// SPDX-License-Identifier: GPL-2.0
/*
* SCMI Powercap support.
*
* Copyright (C) 2022 ARM Ltd.
*/
#include <linux/device.h>
#include <linux/math.h>
#include <linux/limits.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/powercap.h>
#include <linux/scmi_protocol.h>
#include <linux/slab.h>
#define to_scmi_powercap_zone(z) \
container_of(z, struct scmi_powercap_zone, zone)
static const struct scmi_powercap_proto_ops *powercap_ops;
struct scmi_powercap_zone {
bool registered;
bool invalid;
unsigned int height;
struct device *dev;
struct scmi_protocol_handle *ph;
const struct scmi_powercap_info *info;
struct scmi_powercap_zone *spzones;
struct powercap_zone zone;
struct list_head node;
};
struct scmi_powercap_root {
unsigned int num_zones;
struct scmi_powercap_zone *spzones;
struct list_head *registered_zones;
struct list_head scmi_zones;
};
static struct powercap_control_type *scmi_top_pcntrl;
static int scmi_powercap_zone_release(struct powercap_zone *pz)
{
return 0;
}
static int scmi_powercap_get_max_power_range_uw(struct powercap_zone *pz,
u64 *max_power_range_uw)
{
*max_power_range_uw = U32_MAX;
return 0;
}
static int scmi_powercap_get_power_uw(struct powercap_zone *pz,
u64 *power_uw)
{
struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz);
u32 avg_power, pai;
int ret;
if (!spz->info->powercap_monitoring)
return -EINVAL;
ret = powercap_ops->measurements_get(spz->ph, spz->info->id, &avg_power,
&pai);
if (ret)
return ret;
*power_uw = avg_power;
if (spz->info->powercap_scale_mw)
*power_uw *= 1000;
return 0;
}
static int scmi_powercap_zone_enable_set(struct powercap_zone *pz, bool mode)
{
struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz);
return powercap_ops->cap_enable_set(spz->ph, spz->info->id, mode);
}
static int scmi_powercap_zone_enable_get(struct powercap_zone *pz, bool *mode)
{
struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz);
return powercap_ops->cap_enable_get(spz->ph, spz->info->id, mode);
}
static const struct powercap_zone_ops zone_ops = {
.get_max_power_range_uw = scmi_powercap_get_max_power_range_uw,
.get_power_uw = scmi_powercap_get_power_uw,
.release = scmi_powercap_zone_release,
.set_enable = scmi_powercap_zone_enable_set,
.get_enable = scmi_powercap_zone_enable_get,
};
static void scmi_powercap_normalize_cap(const struct scmi_powercap_zone *spz,
u64 power_limit_uw, u32 *norm)
{
bool scale_mw = spz->info->powercap_scale_mw;
u64 val;
val = scale_mw ? DIV_ROUND_UP_ULL(power_limit_uw, 1000) : power_limit_uw;
/*
* This cast is lossless since here @req_power is certain to be within
* the range [min_power_cap, max_power_cap] whose bounds are assured to
* be two unsigned 32bits quantities.
*/
*norm = clamp_t(u32, val, spz->info->min_power_cap,
spz->info->max_power_cap);
*norm = rounddown(*norm, spz->info->power_cap_step);
val = (scale_mw) ? *norm * 1000 : *norm;
if (power_limit_uw != val)
dev_dbg(spz->dev,
"Normalized %s:CAP - requested:%llu - normalized:%llu\n",
spz->info->name, power_limit_uw, val);
}
static int scmi_powercap_set_power_limit_uw(struct powercap_zone *pz, int cid,
u64 power_uw)
{
struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz);
u32 norm_power;
if (!spz->info->powercap_cap_config)
return -EINVAL;
scmi_powercap_normalize_cap(spz, power_uw, &norm_power);
return powercap_ops->cap_set(spz->ph, spz->info->id, norm_power, false);
}
static int scmi_powercap_get_power_limit_uw(struct powercap_zone *pz, int cid,
u64 *power_limit_uw)
{
struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz);
u32 power;
int ret;
ret = powercap_ops->cap_get(spz->ph, spz->info->id, &power);
if (ret)
return ret;
*power_limit_uw = power;
if (spz->info->powercap_scale_mw)
*power_limit_uw *= 1000;
return 0;
}
static void scmi_powercap_normalize_time(const struct scmi_powercap_zone *spz,
u64 time_us, u32 *norm)
{
/*
* This cast is lossless since here @time_us is certain to be within the
* range [min_pai, max_pai] whose bounds are assured to be two unsigned
* 32bits quantities.
