diff options
Diffstat (limited to 'drivers/powercap/arm_scmi_powercap.c')
| -rw-r--r-- | drivers/powercap/arm_scmi_powercap.c | 509 |
1 files changed, 509 insertions, 0 deletions
diff --git a/drivers/powercap/arm_scmi_powercap.c b/drivers/powercap/arm_scmi_powercap.c new file mode 100644 index 000000000000..05d0e516176a --- /dev/null +++ b/drivers/powercap/arm_scmi_powercap.c @@ -0,0 +1,509 @@ +// 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> + +#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 { + 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; +}; + +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 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, +}; + +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 bool +scmi_powercap_is_zone_registered(struct scmi_powercap_zone *spz) +{ + return !list_empty(&spz->node); +} + +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]; +} + +/** + * scmi_powercap_register_zone - Register an SCMI powercap zone recursively + * + * @pr: A reference to the root powercap zones descriptors + * @spz: A reference to the SCMI powercap zone to register + * + * 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 an SCMI powercap zone to register, takes care to walk + * the SCMI powercap zones tree up to the root looking recursively for + * unregistered parent zones before registering the provided zone; 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_powercap_register_zone(struct scmi_powercap_root *pr, + struct scmi_powercap_zone *spz) +{ + int ret = 0; + struct scmi_powercap_zone *parent; + + if (!spz->info) + return ret; + + parent = scmi_powercap_get_parent_zone(spz); + if (parent && !scmi_powercap_is_zone_registered(parent)) { + /* + * Bail out if a parent domain was marked as unsupported: + * only domains participating as leaves can be skipped. + */ + if (!parent->info) + return -ENODEV; + + ret = scmi_powercap_register_zone(pr, parent); + if (ret) + return ret; + } + + if (!scmi_powercap_is_zone_registered(spz)) { + struct powercap_zone *z; + + 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); + list_add(&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); + ret = 0; + } else { + 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; +} + +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; + + 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]); + + /* + * 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->info = NULL; + continue; + } + } + + /* + * Scan array of retrieved SCMI powercap domains and register them + * recursively starting from the root domains. + */ + for (i = 0, spz = pr->spzones; i < pr->num_zones; i++, spz++) { + ret = scmi_powercap_register_zone(pr, spz); + if (ret) { + dev_err(dev, + "Failed to register powercap zone %s - ret:%d\n", + spz->info->name, ret); + scmi_powercap_unregister_all_zones(pr); + return ret; + } + } + + dev_set_drvdata(dev, pr); + + dev_info(dev, "Registered %d SCMI Powercap domains !\n", pr->num_zones); + + 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 <cristian.marussi@arm.com>"); +MODULE_DESCRIPTION("ARM SCMI Powercap driver"); +MODULE_LICENSE("GPL"); |