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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /kernel/power/qos.c
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip
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(). ...
Diffstat (limited to '')
-rw-r--r--kernel/power/qos.c673
1 files changed, 673 insertions, 0 deletions
diff --git a/kernel/power/qos.c b/kernel/power/qos.c
new file mode 100644
index 000000000..af51ed6d4
--- /dev/null
+++ b/kernel/power/qos.c
@@ -0,0 +1,673 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Power Management Quality of Service (PM QoS) support base.
+ *
+ * Copyright (C) 2020 Intel Corporation
+ *
+ * Authors:
+ * Mark Gross <mgross@linux.intel.com>
+ * Rafael J. Wysocki <rafael.j.wysocki@intel.com>
+ *
+ * Provided here is an interface for specifying PM QoS dependencies. It allows
+ * entities depending on QoS constraints to register their requests which are
+ * aggregated as appropriate to produce effective constraints (target values)
+ * that can be monitored by entities needing to respect them, either by polling
+ * or through a built-in notification mechanism.
+ *
+ * In addition to the basic functionality, more specific interfaces for managing
+ * global CPU latency QoS requests and frequency QoS requests are provided.
+ */
+
+/*#define DEBUG*/
+
+#include <linux/pm_qos.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/slab.h>
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/miscdevice.h>
+#include <linux/string.h>
+#include <linux/platform_device.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+#include <linux/uaccess.h>
+#include <linux/export.h>
+#include <trace/events/power.h>
+
+/*
+ * locking rule: all changes to constraints or notifiers lists
+ * or pm_qos_object list and pm_qos_objects need to happen with pm_qos_lock
+ * held, taken with _irqsave. One lock to rule them all
+ */
+static DEFINE_SPINLOCK(pm_qos_lock);
+
+/**
+ * pm_qos_read_value - Return the current effective constraint value.
+ * @c: List of PM QoS constraint requests.
+ */
+s32 pm_qos_read_value(struct pm_qos_constraints *c)
+{
+ return READ_ONCE(c->target_value);
+}
+
+static int pm_qos_get_value(struct pm_qos_constraints *c)
+{
+ if (plist_head_empty(&c->list))
+ return c->no_constraint_value;
+
+ switch (c->type) {
+ case PM_QOS_MIN:
+ return plist_first(&c->list)->prio;
+
+ case PM_QOS_MAX:
+ return plist_last(&c->list)->prio;
+
+ default:
+ WARN(1, "Unknown PM QoS type in %s\n", __func__);
+ return PM_QOS_DEFAULT_VALUE;
+ }
+}
+
+static void pm_qos_set_value(struct pm_qos_constraints *c, s32 value)
+{
+ WRITE_ONCE(c->target_value, value);
+}
+
+/**
+ * pm_qos_update_target - Update a list of PM QoS constraint requests.
+ * @c: List of PM QoS requests.
+ * @node: Target list entry.
+ * @action: Action to carry out (add, update or remove).
+ * @value: New request value for the target list entry.
+ *
+ * Update the given list of PM QoS constraint requests, @c, by carrying an
+ * @action involving the @node list entry and @value on it.
+ *
+ * The recognized values of @action are PM_QOS_ADD_REQ (store @value in @node
+ * and add it to the list), PM_QOS_UPDATE_REQ (remove @node from the list, store
+ * @value in it and add it to the list again), and PM_QOS_REMOVE_REQ (remove
+ * @node from the list, ignore @value).
+ *
+ * Return: 1 if the aggregate constraint value has changed, 0 otherwise.
+ */
+int pm_qos_update_target(struct pm_qos_constraints *c, struct plist_node *node,
+ enum pm_qos_req_action action, int value)
+{
+ int prev_value, curr_value, new_value;
+ unsigned long flags;
+
+ spin_lock_irqsave(&pm_qos_lock, flags);
+
+ prev_value = pm_qos_get_value(c);
+ if (value == PM_QOS_DEFAULT_VALUE)
+ new_value = c->default_value;
+ else
+ new_value = value;
+
+ switch (action) {
+ case PM_QOS_REMOVE_REQ:
+ plist_del(node, &c->list);
+ break;
+ case PM_QOS_UPDATE_REQ:
+ /*
+ * To change the list, atomically remove, reinit with new value
+ * and add, then see if the aggregate has changed.
