- 根目录:
- drivers
- base
- power
- clock_ops.c
/*
* drivers/base/power/clock_ops.c - Generic clock manipulation PM callbacks
*
* Copyright (c) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
*
* This file is released under the GPLv2.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/pm.h>
#include <linux/pm_clock.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/err.h>
#ifdef CONFIG_PM
enum pce_status {
PCE_STATUS_NONE = 0,
PCE_STATUS_ACQUIRED,
PCE_STATUS_ENABLED,
PCE_STATUS_ERROR,
};
struct pm_clock_entry {
struct list_head node;
char *con_id;
struct clk *clk;
enum pce_status status;
};
/**
* pm_clk_enable - Enable a clock, reporting any errors
* @dev: The device for the given clock
* @clk: The clock being enabled.
*/
static inline int __pm_clk_enable(struct device *dev, struct clk *clk)
{
int ret = clk_enable(clk);
if (ret)
dev_err(dev, "%s: failed to enable clk %p, error %d\n",
__func__, clk, ret);
return ret;
}
/**
* pm_clk_acquire - Acquire a device clock.
* @dev: Device whose clock is to be acquired.
* @ce: PM clock entry corresponding to the clock.
*/
static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
{
ce->clk = clk_get(dev, ce->con_id);
if (IS_ERR(ce->clk)) {
ce->status = PCE_STATUS_ERROR;
} else {
clk_prepare(ce->clk);
ce->status = PCE_STATUS_ACQUIRED;
dev_dbg(dev, "Clock %s managed by runtime PM.\n", ce->con_id);
}
}
/**
* pm_clk_add - Start using a device clock for power management.
* @dev: Device whose clock is going to be used for power management.
* @con_id: Connection ID of the clock.
*
* Add the clock represented by @con_id to the list of clocks used for
* the power management of @dev.
*/
int pm_clk_add(struct device *dev, const char *con_id)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
if (!psd)
return -EINVAL;
ce = kzalloc(sizeof(*ce), GFP_KERNEL);
if (!ce) {
dev_err(dev, "Not enough memory for clock entry.\n");
return -ENOMEM;
}
if (con_id) {
ce->con_id = kstrdup(con_id, GFP_KERNEL);
if (!ce->con_id) {
dev_err(dev,
"Not enough memory for clock connection ID.\n");
kfree(ce);
return -ENOMEM;
}
}
pm_clk_acquire(dev, ce);
spin_lock_irq(&psd->lock);
list_add_tail(&ce->node, &psd->clock_list);
spin_unlock_irq(&psd->lock);
return 0;
}
/**
* __pm_clk_remove - Destroy PM clock entry.
* @ce: PM clock entry to destroy.
*/
static void __pm_clk_remove(struct pm_clock_entry *ce)
{
if (!ce)
return;
if (ce->status < PCE_STATUS_ERROR) {
if (ce->status == PCE_STATUS_ENABLED)
clk_disable(ce->clk);
if (ce->status >= PCE_STATUS_ACQUIRED) {
clk_unprepare(ce->clk);
clk_put(ce->clk);
}
}
kfree(ce->con_id);
kfree(ce);
}
/**
* pm_clk_remove - Stop using a device clock for power management.
* @dev: Device whose clock should not be used for PM any more.
* @con_id: Connection ID of the clock.
*
* Remove the clock represented by @con_id from the list of clocks used for
* the power management of @dev.
*/
void pm_clk_remove(struct device *dev, const char *con_id)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
if (!psd)
return;
spin_lock_irq(&psd->lock);
list_for_each_entry(ce, &psd->clock_list, node) {
if (!con_id && !ce->con_id)
goto remove;
else if (!con_id || !ce->con_id)
continue;
else if (!strcmp(con_id, ce->con_id))
goto remove;
}
spin_unlock_irq(&psd->lock);
return;
remove:
list_del(&ce->node);
spin_unlock_irq(&psd->lock);
__pm_clk_remove(ce);
}
/**
* pm_clk_init - Initialize a device's list of power management clocks.
* @dev: Device to initialize the list of PM clocks for.
*
* Initialize the lock and clock_list members of the device's pm_subsys_data
* object.