*/
*norm = clamp_t(u32, time_us, spz->info->min_pai, spz->info->max_pai);
*norm = rounddown(*norm, spz->info->pai_step);
if (time_us != *norm)
dev_dbg(spz->dev,
"Normalized %s:PAI - requested:%llu - normalized:%u\n",
spz->info->name, time_us, *norm);
}
static int scmi_powercap_set_time_window_us(struct powercap_zone *pz, int cid,
u64 time_window_us)
{
struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz);
u32 norm_pai;
if (!spz->info->powercap_pai_config)
return -EINVAL;
scmi_powercap_normalize_time(spz, time_window_us, &norm_pai);
return powercap_ops->pai_set(spz->ph, spz->info->id, norm_pai);
}
static int scmi_powercap_get_time_window_us(struct powercap_zone *pz, int cid,
u64 *time_window_us)
{
struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz);
int ret;
u32 pai;
ret = powercap_ops->pai_get(spz->ph, spz->info->id, &pai);
if (ret)
return ret;
*time_window_us = pai;
return 0;
}
static int scmi_powercap_get_max_power_uw(struct powercap_zone *pz, int cid,
u64 *max_power_uw)
{
struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz);
*max_power_uw = spz->info->max_power_cap;
if (spz->info->powercap_scale_mw)
*max_power_uw *= 1000;
return 0;
}
static int scmi_powercap_get_min_power_uw(struct powercap_zone *pz, int cid,
u64 *min_power_uw)
{
struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz);
*min_power_uw = spz->info->min_power_cap;
if (spz->info->powercap_scale_mw)
*min_power_uw *= 1000;
return 0;
}
static int scmi_powercap_get_max_time_window_us(struct powercap_zone *pz,
int cid, u64 *time_window_us)
{
struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz);
*time_window_us = spz->info->max_pai;
return 0;
}
static int scmi_powercap_get_min_time_window_us(struct powercap_zone *pz,
int cid, u64 *time_window_us)
{
struct scmi_powercap_zone *spz = to_scmi_powercap_zone(pz);
*time_window_us = (u64)spz->info->min_pai;
return 0;
}
static const char *scmi_powercap_get_name(struct powercap_zone *pz, int cid)
{
return "SCMI power-cap";
}
static const struct powercap_zone_constraint_ops constraint_ops = {
.set_power_limit_uw = scmi_powercap_set_power_limit_uw,
.get_power_limit_uw = scmi_powercap_get_power_limit_uw,
.set_time_window_us = scmi_powercap_set_time_window_us,
.get_time_window_us = scmi_powercap_get_time_window_us,
.get_max_power_uw = scmi_powercap_get_max_power_uw,
.get_min_power_uw = scmi_powercap_get_min_power_uw,
.get_max_time_window_us = scmi_powercap_get_max_time_window_us,
.get_min_time_window_us = scmi_powercap_get_min_time_window_us,
.get_name = scmi_powercap_get_name,
};
static void scmi_powercap_unregister_all_zones(struct scmi_powercap_root *pr)
{
int i;
/* Un-register children zones first starting from the leaves */
for (i = pr->num_zones - 1; i >= 0; i--) {
if (!list_empty(&pr->registered_zones[i])) {
struct scmi_powercap_zone *spz;
list_for_each_entry(spz, &pr->registered_zones[i], node)
powercap_unregister_zone(scmi_top_pcntrl,
&spz->zone);
}
}
}
static inline unsigned int
scmi_powercap_get_zone_height(struct scmi_powercap_zone *spz)
{
if (spz->info->parent_id == SCMI_POWERCAP_ROOT_ZONE_ID)
return 0;
return spz->spzones[spz->info->parent_id].height + 1;
}
static inline struct scmi_powercap_zone *
scmi_powercap_get_parent_zone(struct scmi_powercap_zone *spz)
{
if (spz->info->parent_id == SCMI_POWERCAP_ROOT_ZONE_ID)
return NULL;
