mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-24 09:50:04 +00:00
![William Breathitt Gray](/assets/img/avatar_default.png)
Counter subsystem symbols are only relevant to counter drivers. A COUNTER namespace is created to control the availability of these symbols to modules that import this namespace explicitly. Cc: Patrick Havelange <patrick.havelange@essensium.com> Cc: Jarkko Nikula <jarkko.nikula@linux.intel.com> Cc: Oleksij Rempel <linux@rempel-privat.de> Cc: Pengutronix Kernel Team <kernel@pengutronix.de> Cc: Kamel Bouhara <kamel.bouhara@bootlin.com> Cc: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@foss.st.com> Acked-by: David Lechner <david@lechnology.com> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com> Link: https://lore.kernel.org/r/20220815220321.74161-1-william.gray@linaro.org/ Signed-off-by: William Breathitt Gray <william.gray@linaro.org> Link: https://lore.kernel.org/r/8a756df96c24946547a7ece5caa5f654809c5e7f.1664318353.git.william.gray@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
282 lines
6.3 KiB
C
282 lines
6.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Generic Counter interface
|
|
* Copyright (C) 2020 William Breathitt Gray
|
|
*/
|
|
#include <linux/cdev.h>
|
|
#include <linux/counter.h>
|
|
#include <linux/device.h>
|
|
#include <linux/device/bus.h>
|
|
#include <linux/export.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/gfp.h>
|
|
#include <linux/idr.h>
|
|
#include <linux/init.h>
|
|
#include <linux/kdev_t.h>
|
|
#include <linux/module.h>
|
|
#include <linux/mutex.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/types.h>
|
|
#include <linux/wait.h>
|
|
|
|
#include "counter-chrdev.h"
|
|
#include "counter-sysfs.h"
|
|
|
|
#define COUNTER_NAME "counter"
|
|
|
|
/* Provides a unique ID for each counter device */
|
|
static DEFINE_IDA(counter_ida);
|
|
|
|
struct counter_device_allochelper {
|
|
struct counter_device counter;
|
|
|
|
/*
|
|
* This is cache line aligned to ensure private data behaves like if it
|
|
* were kmalloced separately.
|
|
*/
|
|
unsigned long privdata[] ____cacheline_aligned;
|
|
};
|
|
|
|
static void counter_device_release(struct device *dev)
|
|
{
|
|
struct counter_device *const counter =
|
|
container_of(dev, struct counter_device, dev);
|
|
|
|
counter_chrdev_remove(counter);
|
|
ida_free(&counter_ida, dev->id);
|
|
|
|
kfree(container_of(counter, struct counter_device_allochelper, counter));
|
|
}
|
|
|
|
static struct device_type counter_device_type = {
|
|
.name = "counter_device",
|
|
.release = counter_device_release,
|
|
};
|
|
|
|
static struct bus_type counter_bus_type = {
|
|
.name = "counter",
|
|
.dev_name = "counter",
|
|
};
|
|
|
|
static dev_t counter_devt;
|
|
|
|
/**
|
|
* counter_priv - access counter device private data
|
|
* @counter: counter device
|
|
*
|
|
* Get the counter device private data
|
|
*/
|
|
void *counter_priv(const struct counter_device *const counter)
|
|
{
|
|
struct counter_device_allochelper *ch =
|
|
container_of(counter, struct counter_device_allochelper, counter);
|
|
|
|
return &ch->privdata;
|
|
}
|
|
EXPORT_SYMBOL_NS_GPL(counter_priv, COUNTER);
|
|
|
|
/**
|
|
* counter_alloc - allocate a counter_device
|
|
* @sizeof_priv: size of the driver private data
|
|
*
|
|
* This is part one of counter registration. The structure is allocated
|
|
* dynamically to ensure the right lifetime for the embedded struct device.
|
|
*
|
|
* If this succeeds, call counter_put() to get rid of the counter_device again.
|
|
*/
|
|
struct counter_device *counter_alloc(size_t sizeof_priv)
|
|
{
|
|
struct counter_device_allochelper *ch;
|
|
struct counter_device *counter;
|
|
struct device *dev;
|
|
int err;
|
|
|
|
ch = kzalloc(sizeof(*ch) + sizeof_priv, GFP_KERNEL);
|
|
if (!ch)
|
|
return NULL;
|
|
|
|
counter = &ch->counter;
|
|
dev = &counter->dev;
|
|
|
|
/* Acquire unique ID */
|
|
err = ida_alloc(&counter_ida, GFP_KERNEL);
|
|
if (err < 0)
|
|
goto err_ida_alloc;
|
|
dev->id = err;
|
|
|
|
mutex_init(&counter->ops_exist_lock);
|
|
dev->type = &counter_device_type;
|
|
dev->bus = &counter_bus_type;
|
|
dev->devt = MKDEV(MAJOR(counter_devt), dev->id);
|
|
|
|
err = counter_chrdev_add(counter);
|
|
if (err < 0)
|
|
goto err_chrdev_add;
|
|
|
|
device_initialize(dev);
|
|
|
|
err = dev_set_name(dev, COUNTER_NAME "%d", dev->id);
|
|
if (err)
|
|
goto err_dev_set_name;
|
|
|
|
return counter;
|
|
|
|
err_dev_set_name:
|
|
|
|
counter_chrdev_remove(counter);
|
|
err_chrdev_add:
|
|
|
|
ida_free(&counter_ida, dev->id);
|
|
err_ida_alloc:
|
|
|
|
kfree(ch);
|
|
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL_NS_GPL(counter_alloc, COUNTER);
|
|
|
|
void counter_put(struct counter_device *counter)
|
|
{
|
|
put_device(&counter->dev);
|
|
}
|
|
EXPORT_SYMBOL_NS_GPL(counter_put, COUNTER);
|
|
|
|
/**
|
|
* counter_add - complete registration of a counter
|
|
* @counter: the counter to add
|
|
*
|
|
* This is part two of counter registration.