+ */
+ plist_del(node, &c->list);
+ fallthrough;
+ case PM_QOS_ADD_REQ:
+ plist_node_init(node, new_value);
+ plist_add(node, &c->list);
+ break;
+ default:
+ /* no action */
+ ;
+ }
+
+ curr_value = pm_qos_get_value(c);
+ pm_qos_set_value(c, curr_value);
+
+ spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+ trace_pm_qos_update_target(action, prev_value, curr_value);
+
+ if (prev_value == curr_value)
+ return 0;
+
+ if (c->notifiers)
+ blocking_notifier_call_chain(c->notifiers, curr_value, NULL);
+
+ return 1;
+}
+
+/**
+ * pm_qos_flags_remove_req - Remove device PM QoS flags request.
+ * @pqf: Device PM QoS flags set to remove the request from.
+ * @req: Request to remove from the set.
+ */
+static void pm_qos_flags_remove_req(struct pm_qos_flags *pqf,
+ struct pm_qos_flags_request *req)
+{
+ s32 val = 0;
+
+ list_del(&req->node);
+ list_for_each_entry(req, &pqf->list, node)
+ val |= req->flags;
+
+ pqf->effective_flags = val;
+}
+
+/**
+ * pm_qos_update_flags - Update a set of PM QoS flags.
+ * @pqf: Set of PM QoS flags to update.
+ * @req: Request to add to the set, to modify, or to remove from the set.
+ * @action: Action to take on the set.
+ * @val: Value of the request to add or modify.
+ *
+ * Return: 1 if the aggregate constraint value has changed, 0 otherwise.
+ */
+bool pm_qos_update_flags(struct pm_qos_flags *pqf,
+ struct pm_qos_flags_request *req,
+ enum pm_qos_req_action action, s32 val)
+{
+ unsigned long irqflags;
+ s32 prev_value, curr_value;
+
+ spin_lock_irqsave(&pm_qos_lock, irqflags);
+
+ prev_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags;
+
+ switch (action) {
+ case PM_QOS_REMOVE_REQ:
+ pm_qos_flags_remove_req(pqf, req);
+ break;
+ case PM_QOS_UPDATE_REQ:
+ pm_qos_flags_remove_req(pqf, req);
+ fallthrough;
+ case PM_QOS_ADD_REQ:
+ req->flags = val;
+ INIT_LIST_HEAD(&req->node);
+ list_add_tail(&req->node, &pqf->list);
+ pqf->effective_flags |= val;
+ break;
+ default:
+ /* no action */
+ ;
+ }
+
+ curr_value = list_empty(&pqf->list) ? 0 : pqf->effective_flags;
+
+ spin_unlock_irqrestore(&pm_qos_lock, irqflags);
+
+ trace_pm_qos_update_flags(action, prev_value, curr_value);
+
+ return prev_value != curr_value;
+}
+
+#ifdef CONFIG_CPU_IDLE
+/* Definitions related to the CPU latency QoS. */
+
+static struct pm_qos_constraints cpu_latency_constraints = {
+ .list = PLIST_HEAD_INIT(cpu_latency_constraints.list),
+ .target_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE,
+ .default_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE,
+ .no_constraint_value = PM_QOS_CPU_LATENCY_DEFAULT_VALUE,
+ .type = PM_QOS_MIN,
+};
+
+/**
+ * cpu_latency_qos_limit - Return current system-wide CPU latency QoS limit.
+ */
+s32 cpu_latency_qos_limit(void)
+{
+ return pm_qos_read_value(&cpu_latency_constraints);
+}
+
+/**
+ * cpu_latency_qos_request_active - Check the given PM QoS request.
+ * @req: PM QoS request to check.
+ *
+ * Return: 'true' if @req has been added to the CPU latency QoS list, 'false'
+ * otherwise.
+ */
+bool cpu_latency_qos_request_active(struct pm_qos_request *req)
+{
+ return req->qos == &cpu_latency_constraints;
+}
+EXPORT_SYMBOL_GPL(cpu_latency_qos_request_active);
+
+static void cpu_latency_qos_apply(struct pm_qos_request *req,
+ enum pm_qos_req_action action, s32 value)
+{
+ int ret = pm_qos_update_target(req->qos, &req->node, action, value);
+ if (ret > 0)
+ wake_up_all_idle_cpus();
+}
+
+/**
+ * cpu_latency_qos_add_request - Add new CPU latency QoS request.
+ * @req: Pointer to a preallocated handle.
+ * @value: Requested constraint value.
+ *
+ * Use @value to initialize the request handle pointed to by @req, insert it as
+ * a new entry to the CPU latency QoS list and recompute the effective QoS
+ * constraint for that list.