return &spz->spzones[spz->info->parent_id];
}
static int scmi_powercap_register_zone(struct scmi_powercap_root *pr,
struct scmi_powercap_zone *spz,
struct scmi_powercap_zone *parent)
{
int ret = 0;
struct powercap_zone *z;
if (spz->invalid) {
list_del(&spz->node);
return -EINVAL;
}
z = powercap_register_zone(&spz->zone, scmi_top_pcntrl, spz->info->name,
parent ? &parent->zone : NULL,
&zone_ops, 1, &constraint_ops);
if (!IS_ERR(z)) {
spz->height = scmi_powercap_get_zone_height(spz);
spz->registered = true;
list_move(&spz->node, &pr->registered_zones[spz->height]);
dev_dbg(spz->dev, "Registered node %s - parent %s - height:%d\n",
spz->info->name, parent ? parent->info->name : "ROOT",
spz->height);
} else {
list_del(&spz->node);
ret = PTR_ERR(z);
dev_err(spz->dev,
"Error registering node:%s - parent:%s - h:%d - ret:%d\n",
spz->info->name,
parent ? parent->info->name : "ROOT",
spz->height, ret);
}
return ret;
}
/**
* scmi_zones_register- Register SCMI powercap zones starting from parent zones
*
* @dev: A reference to the SCMI device
* @pr: A reference to the root powercap zones descriptors
*
* When registering SCMI powercap zones with the powercap framework we should
* take care to always register zones starting from the root ones and to
* deregister starting from the leaves.
*
* Unfortunately we cannot assume that the array of available SCMI powercap
* zones provided by the SCMI platform firmware is built to comply with such
* requirement.
*
* This function, given the set of SCMI powercap zones to register, takes care
* to walk the SCMI powercap zones trees up to the root registering any
* unregistered parent zone before registering the child zones; at the same
* time each registered-zone height in such a tree is accounted for and each
* zone, once registered, is stored in the @registered_zones array that is
* indexed by zone height: this way will be trivial, at unregister time, to walk
* the @registered_zones array backward and unregister all the zones starting
* from the leaves, removing children zones before parents.
*
* While doing this, we prune away any zone marked as invalid (like the ones
* sporting an SCMI abstract power scale) as long as they are positioned as
* leaves in the SCMI powercap zones hierarchy: any non-leaf invalid zone causes
* the entire process to fail since we cannot assume the correctness of an SCMI
* powercap zones hierarchy if some of the internal nodes are missing.
*
* Note that the array of SCMI powercap zones as returned by the SCMI platform
* is known to be sane, i.e. zones relationships have been validated at the
* protocol layer.
*
* Return: 0 on Success
*/
static int scmi_zones_register(struct device *dev,
struct scmi_powercap_root *pr)
{
int ret = 0;
unsigned int sp = 0, reg_zones = 0;
struct scmi_powercap_zone *spz, **zones_stack;
zones_stack = kcalloc(pr->num_zones, sizeof(spz), GFP_KERNEL);
if (!zones_stack)
return -ENOMEM;
spz = list_first_entry_or_null(&pr->scmi_zones,
struct scmi_powercap_zone, node);
while (spz) {
struct scmi_powercap_zone *parent;
parent = scmi_powercap_get_parent_zone(spz);
if (parent && !parent->registered) {
zones_stack[sp++] = spz;
spz = parent;
} else {
ret = scmi_powercap_register_zone(pr, spz, parent);
if (!ret) {
reg_zones++;
} else if (sp) {
/* Failed to register a non-leaf zone.
* Bail-out.
