linux/drivers/base/power/clock_ops.c

806 lines
19 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* drivers/base/power/clock_ops.c - Generic clock manipulation PM callbacks
*
* Copyright (c) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
*/
#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/clkdev.h>
#include <linux/of_clk.h>
#include <linux/slab.h>
#include <linux/err.h>
#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#ifdef CONFIG_PM_CLK
enum pce_status {
PCE_STATUS_NONE = 0,
PCE_STATUS_ACQUIRED,
PCE_STATUS_PREPARED,
PCE_STATUS_ENABLED,
PCE_STATUS_ERROR,
};
struct pm_clock_entry {
struct list_head node;
char *con_id;
struct clk *clk;
enum pce_status status;
bool enabled_when_prepared;
};
/**
* pm_clk_list_lock - ensure exclusive access for modifying the PM clock
* entry list.
* @psd: pm_subsys_data instance corresponding to the PM clock entry list
* and clk_op_might_sleep count to be modified.
*
* Get exclusive access before modifying the PM clock entry list and the
* clock_op_might_sleep count to guard against concurrent modifications.
* This also protects against a concurrent clock_op_might_sleep and PM clock
* entry list usage in pm_clk_suspend()/pm_clk_resume() that may or may not
* happen in atomic context, hence both the mutex and the spinlock must be
* taken here.
*/
static void pm_clk_list_lock(struct pm_subsys_data *psd)
__acquires(&psd->lock)
{
mutex_lock(&psd->clock_mutex);
spin_lock_irq(&psd->lock);
}
/**
* pm_clk_list_unlock - counterpart to pm_clk_list_lock().
* @psd: the same pm_subsys_data instance previously passed to
* pm_clk_list_lock().
*/
static void pm_clk_list_unlock(struct pm_subsys_data *psd)
__releases(&psd->lock)
{
spin_unlock_irq(&psd->lock);
mutex_unlock(&psd->clock_mutex);
}
/**
* pm_clk_op_lock - ensure exclusive access for performing clock operations.
* @psd: pm_subsys_data instance corresponding to the PM clock entry list
* and clk_op_might_sleep count being used.
* @flags: stored irq flags.
* @fn: string for the caller function's name.
*
* This is used by pm_clk_suspend() and pm_clk_resume() to guard
* against concurrent modifications to the clock entry list and the
* clock_op_might_sleep count. If clock_op_might_sleep is != 0 then
* only the mutex can be locked and those functions can only be used in
* non atomic context. If clock_op_might_sleep == 0 then these functions
* may be used in any context and only the spinlock can be locked.
* Returns -EINVAL if called in atomic context when clock ops might sleep.
*/
static int pm_clk_op_lock(struct pm_subsys_data *psd, unsigned long *flags,
const char *fn)
/* sparse annotations don't work here as exit state isn't static */
{
bool atomic_context = in_atomic() || irqs_disabled();
try_again:
spin_lock_irqsave(&psd->lock, *flags);
if (!psd->clock_op_might_sleep) {
/* the __release is there to work around sparse limitations */
__release(&psd->lock);
return 0;
}
/* bail out if in atomic context */
if (atomic_context) {
pr_err("%s: atomic context with clock_ops_might_sleep = %d",
fn, psd->clock_op_might_sleep);
spin_unlock_irqrestore(&psd->lock, *flags);
might_sleep();
return -EPERM;
}
/* we must switch to the mutex */
spin_unlock_irqrestore(&psd->lock, *flags);
mutex_lock(&psd->clock_mutex);
/*
* There was a possibility for psd->clock_op_might_sleep
* to become 0 above. Keep the mutex only if not the case.
*/
if (likely(psd->clock_op_might_sleep))
return 0;
mutex_unlock(&psd->clock_mutex);
goto try_again;
}
/**
* pm_clk_op_unlock - counterpart to pm_clk_op_lock().
* @psd: the same pm_subsys_data instance previously passed to
* pm_clk_op_lock().
* @flags: irq flags provided by pm_clk_op_lock().
*/
static void pm_clk_op_unlock(struct pm_subsys_data *psd, unsigned long *flags)
/* sparse annotations don't work here as entry state isn't static */
{
if (psd->clock_op_might_sleep) {
mutex_unlock(&psd->clock_mutex);
} else {
/* the __acquire is there to work around sparse limitations */
__acquire(&psd->lock);
spin_unlock_irqrestore(&psd->lock, *flags);
}
}
/**
* __pm_clk_enable - Enable a clock, reporting any errors
* @dev: The device for the given clock
* @ce: PM clock entry corresponding to the clock.
