = kstrtoull(buf, 10, &value); \
        if (err) \
                return -EINVAL; \
        if (pconst && pconst->ops && pconst->ops->set_##_attr) { \
                if (!pconst->ops->set_##_attr(power_zone, id, value)) \
                        return count; \
        } \
        \
        return -ENODATA; \
}

/* Power zone information callbacks */

define_power_zone_show(power_uw);

define_power_zone_show(max_power_range_uw);

define_power_zone_show(energy_uj);

define_power_zone_store(energy_uj);

define_power_zone_show(max_energy_range_uj);

/* Power zone attributes */
static DEVICE_ATTR_RO(max_power_range_uw);
static DEVICE_ATTR_RO(power_uw);
static DEVICE_ATTR_RO(max_energy_range_uj);
static DEVICE_ATTR_RW(energy_uj);

/* Power zone constraint attributes callbacks */

define_power_zone_constraint_show(power_limit_uw);

define_power_zone_constraint_store(power_limit_uw);

define_power_zone_constraint_show(time_window_us);

define_power_zone_constraint_store(time_window_us);

define_power_zone_constraint_show(max_power_uw);

define_power_zone_constraint_show(min_power_uw);

define_power_zone_constraint_show(max_time_window_us);

define_power_zone_constraint_show(min_time_window_us);

/* For one time seeding of constraint device attributes */

struct powercap_constraint_attr {
	
struct device_attribute power_limit_attr;
	
struct device_attribute time_window_attr;
	
struct device_attribute max_power_attr;
	
struct device_attribute min_power_attr;
	
struct device_attribute max_time_window_attr;
	
struct device_attribute min_time_window_attr;
	
struct device_attribute name_attr;
};

static struct powercap_constraint_attr
				
constraint_attrs[MAX_CONSTRAINTS_PER_ZONE];

/* A list of powercap control_types */
static LIST_HEAD(powercap_cntrl_list);
/* Mutex to protect list of powercap control_types */
static DEFINE_MUTEX(powercap_cntrl_list_lock);


#define POWERCAP_CONSTRAINT_NAME_LEN	30 
/* Some limit to avoid overflow */

static ssize_t show_constraint_name(struct device *dev, struct device_attribute *dev_attr, char *buf) { const char *name; struct powercap_zone *power_zone = to_powercap_zone(dev); int id; ssize_t len = -ENODATA; struct powercap_zone_constraint *pconst; if (!sscanf(dev_attr->attr.name, "constraint_%d_", &id)) return -EINVAL; if (id >= power_zone->const_id_cnt) return -EINVAL; pconst = &power_zone->constraints[id]; if (pconst && pconst->ops && pconst->ops->get_name) { name = pconst->ops->get_name(power_zone, id); if (name) { snprintf(buf, POWERCAP_CONSTRAINT_NAME_LEN, "%s\n", name); buf[POWERCAP_CONSTRAINT_NAME_LEN] = '\0'; len = strlen(buf); } } return len; }

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static int create_constraint_attribute(int id, const char *name, int mode, struct device_attribute *dev_attr, ssize_t (*show)(struct device *, struct device_attribute *, char *), ssize_t (*store)(struct device *, struct device_attribute *, const char *, size_t) ) { dev_attr->attr.name = kasprintf(GFP_KERNEL, "constraint_%d_%s", id, name); if (!dev_attr->attr.name) return -ENOMEM; dev_attr->attr.mode = mode; dev_attr->show = show; dev_attr->store = store; return 0; }

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static void free_constraint_attributes(void) { int i; for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) { kfree(constraint_attrs[i].power_limit_attr.attr.name); kfree(constraint_attrs[i].time_window_attr.attr.name); kfree(constraint_attrs[i].name_attr.attr.name); kfree(constraint_attrs[i].max_power_attr.attr.name); kfree(constraint_attrs[i].min_power_attr.attr.name); kfree(constraint_attrs[i].max_time_window_attr.attr.name); kfree(constraint_attrs[i].min_time_window_attr.attr.name); } }

