144 lines
4.6 KiB
C
144 lines
4.6 KiB
C
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/*
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* Generic OPP Interface
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*
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* Copyright (C) 2009-2010 Texas Instruments Incorporated.
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* Nishanth Menon
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* Romit Dasgupta
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* Kevin Hilman
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#ifndef __DRIVER_OPP_H__
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#define __DRIVER_OPP_H__
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/list.h>
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#include <linux/pm_opp.h>
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#include <linux/rculist.h>
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#include <linux/rcupdate.h>
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/*
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* Internal data structure organization with the OPP layer library is as
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* follows:
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* dev_opp_list (root)
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* |- device 1 (represents voltage domain 1)
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* | |- opp 1 (availability, freq, voltage)
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* | |- opp 2 ..
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* ... ...
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* | `- opp n ..
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* |- device 2 (represents the next voltage domain)
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* ...
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* `- device m (represents mth voltage domain)
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* device 1, 2.. are represented by dev_opp structure while each opp
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* is represented by the opp structure.
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*/
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/**
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* struct dev_pm_opp - Generic OPP description structure
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* @node: opp list node. The nodes are maintained throughout the lifetime
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* of boot. It is expected only an optimal set of OPPs are
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* added to the library by the SoC framework.
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* RCU usage: opp list is traversed with RCU locks. node
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* modification is possible realtime, hence the modifications
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* are protected by the dev_opp_list_lock for integrity.
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* IMPORTANT: the opp nodes should be maintained in increasing
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* order.
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* @dynamic: not-created from static DT entries.
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* @available: true/false - marks if this OPP as available or not
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* @turbo: true if turbo (boost) OPP
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* @rate: Frequency in hertz
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* @u_volt: Target voltage in microvolts corresponding to this OPP
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* @u_volt_min: Minimum voltage in microvolts corresponding to this OPP
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* @u_volt_max: Maximum voltage in microvolts corresponding to this OPP
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* @u_amp: Maximum current drawn by the device in microamperes
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* @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
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* frequency from any other OPP's frequency.
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* @dev_opp: points back to the device_opp struct this opp belongs to
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* @rcu_head: RCU callback head used for deferred freeing
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* @np: OPP's device node.
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*
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* This structure stores the OPP information for a given device.
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*/
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struct dev_pm_opp {
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struct list_head node;
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bool available;
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bool dynamic;
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bool turbo;
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unsigned long rate;
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unsigned long u_volt;
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unsigned long u_volt_min;
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unsigned long u_volt_max;
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unsigned long u_amp;
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unsigned long clock_latency_ns;
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struct device_opp *dev_opp;
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struct rcu_head rcu_head;
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struct device_node *np;
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};
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/**
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* struct device_list_opp - devices managed by 'struct device_opp'
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* @node: list node
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* @dev: device to which the struct object belongs
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* @rcu_head: RCU callback head used for deferred freeing
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*
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* This is an internal data structure maintaining the list of devices that are
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* managed by 'struct device_opp'.
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*/
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struct device_list_opp {
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struct list_head node;
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const struct device *dev;
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struct rcu_head rcu_head;
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};
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/**
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* struct device_opp - Device opp structure
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* @node: list node - contains the devices with OPPs that
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* have been registered. Nodes once added are not modified in this
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* list.
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* RCU usage: nodes are not modified in the list of device_opp,
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* however addition is possible and is secured by dev_opp_list_lock
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* @srcu_head: notifier head to notify the OPP availability changes.
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* @rcu_head: RCU callback head used for deferred freeing
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* @dev_list: list of devices that share these OPPs
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* @opp_list: list of opps
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* @np: struct device_node pointer for opp's DT node.
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* @shared_opp: OPP is shared between multiple devices.
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*
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* This is an internal data structure maintaining the link to opps attached to
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* a device. This structure is not meant to be shared to users as it is
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* meant for book keeping and private to OPP library.
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*
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* Because the opp structures can be used from both rcu and srcu readers, we
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* need to wait for the grace period of both of them before freeing any
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* resources. And so we have used kfree_rcu() from within call_srcu() handlers.
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*/
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struct device_opp {
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struct list_head node;
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struct srcu_notifier_head srcu_head;
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struct rcu_head rcu_head;
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struct list_head dev_list;
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struct list_head opp_list;
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struct device_node *np;
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unsigned long clock_latency_ns_max;
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bool shared_opp;
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struct dev_pm_opp *suspend_opp;
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};
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/* Routines internal to opp core */
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struct device_opp *_find_device_opp(struct device *dev);
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struct device_list_opp *_add_list_dev(const struct device *dev,
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struct device_opp *dev_opp);
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struct device_node *_of_get_opp_desc_node(struct device *dev);
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#endif /* __DRIVER_OPP_H__ */
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