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|
/*
* 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.
*/
#include <linux/cpu.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/pm_opp.h>
#include <linux/of.h>
#include <linux/export.h>
/*
* 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;
};
/*
* The root of the list of all devices. All device_opp structures branch off
* from here, with each device_opp containing the list of opp it supports in
* various states of availability.
*/
static LIST_HEAD(dev_opp_list);
/* Lock to allow exclusive modification to the device and opp lists */
static DEFINE_MUTEX(dev_opp_list_lock);
#define opp_rcu_lockdep_assert() \
do { \
RCU_LOCKDEP_WARN(!rcu_read_lock_held() && \
!lockdep_is_held(&dev_opp_list_lock), \
"Missing rcu_read_lock() or " \
"dev_opp_list_lock protection"); \
} while (0)
static struct device_list_opp *_find_list_dev(const struct device *dev,
struct device_opp *dev_opp)
{
struct device_list_opp *list_dev;
list_for_each_entry(list_dev, &dev_opp->dev_list, node)
if (list_dev->dev == dev)
return list_dev;
return NULL;
}
static struct device_opp *_managed_opp(const struct device_node *np)
{
struct device_opp *dev_opp;
list_for_each_entry_rcu(dev_opp, &dev_opp_list, node) {
if (dev_opp->np == np) {
/*
* Multiple devices can point to the same OPP table and
* so will have same node-pointer, np.
*
* But the OPPs will be considered as shared only if the
* OPP table contains a "opp-shared" property.
*/
return dev_opp->shared_opp ? dev_opp : NULL;
}
}
return NULL;
}
/**
* _find_device_opp() - find device_opp struct using device pointer
* @dev: device pointer used to lookup device OPPs
*
* Search list of device OPPs for one containing matching device. Does a RCU
* reader operation to grab the pointer needed.
*
* Return: pointer to 'struct device_opp' if found, otherwise -ENODEV or
* -EINVAL based on type of error.
*
* Locking: This function must be called under rcu_read_lock(). device_opp
* is a RCU protected pointer. This means that device_opp is valid as long
* as we are under RCU lock.
*/
static struct device_opp *_find_device_opp(struct device *dev)
{
struct device_opp *dev_opp;
if (IS_ERR_OR_NULL(dev)) {
pr_err("%s: Invalid parameters\n", __func__);
return ERR_PTR(-EINVAL);
}
list_for_each_entry_rcu(dev_opp, &dev_opp_list, node)
if (_find_list_dev(dev, dev_opp))
return dev_opp;
return ERR_PTR(-ENODEV);
}
/**
* dev_pm_opp_get_voltage() - Gets the voltage corresponding to an available opp
* @opp: opp for which voltage has to be returned for
*
* Return: voltage in micro volt corresponding to the opp, else
* return 0
*
* Locking: This function must be called under rcu_read_lock(). opp is a rcu
* protected pointer. This means that opp which could have been fetched by
* opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
* under RCU lock. The pointer returned by the opp_find_freq family must be
* used in the same section as the usage of this function with the pointer
* prior to unlocking with rcu_read_unlock() to maintain the integrity of the
* pointer.
*/
unsigned long dev_pm_opp_get_voltage(struct dev_pm_opp *opp)
{
struct dev_pm_opp *tmp_opp;
unsigned long v = 0;
opp_rcu_lockdep_assert();
tmp_opp = rcu_dereference(opp);
if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available)
pr_err("%s: Invalid parameters\n", __func__);
else
v = tmp_opp->u_volt;
return v;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_voltage);
/**
* dev_pm_opp_get_freq() - Gets the frequency corresponding to an available opp
* @opp: opp for which frequency has to be returned for
*
* Return: frequency in hertz corresponding to the opp, else
* return 0
*
* Locking: This function must be called under rcu_read_lock(). opp is a rcu
* protected pointer. This means that opp which could have been fetched by
* opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
* under RCU lock. The pointer returned by the opp_find_freq family must be
* used in the same section as the usage of this function with the pointer
* prior to unlocking with rcu_read_unlock() to maintain the integrity of the
* pointer.
*/
unsigned long dev_pm_opp_get_freq(struct dev_pm_opp *opp)
{
struct dev_pm_opp *tmp_opp;
unsigned long f = 0;
opp_rcu_lockdep_assert();
tmp_opp = rcu_dereference(opp);
if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available)
pr_err("%s: Invalid parameters\n", __func__);
else
f = tmp_opp->rate;
return f;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_freq);
/**
* dev_pm_opp_is_turbo() - Returns if opp is turbo OPP or not
* @opp: opp for which turbo mode is being verified
*
* Turbo OPPs are not for normal use, and can be enabled (under certain
* conditions) for short duration of times to finish high throughput work
* quickly. Running on them for longer times may overheat the chip.
*
* Return: true if opp is turbo opp, else false.
