diff options
Diffstat (limited to 'drivers/iio/buffer')
| -rw-r--r-- | drivers/iio/buffer/Kconfig | 55 | ||||
| -rw-r--r-- | drivers/iio/buffer/Makefile | 12 | ||||
| -rw-r--r-- | drivers/iio/buffer/industrialio-buffer-cb.c | 157 | ||||
| -rw-r--r-- | drivers/iio/buffer/industrialio-buffer-dma.c | 875 | ||||
| -rw-r--r-- | drivers/iio/buffer/industrialio-buffer-dmaengine.c | 465 | ||||
| -rw-r--r-- | drivers/iio/buffer/industrialio-hw-consumer.c | 219 | ||||
| -rw-r--r-- | drivers/iio/buffer/industrialio-triggered-buffer.c | 139 | ||||
| -rw-r--r-- | drivers/iio/buffer/kfifo_buf.c | 272 |
8 files changed, 2194 insertions, 0 deletions
diff --git a/drivers/iio/buffer/Kconfig b/drivers/iio/buffer/Kconfig new file mode 100644 index 000000000..047b93159 --- /dev/null +++ b/drivers/iio/buffer/Kconfig @@ -0,0 +1,55 @@ +# SPDX-License-Identifier: GPL-2.0-only +# +# Industrial I/O generic buffer implementations +# +# When adding new entries keep the list in alphabetical order + +config IIO_BUFFER_CB + tristate "IIO callback buffer used for push in-kernel interfaces" + help + Should be selected by any drivers that do in-kernel push + usage. That is, those where the data is pushed to the consumer. + +config IIO_BUFFER_DMA + tristate "Industrial I/O DMA buffer infrastructure" + help + Provides the generic IIO DMA buffer infrastructure that can be used by + drivers for devices with DMA support to implement the IIO buffer. + + Should be selected by drivers that want to use the generic DMA buffer + infrastructure. + +config IIO_BUFFER_DMAENGINE + tristate "Industrial I/O DMA buffer integration with DMAEngine" + select IIO_BUFFER_DMA + help + Provides a bonding of the generic IIO DMA buffer infrastructure with the + DMAEngine framework. This can be used by converter drivers with a DMA port + connected to an external DMA controller which is supported by the + DMAEngine framework. + + Should be selected by drivers that want to use this functionality. + +config IIO_BUFFER_HW_CONSUMER + tristate "Industrial I/O HW buffering" + help + Provides a way to bonding when an IIO device has a direct connection + to another device in hardware. In this case buffers for data transfers + are handled by hardware. + + Should be selected by drivers that want to use the generic Hw consumer + interface. + +config IIO_KFIFO_BUF + tristate "Industrial I/O buffering based on kfifo" + help + A simple fifo based on kfifo. Note that this currently provides + no buffer events so it is up to userspace to work out how + often to read from the buffer. + +config IIO_TRIGGERED_BUFFER + tristate "Industrial I/O triggered buffer support" + select IIO_TRIGGER + select IIO_KFIFO_BUF + help + Provides helper functions for setting up triggered buffers. diff --git a/drivers/iio/buffer/Makefile b/drivers/iio/buffer/Makefile new file mode 100644 index 000000000..1403eb2f9 --- /dev/null +++ b/drivers/iio/buffer/Makefile @@ -0,0 +1,12 @@ +# SPDX-License-Identifier: GPL-2.0 +# +# Makefile for the industrial I/O buffer implementations +# + +# When adding new entries keep the list in alphabetical order +obj-$(CONFIG_IIO_BUFFER_CB) += industrialio-buffer-cb.o +obj-$(CONFIG_IIO_BUFFER_DMA) += industrialio-buffer-dma.o +obj-$(CONFIG_IIO_BUFFER_DMAENGINE) += industrialio-buffer-dmaengine.o +obj-$(CONFIG_IIO_BUFFER_HW_CONSUMER) += industrialio-hw-consumer.o +obj-$(CONFIG_IIO_TRIGGERED_BUFFER) += industrialio-triggered-buffer.o +obj-$(CONFIG_IIO_KFIFO_BUF) += kfifo_buf.o diff --git a/drivers/iio/buffer/industrialio-buffer-cb.c b/drivers/iio/buffer/industrialio-buffer-cb.c new file mode 100644 index 000000000..b58263bcf --- /dev/null +++ b/drivers/iio/buffer/industrialio-buffer-cb.c @@ -0,0 +1,157 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* The industrial I/O callback buffer + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/err.h> +#include <linux/export.h> +#include <linux/iio/iio.h> +#include <linux/iio/buffer_impl.h> +#include <linux/iio/consumer.h> + +struct iio_cb_buffer { + struct iio_buffer buffer; + /* Must be safe to call from any context (e.g. must not sleep). */ + int (*cb)(const void *data, void *private); + void *private; + struct iio_channel *channels; + struct iio_dev *indio_dev; +}; + +static struct iio_cb_buffer *buffer_to_cb_buffer(struct iio_buffer *buffer) +{ + return container_of(buffer, struct iio_cb_buffer, buffer); +} + +static int iio_buffer_cb_store_to(struct iio_buffer *buffer, const void *data) +{ + struct iio_cb_buffer *cb_buff = buffer_to_cb_buffer(buffer); + return cb_buff->cb(data, cb_buff->private); +} + +static void iio_buffer_cb_release(struct iio_buffer *buffer) +{ + struct iio_cb_buffer *cb_buff = buffer_to_cb_buffer(buffer); + + bitmap_free(cb_buff->buffer.scan_mask); + kfree(cb_buff); +} + +static const struct iio_buffer_access_funcs iio_cb_access = { + .store_to = &iio_buffer_cb_store_to, + .release = &iio_buffer_cb_release, + + .modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED, +}; + +struct iio_cb_buffer *iio_channel_get_all_cb(struct device *dev, + int (*cb)(const void *data, + void *private), + void *private) +{ + int ret; + struct iio_cb_buffer *cb_buff; + struct iio_channel *chan; + + if (!cb) { + dev_err(dev, "Invalid arguments: A callback must be provided!\n"); + return ERR_PTR(-EINVAL); + } + + cb_buff = kzalloc_obj(*cb_buff); + if (cb_buff == NULL) + return ERR_PTR(-ENOMEM); + + iio_buffer_init(&cb_buff->buffer); + + cb_buff->private = private; + cb_buff->cb = cb; + cb_buff->buffer.access = &iio_cb_access; + + cb_buff->channels = iio_channel_get_all(dev); + if (IS_ERR(cb_buff->channels)) { + ret = PTR_ERR(cb_buff->channels); + goto error_free_cb_buff; + } + + cb_buff->indio_dev = cb_buff->channels[0].indio_dev; + cb_buff->buffer.scan_mask = bitmap_zalloc(iio_get_masklength(cb_buff->indio_dev), + GFP_KERNEL); + if (cb_buff->buffer.scan_mask == NULL) { + ret = -ENOMEM; + goto error_release_channels; + } + chan = &cb_buff->channels[0]; + while (chan->indio_dev) { + if (chan->indio_dev != cb_buff->indio_dev) { + ret = -EINVAL; + goto error_free_scan_mask; + } + set_bit(chan->channel->scan_index, + cb_buff->buffer.scan_mask); + chan++; + } + + return cb_buff; + +error_free_scan_mask: + bitmap_free(cb_buff->buffer.scan_mask); +error_release_channels: + iio_channel_release_all(cb_buff->channels); +error_free_cb_buff: + kfree(cb_buff); + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(iio_channel_get_all_cb); + +int iio_channel_cb_set_buffer_watermark(struct iio_cb_buffer *cb_buff, + size_t watermark) +{ + if (!watermark) + return -EINVAL; + cb_buff->buffer.watermark = watermark; + + return 0; +} +EXPORT_SYMBOL_GPL(iio_channel_cb_set_buffer_watermark); + +int iio_channel_start_all_cb(struct iio_cb_buffer *cb_buff) +{ + return iio_update_buffers(cb_buff->indio_dev, &cb_buff->buffer, + NULL); +} +EXPORT_SYMBOL_GPL(iio_channel_start_all_cb); + +void iio_channel_stop_all_cb(struct iio_cb_buffer *cb_buff) +{ + iio_update_buffers(cb_buff->indio_dev, NULL, &cb_buff->buffer); +} +EXPORT_SYMBOL_GPL(iio_channel_stop_all_cb); + +void iio_channel_release_all_cb(struct iio_cb_buffer *cb_buff) +{ + iio_channel_release_all(cb_buff->channels); + iio_buffer_put(&cb_buff->buffer); +} +EXPORT_SYMBOL_GPL(iio_channel_release_all_cb); + +struct iio_channel +*iio_channel_cb_get_channels(const struct iio_cb_buffer *cb_buffer) +{ + return cb_buffer->channels; +} +EXPORT_SYMBOL_GPL(iio_channel_cb_get_channels); + +struct iio_dev +*iio_channel_cb_get_iio_dev(const struct iio_cb_buffer *cb_buffer) +{ + return cb_buffer->indio_dev; +} +EXPORT_SYMBOL_GPL(iio_channel_cb_get_iio_dev); + +MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>"); +MODULE_DESCRIPTION("Industrial I/O callback buffer"); +MODULE_LICENSE("GPL"); +MODULE_IMPORT_NS("IIO_CONSUMER"); diff --git a/drivers/iio/buffer/industrialio-buffer-dma.c b/drivers/iio/buffer/industrialio-buffer-dma.c new file mode 100644 index 000000000..1daac2308 --- /dev/null +++ b/drivers/iio/buffer/industrialio-buffer-dma.c @@ -0,0 +1,875 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright 2013-2015 Analog Devices Inc. + * Author: Lars-Peter Clausen <lars@metafoo.de> + */ + +#include <linux/atomic.h> +#include <linux/cleanup.h> +#include <linux/lockdep.h> +#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/workqueue.h> +#include <linux/mutex.h> +#include <linux/sched.h> +#include <linux/poll.h> +#include <linux/iio/buffer_impl.h> +#include <linux/iio/buffer-dma.h> +#include <linux/dma-buf.h> +#include <linux/dma-fence.h> +#include <linux/dma-mapping.h> +#include <linux/sizes.h> + +/* + * For DMA buffers the storage is sub-divided into so called blocks. Each block + * has its own memory buffer. The size of the block is the granularity at which + * memory is exchanged between the hardware and the application. Increasing the + * basic unit of data exchange from one sample to one block decreases the + * management overhead that is associated with each sample. E.g. if we say the + * management overhead for one exchange is x and the unit of exchange is one + * sample the overhead will be x for each sample. Whereas when using a block + * which contains n samples the overhead per sample is reduced to x/n. This + * allows to achieve much higher samplerates than what can be sustained with + * the one sample approach. + * + * Blocks are exchanged between the DMA controller and the application via the + * means of two queues. The incoming queue and the outgoing queue. Blocks on the + * incoming queue are waiting for the DMA controller to pick them up and fill + * them with data. Block on the outgoing queue have been filled with data and + * are waiting for the application to dequeue them and read the data. + * + * A block can be in one of the following states: + * * Owned by the application. In this state the application can read data from + * the block. + * * On the incoming list: Blocks on the incoming list are queued up to be + * processed by the DMA controller. + * * Owned by the DMA controller: The DMA controller is processing the block + * and filling it with data. + * * On the outgoing list: Blocks on the outgoing list have been successfully + * processed by the DMA controller and contain data. They can be dequeued by + * the application. + * * Dead: A block that is dead has been marked as to be freed. It might still + * be owned by either the application or the DMA controller at the moment. + * But once they are done processing it instead of going to either the + * incoming or outgoing queue the block will be freed. + * + * In addition to this blocks are reference counted and the memory associated + * with both the block structure as well as the storage memory for the block + * will be freed when the last reference to the block is dropped. This means a + * block must not be accessed without holding a reference. + * + * The iio_dma_buffer implementation provides a generic infrastructure for + * managing the blocks. + * + * A driver for a specific piece of hardware that has DMA capabilities need to + * implement the submit() callback from the iio_dma_buffer_ops structure. This + * callback is supposed to initiate the DMA transfer copying data from the + * converter to the memory region of the block. Once the DMA transfer has been + * completed the driver must call iio_dma_buffer_block_done() for the completed + * block. + * + * Prior to this it must set the bytes_used field of the block contains + * the actual number of bytes in the buffer. Typically this will be equal to the + * size of the block, but if the DMA hardware has certain alignment requirements + * for the transfer length it might choose to use less than the full size. In + * either case it is expected that bytes_used is a multiple of the bytes per + * datum, i.e. the block must not contain partial samples. + * + * The driver must call iio_dma_buffer_block_done() for each block it has + * received through its submit_block() callback, even if it does not actually + * perform a DMA transfer for the block, e.g. because the buffer was disabled + * before the block transfer was started. In this case it should set bytes_used + * to 0. + * + * In addition it is recommended that a driver implements the abort() callback. + * It will be called when the buffer is disabled and can be used to cancel + * pending and stop active transfers. + * + * The specific driver implementation should use the default callback + * implementations provided by this module for the iio_buffer_access_funcs + * struct. It may overload some callbacks with custom variants if the hardware + * has special requirements that are not handled by the generic functions. If