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static int seed_constraint_attributes(void) { int i; int ret; for (i = 0; i < MAX_CONSTRAINTS_PER_ZONE; ++i) { ret = create_constraint_attribute(i, "power_limit_uw", S_IWUSR | S_IRUGO, &constraint_attrs[i].power_limit_attr, show_constraint_power_limit_uw, store_constraint_power_limit_uw); if (ret) goto err_alloc; ret = create_constraint_attribute(i, "time_window_us", S_IWUSR | S_IRUGO, &constraint_attrs[i].time_window_attr, show_constraint_time_window_us, store_constraint_time_window_us); if (ret) goto err_alloc; ret = create_constraint_attribute(i, "name", S_IRUGO, &constraint_attrs[i].name_attr, show_constraint_name, NULL); if (ret) goto err_alloc; ret = create_constraint_attribute(i, "max_power_uw", S_IRUGO, &constraint_attrs[i].max_power_attr, show_constraint_max_power_uw, NULL); if (ret) goto err_alloc; ret = create_constraint_attribute(i, "min_power_uw", S_IRUGO, &constraint_attrs[i].min_power_attr, show_constraint_min_power_uw, NULL); if (ret) goto err_alloc; ret = create_constraint_attribute(i, "max_time_window_us", S_IRUGO, &constraint_attrs[i].max_time_window_attr, show_constraint_max_time_window_us, NULL); if (ret) goto err_alloc; ret = create_constraint_attribute(i, "min_time_window_us", S_IRUGO, &constraint_attrs[i].min_time_window_attr, show_constraint_min_time_window_us, NULL); if (ret) goto err_alloc; } return 0; err_alloc: free_constraint_attributes(); return ret; }

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static int create_constraints(struct powercap_zone *power_zone, int nr_constraints, const struct powercap_zone_constraint_ops *const_ops) { int i; int ret = 0; int count; struct powercap_zone_constraint *pconst; if (!power_zone || !const_ops || !const_ops->get_power_limit_uw || !const_ops->set_power_limit_uw || !const_ops->get_time_window_us || !const_ops->set_time_window_us) return -EINVAL; count = power_zone->zone_attr_count; for (i = 0; i < nr_constraints; ++i) { pconst = &power_zone->constraints[i]; pconst->ops = const_ops; pconst->id = power_zone->const_id_cnt; power_zone->const_id_cnt++; power_zone->zone_dev_attrs[count++] = &constraint_attrs[i].power_limit_attr.attr; power_zone->zone_dev_attrs[count++] = &constraint_attrs[i].time_window_attr.attr; if (pconst->ops->get_name) power_zone->zone_dev_attrs[count++] = &constraint_attrs[i].name_attr.attr; if (pconst->ops->get_max_power_uw) power_zone->zone_dev_attrs[count++] = &constraint_attrs[i].max_power_attr.attr; if (pconst->ops->get_min_power_uw) power_zone->zone_dev_attrs[count++] = &constraint_attrs[i].min_power_attr.attr; if (pconst->ops->get_max_time_window_us) power_zone->zone_dev_attrs[count++] = &constraint_attrs[i].max_time_window_attr.attr; if (pconst->ops->get_min_time_window_us) power_zone->zone_dev_attrs[count++] = &constraint_attrs[i].min_time_window_attr.attr; } power_zone->zone_attr_count = count; return ret; }

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static bool control_type_valid(void *control_type) { struct powercap_control_type *pos = NULL; bool found = false; mutex_lock(&powercap_cntrl_list_lock); list_for_each_entry(pos, &powercap_cntrl_list, node) { if (pos == control_type) { found = true; break; } } mutex_unlock(&powercap_cntrl_list_lock); return found; }

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static ssize_t name_show(struct device *dev, struct device_attribute *attr, char *buf) { struct powercap_zone *power_zone = to_powercap_zone(dev); return sprintf(buf, "%s\n", power_zone->name); }

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static DEVICE_ATTR_RO(name); /* Create zone and attributes in sysfs */
static void create_power_zone_common_attributes( struct powercap_zone *power_zone) { int count = 0; power_zone->zone_dev_attrs[count++] = &dev_attr_name.attr; if (power_zone->ops->get_max_energy_range_uj) power_zone->zone_dev_attrs[count++] = &dev_attr_max_energy_range_uj.attr; if (power_zone->ops->get_energy_uj) { if (power_zone->ops->reset_energy_uj) dev_attr_energy_uj.attr.mode = S_IWUSR | S_IRUGO; else dev_attr_energy_uj.attr.mode = S_IRUGO; power_zone->zone_dev_attrs[count++] = &dev_attr_energy_uj.attr; } if (power_zone->ops->get_power_uw) power_zone->zone_dev_attrs[count++] = &dev_attr_power_uw.attr; if (power_zone->ops->get_max_power_range_uw) power_zone->zone_dev_attrs[count++] = &dev_attr_max_power_range_uw.attr; power_zone->zone_dev_attrs[count] = NULL; power_zone->zone_attr_count = count; }