+ *
+ * Callers need to save the handle for later use in updates and removal of the
+ * QoS request represented by it.
+ */
+void cpu_latency_qos_add_request(struct pm_qos_request *req, s32 value)
+{
+ if (!req)
+ return;
+
+ if (cpu_latency_qos_request_active(req)) {
+ WARN(1, KERN_ERR "%s called for already added request\n", __func__);
+ return;
+ }
+
+ trace_pm_qos_add_request(value);
+
+ req->qos = &cpu_latency_constraints;
+ cpu_latency_qos_apply(req, PM_QOS_ADD_REQ, value);
+}
+EXPORT_SYMBOL_GPL(cpu_latency_qos_add_request);
+
+/**
+ * cpu_latency_qos_update_request - Modify existing CPU latency QoS request.
+ * @req : QoS request to update.
+ * @new_value: New requested constraint value.
+ *
+ * Use @new_value to update the QoS request represented by @req in the CPU
+ * latency QoS list along with updating the effective constraint value for that
+ * list.
+ */
+void cpu_latency_qos_update_request(struct pm_qos_request *req, s32 new_value)
+{
+ if (!req)
+ return;
+
+ if (!cpu_latency_qos_request_active(req)) {
+ WARN(1, KERN_ERR "%s called for unknown object\n", __func__);
+ return;
+ }
+
+ trace_pm_qos_update_request(new_value);
+
+ if (new_value == req->node.prio)
+ return;
+
+ cpu_latency_qos_apply(req, PM_QOS_UPDATE_REQ, new_value);
+}
+EXPORT_SYMBOL_GPL(cpu_latency_qos_update_request);
+
+/**
+ * cpu_latency_qos_remove_request - Remove existing CPU latency QoS request.
+ * @req: QoS request to remove.
+ *
+ * Remove the CPU latency QoS request represented by @req from the CPU latency
+ * QoS list along with updating the effective constraint value for that list.
+ */
+void cpu_latency_qos_remove_request(struct pm_qos_request *req)
+{
+ if (!req)
+ return;
+
+ if (!cpu_latency_qos_request_active(req)) {
+ WARN(1, KERN_ERR "%s called for unknown object\n", __func__);
+ return;
+ }
+
+ trace_pm_qos_remove_request(PM_QOS_DEFAULT_VALUE);
+
+ cpu_latency_qos_apply(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
+ memset(req, 0, sizeof(*req));
+}
+EXPORT_SYMBOL_GPL(cpu_latency_qos_remove_request);
+
+/* User space interface to the CPU latency QoS via misc device. */
+
+static int cpu_latency_qos_open(struct inode *inode, struct file *filp)
+{
+ struct pm_qos_request *req;
+
+ req = kzalloc(sizeof(*req), GFP_KERNEL);
+ if (!req)
+ return -ENOMEM;
+
+ cpu_latency_qos_add_request(req, PM_QOS_DEFAULT_VALUE);
+ filp->private_data = req;
+
+ return 0;
+}
+
+static int cpu_latency_qos_release(struct inode *inode, struct file *filp)
+{
+ struct pm_qos_request *req = filp->private_data;
+
+ filp->private_data = NULL;
+
+ cpu_latency_qos_remove_request(req);
+ kfree(req);
+
+ return 0;
+}
+
+static ssize_t cpu_latency_qos_read(struct file *filp, char __user *buf,
+ size_t count, loff_t *f_pos)
+{
+ struct pm_qos_request *req = filp->private_data;
+ unsigned long flags;
+ s32 value;
+
+ if (!req || !cpu_latency_qos_request_active(req))
+ return -EINVAL;
+
+ spin_lock_irqsave(&pm_qos_lock, flags);
+ value = pm_qos_get_value(&cpu_latency_constraints);
+ spin_unlock_irqrestore(&pm_qos_lock, flags);
+
+ return simple_read_from_buffer(buf, count, f_pos, &value, sizeof(s32));
+}
+
+static ssize_t cpu_latency_qos_write(struct file *filp, const char __user *buf,
+ size_t count, loff_t *f_pos)
+{
+ s32 value;
+
+ if (count == sizeof(s32)) {
+ if (copy_from_user(&value, buf, sizeof(s32)))
+ return -EFAULT;
+ } else {
+ int ret;
+
+ ret = kstrtos32_from_user(buf, count, 16, &value);
+ if (ret)
+ return ret;
+ }
+
+ cpu_latency_qos_update_request(filp->private_data, value);
+
+ return count;
+}
+
+static const struct file_operations cpu_latency_qos_fops = {
+ .write = cpu_latency_qos_write,
+ .read = cpu_latency_qos_read,
+ .open = cpu_latency_qos_open,
+ .release = cpu_latency_qos_release,
+ .llseek = noop_llseek,
+};
+
+static struct miscdevice cpu_latency_qos_miscdev = {
+ .minor = MISC_DYNAMIC_MINOR,
+ .name = "cpu_dma_latency",
+ .fops = &cpu_latency_qos_fops,
+};
+
+static int __init cpu_latency_qos_init(void)
+{
+ int ret;
+
+ ret = misc_register(&cpu_latency_qos_miscdev);
+ if (ret < 0)
+ pr_err("%s: %s setup failed\n", __func__,
+ cpu_latency_qos_miscdev.name);
+
+ return ret;
+}
+late_initcall(cpu_latency_qos_init);
+#endif /* CONFIG_CPU_IDLE */
+
+/* Definitions related to the frequency QoS below. */
+
+/**
+ * freq_constraints_init - Initialize frequency QoS constraints.