*/
static inline void __pm_clk_enable(struct device *dev, struct pm_clock_entry *ce)
{
int ret;
switch (ce->status) {
case PCE_STATUS_ACQUIRED:
ret = clk_prepare_enable(ce->clk);
break;
case PCE_STATUS_PREPARED:
ret = clk_enable(ce->clk);
break;
default:
return;
}
if (!ret)
ce->status = PCE_STATUS_ENABLED;
else
dev_err(dev, "%s: failed to enable clk %p, error %d\n",
__func__, ce->clk, 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)
{
if (!ce->clk)
ce->clk = clk_get(dev, ce->con_id);
if (IS_ERR(ce->clk)) {
ce->status = PCE_STATUS_ERROR;
return;
} else if (clk_is_enabled_when_prepared(ce->clk)) {
/* we defer preparing the clock in that case */
ce->status = PCE_STATUS_ACQUIRED;
ce->enabled_when_prepared = true;
} else if (clk_prepare(ce->clk)) {
ce->status = PCE_STATUS_ERROR;
dev_err(dev, "clk_prepare() failed\n");
return;
} else {
ce->status = PCE_STATUS_PREPARED;
}
dev_dbg(dev, "Clock %pC con_id %s managed by runtime PM.\n",
ce->clk, ce->con_id);
}
static int __pm_clk_add(struct device *dev, const char *con_id,
struct clk *clk)
{
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)
return -ENOMEM;
if (con_id) {
ce->con_id = kstrdup(con_id, GFP_KERNEL);
if (!ce->con_id) {
kfree(ce);
return -ENOMEM;
}
} else {
if (IS_ERR(clk)) {
kfree(ce);
return -ENOENT;
}
ce->clk = clk;
}
pm_clk_acquire(dev, ce);
pm_clk_list_lock(psd);
list_add_tail(&ce->node, &psd->clock_list);
if (ce->enabled_when_prepared)
psd->clock_op_might_sleep++;
pm_clk_list_unlock(psd);
return 0;
}
/**
* 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)
{
return __pm_clk_add(dev, con_id, NULL);
}
EXPORT_SYMBOL_GPL(pm_clk_add);
/**
* pm_clk_add_clk - Start using a device clock for power management.
* @dev: Device whose clock is going to be used for power management.
* @clk: Clock pointer
*
* Add the clock to the list of clocks used for the power management of @dev.
* The power-management code will take control of the clock reference, so
* callers should not call clk_put() on @clk after this function sucessfully
* returned.
*/
int pm_clk_add_clk(struct device *dev, struct clk *clk)
{
return __pm_clk_add(dev, NULL, clk);
}
EXPORT_SYMBOL_GPL(pm_clk_add_clk);
/**
* of_pm_clk_add_clk - Start using a device clock for power management.
* @dev: Device whose clock is going to be used for power management.
* @name: Name of clock that is going to be used for power management.
*
* Add the clock described in the 'clocks' device-tree node that matches
* with the 'name' provided, to the list of clocks used for the power
* management of @dev. On success, returns 0. Returns a negative error
* code if the clock is not found or cannot be added.
*/
int of_pm_clk_add_clk(struct device *dev, const char *name)
{
struct clk *clk;
int ret;
if (!dev || !dev->of_node || !name)
return -EINVAL;
clk = of_clk_get_by_name(dev->of_node, name);
if (IS_ERR(clk))
return PTR_ERR(clk);
ret = pm_clk_add_clk(dev, clk);
if (ret) {
clk_put(clk);
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(of_pm_clk_add_clk);
/**
* of_pm_clk_add_clks - Start using device clock(s) for power management.
* @dev: Device whose clock(s) is going to be used for power management.
*
* Add a series of clocks described in the 'clocks' device-tree node for
* a device to the list of clocks used for the power management of @dev.
* On success, returns the number of clocks added. Returns a negative
* error code if there are no clocks in the device node for the device
* or if adding a clock fails.
*/
int of_pm_clk_add_clks(struct device *dev)
{
struct clk **clks;
int i, count;
int ret;
if (!dev || !dev->of_node)
return -EINVAL;
count = of_clk_get_parent_count(dev->of_node);
if (count <= 0)
return -ENODEV;
clks = kcalloc(count, sizeof(*clks), GFP_KERNEL);
if (!clks)
return -ENOMEM;
for (i = 0; i < count; i++) {
clks[i] = of_clk_get(dev->of_node, i);
if (IS_ERR(clks[i])) {
ret = PTR_ERR(clks[i]);
goto error;
}
ret = pm_clk_add_clk(dev, clks[i]);
if (ret) {
clk_put(clks[i]);
goto error;
}
}
kfree(clks);
return i;
error:
while (i--)
pm_clk_remove_clk(dev, clks[i]);
kfree(clks);
return ret;
}
EXPORT_SYMBOL_GPL(of_pm_clk_add_clks);
/**
* __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;
switch (ce->status) {
case PCE_STATUS_ENABLED:
clk_disable(ce->clk);
fallthrough;
case PCE_STATUS_PREPARED:
clk_unprepare(ce->clk);
fallthrough;
case PCE_STATUS_ACQUIRED:
case PCE_STATUS_ERROR:
if (!IS_ERR(ce->clk))
clk_put(ce->clk);
break;
default:
break;
}
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;
pm_clk_list_lock(psd);
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;
}
pm_clk_list_unlock(psd);
return;
remove:
list_del(&ce->node);
if (ce->enabled_when_prepared)
psd->clock_op_might_sleep--;
pm_clk_list_unlock(psd);
__pm_clk_remove(ce);
}
EXPORT_SYMBOL_GPL(pm_clk_remove);
/**
* pm_clk_remove_clk - Stop using a device clock for power management.