*
* Locking: This function must be called under rcu_read_lock(). opp is a rcu
* protected pointer. This means that opp which could have been fetched by
* opp_find_freq_{exact,ceil,floor} functions is valid as long as we are
* under RCU lock. The pointer returned by the opp_find_freq family must be
* used in the same section as the usage of this function with the pointer
* prior to unlocking with rcu_read_unlock() to maintain the integrity of the
* pointer.
*/
bool dev_pm_opp_is_turbo(struct dev_pm_opp *opp)
{
struct dev_pm_opp *tmp_opp;
opp_rcu_lockdep_assert();
tmp_opp = rcu_dereference(opp);
if (IS_ERR_OR_NULL(tmp_opp) || !tmp_opp->available) {
pr_err("%s: Invalid parameters\n", __func__);
return false;
}
return tmp_opp->turbo;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_is_turbo);
/**
* dev_pm_opp_get_max_clock_latency() - Get max clock latency in nanoseconds
* @dev: device for which we do this operation
*
* Return: This function returns the max clock latency in nanoseconds.
*
* Locking: This function takes rcu_read_lock().
*/
unsigned long dev_pm_opp_get_max_clock_latency(struct device *dev)
{
struct device_opp *dev_opp;
unsigned long clock_latency_ns;
rcu_read_lock();
dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp))
clock_latency_ns = 0;
else
clock_latency_ns = dev_opp->clock_latency_ns_max;
rcu_read_unlock();
return clock_latency_ns;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_max_clock_latency);
/**
* dev_pm_opp_get_suspend_opp() - Get suspend opp
* @dev: device for which we do this operation
*
* Return: This function returns pointer to the suspend opp if it is
* defined and available, otherwise it returns NULL.
*
* Locking: This function must be called under rcu_read_lock(). opp is a rcu
* protected pointer. The reason for the same is that the opp pointer which is
* returned will remain valid for use with opp_get_{voltage, freq} only while
* under the locked area. The pointer returned must be used prior to unlocking
* with rcu_read_unlock() to maintain the integrity of the pointer.
*/
struct dev_pm_opp *dev_pm_opp_get_suspend_opp(struct device *dev)
{
struct device_opp *dev_opp;
opp_rcu_lockdep_assert();
dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp) || !dev_opp->suspend_opp ||
!dev_opp->suspend_opp->available)
return NULL;
return dev_opp->suspend_opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_suspend_opp);
/**
* dev_pm_opp_get_opp_count() - Get number of opps available in the opp list
* @dev: device for which we do this operation
*
* Return: This function returns the number of available opps if there are any,
* else returns 0 if none or the corresponding error value.
*
* Locking: This function takes rcu_read_lock().
*/
int dev_pm_opp_get_opp_count(struct device *dev)
{
struct device_opp *dev_opp;
struct dev_pm_opp *temp_opp;
int count = 0;
rcu_read_lock();
dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp)) {
count = PTR_ERR(dev_opp);
dev_err(dev, "%s: device OPP not found (%d)\n",
__func__, count);
goto out_unlock;
}
list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
if (temp_opp->available)
count++;
}
out_unlock:
rcu_read_unlock();
return count;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_opp_count);
/**
* dev_pm_opp_find_freq_exact() - search for an exact frequency
* @dev: device for which we do this operation
* @freq: frequency to search for
* @available: true/false - match for available opp
*
* Return: Searches for exact match in the opp list and returns pointer to the
* matching opp if found, else returns ERR_PTR in case of error and should
* be handled using IS_ERR. Error return values can be:
* EINVAL: for bad pointer
* ERANGE: no match found for search
* ENODEV: if device not found in list of registered devices
*
* Note: available is a modifier for the search. if available=true, then the
* match is for exact matching frequency and is available in the stored OPP
* table. if false, the match is for exact frequency which is not available.
*
* This provides a mechanism to enable an opp which is not available currently
* or the opposite as well.
*
* Locking: This function must be called under rcu_read_lock(). opp is a rcu
* protected pointer. The reason for the same is that the opp pointer which is
* returned will remain valid for use with opp_get_{voltage, freq} only while
* under the locked area. The pointer returned must be used prior to unlocking
* with rcu_read_unlock() to maintain the integrity of the pointer.
*/
struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct device *dev,
unsigned long freq,
bool available)
{
struct device_opp *dev_opp;
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
opp_rcu_lockdep_assert();
dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp)) {
int r = PTR_ERR(dev_opp);
dev_err(dev, "%s: device OPP not found (%d)\n", __func__, r);
return ERR_PTR(r);
}
list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
if (temp_opp->available == available &&
temp_opp->rate == freq) {
opp = temp_opp;
break;
}
}
return opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
/**
* dev_pm_opp_find_freq_ceil() - Search for an rounded ceil freq
* @dev: device for which we do this operation
* @freq: Start frequency
*
* Search for the matching ceil *available* OPP from a starting freq
* for a device.