a + * driver chooses to overload a callback it has to ensure that the generic + * callback is called from within the custom callback. + */ + +static void iio_buffer_block_release(struct kref *kref) +{ + struct iio_dma_buffer_block *block = container_of(kref, + struct iio_dma_buffer_block, kref); + struct iio_dma_buffer_queue *queue = block->queue; + + WARN_ON(block->fileio && block->state != IIO_BLOCK_STATE_DEAD); + + if (block->fileio) { + dma_free_coherent(queue->dev, PAGE_ALIGN(block->size), + block->vaddr, block->phys_addr); + } else { + atomic_dec(&queue->num_dmabufs); + } + + iio_buffer_put(&queue->buffer); + kfree(block); +} + +static void iio_buffer_block_get(struct iio_dma_buffer_block *block) +{ + kref_get(&block->kref); +} + +static void iio_buffer_block_put(struct iio_dma_buffer_block *block) +{ + kref_put(&block->kref, iio_buffer_block_release); +} + +/* + * dma_free_coherent can sleep, hence we need to take some special care to be + * able to drop a reference from an atomic context. + */ +static LIST_HEAD(iio_dma_buffer_dead_blocks); +static DEFINE_SPINLOCK(iio_dma_buffer_dead_blocks_lock); + +static void iio_dma_buffer_cleanup_worker(struct work_struct *work) +{ + struct iio_dma_buffer_block *block, *_block; + LIST_HEAD(block_list); + + scoped_guard(spinlock_irq, &iio_dma_buffer_dead_blocks_lock) + list_splice_tail_init(&iio_dma_buffer_dead_blocks, &block_list); + + list_for_each_entry_safe(block, _block, &block_list, head) + iio_buffer_block_release(&block->kref); +} +static DECLARE_WORK(iio_dma_buffer_cleanup_work, iio_dma_buffer_cleanup_worker); + +static void iio_buffer_block_release_atomic(struct kref *kref) +{ + struct iio_dma_buffer_block *block; + + block = container_of(kref, struct iio_dma_buffer_block, kref); + + scoped_guard(spinlock_irqsave, &iio_dma_buffer_dead_blocks_lock) + list_add_tail(&block->head, &iio_dma_buffer_dead_blocks); + + schedule_work(&iio_dma_buffer_cleanup_work); +} + +/* + * Version of iio_buffer_block_put() that can be called from atomic context + */ +static void iio_buffer_block_put_atomic(struct iio_dma_buffer_block *block) +{ + kref_put(&block->kref, iio_buffer_block_release_atomic); +} + +static struct iio_dma_buffer_queue *iio_buffer_to_queue(struct iio_buffer *buf) +{ + return container_of(buf, struct iio_dma_buffer_queue, buffer); +} + +static struct iio_dma_buffer_block * +iio_dma_buffer_alloc_block(struct iio_dma_buffer_queue *queue, size_t size, + bool fileio) +{ + struct iio_dma_buffer_block *block __free(kfree) = + kzalloc_obj(*block); + if (!block) + return NULL; + + if (fileio) { + block->vaddr = dma_alloc_coherent(queue->dev, PAGE_ALIGN(size), + &block->phys_addr, GFP_KERNEL); + if (!block->vaddr) + return NULL; + } + + block->fileio = fileio; + block->size = size; + block->state = IIO_BLOCK_STATE_DONE; + block->queue = queue; + INIT_LIST_HEAD(&block->head); + kref_init(&block->kref); + + iio_buffer_get(&queue->buffer); + + if (!fileio) + atomic_inc(&queue->num_dmabufs); + + return_ptr(block); +} + +static void _iio_dma_buffer_block_done(struct iio_dma_buffer_block *block) +{ + if (block->state != IIO_BLOCK_STATE_DEAD) + block->state = IIO_BLOCK_STATE_DONE; +} + +static void iio_dma_buffer_queue_wake(struct iio_dma_buffer_queue *queue) +{ + __poll_t flags; + + if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) + flags = EPOLLIN | EPOLLRDNORM; + else + flags = EPOLLOUT | EPOLLWRNORM; + + wake_up_interruptible_poll(&queue->buffer.pollq, flags); +} + +/** + * iio_dma_buffer_block_done() - Indicate that a block has been completed + * @block: The completed block + * + * Should be called when the DMA controller has finished handling the block to + * pass back ownership of the block to the queue. + */ +void iio_dma_buffer_block_done(struct iio_dma_buffer_block *block) +{ + struct iio_dma_buffer_queue *queue = block->queue; + bool cookie; + + cookie = dma_fence_begin_signalling(); + + scoped_guard(spinlock_irqsave, &queue->list_lock) + _iio_dma_buffer_block_done(block); + + if (!block->fileio) + iio_buffer_signal_dmabuf_done(block->fence, 0); + + iio_buffer_block_put_atomic(block); + iio_dma_buffer_queue_wake(queue); + dma_fence_end_signalling(cookie); +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_block_done, "IIO_DMA_BUFFER"); + +/** + * iio_dma_buffer_block_list_abort() - Indicate that a list block has been + * aborted + * @queue: Queue for which to complete blocks. + * @list: List of aborted blocks. All blocks in this list must be from @queue. + * + * Typically called from the abort() callback after the DMA controller has been + * stopped. This will set bytes_used to 0 for each block in the list and then + * hand the blocks back to the queue. + */ +void iio_dma_buffer_block_list_abort(struct iio_dma_buffer_queue *queue, + struct list_head *list) +{ + struct iio_dma_buffer_block *block, *_block; + bool cookie; + + cookie = dma_fence_begin_signalling(); + + scoped_guard(spinlock_irqsave, &queue->list_lock) { + list_for_each_entry_safe(block, _block, list, head) { + list_del(&block->head); + block->bytes_used = 0; + _iio_dma_buffer_block_done(block); + + if (!block->fileio) + iio_buffer_signal_dmabuf_done(block->fence, + -EINTR); + iio_buffer_block_put_atomic(block); + } + } + + if (queue->fileio.enabled) + queue->fileio.enabled = false; + + iio_dma_buffer_queue_wake(queue); + dma_fence_end_signalling(cookie); +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_block_list_abort, "IIO_DMA_BUFFER"); + +static bool iio_dma_block_reusable(struct iio_dma_buffer_block *block) +{ + /* + * If the core owns the block it can be re-used. This should be the + * default case when enabling the buffer, unless the DMA controller does + * not support abort and has not given back the block yet. + */ + switch (block->state) { + case IIO_BLOCK_STATE_QUEUED: + case IIO_BLOCK_STATE_DONE: + return true; + default: + return false; + } +} + +static bool iio_dma_buffer_can_use_fileio(struct iio_dma_buffer_queue *queue) +{ + /* + * Note that queue->num_dmabufs cannot increase while the queue is + * locked, it can only decrease, so it does not race against + * iio_dma_buffer_alloc_block(). + */ + return queue->fileio.enabled || !atomic_read(&queue->num_dmabufs); +} + +/** + * iio_dma_buffer_request_update() - DMA buffer request_update callback + * @buffer: The buffer which to request an update + * + * Should be used as the iio_dma_buffer_request_update() callback for + * iio_buffer_access_ops struct for DMA buffers. + */ +int iio_dma_buffer_request_update(struct iio_buffer *buffer) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + struct iio_dma_buffer_block *block; + bool try_reuse = false; + size_t size; + int i; + + /* + * Split the buffer into two even parts. This is used as a double + * buffering scheme with usually one block at a time being used by the + * DMA and the other one by the application. + */ + size = DIV_ROUND_UP(queue->buffer.bytes_per_datum * + queue->buffer.length, 2); + + guard(mutex)(&queue->lock); + + queue->fileio.enabled = iio_dma_buffer_can_use_fileio(queue); + + /* If DMABUFs were created, disable fileio interface */ + if (!queue->fileio.enabled) + return 0; + + /* Allocations are page aligned */ + if (PAGE_ALIGN(queue->fileio.block_size) == PAGE_ALIGN(size)) + try_reuse = true; + + queue->fileio.block_size = size; + queue->fileio.active_block = NULL; + + scoped_guard(spinlock_irq, &queue->list_lock) { + for (i = 0; i < ARRAY_SIZE(queue->fileio.blocks); i++) { + block = queue->fileio.blocks[i]; + + /* If we can't re-use it free it */ + if (block && (!iio_dma_block_reusable(block) || !try_reuse)) + block->state = IIO_BLOCK_STATE_DEAD; + } + + /* + * At this point all blocks are either owned by the core or + * marked as dead. This means we can reset the lists without + * having to fear corruption. + */ + } + + INIT_LIST_HEAD(&queue->incoming); + + for (i = 0; i < ARRAY_SIZE(queue->fileio.blocks); i++) { + if (queue->fileio.blocks[i]) { + block = queue->fileio.blocks[i]; + if (block->state == IIO_BLOCK_STATE_DEAD) { + /* Could not reuse it */ + iio_buffer_block_put(block); + block = NULL; + } else { + block->size = size; + } + } else { + block = NULL; + } + + if (!block) { + block = iio_dma_buffer_alloc_block(queue, size, true); + if (!block) + return -ENOMEM; + + queue->fileio.blocks[i] = block; + } + + /* + * block->bytes_used may have been modified previously, e.g. by + * iio_dma_buffer_block_list_abort(). Reset it here to the + * block's so that iio_dma_buffer_io() will work. + */ + block->bytes_used = block->size; + + /* + * If it's an input buffer, mark the block as queued, and + * iio_dma_buffer_enable() will submit it. Otherwise mark it as + * done, which means it's ready to be dequeued. + */ + if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) { + block->state = IIO_BLOCK_STATE_QUEUED; + list_add_tail(&block->head, &queue->incoming); + } else { + block->state = IIO_BLOCK_STATE_DONE; + } + } + + return 0; +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_request_update, "IIO_DMA_BUFFER"); + +static void iio_dma_buffer_fileio_free(struct iio_dma_buffer_queue *queue) +{ + unsigned int i; + + scoped_guard(spinlock_irq, &queue->list_lock) { + for (i = 0; i < ARRAY_SIZE(queue->fileio.blocks); i++) { + if (!queue->fileio.blocks[i]) + continue; + queue->fileio.blocks[i]->state = IIO_BLOCK_STATE_DEAD; + } + } + + INIT_LIST_HEAD(&queue->incoming); + + for (i = 0; i < ARRAY_SIZE(queue->fileio.blocks); i++) { + if (!queue->fileio.blocks[i]) + continue; + iio_buffer_block_put(queue->fileio.blocks[i]); + queue->fileio.blocks[i] = NULL; + } + queue->fileio.active_block = NULL; +} + +static void iio_dma_buffer_submit_block(struct iio_dma_buffer_queue *queue, + struct iio_dma_buffer_block *block) +{ + int ret; + + /* + * If the hardware has already been removed we put the block into + * limbo. It will neither be on the incoming nor outgoing list, nor will + * it ever complete. It will just wait to be freed eventually. + */ + if (!queue->ops) + return; + + block->state = IIO_BLOCK_STATE_ACTIVE; + iio_buffer_block_get(block); + + ret = queue->ops->submit(queue, block); + if (ret) { + if (!block->fileio) + iio_buffer_signal_dmabuf_done(block->fence, ret); + + /* + * This is a bit of a problem and there is not much we can do + * other then wait for the buffer to be disabled and re-enabled + * and try again. But it should not really happen unless we run + * out of memory or something similar. + * + * TODO: Implement support in the IIO core to allow buffers to + * notify consumers that something went wrong and the buffer + * should be disabled. + */ + iio_buffer_block_put(block); + } +} + +/** + * iio_dma_buffer_enable() - Enable DMA buffer + * @buffer: IIO buffer to enable + * @indio_dev: IIO device the buffer is attached to + * + * Needs to be called when the device that the buffer is attached to starts + * sampling. Typically should be the iio_buffer_access_ops enable callback. + * + * This will allocate the DMA buffers and start the DMA transfers. + */ +int iio_dma_buffer_enable(struct iio_buffer *buffer, struct iio_dev *indio_dev) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + struct iio_dma_buffer_block *block, *_block; + + guard(mutex)(&queue->lock); + queue->active = true; + list_for_each_entry_safe(block, _block, &queue->incoming, head) { + list_del(&block->head); + iio_dma_buffer_submit_block(queue, block); + } + + return 0; +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_enable, "IIO_DMA_BUFFER"); + +/** + * iio_dma_buffer_disable() - Disable DMA buffer + * @buffer: IIO DMA buffer to disable + * @indio_dev: IIO device the buffer is attached to + * + * Needs to be called when the device that the buffer is attached to stops + * sampling. Typically should be the iio_buffer_access_ops disable callback. + */ +int iio_dma_buffer_disable(struct iio_buffer *buffer, struct iio_dev *indio_dev) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + + guard(mutex)(&queue->lock); + queue->active = false; + + if (queue->ops && queue->ops->abort) + queue->ops->abort(queue); + + return 0; +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_disable, "IIO_DMA_BUFFER"); + +static void iio_dma_buffer_enqueue(struct iio_dma_buffer_queue *queue, + struct iio_dma_buffer_block *block) +{ + if (block->state == IIO_BLOCK_STATE_DEAD) { + iio_buffer_block_put(block); + } else if (queue->active) { + iio_dma_buffer_submit_block(queue, block); + } else { + block->state = IIO_BLOCK_STATE_QUEUED; + list_add_tail(&block->head, &queue->incoming); + } +} + +static struct iio_dma_buffer_block * +iio_dma_buffer_dequeue(struct iio_dma_buffer_queue *queue) +{ + struct iio_dma_buffer_block *block; + unsigned int idx; + + guard(spinlock_irq)(&queue->list_lock); + + idx = queue->fileio.next_dequeue; + block = queue->fileio.blocks[idx]; + + if (block->state != IIO_BLOCK_STATE_DONE) + return NULL; + + idx = (idx + 1) % ARRAY_SIZE(queue->fileio.blocks); + queue->fileio.next_dequeue = idx; + + return block; +} + +static int iio_dma_buffer_io(struct iio_buffer *buffer, size_t n, + char __user *user_buffer, bool is_from_user) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + struct iio_dma_buffer_block *block; + void *addr; + int ret; + + if (n < buffer->bytes_per_datum) + return -EINVAL; + + guard(mutex)(&queue->lock); + + if (!queue->fileio.active_block) { + block = iio_dma_buffer_dequeue(queue); + if (!block) + return 0; + + queue->fileio.pos = 0; + queue->fileio.active_block = block; + } else { + block = queue->fileio.active_block; + } + + n = rounddown(n, buffer->bytes_per_datum); + if (n > block->bytes_used - queue->fileio.pos) + n = block->bytes_used - queue->fileio.pos; + addr = block->vaddr + queue->fileio.pos; + + if (is_from_user) + ret = copy_from_user(addr, user_buffer, n); + else + ret = copy_to_user(user_buffer, addr, n); + if (ret) + return -EFAULT; + + queue->fileio.pos += n; + + if (queue->fileio.pos == block->bytes_used) { + queue->fileio.active_block = NULL; + iio_dma_buffer_enqueue(queue, block); + } + + return n; +} + +/** + * iio_dma_buffer_read() - DMA buffer read callback + * @buffer: Buffer to read from + * @n: Number of bytes to read + * @user_buffer: Userspace buffer to copy the data to + * + * Should be used as the read callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +int iio_dma_buffer_read(struct iio_buffer *buffer, size_t n, + char __user *user_buffer) +{ + return iio_dma_buffer_io(buffer, n, user_buffer, false); +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_read, "IIO_DMA_BUFFER"); + +/** + * iio_dma_buffer_write() - DMA buffer write callback + * @buffer: Buffer to write to + * @n: Number of bytes to read + * @user_buffer: Userspace buffer to copy the data from + * + * Should be used as the write callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +int iio_dma_buffer_write(struct iio_buffer *buffer, size_t n, + const char __user *user_buffer) +{ + return iio_dma_buffer_io(buffer, n, + (__force __user char *)user_buffer, true); +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_write, "IIO_DMA_BUFFER"); + +/** + * iio_dma_buffer_usage() - DMA buffer data_available and + * space_available callback + * @buf: Buffer to check for data availability + * + * Should be used as the data_available and space_available callbacks for + * iio_buffer_access_ops struct for DMA buffers. + */ +size_t iio_dma_buffer_usage(struct iio_buffer *buf) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buf); + struct iio_dma_buffer_block *block; + size_t data_available = 0; + unsigned int i; + + /* + * For counting the available bytes we'll use the size of the block not + * the number of actual bytes available in the block. Otherwise it is + * possible that we end up with a value that is lower than the watermark + * but won't increase since all blocks are in use. + */ + + guard(mutex)(&queue->lock); + if (queue->fileio.active_block) + data_available += queue->fileio.active_block->size; + + guard(spinlock_irq)(&queue->list_lock); + + for (i = 0; i < ARRAY_SIZE(queue->fileio.blocks); i++) { + block = queue->fileio.blocks[i]; + + if (block != queue->fileio.active_block && block->state == IIO_BLOCK_STATE_DONE) + data_available += block->size; + } + + return data_available; +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_usage, "IIO_DMA_BUFFER"); + +struct iio_dma_buffer_block * +iio_dma_buffer_attach_dmabuf(struct iio_buffer *buffer, + struct dma_buf_attachment *attach) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + struct iio_dma_buffer_block *block; + + guard(mutex)(&queue->lock); + + /* + * If the buffer is enabled and in fileio mode new blocks can't be + * allocated. + */ + if (queue->fileio.enabled) + return ERR_PTR(-EBUSY); + + block = iio_dma_buffer_alloc_block(queue, attach->dmabuf->size, false); + if (!block) + return ERR_PTR(-ENOMEM); + + /* Free memory that might be in use for fileio mode */ + iio_dma_buffer_fileio_free(queue); + + return block; +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_attach_dmabuf, "IIO_DMA_BUFFER"); + +void iio_dma_buffer_detach_dmabuf(struct iio_buffer *buffer, + struct iio_dma_buffer_block *block) +{ + block->state = IIO_BLOCK_STATE_DEAD; + iio_buffer_block_put_atomic(block); +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_detach_dmabuf, "IIO_DMA_BUFFER"); + +static int iio_dma_can_enqueue_block(struct iio_dma_buffer_block *block) +{ + struct iio_dma_buffer_queue *queue = block->queue; + + /* If in fileio mode buffers can't be enqueued. */ + if (queue->fileio.enabled) + return -EBUSY; + + switch (block->state) { + case IIO_BLOCK_STATE_QUEUED: + return -EPERM; + case IIO_BLOCK_STATE_ACTIVE: + case IIO_BLOCK_STATE_DEAD: + return -EBUSY; + case IIO_BLOCK_STATE_DONE: + break; + } + + return 0; +} + +int iio_dma_buffer_enqueue_dmabuf(struct iio_buffer *buffer, + struct iio_dma_buffer_block *block, + struct dma_fence *fence, + struct sg_table *sgt, + size_t size, bool cyclic) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + bool cookie; + int ret; + + lockdep_assert_held(&queue->lock); + + cookie = dma_fence_begin_signalling(); + + ret = iio_dma_can_enqueue_block(block); + if (ret < 0) + goto out_end_signalling; + + block->bytes_used = size; + block->cyclic = cyclic; + block->sg_table = sgt; + block->fence = fence; + + iio_dma_buffer_enqueue(queue, block); + +out_end_signalling: + dma_fence_end_signalling(cookie); + + return ret; +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_enqueue_dmabuf, "IIO_DMA_BUFFER"); + +struct device *iio_dma_buffer_get_dma_dev(struct iio_buffer *buffer) +{ + return iio_buffer_to_queue(buffer)->dev; +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_get_dma_dev, "IIO_DMA_BUFFER"); + +void iio_dma_buffer_lock_queue(struct iio_buffer *buffer) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + + mutex_lock(&queue->lock); +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_lock_queue, "IIO_DMA_BUFFER"); + +void