*/
dev_err(dev,
"Failed to register non-leaf zone - ret:%d\n",
ret);
scmi_powercap_unregister_all_zones(pr);
reg_zones = 0;
goto out;
}
/* Pick next zone to process */
if (sp)
spz = zones_stack[--sp];
else
spz = list_first_entry_or_null(&pr->scmi_zones,
struct scmi_powercap_zone,
node);
}
}
out:
kfree(zones_stack);
dev_info(dev, "Registered %d SCMI Powercap domains !\n", reg_zones);
return ret;
}
static int scmi_powercap_probe(struct scmi_device *sdev)
{
int ret, i;
struct scmi_powercap_root *pr;
struct scmi_powercap_zone *spz;
struct scmi_protocol_handle *ph;
struct device *dev = &sdev->dev;
if (!sdev->handle)
return -ENODEV;
powercap_ops = sdev->handle->devm_protocol_get(sdev,
SCMI_PROTOCOL_POWERCAP,
&ph);
if (IS_ERR(powercap_ops))
return PTR_ERR(powercap_ops);
pr = devm_kzalloc(dev, sizeof(*pr), GFP_KERNEL);
if (!pr)
return -ENOMEM;
ret = powercap_ops->num_domains_get(ph);
if (ret < 0) {
dev_err(dev, "number of powercap domains not found\n");
return ret;
}
pr->num_zones = ret;
pr->spzones = devm_kcalloc(dev, pr->num_zones,
sizeof(*pr->spzones), GFP_KERNEL);
if (!pr->spzones)
return -ENOMEM;
/* Allocate for worst possible scenario of maximum tree height. */
pr->registered_zones = devm_kcalloc(dev, pr->num_zones,
sizeof(*pr->registered_zones),
GFP_KERNEL);
if (!pr->registered_zones)
return -ENOMEM;
INIT_LIST_HEAD(&pr->scmi_zones);
for (i = 0, spz = pr->spzones; i < pr->num_zones; i++, spz++) {
/*
* Powercap domains are validate by the protocol layer, i.e.
* when only non-NULL domains are returned here, whose
* parent_id is assured to point to another valid domain.
*/
spz->info = powercap_ops->info_get(ph, i);
spz->dev = dev;
spz->ph = ph;
spz->spzones = pr->spzones;
INIT_LIST_HEAD(&spz->node);
INIT_LIST_HEAD(&pr->registered_zones[i]);
list_add_tail(&spz->node, &pr->scmi_zones);
/*
* Forcibly skip powercap domains using an abstract scale.
* Note that only leaves domains can be skipped, so this could
* lead later to a global failure.
*/
if (!spz->info->powercap_scale_uw &&
!spz->info->powercap_scale_mw) {
dev_warn(dev,
"Abstract power scale not supported. Skip %s.\n",
spz->info->name);
spz->invalid = true;
continue;
}
}
/*
* Scan array of retrieved SCMI powercap domains and register them
* recursively starting from the root domains.
*/
ret = scmi_zones_register(dev, pr);
if (ret)
return ret;
dev_set_drvdata(dev, pr);
return ret;
}
static void scmi_powercap_remove(struct scmi_device *sdev)
{
struct device *dev = &sdev->dev;
struct scmi_powercap_root *pr = dev_get_drvdata(dev);
scmi_powercap_unregister_all_zones(pr);
}
static const struct scmi_device_id scmi_id_table[] = {
{ SCMI_PROTOCOL_POWERCAP, "powercap" },
{ },
};
MODULE_DEVICE_TABLE(scmi, scmi_id_table);
static struct scmi_driver scmi_powercap_driver = {
.name = "scmi-powercap",
.probe = scmi_powercap_probe,
.remove = scmi_powercap_remove,
.id_table = scmi_id_table,
};
static int __init scmi_powercap_init(void)
{
int ret;
scmi_top_pcntrl = powercap_register_control_type(NULL, "arm-scmi", NULL);
if (IS_ERR(scmi_top_pcntrl))
return PTR_ERR(scmi_top_pcntrl);
ret = scmi_register(&scmi_powercap_driver);
if (ret)
powercap_unregister_control_type(scmi_top_pcntrl);
return ret;
}
module_init(scmi_powercap_init);
static void __exit scmi_powercap_exit(void)
{
scmi_unregister(&scmi_powercap_driver);
powercap_unregister_control_type(scmi_top_pcntrl);
}
module_exit(scmi_powercap_exit);
MODULE_AUTHOR("Cristian Marussi <[email protected]>");
MODULE_DESCRIPTION("ARM SCMI Powercap driver");
MODULE_LICENSE("GPL");
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