--- /dev/null
+// 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");
projects / platform / kernel / linux-rpi.git / commitdiff