diff options
Diffstat (limited to 'drivers/powercap/dtpm.c')
| -rw-r--r-- | drivers/powercap/dtpm.c | 661 |
1 files changed, 661 insertions, 0 deletions
diff --git a/drivers/powercap/dtpm.c b/drivers/powercap/dtpm.c new file mode 100644 index 000000000..ce920f17f --- /dev/null +++ b/drivers/powercap/dtpm.c @@ -0,0 +1,661 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2020 Linaro Limited + * + * Author: Daniel Lezcano <daniel.lezcano@linaro.org> + * + * The powercap based Dynamic Thermal Power Management framework + * provides to the userspace a consistent API to set the power limit + * on some devices. + * + * DTPM defines the functions to create a tree of constraints. Each + * parent node is a virtual description of the aggregation of the + * children. It propagates the constraints set at its level to its + * children and collect the children power information. The leaves of + * the tree are the real devices which have the ability to get their + * current power consumption and set their power limit. + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/dtpm.h> +#include <linux/init.h> +#include <linux/kernel.h> +#include <linux/powercap.h> +#include <linux/slab.h> +#include <linux/mutex.h> +#include <linux/of.h> + +#include "dtpm_subsys.h" + +#define DTPM_POWER_LIMIT_FLAG 0 + +static const char *constraint_name[] = { + "Instantaneous", +}; + +static DEFINE_MUTEX(dtpm_lock); +static struct powercap_control_type *pct; +static struct dtpm *root; + +static int get_time_window_us(struct powercap_zone *pcz, int cid, u64 *window) +{ + return -ENOSYS; +} + +static int set_time_window_us(struct powercap_zone *pcz, int cid, u64 window) +{ + return -ENOSYS; +} + +static int get_max_power_range_uw(struct powercap_zone *pcz, u64 *max_power_uw) +{ + struct dtpm *dtpm = to_dtpm(pcz); + + *max_power_uw = dtpm->power_max - dtpm->power_min; + + return 0; +} + +static int __get_power_uw(struct dtpm *dtpm, u64 *power_uw) +{ + struct dtpm *child; + u64 power; + int ret = 0; + + if (dtpm->ops) { + *power_uw = dtpm->ops->get_power_uw(dtpm); + return 0; + } + + *power_uw = 0; + + list_for_each_entry(child, &dtpm->children, sibling) { + ret = __get_power_uw(child, &power); + if (ret) + break; + *power_uw += power; + } + + return ret; +} + +static int get_power_uw(struct powercap_zone *pcz, u64 *power_uw) +{ + return __get_power_uw(to_dtpm(pcz), power_uw); +} + +static void __dtpm_rebalance_weight(struct dtpm *dtpm) +{ + struct dtpm *child; + + list_for_each_entry(child, &dtpm->children, sibling) { + + pr_debug("Setting weight '%d' for '%s'\n", + child->weight, child->zone.name); + + child->weight = DIV64_U64_ROUND_CLOSEST( + child->power_max * 1024, dtpm->power_max); + + __dtpm_rebalance_weight(child); + } +} + +static void __dtpm_sub_power(struct dtpm *dtpm) +{ + struct dtpm *parent = dtpm->parent; + + while (parent) { + parent->power_min -= dtpm->power_min; + parent->power_max -= dtpm->power_max; + parent->power_limit -= dtpm->power_limit; + parent = parent->parent; + } +} + +static void __dtpm_add_power(struct dtpm *dtpm) +{ + struct dtpm *parent = dtpm->parent; + + while (parent) { + parent->power_min += dtpm->power_min; + parent->power_max += dtpm->power_max; + parent->power_limit += dtpm->power_limit; + parent = parent->parent; + } +} + +/** + * dtpm_update_power - Update the power on the dtpm + * @dtpm: a pointer to a dtpm structure to update + * + * Function to update the power values of the dtpm node specified in + * parameter. These new values will be propagated to the tree. + * + * Return: zero on success, -EINVAL if the values are inconsistent + */ +int dtpm_update_power(struct dtpm *dtpm) +{ + int ret; + + __dtpm_sub_power(dtpm); + + ret = dtpm->ops->update_power_uw(dtpm); + if (ret) + pr_err("Failed to update power for '%s': %d\n", + dtpm->zone.name, ret); + + if (!test_bit(DTPM_POWER_LIMIT_FLAG, &dtpm->flags)) + dtpm->power_limit = dtpm->power_max; + + __dtpm_add_power(dtpm); + + if (root) + __dtpm_rebalance_weight(root); + + return ret; +} + +/** + * dtpm_release_zone - Cleanup when the node is released + * @pcz: a pointer to a powercap_zone