*
* Return: matching *opp and refreshes *freq accordingly, else returns
* ERR_PTR in case of error and should be handled using IS_ERR. Error return
* values can be:
* EINVAL: for bad pointer
* ERANGE: no match found for search
* ENODEV: if device not found in list of registered devices
*
* Locking: This function must be called under rcu_read_lock(). opp is a rcu
* protected pointer. The reason for the same is that the opp pointer which is
* returned will remain valid for use with opp_get_{voltage, freq} only while
* under the locked area. The pointer returned must be used prior to unlocking
* with rcu_read_unlock() to maintain the integrity of the pointer.
*/
struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device *dev,
unsigned long *freq)
{
struct device_opp *dev_opp;
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
opp_rcu_lockdep_assert();
if (!dev || !freq) {
dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
return ERR_PTR(-EINVAL);
}
dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp))
return ERR_CAST(dev_opp);
list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
if (temp_opp->available && temp_opp->rate >= *freq) {
opp = temp_opp;
*freq = opp->rate;
break;
}
}
return opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
/**
* dev_pm_opp_find_freq_floor() - Search for a rounded floor freq
* @dev: device for which we do this operation
* @freq: Start frequency
*
* Search for the matching floor *available* OPP from a starting freq
* for a device.
*
* Return: matching *opp and refreshes *freq accordingly, else returns
* ERR_PTR in case of error and should be handled using IS_ERR. Error return
* values can be:
* EINVAL: for bad pointer
* ERANGE: no match found for search
* ENODEV: if device not found in list of registered devices
*
* Locking: This function must be called under rcu_read_lock(). opp is a rcu
* protected pointer. The reason for the same is that the opp pointer which is
* returned will remain valid for use with opp_get_{voltage, freq} only while
* under the locked area. The pointer returned must be used prior to unlocking
* with rcu_read_unlock() to maintain the integrity of the pointer.
*/
struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct device *dev,
unsigned long *freq)
{
struct device_opp *dev_opp;
struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
opp_rcu_lockdep_assert();
if (!dev || !freq) {
dev_err(dev, "%s: Invalid argument freq=%p\n", __func__, freq);
return ERR_PTR(-EINVAL);
}
dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp))
return ERR_CAST(dev_opp);
list_for_each_entry_rcu(temp_opp, &dev_opp->opp_list, node) {
if (temp_opp->available) {
/* go to the next node, before choosing prev */
if (temp_opp->rate > *freq)
break;
else
opp = temp_opp;
}
}
if (!IS_ERR(opp))
*freq = opp->rate;
return opp;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
/* List-dev Helpers */
static void _kfree_list_dev_rcu(struct rcu_head *head)
{
struct device_list_opp *list_dev;
list_dev = container_of(head, struct device_list_opp, rcu_head);
kfree_rcu(list_dev, rcu_head);
}
static void _remove_list_dev(struct device_list_opp *list_dev,
struct device_opp *dev_opp)
{
list_del(&list_dev->node);
call_srcu(&dev_opp->srcu_head.srcu, &list_dev->rcu_head,
_kfree_list_dev_rcu);
}
static struct device_list_opp *_add_list_dev(const struct device *dev,
struct device_opp *dev_opp)
{
struct device_list_opp *list_dev;
list_dev = kzalloc(sizeof(*list_dev), GFP_KERNEL);
if (!list_dev)
return NULL;
/* Initialize list-dev */
list_dev->dev = dev;
list_add_rcu(&list_dev->node, &dev_opp->dev_list);
return list_dev;
}
/**
* _add_device_opp() - Find device OPP table or allocate a new one
* @dev: device for which we do this operation
*
* It tries to find an existing table first, if it couldn't find one, it
* allocates a new OPP table and returns that.
*
* Return: valid device_opp pointer if success, else NULL.
*/
static struct device_opp *_add_device_opp(struct device *dev)
{
struct device_opp *dev_opp;
struct device_list_opp *list_dev;
/* Check for existing list for 'dev' first */
dev_opp = _find_device_opp(dev);
if (!IS_ERR(dev_opp))
return dev_opp;
/*
* Allocate a new device OPP table. In the infrequent case where a new
* device is needed to be added, we pay this penalty.
*/
dev_opp = kzalloc(sizeof(*dev_opp), GFP_KERNEL);
if (!dev_opp)
return NULL;
INIT_LIST_HEAD(&dev_opp->dev_list);
list_dev = _add_list_dev(dev, dev_opp);
if (!list_dev) {
kfree(dev_opp);
return NULL;
}
srcu_init_notifier_head(&dev_opp->srcu_head);
INIT_LIST_HEAD(&dev_opp->opp_list);
/* Secure the device list modification */
list_add_rcu(&dev_opp->node, &dev_opp_list);
return dev_opp;
}
/**
* _kfree_device_rcu() - Free device_opp RCU handler
* @head: RCU head
*/
static void _kfree_device_rcu(struct rcu_head *head)
{
struct device_opp *device_opp = container_of(head, struct device_opp, rcu_head);
kfree_rcu(device_opp, rcu_head);
}
/**
* _remove_device_opp() - Removes a device OPP table
* @dev_opp: device OPP table to be removed.
*
* Removes/frees device OPP table it it doesn't contain any OPPs.