+ * @qos: Frequency QoS constraints to initialize.
+ */
+void freq_constraints_init(struct freq_constraints *qos)
+{
+ struct pm_qos_constraints *c;
+
+ c = &qos->min_freq;
+ plist_head_init(&c->list);
+ c->target_value = FREQ_QOS_MIN_DEFAULT_VALUE;
+ c->default_value = FREQ_QOS_MIN_DEFAULT_VALUE;
+ c->no_constraint_value = FREQ_QOS_MIN_DEFAULT_VALUE;
+ c->type = PM_QOS_MAX;
+ c->notifiers = &qos->min_freq_notifiers;
+ BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers);
+
+ c = &qos->max_freq;
+ plist_head_init(&c->list);
+ c->target_value = FREQ_QOS_MAX_DEFAULT_VALUE;
+ c->default_value = FREQ_QOS_MAX_DEFAULT_VALUE;
+ c->no_constraint_value = FREQ_QOS_MAX_DEFAULT_VALUE;
+ c->type = PM_QOS_MIN;
+ c->notifiers = &qos->max_freq_notifiers;
+ BLOCKING_INIT_NOTIFIER_HEAD(c->notifiers);
+}
+
+/**
+ * freq_qos_read_value - Get frequency QoS constraint for a given list.
+ * @qos: Constraints to evaluate.
+ * @type: QoS request type.
+ */
+s32 freq_qos_read_value(struct freq_constraints *qos,
+ enum freq_qos_req_type type)
+{
+ s32 ret;
+
+ switch (type) {
+ case FREQ_QOS_MIN:
+ ret = IS_ERR_OR_NULL(qos) ?
+ FREQ_QOS_MIN_DEFAULT_VALUE :
+ pm_qos_read_value(&qos->min_freq);
+ break;
+ case FREQ_QOS_MAX:
+ ret = IS_ERR_OR_NULL(qos) ?
+ FREQ_QOS_MAX_DEFAULT_VALUE :
+ pm_qos_read_value(&qos->max_freq);
+ break;
+ default:
+ WARN_ON(1);
+ ret = 0;
+ }
+
+ return ret;
+}
+
+/**
+ * freq_qos_apply - Add/modify/remove frequency QoS request.
+ * @req: Constraint request to apply.
+ * @action: Action to perform (add/update/remove).
+ * @value: Value to assign to the QoS request.
+ *
+ * This is only meant to be called from inside pm_qos, not drivers.
+ */
+int freq_qos_apply(struct freq_qos_request *req,
+ enum pm_qos_req_action action, s32 value)
+{
+ int ret;
+
+ switch(req->type) {
+ case FREQ_QOS_MIN:
+ ret = pm_qos_update_target(&req->qos->min_freq, &req->pnode,
+ action, value);
+ break;
+ case FREQ_QOS_MAX:
+ ret = pm_qos_update_target(&req->qos->max_freq, &req->pnode,
+ action, value);
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+/**
+ * freq_qos_add_request - Insert new frequency QoS request into a given list.
+ * @qos: Constraints to update.
+ * @req: Preallocated request object.
+ * @type: Request type.
+ * @value: Request value.
+ *
+ * Insert a new entry into the @qos list of requests, recompute the effective
+ * QoS constraint value for that list and initialize the @req object. The
+ * caller needs to save that object for later use in updates and removal.
