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