*/
static void _remove_device_opp(struct device_opp *dev_opp)
{
struct device_list_opp *list_dev;
if (!list_empty(&dev_opp->opp_list))
return;
list_dev = list_first_entry(&dev_opp->dev_list, struct device_list_opp,
node);
_remove_list_dev(list_dev, dev_opp);
/* dev_list must be empty now */
WARN_ON(!list_empty(&dev_opp->dev_list));
list_del_rcu(&dev_opp->node);
call_srcu(&dev_opp->srcu_head.srcu, &dev_opp->rcu_head,
_kfree_device_rcu);
}
/**
* _kfree_opp_rcu() - Free OPP RCU handler
* @head: RCU head
*/
static void _kfree_opp_rcu(struct rcu_head *head)
{
struct dev_pm_opp *opp = container_of(head, struct dev_pm_opp, rcu_head);
kfree_rcu(opp, rcu_head);
}
/**
* _opp_remove() - Remove an OPP from a table definition
* @dev_opp: points back to the device_opp struct this opp belongs to
* @opp: pointer to the OPP to remove
* @notify: OPP_EVENT_REMOVE notification should be sent or not
*
* This function removes an opp definition from the opp list.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* It is assumed that the caller holds required mutex for an RCU updater
* strategy.
*/
static void _opp_remove(struct device_opp *dev_opp,
struct dev_pm_opp *opp, bool notify)
{
/*
* Notify the changes in the availability of the operable
* frequency/voltage list.
*/
if (notify)
srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_REMOVE, opp);
list_del_rcu(&opp->node);
call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
_remove_device_opp(dev_opp);
}
/**
* dev_pm_opp_remove() - Remove an OPP from OPP list
* @dev: device for which we do this operation
* @freq: OPP to remove with matching 'freq'
*
* This function removes an opp from the opp list.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function internally uses RCU updater strategy with mutex locks
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
*/
void dev_pm_opp_remove(struct device *dev, unsigned long freq)
{
struct dev_pm_opp *opp;
struct device_opp *dev_opp;
bool found = false;
/* Hold our list modification lock here */
mutex_lock(&dev_opp_list_lock);
dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp))
goto unlock;
list_for_each_entry(opp, &dev_opp->opp_list, node) {
if (opp->rate == freq) {
found = true;
break;
}
}
if (!found) {
dev_warn(dev, "%s: Couldn't find OPP with freq: %lu\n",
__func__, freq);
goto unlock;
}
_opp_remove(dev_opp, opp, true);
unlock:
mutex_unlock(&dev_opp_list_lock);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_remove);
static struct dev_pm_opp *_allocate_opp(struct device *dev,
struct device_opp **dev_opp)
{
struct dev_pm_opp *opp;
/* allocate new OPP node */
opp = kzalloc(sizeof(*opp), GFP_KERNEL);
if (!opp)
return NULL;
INIT_LIST_HEAD(&opp->node);
*dev_opp = _add_device_opp(dev);
if (!*dev_opp) {
kfree(opp);
return NULL;
}
return opp;
}
static int _opp_add(struct device *dev, struct dev_pm_opp *new_opp,
struct device_opp *dev_opp)
{
struct dev_pm_opp *opp;
struct list_head *head = &dev_opp->opp_list;
/*
* Insert new OPP in order of increasing frequency and discard if
* already present.
*
* Need to use &dev_opp->opp_list in the condition part of the 'for'
* loop, don't replace it with head otherwise it will become an infinite
* loop.
*/
list_for_each_entry_rcu(opp, &dev_opp->opp_list, node) {
if (new_opp->rate > opp->rate) {
head = &opp->node;
continue;
}
if (new_opp->rate < opp->rate)
break;
/* Duplicate OPPs */
dev_warn(dev, "%s: duplicate OPPs detected. Existing: freq: %lu, volt: %lu, enabled: %d. New: freq: %lu, volt: %lu, enabled: %d\n",
__func__, opp->rate, opp->u_volt, opp->available,
new_opp->rate, new_opp->u_volt, new_opp->available);
return opp->available && new_opp->u_volt == opp->u_volt ?
0 : -EEXIST;
}
new_opp->dev_opp = dev_opp;
list_add_rcu(&new_opp->node, head);
return 0;
}
/**
* _opp_add_dynamic() - Allocate a dynamic OPP.
* @dev: device for which we do this operation
* @freq: Frequency in Hz for this OPP
* @u_volt: Voltage in uVolts for this OPP
* @dynamic: Dynamically added OPPs.
*
* This function adds an opp definition to the opp list and returns status.
* The opp is made available by default and it can be controlled using
* dev_pm_opp_enable/disable functions and may be removed by dev_pm_opp_remove.