+ *
+ * Return 1 if the effective constraint value has changed, 0 if the effective
+ * constraint value has not changed, or a negative error code on failures.
+ */
+int freq_qos_add_request(struct freq_constraints *qos,
+ struct freq_qos_request *req,
+ enum freq_qos_req_type type, s32 value)
+{
+ int ret;
+
+ if (IS_ERR_OR_NULL(qos) || !req || value < 0)
+ return -EINVAL;
+
+ if (WARN(freq_qos_request_active(req),
+ "%s() called for active request\n", __func__))
+ return -EINVAL;
+
+ req->qos = qos;
+ req->type = type;
+ ret = freq_qos_apply(req, PM_QOS_ADD_REQ, value);
+ if (ret < 0) {
+ req->qos = NULL;
+ req->type = 0;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(freq_qos_add_request);
+
+/**
+ * freq_qos_update_request - Modify existing frequency QoS request.
+ * @req: Request to modify.
+ * @new_value: New request value.
+ *
+ * Update an existing frequency QoS request along with the effective constraint
+ * value for the list of requests it belongs to.
+ *
+ * Return 1 if the effective constraint value has changed, 0 if the effective
+ * constraint value has not changed, or a negative error code on failures.
+ */
+int freq_qos_update_request(struct freq_qos_request *req, s32 new_value)
+{
+ if (!req || new_value < 0)
+ return -EINVAL;
+
+ if (WARN(!freq_qos_request_active(req),
+ "%s() called for unknown object\n", __func__))
+ return -EINVAL;
+
+ if (req->pnode.prio == new_value)
+ return 0;
+
+ return freq_qos_apply(req, PM_QOS_UPDATE_REQ, new_value);
+}
+EXPORT_SYMBOL_GPL(freq_qos_update_request);
+
+/**
+ * freq_qos_remove_request - Remove frequency QoS request from its list.
+ * @req: Request to remove.
+ *
+ * Remove the given frequency QoS request from the list of constraints it
+ * belongs to and recompute the effective constraint value for that list.
+ *
+ * Return 1 if the effective constraint value has changed, 0 if the effective
+ * constraint value has not changed, or a negative error code on failures.
+ */
+int freq_qos_remove_request(struct freq_qos_request *req)
+{
+ int ret;
+
+ if (!req)
+ return -EINVAL;
+
+ if (WARN(!freq_qos_request_active(req),
+ "%s() called for unknown object\n", __func__))
+ return -EINVAL;
+
+ ret = freq_qos_apply(req, PM_QOS_REMOVE_REQ, PM_QOS_DEFAULT_VALUE);
+ req->qos = NULL;
+ req->type = 0;
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(freq_qos_remove_request);
+
+/**
+ * freq_qos_add_notifier - Add frequency QoS change notifier.
+ * @qos: List of requests to add the notifier to.
+ * @type: Request type.
+ * @notifier: Notifier block to add.
+ */
+int freq_qos_add_notifier(struct freq_constraints *qos,
+ enum freq_qos_req_type type,
+ struct notifier_block *notifier)
+{
+ int ret;
+
+ if (IS_ERR_OR_NULL(qos) || !notifier)
+ return -EINVAL;
+
+ switch (type) {
+ case FREQ_QOS_MIN:
+ ret = blocking_notifier_chain_register(qos->min_freq.notifiers,
+ notifier);
+ break;
+ case FREQ_QOS_MAX:
+ ret = blocking_notifier_chain_register(qos->max_freq.notifiers,
+ notifier);
+ break;
+ default:
+ WARN_ON(1);
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(freq_qos_add_notifier);
+
+/**
+ * freq_qos_remove_notifier - Remove frequency QoS change notifier.
+ * @qos: List of requests to remove the notifier from.
+ * @type: Request type.
+ * @notifier: Notifier block to remove.
+ */
+int freq_qos_remove_notifier(struct freq_constraints *qos,
+ enum freq_qos_req_type type,
+ struct notifier_block *notifier)
+{
+ int ret;
+
+ if (IS_ERR_OR_NULL(qos) || !notifier)
+ return -EINVAL;
+
+ switch (type) {
+ case FREQ_QOS_MIN:
+ ret = blocking_notifier_chain_unregister(qos->min_freq.notifiers,
+ notifier);
+ break;
+ case FREQ_QOS_MAX:
+ ret = blocking_notifier_chain_unregister(qos->max_freq.notifiers,
+ notifier);
+ break;
+ default:
+ WARN_ON(1);
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(freq_qos_remove_notifier);