iio_dma_buffer_unlock_queue(struct iio_buffer *buffer) +{ + struct iio_dma_buffer_queue *queue = iio_buffer_to_queue(buffer); + + mutex_unlock(&queue->lock); +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_unlock_queue, "IIO_DMA_BUFFER"); + +/** + * iio_dma_buffer_set_bytes_per_datum() - DMA buffer set_bytes_per_datum callback + * @buffer: Buffer to set the bytes-per-datum for + * @bpd: The new bytes-per-datum value + * + * Should be used as the set_bytes_per_datum callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +int iio_dma_buffer_set_bytes_per_datum(struct iio_buffer *buffer, size_t bpd) +{ + buffer->bytes_per_datum = bpd; + + return 0; +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_set_bytes_per_datum, "IIO_DMA_BUFFER"); + +/** + * iio_dma_buffer_set_length - DMA buffer set_length callback + * @buffer: Buffer to set the length for + * @length: The new buffer length + * + * Should be used as the set_length callback for iio_buffer_access_ops + * struct for DMA buffers. + */ +int iio_dma_buffer_set_length(struct iio_buffer *buffer, unsigned int length) +{ + /* Avoid an invalid state */ + if (length < 2) + length = 2; + buffer->length = length; + buffer->watermark = length / 2; + + return 0; +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_set_length, "IIO_DMA_BUFFER"); + +/** + * iio_dma_buffer_init() - Initialize DMA buffer queue + * @queue: Buffer to initialize + * @dev: DMA device + * @ops: DMA buffer queue callback operations + * + * The DMA device will be used by the queue to do DMA memory allocations. So it + * should refer to the device that will perform the DMA to ensure that + * allocations are done from a memory region that can be accessed by the device. + */ +void iio_dma_buffer_init(struct iio_dma_buffer_queue *queue, struct device *dev, + const struct iio_dma_buffer_ops *ops) +{ + iio_buffer_init(&queue->buffer); + queue->buffer.length = PAGE_SIZE; + queue->buffer.watermark = queue->buffer.length / 2; + queue->dev = dev; + queue->ops = ops; + + INIT_LIST_HEAD(&queue->incoming); + + mutex_init(&queue->lock); + spin_lock_init(&queue->list_lock); +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_init, "IIO_DMA_BUFFER"); + +/** + * iio_dma_buffer_exit() - Cleanup DMA buffer queue + * @queue: Buffer to cleanup + * + * After this function has completed it is safe to free any resources that are + * associated with the buffer and are accessed inside the callback operations. + */ +void iio_dma_buffer_exit(struct iio_dma_buffer_queue *queue) +{ + guard(mutex)(&queue->lock); + + iio_dma_buffer_fileio_free(queue); + queue->ops = NULL; +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_exit, "IIO_DMA_BUFFER"); + +/** + * iio_dma_buffer_release() - Release final buffer resources + * @queue: Buffer to release + * + * Frees resources that can't yet be freed in iio_dma_buffer_exit(). Should be + * called in the buffers release callback implementation right before freeing + * the memory associated with the buffer. + */ +void iio_dma_buffer_release(struct iio_dma_buffer_queue *queue) +{ + mutex_destroy(&queue->lock); +} +EXPORT_SYMBOL_NS_GPL(iio_dma_buffer_release, "IIO_DMA_BUFFER"); + +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); +MODULE_DESCRIPTION("DMA buffer for the IIO framework"); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/iio/buffer/industrialio-buffer-dmaengine.c b/drivers/iio/buffer/industrialio-buffer-dmaengine.c new file mode 100644 index 000000000..376486be3 --- /dev/null +++ b/drivers/iio/buffer/industrialio-buffer-dmaengine.c @@ -0,0 +1,465 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright 2014-2015 Analog Devices Inc. + * Author: Lars-Peter Clausen <lars@metafoo.de> + */ + +#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/cleanup.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 { + struct iio_dma_buffer_queue queue; + + struct dma_chan *chan; + struct list_head active; + + size_t align; + size_t max_size; +}; + +static struct dmaengine_buffer *iio_buffer_to_dmaengine_buffer(struct iio_buffer *buffer) +{ + return container_of(buffer, struct dmaengine_buffer, queue.buffer); +} + +static void iio_dmaengine_buffer_block_done(void *data, + const struct dmaengine_result *result) +{ + struct iio_dma_buffer_block *block = data; + + scoped_guard(spinlock_irqsave, &block->queue->list_lock) + list_del(&block->head); + block->bytes_used -= result->residue; + iio_dma_buffer_block_done(block); +} + +/* + * Cyclic transfers run until abort. Cap active cyclic blocks to one until there + * is a use case for more. + */ +static bool iio_dmaengine_buffer_has_active_cyclic(struct dmaengine_buffer *dmaengine_buffer) +{ + struct iio_dma_buffer_block *block; + + guard(spinlock_irqsave)(&dmaengine_buffer->queue.list_lock); + list_for_each_entry(block, &dmaengine_buffer->active, head) { + if (block->cyclic) + return true; + } + + return false; +} + +static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue, + struct iio_dma_buffer_block *block) +{ + struct dmaengine_buffer *dmaengine_buffer = + iio_buffer_to_dmaengine_buffer(&queue->buffer); + struct dma_async_tx_descriptor *desc; + enum dma_transfer_direction dma_dir; + struct scatterlist *sgl; + struct dma_vec *vecs; + size_t max_size; + dma_cookie_t cookie; + size_t len_total; + unsigned int i; + int nents; + + max_size = min(block->size, dmaengine_buffer->max_size); + max_size = round_down(max_size, dmaengine_buffer->align); + + if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) + dma_dir = DMA_DEV_TO_MEM; + else + dma_dir = DMA_MEM_TO_DEV; + + if (block->cyclic && iio_dmaengine_buffer_has_active_cyclic(dmaengine_buffer)) { + dev_err(queue->dev, "cyclic DMA transfer already active\n"); + return -EBUSY; + } + + if (block->sg_table) { + unsigned long flags; + + /* + * Only the first sgt->nents entries carry a valid + * sg_dma_address()/sg_dma_len() pair as mapping the table may + * have coalesced entries, in which case nents is smaller than + * orig_nents. + */ + nents = block->sg_table->nents; + + vecs = kmalloc_array(nents, sizeof(*vecs), GFP_ATOMIC); + if (!vecs) + return -ENOMEM; + + len_total = block->bytes_used; + + sgl = block->sg_table->sgl; + for (i = 0; i < nents && len_total; i++) { + vecs[i].addr = sg_dma_address(sgl); + vecs[i].len = min(sg_dma_len(sgl), len_total); + len_total -= vecs[i].len; + + sgl = sg_next(sgl); + } + + nents = i; + + if (block->cyclic) + flags = DMA_PREP_REPEAT; + else + flags = DMA_PREP_INTERRUPT; + + /* + * A new transfer may need to end an already active cyclic transfer + * before it can run, so always set the EOT flag. + */ + flags |= DMA_PREP_LOAD_EOT; + desc = dmaengine_prep_peripheral_dma_vec(dmaengine_buffer->chan, + vecs, nents, dma_dir, + flags); + kfree(vecs); + } else { + max_size = min(block->size, dmaengine_buffer->max_size); + max_size = round_down(max_size, dmaengine_buffer->align); + + if (queue->buffer.direction == IIO_BUFFER_DIRECTION_IN) + block->bytes_used = max_size; + + if (!block->bytes_used || block->bytes_used > max_size) + return -EINVAL; + + desc = dmaengine_prep_slave_single(dmaengine_buffer->chan, + block->phys_addr, + block->bytes_used, + dma_dir, + DMA_PREP_INTERRUPT); + } + if (!desc) + return -ENOMEM; + + if (!block->cyclic) { + desc->callback_result = iio_dmaengine_buffer_block_done; + desc->callback_param = block; + } + + cookie = dmaengine_submit(desc); + if (dma_submit_error(cookie)) + return dma_submit_error(cookie); + + scoped_guard(spinlock_irq, &dmaengine_buffer->queue.list_lock) + list_add_tail(&block->head, &dmaengine_buffer->active); + + dma_async_issue_pending(dmaengine_buffer->chan); + + return 0; +} + +static void iio_dmaengine_buffer_abort(struct iio_dma_buffer_queue *queue) +{ + struct dmaengine_buffer *dmaengine_buffer = + iio_buffer_to_dmaengine_buffer(&queue->buffer); + + dmaengine_terminate_sync(dmaengine_buffer->chan); + iio_dma_buffer_block_list_abort(queue, &dmaengine_buffer->active); +} + +static void iio_dmaengine_buffer_release(struct iio_buffer *buf) +{ + struct dmaengine_buffer *dmaengine_buffer = + iio_buffer_to_dmaengine_buffer(buf); + + iio_dma_buffer_release(&dmaengine_buffer->queue); + kfree(dmaengine_buffer); +} + +static const struct iio_buffer_access_funcs iio_dmaengine_buffer_ops = { + .read = iio_dma_buffer_read, + .write = iio_dma_buffer_write, + .set_bytes_per_datum = iio_dma_buffer_set_bytes_per_datum, + .set_length = iio_dma_buffer_set_length, + .request_update = iio_dma_buffer_request_update, + .enable = iio_dma_buffer_enable, + .disable = iio_dma_buffer_disable, + .data_available = iio_dma_buffer_usage, + .space_available = iio_dma_buffer_usage, + .release = iio_dmaengine_buffer_release, + + .enqueue_dmabuf = iio_dma_buffer_enqueue_dmabuf, + .attach_dmabuf = iio_dma_buffer_attach_dmabuf, + .detach_dmabuf = iio_dma_buffer_detach_dmabuf, + + .lock_queue = iio_dma_buffer_lock_queue, + .unlock_queue = iio_dma_buffer_unlock_queue, + + .get_dma_dev = iio_dma_buffer_get_dma_dev, + + .modes = INDIO_BUFFER_HARDWARE, + .flags = INDIO_BUFFER_FLAG_FIXED_WATERMARK, +}; + +static const struct iio_dma_buffer_ops iio_dmaengine_default_ops = { + .submit = iio_dmaengine_buffer_submit_block, + .abort = iio_dmaengine_buffer_abort, +}; + +static ssize_t iio_dmaengine_buffer_get_length_align(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer; + struct dmaengine_buffer *dmaengine_buffer = + iio_buffer_to_dmaengine_buffer(buffer); + + return sysfs_emit(buf, "%zu\n", dmaengine_buffer->align); +} + +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_dev_attr_length_align_bytes, + NULL, +}; + +/** + * iio_dmaengine_buffer_alloc() - Allocate new buffer which uses DMAengine + * @chan: DMA channel. + * + * This allocates a new IIO buffer which internally uses the DMAengine framework + * to perform its transfers. + * + * Once done using the buffer iio_dmaengine_buffer_free() should be used to + * release it. + */ +static struct iio_buffer *iio_dmaengine_buffer_alloc(struct dma_chan *chan) +{ + struct dmaengine_buffer *dmaengine_buffer; + unsigned int width, src_width, dest_width; + struct dma_slave_caps caps; + int ret; + + ret = dma_get_slave_caps(chan, &caps); + if (ret < 0) + return ERR_PTR(ret); + + dmaengine_buffer = kzalloc_obj(*dmaengine_buffer); + if (!dmaengine_buffer) + return ERR_PTR(-ENOMEM); + + /* Needs to be aligned to the maximum of the minimums */ + if (caps.src_addr_widths) + src_width = __ffs(caps.src_addr_widths); + else + src_width = 1; + if (caps.dst_addr_widths) + dest_width = __ffs(caps.dst_addr_widths); + else + dest_width = 1; + width = max(src_width, dest_width); + + INIT_LIST_HEAD(&dmaengine_buffer->active); + dmaengine_buffer->chan = chan; + dmaengine_buffer->align = width; + dmaengine_buffer->max_size = dma_get_max_seg_size(chan->device->dev); + + iio_dma_buffer_init(&dmaengine_buffer->queue, chan->device->dev, + &iio_dmaengine_default_ops); + + dmaengine_buffer->queue.buffer.attrs = iio_dmaengine_buffer_attrs; + dmaengine_buffer->queue.buffer.access = &iio_dmaengine_buffer_ops; + + return &dmaengine_buffer->queue.buffer; +} + +/** + * iio_dmaengine_buffer_free() - Free dmaengine buffer + * @buffer: Buffer to free + * + * Frees a buffer previously allocated with iio_dmaengine_buffer_alloc(). + */ +static void iio_dmaengine_buffer_free(struct iio_buffer *buffer) +{ + struct dmaengine_buffer *dmaengine_buffer = + iio_buffer_to_dmaengine_buffer(buffer); + + iio_dma_buffer_exit(&dmaengine_buffer->queue); + iio_buffer_put(buffer); +} + +/** + * iio_dmaengine_buffer_teardown() - Releases DMA channel and frees buffer + * @buffer: Buffer to free + * + * Releases the DMA channel and frees the buffer previously setup with + * iio_dmaengine_buffer_setup_ext(). + */ +void iio_dmaengine_buffer_teardown(struct iio_buffer *buffer) +{ + struct dmaengine_buffer *dmaengine_buffer = + iio_buffer_to_dmaengine_buffer(buffer); + struct dma_chan *chan = dmaengine_buffer->chan; + + iio_dmaengine_buffer_free(buffer); + dma_release_channel(chan); +} +EXPORT_SYMBOL_NS_GPL(iio_dmaengine_buffer_teardown, "IIO_DMAENGINE_BUFFER"); + +static struct iio_buffer +*__iio_dmaengine_buffer_setup_ext(struct iio_dev *indio_dev, + struct dma_chan *chan, + enum iio_buffer_direction dir) +{ + struct iio_buffer *buffer; + int ret; + + buffer = iio_dmaengine_buffer_alloc(chan); + if (IS_ERR(buffer)) + return ERR_CAST(buffer); + + indio_dev->modes |= INDIO_BUFFER_HARDWARE; + + buffer->direction = dir; + + ret = iio_device_attach_buffer(indio_dev, buffer); + if (ret) { + iio_dmaengine_buffer_free(buffer); + return ERR_PTR(ret); + } + + return buffer; +} + +/** + * iio_dmaengine_buffer_setup_ext() - Setup a DMA buffer