*/
void pm_clk_init(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
if (psd)
INIT_LIST_HEAD(&psd->clock_list);
}
/**
* pm_clk_create - Create and initialize a device's list of PM clocks.
* @dev: Device to create and initialize the list of PM clocks for.
*
* Allocate a struct pm_subsys_data object, initialize its lock and clock_list
* members and make the @dev's power.subsys_data field point to it.
*/
int pm_clk_create(struct device *dev)
{
return dev_pm_get_subsys_data(dev);
}
/**
* pm_clk_destroy - Destroy a device's list of power management clocks.
* @dev: Device to destroy the list of PM clocks for.
*
* Clear the @dev's power.subsys_data field, remove the list of clock entries
* from the struct pm_subsys_data object pointed to by it before and free
* that object.
*/
void pm_clk_destroy(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce, *c;
struct list_head list;
if (!psd)
return;
INIT_LIST_HEAD(&list);
spin_lock_irq(&psd->lock);
list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
list_move(&ce->node, &list);
spin_unlock_irq(&psd->lock);
dev_pm_put_subsys_data(dev);
list_for_each_entry_safe_reverse(ce, c, &list, node) {
list_del(&ce->node);
__pm_clk_remove(ce);
}
}
#endif /* CONFIG_PM */
#ifdef CONFIG_PM_RUNTIME
/**
* pm_clk_suspend - Disable clocks in a device's PM clock list.
* @dev: Device to disable the clocks for.
*/
int pm_clk_suspend(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
unsigned long flags;
dev_dbg(dev, "%s()\n", __func__);
if (!psd)
return 0;
spin_lock_irqsave(&psd->lock, flags);
list_for_each_entry_reverse(ce, &psd->clock_list, node) {
if (ce->status < PCE_STATUS_ERROR) {
if (ce->status == PCE_STATUS_ENABLED)
clk_disable(ce->clk);
ce->status = PCE_STATUS_ACQUIRED;
}
}
spin_unlock_irqrestore(&psd->lock, flags);
return 0;
}
/**
* pm_clk_resume - Enable clocks in a device's PM clock list.
* @dev: Device to enable the clocks for.
*/
int pm_clk_resume(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
unsigned long flags;
int ret;
dev_dbg(dev, "%s()\n", __func__);
if (!psd)
return 0;
spin_lock_irqsave(&psd->lock, flags);
list_for_each_entry(ce, &psd->clock_list, node) {
if (ce->status < PCE_STATUS_ERROR) {
ret = __pm_clk_enable(dev, ce->clk);
if (!ret)
ce->status = PCE_STATUS_ENABLED;
}
}
spin_unlock_irqrestore(&psd->lock, flags);
return 0;
}
/**
* pm_clk_notify - Notify routine for device addition and removal.
* @nb: Notifier block object this function is a member of.
* @action: Operation being carried out by the caller.
* @data: Device the routine is being run for.
*
* For this function to work, @nb must be a member of an object of type
* struct pm_clk_notifier_block containing all of the requisite data.
* Specifically, the pm_domain member of that object is copied to the device's
* pm_domain field and its con_ids member is used to populate the device's list
* of PM clocks, depending on @action.
*
* If the device's pm_domain field is already populated with a value different
* from the one stored in the struct pm_clk_notifier_block object, the function
* does nothing.
*/
static int pm_clk_notify(struct notifier_block *nb,
unsigned long action, void *data)
{
struct pm_clk_notifier_block *clknb;
struct device *dev = data;
char **con_id;
int error;
dev_dbg(dev, "%s() %ld\n", __func__, action);
clknb = container_of(nb, struct pm_clk_notifier_block, nb);
switch (action) {
case BUS_NOTIFY_ADD_DEVICE:
if (dev->pm_domain)
break;
error = pm_clk_create(dev);
if (error)
break;
dev->pm_domain = clknb->pm_domain;
if (clknb->con_ids[0]) {
for (con_id = clknb->con_ids; *con_id; con_id++)
pm_clk_add(dev, *con_id);
} else {
pm_clk_add(dev, NULL);
}
break;
case BUS_NOTIFY_DEL_DEVICE:
if (dev->pm_domain != clknb->pm_domain)
break;
dev->pm_domain = NULL;
pm_clk_destroy(dev);
break;
}
return 0;
}
#else /* !CONFIG_PM_RUNTIME */
#ifdef CONFIG_PM
/**
* pm_clk_suspend - Disable clocks in a device's PM clock list.
