linux/drivers/iio/buffer/industrialio-buffer-dmaengine.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * Copyright 2014-2015 Analog Devices Inc.
 *  Author: Lars-Peter Clausen <[email protected]>
 */

#include <linux/slab.h>
#include <linux/kernel.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/spinlock.h>
#include <linux/err.h>
#include <linux/module.h>

#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
#include <linux/iio/buffer.h>
#include <linux/iio/buffer_impl.h>
#include <linux/iio/buffer-dma.h>
#include <linux/iio/buffer-dmaengine.h>

/*
 * The IIO DMAengine buffer combines the generic IIO DMA buffer infrastructure
 * with the DMAengine framework. The generic IIO DMA buffer infrastructure is
 * used to manage the buffer memory and implement the IIO buffer operations
 * while the DMAengine framework is used to perform the DMA transfers. Combined
 * this results in a device independent fully functional DMA buffer
 * implementation that can be used by device drivers for peripherals which are
 * connected to a DMA controller which has a DMAengine driver implementation.
 */

struct dmaengine_buffer { … };

static struct dmaengine_buffer *iio_buffer_to_dmaengine_buffer(
		struct iio_buffer *buffer)
{ … }

static void iio_dmaengine_buffer_block_done(void *data,
		const struct dmaengine_result *result)
{ … }

static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue,
	struct iio_dma_buffer_block *block)
{ … }

static void iio_dmaengine_buffer_abort(struct iio_dma_buffer_queue *queue)
{ … }

static void iio_dmaengine_buffer_release(struct iio_buffer *buf)
{ … }

static const struct iio_buffer_access_funcs iio_dmaengine_buffer_ops = …;

static const struct iio_dma_buffer_ops iio_dmaengine_default_ops = …;

static ssize_t iio_dmaengine_buffer_get_length_align(struct device *dev,
	struct device_attribute *attr, char *buf)
{ … }

static IIO_DEVICE_ATTR(length_align_bytes, 0444,
		       iio_dmaengine_buffer_get_length_align, NULL, 0);

static const struct iio_dev_attr *iio_dmaengine_buffer_attrs[] = …;

/**
 * iio_dmaengine_buffer_alloc() - Allocate new buffer which uses DMAengine
 * @dev: Parent device for the buffer
 * @channel: DMA channel name, typically "rx".
 *
 * This allocates a new IIO buffer which internally uses the DMAengine framework
 * to perform its transfers. The parent device will be used to request the DMA
 * channel.
 *
 * Once done using the buffer iio_dmaengine_buffer_free() should be used to
 * release it.
 */
static struct iio_buffer *iio_dmaengine_buffer_alloc(struct device *dev,
	const char *channel)
{ … }

/**
 * iio_dmaengine_buffer_free() - Free dmaengine buffer
 * @buffer: Buffer to free
 *
 * Frees a buffer previously allocated with iio_dmaengine_buffer_alloc().
 */
void iio_dmaengine_buffer_free(struct iio_buffer *buffer)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

struct iio_buffer *iio_dmaengine_buffer_setup_ext(struct device *dev,
						  struct iio_dev *indio_dev,
						  const char *channel,
						  enum iio_buffer_direction dir)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

static void __devm_iio_dmaengine_buffer_free(void *buffer)
{ … }

/**
 * devm_iio_dmaengine_buffer_setup_ext() - Setup a DMA buffer for an IIO device
 * @dev: Parent device for the buffer
 * @indio_dev: IIO device to which to attach this buffer.
 * @channel: DMA channel name, typically "rx".
 * @dir: Direction of buffer (in or out)
 *
 * This allocates a new IIO buffer with devm_iio_dmaengine_buffer_alloc()
 * and attaches it to an IIO device with iio_device_attach_buffer().
 * It also appends the INDIO_BUFFER_HARDWARE mode to the supported modes of the
 * IIO device.
 */
int devm_iio_dmaengine_buffer_setup_ext(struct device *dev,
					struct iio_dev *indio_dev,
					const char *channel,
					enum iio_buffer_direction dir)
{ … }
EXPORT_SYMBOL_NS_GPL(…);

MODULE_AUTHOR(…) …;
MODULE_DESCRIPTION(…) …;
MODULE_LICENSE(…) …;
MODULE_IMPORT_NS(…);