* @dev: Device whose clock should not be used for PM any more.
* @clk: Clock pointer
*
* Remove the clock pointed to by @clk from the list of clocks used for
* the power management of @dev.
*/
void pm_clk_remove_clk(struct device *dev, struct clk *clk)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
struct pm_clock_entry *ce;
if (!psd || !clk)
return;
pm_clk_list_lock(psd);
list_for_each_entry(ce, &psd->clock_list, node) {
if (clk == ce->clk)
goto remove;
}
pm_clk_list_unlock(psd);
return;
remove:
list_del(&ce->node);
if (ce->enabled_when_prepared)
psd->clock_op_might_sleep--;
pm_clk_list_unlock(psd);
__pm_clk_remove(ce);
}
EXPORT_SYMBOL_GPL(pm_clk_remove_clk);
/**
* 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, set the count of clocks that might sleep to 0.
*/
void pm_clk_init(struct device *dev)
{
struct pm_subsys_data *psd = dev_to_psd(dev);
if (psd) {
INIT_LIST_HEAD(&psd->clock_list);
mutex_init(&psd->clock_mutex);
psd->clock_op_might_sleep = 0;
}
}
EXPORT_SYMBOL_GPL(pm_clk_init);
/**
* 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);
}
EXPORT_SYMBOL_GPL(pm_clk_create);
/**
* 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);
pm_clk_list_lock(psd);
list_for_each_entry_safe_reverse(ce, c, &psd->clock_list, node)
list_move(&ce->node, &list);
psd->clock_op_might_sleep = 0;
pm_clk_list_unlock(psd);
dev_pm_put_subsys_data(dev);
list_for_each_entry_safe_reverse(ce, c, &list, node) {
list_del(&ce->node);
__pm_clk_remove(ce);
}
}
EXPORT_SYMBOL_GPL(pm_clk_destroy);
static void pm_clk_destroy_action(void *data)
{
pm_clk_destroy(data);
}
int devm_pm_clk_create(struct device *dev)
{
int ret;
ret = pm_clk_create(dev);
if (ret)
return ret;
return devm_add_action_or_reset(dev, pm_clk_destroy_action, dev);
}
EXPORT_SYMBOL_GPL(devm_pm_clk_create);
/**
* 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;
int ret;
dev_dbg(dev, "%s()\n", __func__);
if (!psd)
return 0;
ret = pm_clk_op_lock(psd, &flags, __func__);
if (ret)
return ret;
list_for_each_entry_reverse(ce, &psd->clock_list, node) {
if (ce->status == PCE_STATUS_ENABLED) {
if (ce->enabled_when_prepared) {
clk_disable_unprepare(ce->clk);
ce->status = PCE_STATUS_ACQUIRED;
} else {
clk_disable(ce->clk);
ce->status = PCE_STATUS_PREPARED;
}
}
}
pm_clk_op_unlock(psd, &flags);
return 0;
}
EXPORT_SYMBOL_GPL(pm_clk_suspend);
/**
* 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;
ret = pm_clk_op_lock(psd, &flags, __func__);
if (ret)
return ret;
list_for_each_entry(ce, &psd->clock_list, node)
__pm_clk_enable(dev, ce);
pm_clk_op_unlock(psd, &flags);
return 0;
}
EXPORT_SYMBOL_GPL(pm_clk_resume);
/**
* 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_set(dev, 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_set(dev, NULL);
pm_clk_destroy(dev);
break;
}
return 0;
}
int pm_clk_runtime_suspend(struct device *dev)
{
int ret;
dev_dbg(dev, "%s\n", __func__);
ret = pm_generic_runtime_suspend(dev);
if (ret) {
dev_err(dev, "failed to suspend device\n");
return ret;
}
ret = pm_clk_suspend(dev);
if (ret) {
dev_err(dev, "failed to suspend clock\n");
pm_generic_runtime_resume(dev);
return ret;
}
return 0;
}
EXPORT_SYMBOL_GPL(pm_clk_runtime_suspend);
int pm_clk_runtime_resume(struct device *dev)
{
int ret;
dev_dbg(dev, "%s\n", __func__);
ret = pm_clk_resume(dev);
if (ret) {
dev_err(dev, "failed to resume clock\n");
return ret;
}
return pm_generic_runtime_resume(dev);
}
EXPORT_SYMBOL_GPL(pm_clk_runtime_resume);
#else /* !CONFIG_PM_CLK */
/**
* 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_DRIVER_NOT_BOUND:
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_CLK */
/**
* 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);
}
EXPORT_SYMBOL_GPL(pm_clk_add_notifier);