*
* NOTE: "dynamic" parameter impacts OPPs added by the of_init_opp_table and
* freed by of_free_opp_table.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function internally uses RCU updater strategy with mutex locks
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
*
* Return:
* 0 On success OR
* Duplicate OPPs (both freq and volt are same) and opp->available
* -EEXIST Freq are same and volt are different OR
* Duplicate OPPs (both freq and volt are same) and !opp->available
* -ENOMEM Memory allocation failure
*/
static int _opp_add_dynamic(struct device *dev, unsigned long freq,
long u_volt, bool dynamic)
{
struct device_opp *dev_opp;
struct dev_pm_opp *new_opp;
int ret;
/* Hold our list modification lock here */
mutex_lock(&dev_opp_list_lock);
new_opp = _allocate_opp(dev, &dev_opp);
if (!new_opp) {
ret = -ENOMEM;
goto unlock;
}
/* populate the opp table */
new_opp->rate = freq;
new_opp->u_volt = u_volt;
new_opp->available = true;
new_opp->dynamic = dynamic;
ret = _opp_add(dev, new_opp, dev_opp);
if (ret)
goto free_opp;
mutex_unlock(&dev_opp_list_lock);
/*
* Notify the changes in the availability of the operable
* frequency/voltage list.
*/
srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADD, new_opp);
return 0;
free_opp:
_opp_remove(dev_opp, new_opp, false);
unlock:
mutex_unlock(&dev_opp_list_lock);
return ret;
}
/* TODO: Support multiple regulators */
static int opp_get_microvolt(struct dev_pm_opp *opp, struct device *dev)
{
u32 microvolt[3] = {0};
int count, ret;
count = of_property_count_u32_elems(opp->np, "opp-microvolt");
if (!count)
return 0;
/* There can be one or three elements here */
if (count != 1 && count != 3) {
dev_err(dev, "%s: Invalid number of elements in opp-microvolt property (%d)\n",
__func__, count);
return -EINVAL;
}
ret = of_property_read_u32_array(opp->np, "opp-microvolt", microvolt,
count);
if (ret) {
dev_err(dev, "%s: error parsing opp-microvolt: %d\n", __func__,
ret);
return -EINVAL;
}
opp->u_volt = microvolt[0];
opp->u_volt_min = microvolt[1];
opp->u_volt_max = microvolt[2];
return 0;
}
/**
* _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
* @dev: device for which we do this operation
* @np: device node
*
* This function adds an opp definition to the opp list and returns status. The
* opp can be controlled using dev_pm_opp_enable/disable functions and may be
* removed by dev_pm_opp_remove.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function internally uses RCU updater strategy with mutex locks
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
*
* Return:
* 0 On success OR
* Duplicate OPPs (both freq and volt are same) and opp->available
* -EEXIST Freq are same and volt are different OR
* Duplicate OPPs (both freq and volt are same) and !opp->available
* -ENOMEM Memory allocation failure
* -EINVAL Failed parsing the OPP node
*/
static int _opp_add_static_v2(struct device *dev, struct device_node *np)
{
struct device_opp *dev_opp;
struct dev_pm_opp *new_opp;
u64 rate;
u32 val;
int ret;
/* Hold our list modification lock here */
mutex_lock(&dev_opp_list_lock);
new_opp = _allocate_opp(dev, &dev_opp);
if (!new_opp) {
ret = -ENOMEM;
goto unlock;
}
ret = of_property_read_u64(np, "opp-hz", &rate);
if (ret < 0) {
dev_err(dev, "%s: opp-hz not found\n", __func__);
goto free_opp;
}
/*
* Rate is defined as an unsigned long in clk API, and so casting
* explicitly to its type. Must be fixed once rate is 64 bit
* guaranteed in clk API.
*/
new_opp->rate = (unsigned long)rate;
new_opp->turbo = of_property_read_bool(np, "turbo-mode");
new_opp->np = np;
new_opp->dynamic = false;
new_opp->available = true;
if (!of_property_read_u32(np, "clock-latency-ns", &val))
new_opp->clock_latency_ns = val;
ret = opp_get_microvolt(new_opp, dev);
if (ret)
goto free_opp;
if (!of_property_read_u32(new_opp->np, "opp-microamp", &val))
new_opp->u_amp = val;
ret = _opp_add(dev, new_opp, dev_opp);
if (ret)
goto free_opp;
/* OPP to select on device suspend */
if (of_property_read_bool(np, "opp-suspend")) {
if (dev_opp->suspend_opp)
dev_warn(dev, "%s: Multiple suspend OPPs found (%lu %lu)\n",
__func__, dev_opp->suspend_opp->rate,
new_opp->rate);
else
dev_opp->suspend_opp = new_opp;
}
if (new_opp->clock_latency_ns > dev_opp->clock_latency_ns_max)
dev_opp->clock_latency_ns_max = new_opp->clock_latency_ns;
mutex_unlock(&dev_opp_list_lock);
pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu\n",
__func__, new_opp->turbo, new_opp->rate, new_opp->u_volt,
new_opp->u_volt_min, new_opp->u_volt_max,
new_opp->clock_latency_ns);
/*
* Notify the changes in the availability of the operable
* frequency/voltage list.
