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ef27bed187
Since the power.subsys_data device field will be used by multiple filesystems, introduce a reference counting mechanism for it to avoid freeing it prematurely or changing its value at a wrong time. Make the PM clocks management code that currently is the only user of power.subsys_data use the new reference counting. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
88 lines
1.9 KiB
C
88 lines
1.9 KiB
C
/*
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* drivers/base/power/common.c - Common device power management code.
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*
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* Copyright (C) 2011 Rafael J. Wysocki <rjw@sisk.pl>, Renesas Electronics Corp.
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*
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* This file is released under the GPLv2.
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*/
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/device.h>
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#include <linux/pm_runtime.h>
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/**
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* dev_pm_get_subsys_data - Create or refcount power.subsys_data for device.
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* @dev: Device to handle.
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*
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* If power.subsys_data is NULL, point it to a new object, otherwise increment
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* its reference counter. Return 1 if a new object has been created, otherwise
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* return 0 or error code.
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*/
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int dev_pm_get_subsys_data(struct device *dev)
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{
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struct pm_subsys_data *psd;
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int ret = 0;
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psd = kzalloc(sizeof(*psd), GFP_KERNEL);
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if (!psd)
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return -ENOMEM;
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spin_lock_irq(&dev->power.lock);
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if (dev->power.subsys_data) {
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dev->power.subsys_data->refcount++;
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} else {
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spin_lock_init(&psd->lock);
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psd->refcount = 1;
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dev->power.subsys_data = psd;
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pm_clk_init(dev);
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psd = NULL;
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ret = 1;
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}
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spin_unlock_irq(&dev->power.lock);
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/* kfree() verifies that its argument is nonzero. */
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kfree(psd);
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return ret;
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}
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EXPORT_SYMBOL_GPL(dev_pm_get_subsys_data);
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/**
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* dev_pm_put_subsys_data - Drop reference to power.subsys_data.
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* @dev: Device to handle.
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*
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* If the reference counter of power.subsys_data is zero after dropping the
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* reference, power.subsys_data is removed. Return 1 if that happens or 0
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* otherwise.
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*/
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int dev_pm_put_subsys_data(struct device *dev)
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{
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struct pm_subsys_data *psd;
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int ret = 0;
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spin_lock_irq(&dev->power.lock);
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psd = dev_to_psd(dev);
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if (!psd) {
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ret = -EINVAL;
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goto out;
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}
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if (--psd->refcount == 0) {
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dev->power.subsys_data = NULL;
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kfree(psd);
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ret = 1;
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}
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out:
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spin_unlock_irq(&dev->power.lock);
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return ret;
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}
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EXPORT_SYMBOL_GPL(dev_pm_put_subsys_data);
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