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static void powercap_release(struct device *dev) { bool allocated; if (dev->parent) { struct powercap_zone *power_zone = to_powercap_zone(dev); /* Store flag as the release() may free memory */ allocated = power_zone->allocated; /* Remove id from parent idr struct */ idr_remove(power_zone->parent_idr, power_zone->id); /* Destroy idrs allocated for this zone */ idr_destroy(&power_zone->idr); kfree(power_zone->name); kfree(power_zone->zone_dev_attrs); kfree(power_zone->constraints); if (power_zone->ops->release) power_zone->ops->release(power_zone); if (allocated) kfree(power_zone); } else { struct powercap_control_type *control_type = to_powercap_control_type(dev); /* Store flag as the release() may free memory */ allocated = control_type->allocated; idr_destroy(&control_type->idr); mutex_destroy(&control_type->lock); if (control_type->ops && control_type->ops->release) control_type->ops->release(control_type); if (allocated) kfree(control_type); } }

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static ssize_t enabled_show(struct device *dev, struct device_attribute *attr, char *buf) { bool mode = true; /* Default is enabled */ if (dev->parent) { struct powercap_zone *power_zone = to_powercap_zone(dev); if (power_zone->ops->get_enable) if (power_zone->ops->get_enable(power_zone, &mode)) mode = false; } else { struct powercap_control_type *control_type = to_powercap_control_type(dev); if (control_type->ops && control_type->ops->get_enable) if (control_type->ops->get_enable(control_type, &mode)) mode = false; } return sprintf(buf, "%d\n", mode); }

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static ssize_t enabled_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { bool mode; if (strtobool(buf, &mode)) return -EINVAL; if (dev->parent) { struct powercap_zone *power_zone = to_powercap_zone(dev); if (power_zone->ops->set_enable) if (!power_zone->ops->set_enable(power_zone, mode)) return len; } else { struct powercap_control_type *control_type = to_powercap_control_type(dev); if (control_type->ops && control_type->ops->set_enable) if (!control_type->ops->set_enable(control_type, mode)) return len; } return -ENOSYS; }

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static DEVICE_ATTR_RW(enabled); static struct attribute *powercap_attrs[] = { &dev_attr_enabled.attr, NULL, }; ATTRIBUTE_GROUPS(powercap); static struct class powercap_class = { .name = "powercap", .dev_release = powercap_release, .dev_groups = powercap_groups, };
struct powercap_zone *powercap_register_zone( struct powercap_zone *power_zone, struct powercap_control_type *control_type, const char *name, struct powercap_zone *parent, const struct powercap_zone_ops *ops, int nr_constraints, const struct powercap_zone_constraint_ops *const_ops) { int result; int nr_attrs; if (!name || !control_type || !ops || nr_constraints > MAX_CONSTRAINTS_PER_ZONE || (!ops->get_energy_uj && !ops->get_power_uw) || !control_type_valid(control_type)) return ERR_PTR(-EINVAL); if (power_zone) { if (!ops->release) return ERR_PTR(-EINVAL); memset(power_zone, 0, sizeof(*power_zone)); } else { power_zone = kzalloc(sizeof(*power_zone), GFP_KERNEL); if (!power_zone) return ERR_PTR(-ENOMEM); power_zone->allocated = true; } power_zone->ops = ops; power_zone->control_type_inst = control_type; if (!parent) { power_zone->dev.parent = &control_type->dev; power_zone->parent_idr = &control_type->idr; } else { power_zone->dev.parent = &parent->dev; power_zone->parent_idr = &parent->idr; } power_zone->dev.class = &powercap_class; mutex_lock(&control_type->lock); /* Using idr to get the unique id */ result = idr_alloc(power_zone->parent_idr, NULL, 0, 0, GFP_KERNEL); if (result < 0) goto err_idr_alloc; power_zone->id = result; idr_init(&power_zone->idr); power_zone->name = kstrdup(name, GFP_KERNEL); if (!power_zone->name) goto err_name_alloc; dev_set_name(&power_zone->dev, "%s:%x", dev_name(power_zone->dev.parent), power_zone->id); power_zone->constraints = kzalloc(sizeof(*power_zone->constraints) * nr_constraints, GFP_KERNEL); if (!power_zone->constraints) goto err_const_alloc; nr_attrs = nr_constraints * POWERCAP_CONSTRAINTS_ATTRS + POWERCAP_ZONE_MAX_ATTRS + 1; power_zone->zone_dev_attrs = kzalloc(sizeof(void *) * nr_attrs, GFP_KERNEL); if (!power_zone->zone_dev_attrs) goto err_attr_alloc; create_power_zone_common_attributes(power_zone); result = create_constraints(power_zone, nr_constraints, const_ops); if (result) goto err_dev_ret; power_zone->zone_dev_attrs[power_zone->zone_attr_count] = NULL; power_zone->dev_zone_attr_group.attrs = power_zone->zone_dev_attrs; power_zone->dev_attr_groups[0] = &power_zone->dev_zone_attr_group; power_zone->dev_attr_groups[1] = NULL; power_zone->dev.groups = power_zone->dev_attr_groups; result = device_register(&power_zone->dev); if (result) goto err_dev_ret; control_type->nr_zones++; mutex_unlock(&control_type->lock); return power_zone; err_dev_ret: kfree(power_zone->zone_dev_attrs); err_attr_alloc: kfree(power_zone->constraints); err_const_alloc: kfree(power_zone->name); err_name_alloc: idr_remove(power_zone->parent_idr, power_zone->id); err_idr_alloc: if (power_zone->allocated) kfree(power_zone); mutex_unlock(&control_type->lock); return ERR_PTR(result); }