*/
srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADD, new_opp);
return 0;
free_opp:
_opp_remove(dev_opp, new_opp, false);
unlock:
mutex_unlock(&dev_opp_list_lock);
return ret;
}
/**
* dev_pm_opp_add() - Add an OPP table from a table definitions
* @dev: device for which we do this operation
* @freq: Frequency in Hz for this OPP
* @u_volt: Voltage in uVolts for this OPP
*
* This function adds an opp definition to the opp list and returns status.
* The opp is made available by default and it can be controlled using
* dev_pm_opp_enable/disable functions.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function internally uses RCU updater strategy with mutex locks
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
*
* Return:
* 0 On success OR
* Duplicate OPPs (both freq and volt are same) and opp->available
* -EEXIST Freq are same and volt are different OR
* Duplicate OPPs (both freq and volt are same) and !opp->available
* -ENOMEM Memory allocation failure
*/
int dev_pm_opp_add(struct device *dev, unsigned long freq, unsigned long u_volt)
{
return _opp_add_dynamic(dev, freq, u_volt, true);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_add);
/**
* _opp_set_availability() - helper to set the availability of an opp
* @dev: device for which we do this operation
* @freq: OPP frequency to modify availability
* @availability_req: availability status requested for this opp
*
* Set the availability of an OPP with an RCU operation, opp_{enable,disable}
* share a common logic which is isolated here.
*
* Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
* copy operation, returns 0 if no modifcation was done OR modification was
* successful.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function internally uses RCU updater strategy with mutex locks to
* keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex locking or synchronize_rcu() blocking calls cannot be used.
*/
static int _opp_set_availability(struct device *dev, unsigned long freq,
bool availability_req)
{
struct device_opp *dev_opp;
struct dev_pm_opp *new_opp, *tmp_opp, *opp = ERR_PTR(-ENODEV);
int r = 0;
/* keep the node allocated */
new_opp = kmalloc(sizeof(*new_opp), GFP_KERNEL);
if (!new_opp)
return -ENOMEM;
mutex_lock(&dev_opp_list_lock);
/* Find the device_opp */
dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp)) {
r = PTR_ERR(dev_opp);
dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
goto unlock;
}
/* Do we have the frequency? */
list_for_each_entry(tmp_opp, &dev_opp->opp_list, node) {
if (tmp_opp->rate == freq) {
opp = tmp_opp;
break;
}
}
if (IS_ERR(opp)) {
r = PTR_ERR(opp);
goto unlock;
}
/* Is update really needed? */
if (opp->available == availability_req)
goto unlock;
/* copy the old data over */
*new_opp = *opp;
/* plug in new node */
new_opp->available = availability_req;
list_replace_rcu(&opp->node, &new_opp->node);
mutex_unlock(&dev_opp_list_lock);
call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
/* Notify the change of the OPP availability */
if (availability_req)
srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ENABLE,
new_opp);
else
srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_DISABLE,
new_opp);
return 0;
unlock:
mutex_unlock(&dev_opp_list_lock);
kfree(new_opp);
return r;
}
/**
* dev_pm_opp_enable() - Enable a specific OPP
* @dev: device for which we do this operation
* @freq: OPP frequency to enable
*
* Enables a provided opp. If the operation is valid, this returns 0, else the
* corresponding error value. It is meant to be used for users an OPP available
* after being temporarily made unavailable with dev_pm_opp_disable.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function indirectly uses RCU and mutex locks to keep the
* integrity of the internal data structures. Callers should ensure that
* this function is *NOT* called under RCU protection or in contexts where
* mutex locking or synchronize_rcu() blocking calls cannot be used.
*
* Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
* copy operation, returns 0 if no modifcation was done OR modification was
* successful.
*/
int dev_pm_opp_enable(struct device *dev, unsigned long freq)
{
return _opp_set_availability(dev, freq, true);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_enable);
/**
* dev_pm_opp_disable() - Disable a specific OPP
* @dev: device for which we do this operation
* @freq: OPP frequency to disable
*
* Disables a provided opp. If the operation is valid, this returns
* 0, else the corresponding error value. It is meant to be a temporary
* control by users to make this OPP not available until the circumstances are
* right to make it available again (with a call to dev_pm_opp_enable).
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function indirectly uses RCU and mutex locks to keep the
* integrity of the internal data structures. Callers should ensure that
* this function is *NOT* called under RCU protection or in contexts where
* mutex locking or synchronize_rcu() blocking calls cannot be used.
*
* Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
* copy operation, returns 0 if no modifcation was done OR modification was
* successful.
*/
int dev_pm_opp_disable(struct device *dev, unsigned long freq)
{
return _opp_set_availability(dev, freq, false);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_disable);
/**
* dev_pm_opp_get_notifier() - find notifier_head of the device with opp
* @dev: device pointer used to lookup device OPPs.
*
* Return: pointer to notifier head if found, otherwise -ENODEV or
* -EINVAL based on type of error casted as pointer. value must be checked
* with IS_ERR to determine valid pointer or error result.