|
|
*
|
|
* If this succeeds, call counter_unregister() to get rid of the counter_device again.
|
|
*/
|
|
int counter_add(struct counter_device *counter)
|
|
{
|
|
int err;
|
|
struct device *dev = &counter->dev;
|
|
|
|
if (counter->parent) {
|
|
dev->parent = counter->parent;
|
|
dev->of_node = counter->parent->of_node;
|
|
}
|
|
|
|
err = counter_sysfs_add(counter);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
/* implies device_add(dev) */
|
|
return cdev_device_add(&counter->chrdev, dev);
|
|
}
|
|
EXPORT_SYMBOL_NS_GPL(counter_add, COUNTER);
|
|
|
|
/**
|
|
* counter_unregister - unregister Counter from the system
|
|
* @counter: pointer to Counter to unregister
|
|
*
|
|
* The Counter is unregistered from the system.
|
|
*/
|
|
void counter_unregister(struct counter_device *const counter)
|
|
{
|
|
if (!counter)
|
|
return;
|
|
|
|
cdev_device_del(&counter->chrdev, &counter->dev);
|
|
|
|
mutex_lock(&counter->ops_exist_lock);
|
|
|
|
counter->ops = NULL;
|
|
wake_up(&counter->events_wait);
|
|
|
|
mutex_unlock(&counter->ops_exist_lock);
|
|
}
|
|
EXPORT_SYMBOL_NS_GPL(counter_unregister, COUNTER);
|
|
|
|
static void devm_counter_release(void *counter)
|
|
{
|
|
counter_unregister(counter);
|
|
}
|
|
|
|
static void devm_counter_put(void *counter)
|
|
{
|
|
counter_put(counter);
|
|
}
|
|
|
|
/**
|
|
* devm_counter_alloc - allocate a counter_device
|
|
* @dev: the device to register the release callback for
|
|
* @sizeof_priv: size of the driver private data
|
|
*
|
|
* This is the device managed version of counter_add(). It registers a cleanup
|
|
* callback to care for calling counter_put().
|
|
*/
|
|
struct counter_device *devm_counter_alloc(struct device *dev, size_t sizeof_priv)
|
|
{
|
|
struct counter_device *counter;
|
|
int err;
|
|
|
|
counter = counter_alloc(sizeof_priv);
|
|
if (!counter)
|
|
return NULL;
|
|
|
|
err = devm_add_action_or_reset(dev, devm_counter_put, counter);
|
|
if (err < 0)
|
|
return NULL;
|
|
|
|
return counter;
|
|
}
|
|
EXPORT_SYMBOL_NS_GPL(devm_counter_alloc, COUNTER);
|
|
|
|
/**
|
|
* devm_counter_add - complete registration of a counter
|
|
* @dev: the device to register the release callback for
|
|
* @counter: the counter to add
|
|
*
|
|
* This is the device managed version of counter_add(). It registers a cleanup
|
|
* callback to care for calling counter_unregister().
|
|
*/
|
|
int devm_counter_add(struct device *dev,
|
|
struct counter_device *const counter)
|
|
{
|
|
int err;
|
|
|
|
err = counter_add(counter);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
return devm_add_action_or_reset(dev, devm_counter_release, counter);
|
|
}
|
|
EXPORT_SYMBOL_NS_GPL(devm_counter_add, COUNTER);
|
|
|
|
#define COUNTER_DEV_MAX 256
|
|
|
|
static int __init counter_init(void)
|
|
{
|
|
int err;
|
|
|
|
err = bus_register(&counter_bus_type);
|
|
if (err < 0)
|
|
return err;
|
|
|
|
err = alloc_chrdev_region(&counter_devt, 0, COUNTER_DEV_MAX,
|
|
COUNTER_NAME);
|
|
if (err < 0)
|
|
goto err_unregister_bus;
|
|
|
|
return 0;
|
|
|
|
err_unregister_bus:
|
|
bus_unregister(&counter_bus_type);
|
|
return err;
|
|
}
|
|
|
|
static void __exit counter_exit(void)
|
|
{
|
|
unregister_chrdev_region(counter_devt, COUNTER_DEV_MAX);
|
|
bus_unregister(&counter_bus_type);
|
|
}
|
|
|
|
subsys_initcall(counter_init);
|
|
module_exit(counter_exit);
|
|
|
|
MODULE_AUTHOR("William Breathitt Gray <vilhelm.gray@gmail.com>");
|
|
MODULE_DESCRIPTION("Generic Counter interface");
|
|
MODULE_LICENSE("GPL v2");
|