iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity
61e2c70da9
linux/drivers/iio/industrialio-triggered-buffer.c

104 lines
3.1 KiB
C
Raw Normal View History

iio: Add helper function for initializing triggered buffers Add a helper function for executing the common tasks which are usually involved in setting up a simple software ringbuffer. It will allocate the buffer, allocate the pollfunc and register the buffer. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-18 20:33:48 +04:00
/*
* Copyright (c) 2012 Analog Devices, Inc.
* Author: Lars-Peter Clausen <lars@metafoo.de>
*
* 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/kernel.h>
#include <linux/export.h>
#include <linux/module.h>
#include <linux/iio/iio.h>
#include <linux/iio/buffer.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/trigger_consumer.h>
static const struct iio_buffer_setup_ops iio_triggered_buffer_setup_ops = {
.postenable = &iio_triggered_buffer_postenable,
.predisable = &iio_triggered_buffer_predisable,
};
/**
* iio_triggered_buffer_setup() - Setup triggered buffer and pollfunc
* @indio_dev: IIO device structure
* @pollfunc_bh: Function which will be used as pollfunc bottom half
* @pollfunc_th: Function which will be used as pollfunc top half
* @setup_ops: Buffer setup functions to use for this device.
* If NULL the default setup functions for triggered
* buffers will be used.
*
* This function combines some common tasks which will normally be performed
* when setting up a triggered buffer. It will allocate the buffer and the
iio: Move buffer registration to the core Originally device and buffer registration were kept as separate operations in IIO to allow to register two distinct sets of channels for buffered and non-buffered operations. This has since already been further restricted and the channel set registered for the buffer needs to be a subset of the channel set registered for the device. Additionally the possibility to not have a raw (or processed) attribute for a channel which was registered for the device was added a while ago. This means it is possible to not register any device level attributes for a channel even if it is registered for the device. Also if a channel's scan_index is set to -1 and the channel is registered for the buffer it is ignored. So in summary it means it is possible to register the same channel array for both the device and the buffer yet still end up with distinctive sets of channels for both of them. This makes the argument for having to have to manually register the channels for both the device and the buffer invalid. Considering that the vast majority of all drivers want to register the same set of channels for both the buffer and the device it makes sense to move the buffer registration into the core to avoid some boiler-plate code in the device driver setup path. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-11-26 20:55:12 +03:00
* pollfunc.
iio: Add helper function for initializing triggered buffers Add a helper function for executing the common tasks which are usually involved in setting up a simple software ringbuffer. It will allocate the buffer, allocate the pollfunc and register the buffer. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-18 20:33:48 +04:00
*
* Before calling this function the indio_dev structure should already be
* completely initialized, but not yet registered. In practice this means that
* this function should be called right before iio_device_register().
*
* To free the resources allocated by this function call
* iio_triggered_buffer_cleanup().
*/
int iio_triggered_buffer_setup(struct iio_dev *indio_dev,
irqreturn_t (*pollfunc_bh)(int irq, void *p),
irqreturn_t (*pollfunc_th)(int irq, void *p),
const struct iio_buffer_setup_ops *setup_ops)
{
iio: Add reference counting for buffers Since the buffer is accessed by userspace we can not just free the buffers memory once we are done with it in kernel space. There might still be open file descriptors and userspace still might be accessing the buffer. This patch adds support for reference counting to the IIO buffers. When a buffer is created and initialized its initial reference count is set to 1. Instead of freeing the memory of the buffer the buffer's _free() function will drop that reference again. But only after the last reference to the buffer has been dropped the buffer the buffer's memory will be freed. The IIO device will take a reference to its primary buffer. The patch adds a small helper function for this called iio_device_attach_buffer() which will get a reference to the buffer and assign the buffer to the IIO device. This function must be used instead of assigning the buffer to the device by hand. The reference is only dropped once the IIO device is freed and we can be sure that there are no more open file handles. A reference to a buffer will also be taken whenever the buffer is active to avoid the buffer being freed while data is still being send to it. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-04 15:06:00 +04:00
struct iio_buffer *buffer;
