123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439440441442443444445446447448449450451452453454455456457458459460461462463464465466467468469470471472473474475476477478479480481482483484485486487488489490491492493494495496497498499500501502503504505506507508509510511512513514515516517518519520521522523524525526527528529530531532533534535536537538539540541542543544545546547548549550551552553554555556557558559560561562563564565566567568569570571572573574575576577578579580581582583584585586587588589590591592593594595596597598599600601602603604605606607608609610611612613614615616617618619620621622623624625626627628629630631632633634635636637638639640641642643644645646647648649650651652653654655656657658659660661 |
- // SPDX-License-Identifier: GPL-2.0-only
- /*
- * Copyright 2020 Linaro Limited
- *
- * Author: Daniel Lezcano <[email protected]>
- *
- * 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);
|