*
* Locking: This function must be called under rcu_read_lock(). dev_opp is a RCU
* protected pointer. The reason for the same is that the opp pointer which is
* returned will remain valid for use with opp_get_{voltage, freq} only while
* under the locked area. The pointer returned must be used prior to unlocking
* with rcu_read_unlock() to maintain the integrity of the pointer.
*/
struct srcu_notifier_head *dev_pm_opp_get_notifier(struct device *dev)
{
struct device_opp *dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp))
return ERR_CAST(dev_opp); /* matching type */
return &dev_opp->srcu_head;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_notifier);
#ifdef CONFIG_OF
/**
* of_free_opp_table() - Free OPP table entries created from static DT entries
* @dev: device pointer used to lookup device OPPs.
*
* Free OPPs created using static entries present in DT.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function indirectly uses RCU updater strategy with mutex locks
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
*/
void of_free_opp_table(struct device *dev)
{
struct device_opp *dev_opp;
struct dev_pm_opp *opp, *tmp;
/* Hold our list modification lock here */
mutex_lock(&dev_opp_list_lock);
/* Check for existing list for 'dev' */
dev_opp = _find_device_opp(dev);
if (IS_ERR(dev_opp)) {
int error = PTR_ERR(dev_opp);
if (error != -ENODEV)
WARN(1, "%s: dev_opp: %d\n",
IS_ERR_OR_NULL(dev) ?
"Invalid device" : dev_name(dev),
error);
goto unlock;
}
/* Find if dev_opp manages a single device */
if (list_is_singular(&dev_opp->dev_list)) {
/* Free static OPPs */
list_for_each_entry_safe(opp, tmp, &dev_opp->opp_list, node) {
if (!opp->dynamic)
_opp_remove(dev_opp, opp, true);
}
} else {
_remove_list_dev(_find_list_dev(dev, dev_opp), dev_opp);
}
unlock:
mutex_unlock(&dev_opp_list_lock);
}
EXPORT_SYMBOL_GPL(of_free_opp_table);
void of_cpumask_free_opp_table(cpumask_var_t cpumask)
{
struct device *cpu_dev;
int cpu;
WARN_ON(cpumask_empty(cpumask));
for_each_cpu(cpu, cpumask) {
cpu_dev = get_cpu_device(cpu);
if (!cpu_dev) {
pr_err("%s: failed to get cpu%d device\n", __func__,
cpu);
continue;
}
of_free_opp_table(cpu_dev);
}
}
EXPORT_SYMBOL_GPL(of_cpumask_free_opp_table);
/* Returns opp descriptor node for a device, caller must do of_node_put() */
static struct device_node *_of_get_opp_desc_node(struct device *dev)
{
/*
* TODO: Support for multiple OPP tables.
*
* There should be only ONE phandle present in "operating-points-v2"
* property.
*/
return of_parse_phandle(dev->of_node, "operating-points-v2", 0);
}
/* Initializes OPP tables based on new bindings */
static int _of_init_opp_table_v2(struct device *dev,
struct device_node *opp_np)
{
struct device_node *np;
struct device_opp *dev_opp;
int ret = 0, count = 0;
dev_opp = _managed_opp(opp_np);
if (dev_opp) {
/* OPPs are already managed */
if (!_add_list_dev(dev, dev_opp))
ret = -ENOMEM;
return ret;
}
/* We have opp-list node now, iterate over it and add OPPs */
for_each_available_child_of_node(opp_np, np) {
count++;
ret = _opp_add_static_v2(dev, np);
if (ret) {
dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
ret);
goto free_table;
}
}
/* There should be one of more OPP defined */
if (WARN_ON(!count))
return -ENOENT;
dev_opp = _find_device_opp(dev);
if (WARN_ON(IS_ERR(dev_opp))) {
ret = PTR_ERR(dev_opp);
goto free_table;
}
dev_opp->np = opp_np;
dev_opp->shared_opp = of_property_read_bool(opp_np, "opp-shared");
return 0;
free_table:
of_free_opp_table(dev);
return ret;
}
/* Initializes OPP tables based on old-deprecated bindings */
static int _of_init_opp_table_v1(struct device *dev)
{
const struct property *prop;
const __be32 *val;
int nr;
prop = of_find_property(dev->of_node, "operating-points", NULL);
if (!prop)
return -ENODEV;
if (!prop->value)
return -ENODATA;
/*
* Each OPP is a set of tuples consisting of frequency and
* voltage like <freq-kHz vol-uV>.
*/
nr = prop->length / sizeof(u32);
if (nr % 2) {
dev_err(dev, "%s: Invalid OPP list\n", __func__);
return -EINVAL;
}
val = prop->value;
while (nr) {
unsigned long freq = be32_to_cpup(val++) * 1000;
unsigned long volt = be32_to_cpup(val++);
if (_opp_add_dynamic(dev, freq, volt, false))
dev_warn(dev, "%s: Failed to add OPP %ld\n",
__func__, freq);
nr -= 2;
}
return 0;
}
/**
* of_init_opp_table() - Initialize opp table from device tree
* @dev: device pointer used to lookup device OPPs.