iio: Add helper function for initializing triggered buffers Add a helper function for executing the common tasks which are usually involved in setting up a simple software ringbuffer. It will allocate the buffer, allocate the pollfunc and register the buffer. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-18 20:33:48 +04:00
int ret;
iio: kfifo: Remove unused argument in iio_kfifo_allocate indio_dev was unused in function body plus some small style fix - add new lines after "if(sth) return sth" and before the last return statement. The argument was removed also in its client. Signed-off-by: Karol Wrona <k.wrona@samsung.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2014-12-19 20:39:24 +03:00
buffer = iio_kfifo_allocate();
iio: Add reference counting for buffers Since the buffer is accessed by userspace we can not just free the buffers memory once we are done with it in kernel space. There might still be open file descriptors and userspace still might be accessing the buffer. This patch adds support for reference counting to the IIO buffers. When a buffer is created and initialized its initial reference count is set to 1. Instead of freeing the memory of the buffer the buffer's _free() function will drop that reference again. But only after the last reference to the buffer has been dropped the buffer the buffer's memory will be freed. The IIO device will take a reference to its primary buffer. The patch adds a small helper function for this called iio_device_attach_buffer() which will get a reference to the buffer and assign the buffer to the IIO device. This function must be used instead of assigning the buffer to the device by hand. The reference is only dropped once the IIO device is freed and we can be sure that there are no more open file handles. A reference to a buffer will also be taken whenever the buffer is active to avoid the buffer being freed while data is still being send to it. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-04 15:06:00 +04:00
if (!buffer) {
iio: Add helper function for initializing triggered buffers Add a helper function for executing the common tasks which are usually involved in setting up a simple software ringbuffer. It will allocate the buffer, allocate the pollfunc and register the buffer. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-18 20:33:48 +04:00
ret = -ENOMEM;
goto error_ret;
}
iio: Add reference counting for buffers Since the buffer is accessed by userspace we can not just free the buffers memory once we are done with it in kernel space. There might still be open file descriptors and userspace still might be accessing the buffer. This patch adds support for reference counting to the IIO buffers. When a buffer is created and initialized its initial reference count is set to 1. Instead of freeing the memory of the buffer the buffer's _free() function will drop that reference again. But only after the last reference to the buffer has been dropped the buffer the buffer's memory will be freed. The IIO device will take a reference to its primary buffer. The patch adds a small helper function for this called iio_device_attach_buffer() which will get a reference to the buffer and assign the buffer to the IIO device. This function must be used instead of assigning the buffer to the device by hand. The reference is only dropped once the IIO device is freed and we can be sure that there are no more open file handles. A reference to a buffer will also be taken whenever the buffer is active to avoid the buffer being freed while data is still being send to it. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-10-04 15:06:00 +04:00
iio_device_attach_buffer(indio_dev, buffer);
iio: Add helper function for initializing triggered buffers Add a helper function for executing the common tasks which are usually involved in setting up a simple software ringbuffer. It will allocate the buffer, allocate the pollfunc and register the buffer. Signed-off-by: Lars-Peter Clausen <lars@metafoo.de> Acked-by: Jonathan Cameron <jic23@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-06-18 20:33:48 +04:00
indio_dev->pollfunc = iio_alloc_pollfunc(pollfunc_bh,
pollfunc_th,
IRQF_ONESHOT,
indio_dev,
"%s_consumer%d",
indio_dev->name,
indio_dev->id);
if (indio_dev->pollfunc == NULL) {
ret = -ENOMEM;
goto error_kfifo_free;
}
/* Ring buffer functions - here trigger setup related */
if (setup_ops)
indio_dev->setup_ops = setup_ops;
else
indio_dev->setup_ops = &iio_triggered_buffer_setup_ops;
/* Flag that polled ring buffering is possible */
indio_dev->modes |= INDIO_BUFFER_TRIGGERED;
return 0;
error_kfifo_free:
iio_kfifo_free(indio_dev->buffer);
error_ret:
return ret;
}
EXPORT_SYMBOL(iio_triggered_buffer_setup);
/**
* iio_triggered_buffer_cleanup() - Free resources allocated by iio_triggered_buffer_setup()
* @indio_dev: IIO device structure
*/
void iio_triggered_buffer_cleanup(struct iio_dev *indio_dev)
{
iio_dealloc_pollfunc(indio_dev->pollfunc);
iio_kfifo_free(indio_dev->buffer);
}
EXPORT_SYMBOL(iio_triggered_buffer_cleanup);
MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
MODULE_DESCRIPTION("IIO helper functions for setting up triggered buffers");
MODULE_LICENSE("GPL");
Reference in New Issue Copy Permalink