structure + * + * Do some housecleaning and update the weight on the tree. The + * release will be denied if the node has children. This function must + * be called by the specific release callback of the different + * backends. + * + * Return: 0 on success, -EBUSY if there are children + */ +int dtpm_release_zone(struct powercap_zone *pcz) +{ + struct dtpm *dtpm = to_dtpm(pcz); + struct dtpm *parent = dtpm->parent; + + if (!list_empty(&dtpm->children)) + return -EBUSY; + + if (parent) + list_del(&dtpm->sibling); + + __dtpm_sub_power(dtpm); + + if (dtpm->ops) + dtpm->ops->release(dtpm); + else + kfree(dtpm); + + return 0; +} + +static int get_power_limit_uw(struct powercap_zone *pcz, + int cid, u64 *power_limit) +{ + *power_limit = to_dtpm(pcz)->power_limit; + + return 0; +} + +/* + * Set the power limit on the nodes, the power limit is distributed + * given the weight of the children. + * + * The dtpm node lock must be held when calling this function. + */ +static int __set_power_limit_uw(struct dtpm *dtpm, int cid, u64 power_limit) +{ + struct dtpm *child; + int ret = 0; + u64 power; + + /* + * A max power limitation means we remove the power limit, + * otherwise we set a constraint and flag the dtpm node. + */ + if (power_limit == dtpm->power_max) { + clear_bit(DTPM_POWER_LIMIT_FLAG, &dtpm->flags); + } else { + set_bit(DTPM_POWER_LIMIT_FLAG, &dtpm->flags); + } + + pr_debug("Setting power limit for '%s': %llu uW\n", + dtpm->zone.name, power_limit); + + /* + * Only leaves of the dtpm tree has ops to get/set the power + */ + if (dtpm->ops) { + dtpm->power_limit = dtpm->ops->set_power_uw(dtpm, power_limit); + } else { + dtpm->power_limit = 0; + + list_for_each_entry(child, &dtpm->children, sibling) { + + /* + * Integer division rounding will inevitably + * lead to a different min or max value when + * set several times. In order to restore the + * initial value, we force the child's min or + * max power every time if the constraint is + * at the boundaries. + */ + if (power_limit == dtpm->power_max) { + power = child->power_max; + } else if (power_limit == dtpm->power_min) { + power = child->power_min; + } else { + power = DIV_ROUND_CLOSEST_ULL( + power_limit * child->weight, 1024); + } + + pr_debug("Setting power limit for '%s': %llu uW\n", + child->zone.name, power); + + ret = __set_power_limit_uw(child, cid, power); + if (!ret) + ret = get_power_limit_uw(&child->zone, cid, &power); + + if (ret) + break; + + dtpm->power_limit += power; + } + } + + return ret; +} + +static int set_power_limit_uw(struct powercap_zone *pcz, + int cid, u64 power_limit) +{ + struct dtpm *dtpm = to_dtpm(pcz); + int ret; + + /* + * Don't allow values outside of the power range previously + * set when initializing the power numbers. + */ + power_limit = clamp_val(power_limit, dtpm->power_min, dtpm->power_max); + + ret = __set_power_limit_uw(dtpm, cid, power_limit); + + pr_debug("%s: power limit: %llu uW, power max: %llu uW\n", + dtpm->zone.name, dtpm->power_limit, dtpm->power_max); + + return ret; +} + +static const char *get_constraint_name(struct powercap_zone *pcz, int cid) +{ + return constraint_name[cid]; +} + +static int get_max_power_uw(struct powercap_zone *pcz, int id, u64 *max_power) +{ + *max_power = to_dtpm(pcz)->power_max; + + return 0; +} + +static struct powercap_zone_constraint_ops constraint_ops = { + .set_power_limit_uw = set_power_limit_uw, + .get_power_limit_uw = get_power_limit_uw, + .set_time_window_us = set_time_window_us, + .get_time_window_us = get_time_window_us, + .get_max_power_uw = get_max_power_uw, + .get_name = get_constraint_name, +}; + +static struct powercap_zone_ops zone_ops = { + .get_max_power_range_uw = get_max_power_range_uw, + .get_power_uw = get_power_uw, + .release = dtpm_release_zone, +}; + +/** + * dtpm_init - Allocate and initialize a dtpm struct + * @dtpm: The dtpm struct pointer to be initialized + * @ops: The dtpm device specific ops, NULL for a virtual node + */ +void dtpm_init(struct dtpm *dtpm, struct dtpm_ops *ops) +{ + if (dtpm) { + INIT_LIST_HEAD(&dtpm->children); + INIT_LIST_HEAD(&dtpm->sibling); + dtpm->weight = 1024; + dtpm->ops = ops; + } +} + +/** + * dtpm_unregister - Unregister a dtpm node from the hierarchy tree + * @dtpm: a pointer to a dtpm structure corresponding to the node to be removed + * + * Call the underlying powercap unregister function. That will call + * the release callback of the powercap zone. + */ +void dtpm_unregister(struct dtpm *dtpm) +{ + powercap_unregister_zone(pct, &dtpm->zone); + + pr_debug("Unregistered dtpm node '%s'\n", dtpm->zone.name); +} + +/** + * dtpm_register - Register a dtpm node in the hierarchy tree + * @name: a string specifying the name of the node + * @dtpm: a pointer to a dtpm structure corresponding to the new node + * @parent: a pointer to a dtpm structure corresponding to the parent node + * + * Create a dtpm node in the tree. If no parent is specified, the node + * is the root node of the hierarchy. If the root node already exists, + * then the registration will fail. The powercap controller must be + * initialized before calling this function. + * + * The dtpm structure must be initialized with the power numbers + * before calling this function. + * + * Return: zero on success, a negative value in case of error: + * -EAGAIN: the function is called before the framework is initialized. + * -EBUSY: the root node is already inserted + * -EINVAL: * there is no root node yet and @parent is specified + * * no all ops are defined + * * parent have ops which are reserved for leaves + * Other negative values are reported back from the powercap framework + */ +int dtpm_register(const char *name, struct dtpm *dtpm, struct dtpm *parent) +{ + struct powercap_zone *pcz; + + if (!pct) + return -EAGAIN; + + if (root && !parent) + return -EBUSY; + + if (!root && parent) + return -EINVAL; + + if (parent && parent->ops) + return -EINVAL; + + if (!dtpm) + return -EINVAL; + + if (dtpm->ops && !(dtpm->ops->set_power_uw && + dtpm->ops->get_power_uw && + dtpm->ops->update_power_uw && + dtpm->ops->release)) + return -EINVAL; + + pcz = powercap_register_zone(&dtpm->zone, pct, name, + parent ? &parent->zone : NULL, + &zone_ops, MAX_DTPM_CONSTRAINTS, + &constraint_ops); + if (IS_ERR(pcz)) + return PTR_ERR(pcz); + + if (parent) { + list_add_tail(&dtpm->sibling, &parent->children); + dtpm->parent = parent; + } else { + root = dtpm; + } + + if (dtpm->ops && !dtpm->ops->update_power_uw(dtpm)) { + __dtpm_add_power(dtpm); + dtpm->power_limit = dtpm->power_max; + } + + pr_debug("Registered dtpm node '%s' / %llu-%llu uW, \n", + dtpm->zone.name, dtpm->power_min, dtpm->power_max); + + return 0; +} + +static struct dtpm *dtpm_setup_virtual(const struct dtpm_node *hierarchy, + struct dtpm *parent) +{ + struct dtpm *dtpm; + int ret; + + dtpm = kzalloc(sizeof(*dtpm), GFP_KERNEL); + if (!dtpm) + return ERR_PTR(-ENOMEM); + dtpm_init(dtpm, NULL); + + ret = dtpm_register(hierarchy->name, dtpm, parent); + if (ret) { + pr_err("Failed to register dtpm node '%s': %d\n", + hierarchy->name, ret); + kfree(dtpm); + return ERR_PTR(ret); + } + + return dtpm; +} + +static struct dtpm *dtpm_setup_dt(const struct dtpm_node *hierarchy, + struct dtpm *parent) +{ + struct device_node *np; + int i, ret; + + np = of_find_node_by_path(hierarchy->name); + if (!np) { + pr_err("Failed to find '%s'\n", hierarchy->name); + return ERR_PTR(-ENXIO); + } + + for (i = 0; i < ARRAY_SIZE(dtpm_subsys); i++) { + + if (!dtpm_subsys[i]->setup) + continue; + + ret = dtpm_subsys[i]->setup(parent, np); + if (ret) { + pr_err("Failed to setup '%s': %d\n", dtpm_subsys[i]->name, ret); + of_node_put(np); + return ERR_PTR(ret); + } + } + + of_node_put(np); + + /* + * By returning a NULL pointer, we let know the caller there + * is no child for us as we are a leaf of the tree + */ + return NULL; +} + +typedef struct dtpm * (*dtpm_node_callback_t)(const struct dtpm_node *, struct dtpm *); + +static dtpm_node_callback_t dtpm_node_callback[] = { + [DTPM_NODE_VIRTUAL] = dtpm_setup_virtual, + [DTPM_NODE_DT] = dtpm_setup_dt, +}; + +static int dtpm_for_each_child(const struct dtpm_node *hierarchy, + const struct dtpm_node *it, struct dtpm *parent) +{ + struct dtpm *dtpm; + int i, ret; + + for (i = 0; hierarchy[i].name; i++) { + + if (hierarchy[i].parent != it) + continue; + + dtpm = dtpm_node_callback[hierarchy[i].type](&hierarchy[i], parent); + + /* + * A NULL pointer means there is no children, hence we + * continue without going deeper in the recursivity. + */ + if (!dtpm) + continue; + + /* + * There are multiple reasons why the callback could + * fail. The generic glue is abstracting the backend + * and therefore it is not possible to report back or + * take a decision based on the error. In any case, + * if this call fails, it is not critical in the + * hierarchy creation, we can assume the underlying + * service is not found, so we continue without this + * branch in the tree but with a warning to log the + * information the node was not created. + */ + if (IS_ERR(dtpm)) { + pr_warn("Failed to create '%s' in the hierarchy\n", + hierarchy[i].name); + continue; + } + + ret = dtpm_for_each_child(hierarchy, &hierarchy[i], dtpm); + if (ret) + return ret; + } + + return 0; +} + +/** + * dtpm_create_hierarchy - Create the dtpm hierarchy + * @hierarchy: An array of struct dtpm_node describing the hierarchy + * + * The function is called by the platform specific code with the + * description of the different node in the hierarchy. It creates the + * tree in the sysfs filesystem under the powercap dtpm entry. + * + * The expected tree has the format: + * + * struct dtpm_node hierarchy[] = { + * [0] { .name = "topmost", type = DTPM_NODE_VIRTUAL }, + * [1] { .name = "package", .type = DTPM_NODE_VIRTUAL, .parent = &hierarchy[0] }, + * [2] { .name = "/cpus/cpu0", .type = DTPM_NODE_DT, .parent = &hierarchy[1] }, + * [3] { .name = "/cpus/cpu1", .type = DTPM_NODE_DT, .parent = &hierarchy[1] }, + * [4] { .name = "/cpus/cpu2", .type = DTPM_NODE_DT, .parent = &hierarchy[1] }, + * [5] { .name = "/cpus/cpu3", .type = DTPM_NODE_DT, .parent = &hierarchy[1] }, + * [6] { } + * }; + * + * The last element is always an empty one and marks the end of the + * array. + * + * Return: zero on success, a negative value in case of error. Errors + * are reported back from the underlying functions. + */ +int dtpm_create_hierarchy(struct of_device_id *dtpm_match_table) +{ + const struct of_device_id *match; + const struct dtpm_node *hierarchy; + struct device_node *np; + int i, ret; + + mutex_lock(&dtpm_lock); + + if (pct) { + ret = -EBUSY; + goto out_unlock; + } + + pct = powercap_register_control_type(NULL, "dtpm", NULL); + if (IS_ERR(pct)) { + pr_err("Failed to register control type\n"); + ret = PTR_ERR(pct); + goto out_pct; + } + + ret = -ENODEV; + np = of_find_node_by_path("/"); + if (!np) + goto out_err; + + match = of_match_node(dtpm_match_table, np); + + of_node_put(np); + + if (!match) + goto out_err; + + hierarchy = match->data; + if (!hierarchy) { + ret = -EFAULT; + goto out_err; + } + + ret = dtpm_for_each_child(hierarchy, NULL, NULL); + if (ret) + goto out_err; + + for (i = 0; i < ARRAY_SIZE(dtpm_subsys); i++) { + + if (!dtpm_subsys[i]->init) + continue; + + ret = dtpm_subsys[i]->init(); + if (ret) + pr_info("Failed to initialize '%s': %d", + dtpm_subsys[i]->name, ret); + } + + mutex_unlock(&dtpm_lock); + + return 0; + +out_err: + powercap_unregister_control_type(pct); +out_pct: + pct = NULL; +out_unlock: + mutex_unlock(&dtpm_lock); + + return ret; +} +EXPORT_SYMBOL_GPL(dtpm_create_hierarchy); + +static void __dtpm_destroy_hierarchy(struct dtpm *dtpm) +{ + struct dtpm *child, *aux; + + list_for_each_entry_safe(child, aux, &dtpm->children, sibling) + __dtpm_destroy_hierarchy(child); + + /* + * At this point, we know all children were removed from the + * recursive call before + */ + dtpm_unregister(dtpm); +} + +void dtpm_destroy_hierarchy(void) +{ + int i; + + mutex_lock(&dtpm_lock); + + if (!pct) + goto out_unlock; + + __dtpm_destroy_hierarchy(root); + + + for (i = 0; i < ARRAY_SIZE(dtpm_subsys); i++) { + + if (!dtpm_subsys[i]->exit) + continue; + + dtpm_subsys[i]->exit(); + } + + powercap_unregister_control_type(pct); + + pct = NULL; + + root = NULL; + +out_unlock: + mutex_unlock(&dtpm_lock); +} +EXPORT_SYMBOL_GPL(dtpm_destroy_hierarchy); |