Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

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 000000000..05d0e5161
--- /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");