* @dev: Device to disable the clocks for.
*/
int pm_clk_suspend(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
unsigned long flags;
dev_dbg(dev, "%s()\n", __func__);
/* If there is no driver, the clocks are already disabled. */
if (!psd || !dev->driver)
return 0;
spin_lock_irqsave(&psd->lock, flags);
list_for_each_entry_reverse(ce, &psd->clock_list, node)
clk_disable(ce->clk);
spin_unlock_irqrestore(&psd->lock, flags);
return 0;
}
/**
* pm_clk_resume - Enable clocks in a device's PM clock list.
* @dev: Device to enable the clocks for.
*/
int pm_clk_resume(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
unsigned long flags;
dev_dbg(dev, "%s()\n", __func__);
/* If there is no driver, the clocks should remain disabled. */
if (!psd || !dev->driver)
return 0;
spin_lock_irqsave(&psd->lock, flags);
list_for_each_entry(ce, &psd->clock_list, node)
__pm_clk_enable(dev, ce->clk);
spin_unlock_irqrestore(&psd->lock, flags);
return 0;
}
#endif /* CONFIG_PM */
/**
* enable_clock - Enable a device clock.
* @dev: Device whose clock is to be enabled.
* @con_id: Connection ID of the clock.
*/
static void enable_clock(struct device *dev, const char *con_id)
{
struct clk *clk;
clk = clk_get(dev, con_id);
if (!IS_ERR(clk)) {
clk_prepare_enable(clk);
clk_put(clk);
dev_info(dev, "Runtime PM disabled, clock forced on.\n");
}
}
/**
* disable_clock - Disable a device clock.
* @dev: Device whose clock is to be disabled.
* @con_id: Connection ID of the clock.
*/
static void disable_clock(struct device *dev, const char *con_id)
{
struct clk *clk;
clk = clk_get(dev, con_id);
if (!IS_ERR(clk)) {
clk_disable_unprepare(clk);
clk_put(clk);
dev_info(dev, "Runtime PM disabled, clock forced off.\n");
}
}
/**
* pm_clk_notify - Notify routine for device addition and removal.
* @nb: Notifier block object this function is a member of.
* @action: Operation being carried out by the caller.
* @data: Device the routine is being run for.
*
* For this function to work, @nb must be a member of an object of type
* struct pm_clk_notifier_block containing all of the requisite data.
* Specifically, the con_ids member of that object is used to enable or disable
* the device's clocks, depending on @action.
*/
static int pm_clk_notify(struct notifier_block *nb,
unsigned long action, void *data)
{
struct pm_clk_notifier_block *clknb;
struct device *dev = data;
char **con_id;
dev_dbg(dev, "%s() %ld\n", __func__, action);
clknb = container_of(nb, struct pm_clk_notifier_block, nb);
switch (action) {
case BUS_NOTIFY_BIND_DRIVER:
if (clknb->con_ids[0]) {
for (con_id = clknb->con_ids; *con_id; con_id++)
enable_clock(dev, *con_id);
} else {
enable_clock(dev, NULL);
}
break;
case BUS_NOTIFY_UNBOUND_DRIVER:
if (clknb->con_ids[0]) {
for (con_id = clknb->con_ids; *con_id; con_id++)
disable_clock(dev, *con_id);
} else {
disable_clock(dev, NULL);
}
break;
}
return 0;
}
#endif /* !CONFIG_PM_RUNTIME */
/**
* pm_clk_add_notifier - Add bus type notifier for power management clocks.
* @bus: Bus type to add the notifier to.
* @clknb: Notifier to be added to the given bus type.
*
* The nb member of @clknb is not expected to be initialized and its
* notifier_call member will be replaced with pm_clk_notify(). However,
* the remaining members of @clknb should be populated prior to calling this
* routine.
*/
void pm_clk_add_notifier(struct bus_type *bus,
struct pm_clk_notifier_block *clknb)
{
if (!bus || !clknb)
return;
clknb->nb.notifier_call = pm_clk_notify;
bus_register_notifier(bus, &clknb->nb);
}