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EXPORT_SYMBOL_GPL(powercap_register_zone);
int powercap_unregister_zone(struct powercap_control_type *control_type, struct powercap_zone *power_zone) { if (!power_zone || !control_type) return -EINVAL; mutex_lock(&control_type->lock); control_type->nr_zones--; mutex_unlock(&control_type->lock); device_unregister(&power_zone->dev); return 0; }

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EXPORT_SYMBOL_GPL(powercap_unregister_zone);
struct powercap_control_type *powercap_register_control_type( struct powercap_control_type *control_type, const char *name, const struct powercap_control_type_ops *ops) { int result; if (!name) return ERR_PTR(-EINVAL); if (control_type) { if (!ops || !ops->release) return ERR_PTR(-EINVAL); memset(control_type, 0, sizeof(*control_type)); } else { control_type = kzalloc(sizeof(*control_type), GFP_KERNEL); if (!control_type) return ERR_PTR(-ENOMEM); control_type->allocated = true; } mutex_init(&control_type->lock); control_type->ops = ops; INIT_LIST_HEAD(&control_type->node); control_type->dev.class = &powercap_class; dev_set_name(&control_type->dev, "%s", name); result = device_register(&control_type->dev); if (result) { if (control_type->allocated) kfree(control_type); return ERR_PTR(result); } idr_init(&control_type->idr); mutex_lock(&powercap_cntrl_list_lock); list_add_tail(&control_type->node, &powercap_cntrl_list); mutex_unlock(&powercap_cntrl_list_lock); return control_type; }

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EXPORT_SYMBOL_GPL(powercap_register_control_type);
int powercap_unregister_control_type(struct powercap_control_type *control_type) { struct powercap_control_type *pos = NULL; if (control_type->nr_zones) { dev_err(&control_type->dev, "Zones of this type still not freed\n"); return -EINVAL; } mutex_lock(&powercap_cntrl_list_lock); list_for_each_entry(pos, &powercap_cntrl_list, node) { if (pos == control_type) { list_del(&control_type->node); mutex_unlock(&powercap_cntrl_list_lock); device_unregister(&control_type->dev); return 0; } } mutex_unlock(&powercap_cntrl_list_lock); return -ENODEV; }

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EXPORT_SYMBOL_GPL(powercap_unregister_control_type);
static int __init powercap_init(void) { int result = 0; result = seed_constraint_attributes(); if (result) return result; result = class_register(&powercap_class); return result; }

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device_initcall(powercap_init); MODULE_DESCRIPTION("PowerCap sysfs Driver"); MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>"); MODULE_LICENSE("GPL v2");

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Directory: drivers/powercap
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