*
* Register the initial OPP table with the OPP library for given device.
*
* Locking: The internal device_opp and opp structures are RCU protected.
* Hence this function indirectly uses RCU updater strategy with mutex locks
* to keep the integrity of the internal data structures. Callers should ensure
* that this function is *NOT* called under RCU protection or in contexts where
* mutex cannot be locked.
*
* Return:
* 0 On success OR
* Duplicate OPPs (both freq and volt are same) and opp->available
* -EEXIST Freq are same and volt are different OR
* Duplicate OPPs (both freq and volt are same) and !opp->available
* -ENOMEM Memory allocation failure
* -ENODEV when 'operating-points' property is not found or is invalid data
* in device node.
* -ENODATA when empty 'operating-points' property is found
* -EINVAL when invalid entries are found in opp-v2 table
*/
int of_init_opp_table(struct device *dev)
{
struct device_node *opp_np;
int ret;
/*
* OPPs have two version of bindings now. The older one is deprecated,
* try for the new binding first.
*/
opp_np = _of_get_opp_desc_node(dev);
if (!opp_np) {
/*
* Try old-deprecated bindings for backward compatibility with
* older dtbs.
*/
return _of_init_opp_table_v1(dev);
}
ret = _of_init_opp_table_v2(dev, opp_np);
of_node_put(opp_np);
return ret;
}
EXPORT_SYMBOL_GPL(of_init_opp_table);
int of_cpumask_init_opp_table(cpumask_var_t cpumask)
{
struct device *cpu_dev;
int cpu, ret = 0;
WARN_ON(cpumask_empty(cpumask));
for_each_cpu(cpu, cpumask) {
cpu_dev = get_cpu_device(cpu);
if (!cpu_dev) {
pr_err("%s: failed to get cpu%d device\n", __func__,
cpu);
continue;
}
ret = of_init_opp_table(cpu_dev);
if (ret) {
pr_err("%s: couldn't find opp table for cpu:%d, %d\n",
__func__, cpu, ret);
/* Free all other OPPs */
of_cpumask_free_opp_table(cpumask);
break;
}
}
return ret;
}
EXPORT_SYMBOL_GPL(of_cpumask_init_opp_table);
/* Required only for V1 bindings, as v2 can manage it from DT itself */
int set_cpus_sharing_opps(struct device *cpu_dev, cpumask_var_t cpumask)
{
struct device_list_opp *list_dev;
struct device_opp *dev_opp;
struct device *dev;
int cpu, ret = 0;
rcu_read_lock();
dev_opp = _find_device_opp(cpu_dev);
if (IS_ERR(dev_opp)) {
ret = -EINVAL;
goto out_rcu_read_unlock;
}
for_each_cpu(cpu, cpumask) {
if (cpu == cpu_dev->id)
continue;
dev = get_cpu_device(cpu);
if (!dev) {
dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
__func__, cpu);
continue;
}
list_dev = _add_list_dev(dev, dev_opp);
if (!list_dev) {
dev_err(dev, "%s: failed to add list-dev for cpu%d device\n",
__func__, cpu);
continue;
}
}
out_rcu_read_unlock:
rcu_read_unlock();
return 0;
}
EXPORT_SYMBOL_GPL(set_cpus_sharing_opps);
/*
* Works only for OPP v2 bindings.
*
* cpumask should be already set to mask of cpu_dev->id.
* Returns -ENOENT if operating-points-v2 bindings aren't supported.
*/
int of_get_cpus_sharing_opps(struct device *cpu_dev, cpumask_var_t cpumask)
{
struct device_node *np, *tmp_np;
struct device *tcpu_dev;
int cpu, ret = 0;
/* Get OPP descriptor node */
np = _of_get_opp_desc_node(cpu_dev);
if (!np) {
dev_dbg(cpu_dev, "%s: Couldn't find opp node: %ld\n", __func__,
PTR_ERR(np));
return -ENOENT;
}
/* OPPs are shared ? */
if (!of_property_read_bool(np, "opp-shared"))
goto put_cpu_node;
for_each_possible_cpu(cpu) {
if (cpu == cpu_dev->id)
continue;
tcpu_dev = get_cpu_device(cpu);
if (!tcpu_dev) {
dev_err(cpu_dev, "%s: failed to get cpu%d device\n",
__func__, cpu);
ret = -ENODEV;
goto put_cpu_node;
}
/* Get OPP descriptor node */
tmp_np = _of_get_opp_desc_node(tcpu_dev);
if (!tmp_np) {
dev_err(tcpu_dev, "%s: Couldn't find opp node: %ld\n",
__func__, PTR_ERR(tmp_np));
ret = PTR_ERR(tmp_np);
goto put_cpu_node;
}
/* CPUs are sharing opp node */
if (np == tmp_np)
cpumask_set_cpu(cpu, cpumask);
of_node_put(tmp_np);
}
put_cpu_node:
of_node_put(np);
return ret;
}
EXPORT_SYMBOL_GPL(of_get_cpus_sharing_opps);
#endif
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