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Diffstat (limited to 'drivers/base/power/opp/opp.h')
| -rw-r--r-- | drivers/base/power/opp/opp.h | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h new file mode 100644 index 000000000000..7366b2aa8997 --- /dev/null +++ b/drivers/base/power/opp/opp.h @@ -0,0 +1,146 @@ +/* + * Generic OPP Interface + * + * Copyright (C) 2009-2010 Texas Instruments Incorporated. + * Nishanth Menon + * Romit Dasgupta + * Kevin Hilman + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef __DRIVER_OPP_H__ +#define __DRIVER_OPP_H__ + +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/pm_opp.h> +#include <linux/rculist.h> +#include <linux/rcupdate.h> + +/* Lock to allow exclusive modification to the device and opp lists */ +extern struct mutex dev_opp_list_lock; + +/* + * Internal data structure organization with the OPP layer library is as + * follows: + * dev_opp_list (root) + * |- device 1 (represents voltage domain 1) + * | |- opp 1 (availability, freq, voltage) + * | |- opp 2 .. + * ... ... + * | `- opp n .. + * |- device 2 (represents the next voltage domain) + * ... + * `- device m (represents mth voltage domain) + * device 1, 2.. are represented by dev_opp structure while each opp + * is represented by the opp structure. + */ + +/** + * struct dev_pm_opp - Generic OPP description structure + * @node: opp list node. The nodes are maintained throughout the lifetime + * of boot. It is expected only an optimal set of OPPs are + * added to the library by the SoC framework. + * RCU usage: opp list is traversed with RCU locks. node + * modification is possible realtime, hence the modifications + * are protected by the dev_opp_list_lock for integrity. + * IMPORTANT: the opp nodes should be maintained in increasing + * order. + * @dynamic: not-created from static DT entries. + * @available: true/false - marks if this OPP as available or not + * @turbo: true if turbo (boost) OPP + * @rate: Frequency in hertz + * @u_volt: Target voltage in microvolts corresponding to this OPP + * @u_volt_min: Minimum voltage in microvolts corresponding to this OPP + * @u_volt_max: Maximum voltage in microvolts corresponding to this OPP + * @u_amp: Maximum current drawn by the device in microamperes + * @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's + * frequency from any other OPP's frequency. + * @dev_opp: points back to the device_opp struct this opp belongs to + * @rcu_head: RCU callback head used for deferred freeing + * @np: OPP's device node. + * + * This structure stores the OPP information for a given device. + */ +struct dev_pm_opp { + struct list_head node; + + bool available; + bool dynamic; + bool turbo; + unsigned long rate; + + unsigned long u_volt; + unsigned long u_volt_min; + unsigned long u_volt_max; + unsigned long u_amp; + unsigned long clock_latency_ns; + + struct device_opp *dev_opp; + struct rcu_head rcu_head; + + struct device_node *np; +}; + +/** + * struct device_list_opp - devices managed by 'struct device_opp' + * @node: list node + * @dev: device to which the struct object belongs + * @rcu_head: RCU callback head used for deferred freeing + * + * This is an internal data structure maintaining the list of devices that are + * managed by 'struct device_opp'. + */ +struct device_list_opp { + struct list_head node; + const struct device *dev; + struct rcu_head rcu_head; +}; + +/** + * struct device_opp - Device opp structure + * @node: list node - contains the devices with OPPs that + * have been registered. Nodes once added are not modified in this + * list. + * RCU usage: nodes are not modified in the list of device_opp, + * however addition is possible and is secured by dev_opp_list_lock + * @srcu_head: notifier head to notify the OPP availability changes. + * @rcu_head: RCU callback head used for deferred freeing + * @dev_list: list of devices that share these OPPs + * @opp_list: list of opps + * @np: struct device_node pointer for opp's DT node. + * @shared_opp: OPP is shared between multiple devices. + * + * This is an internal data structure maintaining the link to opps attached to + * a device. This structure is not meant to be shared to users as it is + * meant for book keeping and private to OPP library. + * + * Because the opp structures can be used from both rcu and srcu readers, we + * need to wait for the grace period of both of them before freeing any + * resources. And so we have used kfree_rcu() from within call_srcu() handlers. + */ +struct device_opp { + struct list_head node; + + struct srcu_notifier_head srcu_head; + struct rcu_head rcu_head; + struct list_head dev_list; + struct list_head opp_list; + + struct device_node *np; + unsigned long clock_latency_ns_max; + bool shared_opp; + struct dev_pm_opp *suspend_opp; +}; + +/* Routines internal to opp core */ +struct device_opp *_find_device_opp(struct device *dev); +struct device_list_opp *_add_list_dev(const struct device *dev, + struct device_opp *dev_opp); +struct device_node *_of_get_opp_desc_node(struct device *dev); + +#endif /* __DRIVER_OPP_H__ */ |