for an IIO device + * @dev: DMA channel consumer device + * @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. + * + * Once done using the buffer iio_dmaengine_buffer_teardown() should be used to + * release it. + */ +struct iio_buffer *iio_dmaengine_buffer_setup_ext(struct device *dev, + struct iio_dev *indio_dev, + const char *channel, + enum iio_buffer_direction dir) +{ + struct dma_chan *chan; + struct iio_buffer *buffer; + + chan = dma_request_chan(dev, channel); + if (IS_ERR(chan)) + return ERR_CAST(chan); + + buffer = __iio_dmaengine_buffer_setup_ext(indio_dev, chan, dir); + if (IS_ERR(buffer)) + dma_release_channel(chan); + + return buffer; +} +EXPORT_SYMBOL_NS_GPL(iio_dmaengine_buffer_setup_ext, "IIO_DMAENGINE_BUFFER"); + +static void devm_iio_dmaengine_buffer_teardown(void *buffer) +{ + iio_dmaengine_buffer_teardown(buffer); +} + +/** + * devm_iio_dmaengine_buffer_setup_ext() - Setup a DMA buffer for an IIO device + * @dev: Device for devm ownership and DMA channel consumer device + * @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) +{ + struct iio_buffer *buffer; + + buffer = iio_dmaengine_buffer_setup_ext(dev, indio_dev, channel, dir); + if (IS_ERR(buffer)) + return PTR_ERR(buffer); + + return devm_add_action_or_reset(dev, devm_iio_dmaengine_buffer_teardown, + buffer); +} +EXPORT_SYMBOL_NS_GPL(devm_iio_dmaengine_buffer_setup_ext, "IIO_DMAENGINE_BUFFER"); + +static void devm_iio_dmaengine_buffer_free(void *buffer) +{ + iio_dmaengine_buffer_free(buffer); +} + +/** + * devm_iio_dmaengine_buffer_setup_with_handle() - Setup a DMA buffer for an + * IIO device + * @dev: Device for devm ownership + * @indio_dev: IIO device to which to attach this buffer. + * @chan: DMA channel + * @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. + * + * This is the same as devm_iio_dmaengine_buffer_setup_ext() except that the + * caller manages requesting and releasing the DMA channel handle. + */ +int devm_iio_dmaengine_buffer_setup_with_handle(struct device *dev, + struct iio_dev *indio_dev, + struct dma_chan *chan, + enum iio_buffer_direction dir) +{ + struct iio_buffer *buffer; + + buffer = __iio_dmaengine_buffer_setup_ext(indio_dev, chan, dir); + if (IS_ERR(buffer)) + return PTR_ERR(buffer); + + return devm_add_action_or_reset(dev, devm_iio_dmaengine_buffer_free, + buffer); +} +EXPORT_SYMBOL_NS_GPL(devm_iio_dmaengine_buffer_setup_with_handle, + "IIO_DMAENGINE_BUFFER"); + +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); +MODULE_DESCRIPTION("DMA buffer for the IIO framework"); +MODULE_LICENSE("GPL"); +MODULE_IMPORT_NS("IIO_DMA_BUFFER"); diff --git a/drivers/iio/buffer/industrialio-hw-consumer.c b/drivers/iio/buffer/industrialio-hw-consumer.c new file mode 100644 index 000000000..d035aa33b --- /dev/null +++ b/drivers/iio/buffer/industrialio-hw-consumer.c @@ -0,0 +1,219 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright 2017 Analog Devices Inc. + * Author: Lars-Peter Clausen <lars@metafoo.de> + */ + +#include <linux/err.h> +#include <linux/export.h> +#include <linux/slab.h> +#include <linux/module.h> + +#include <linux/iio/iio.h> +#include <linux/iio/consumer.h> +#include <linux/iio/hw-consumer.h> +#include <linux/iio/buffer_impl.h> + +/** + * struct iio_hw_consumer - IIO hw consumer block + * @buffers: hardware buffers list head. + * @channels: IIO provider channels. + */ +struct iio_hw_consumer { + struct list_head buffers; + struct iio_channel *channels; +}; + +struct hw_consumer_buffer { + struct list_head head; + struct iio_dev *indio_dev; + struct iio_buffer buffer; +}; + +static struct hw_consumer_buffer *iio_buffer_to_hw_consumer_buffer( + struct iio_buffer *buffer) +{ + return container_of(buffer, struct hw_consumer_buffer, buffer); +} + +static void iio_hw_buf_release(struct iio_buffer *buffer) +{ + struct hw_consumer_buffer *hw_buf = + iio_buffer_to_hw_consumer_buffer(buffer); + + bitmap_free(buffer->scan_mask); + kfree(hw_buf); +} + +static const struct iio_buffer_access_funcs iio_hw_buf_access = { + .release = &iio_hw_buf_release, + .modes = INDIO_BUFFER_HARDWARE, +}; + +static struct hw_consumer_buffer *iio_hw_consumer_get_buffer( + struct iio_hw_consumer *hwc, struct iio_dev *indio_dev) +{ + struct hw_consumer_buffer *buf; + + list_for_each_entry(buf, &hwc->buffers, head) { + if (buf->indio_dev == indio_dev) + return buf; + } + + buf = kzalloc_obj(*buf); + if (!buf) + return NULL; + + buf->buffer.access = &iio_hw_buf_access; + buf->indio_dev = indio_dev; + buf->buffer.scan_mask = bitmap_zalloc(iio_get_masklength(indio_dev), + GFP_KERNEL); + if (!buf->buffer.scan_mask) { + kfree(buf); + return NULL; + } + + iio_buffer_init(&buf->buffer); + list_add_tail(&buf->head, &hwc->buffers); + + return buf; +} + +/** + * iio_hw_consumer_alloc() - Allocate IIO hardware consumer + * @dev: Pointer to consumer device. + * + * Returns a valid iio_hw_consumer on success or a ERR_PTR() on failure. + */ +struct iio_hw_consumer *iio_hw_consumer_alloc(struct device *dev) +{ + struct hw_consumer_buffer *buf, *tmp; + struct iio_hw_consumer *hwc; + struct iio_channel *chan; + int ret; + + hwc = kzalloc_obj(*hwc); + if (!hwc) + return ERR_PTR(-ENOMEM); + + INIT_LIST_HEAD(&hwc->buffers); + + hwc->channels = iio_channel_get_all(dev); + if (IS_ERR(hwc->channels)) { + ret = PTR_ERR(hwc->channels); + goto err_free_hwc; + } + + chan = &hwc->channels[0]; + while (chan->indio_dev) { + buf = iio_hw_consumer_get_buffer(hwc, chan->indio_dev); + if (!buf) { + ret = -ENOMEM; + goto err_put_buffers; + } + set_bit(chan->channel->scan_index, buf->buffer.scan_mask); + chan++; + } + + return hwc; + +err_put_buffers: + list_for_each_entry_safe(buf, tmp, &hwc->buffers, head) + iio_buffer_put(&buf->buffer); + iio_channel_release_all(hwc->channels); +err_free_hwc: + kfree(hwc); + return ERR_PTR(ret); +} +EXPORT_SYMBOL_GPL(iio_hw_consumer_alloc); + +/** + * iio_hw_consumer_free() - Free IIO hardware consumer + * @hwc: hw consumer to free. + */ +void iio_hw_consumer_free(struct iio_hw_consumer *hwc) +{ + struct hw_consumer_buffer *buf, *n; + + iio_channel_release_all(hwc->channels); + list_for_each_entry_safe(buf, n, &hwc->buffers, head) + iio_buffer_put(&buf->buffer); + kfree(hwc); +} +EXPORT_SYMBOL_GPL(iio_hw_consumer_free); + +static void devm_iio_hw_consumer_release(void *iio_hwc) +{ + iio_hw_consumer_free(iio_hwc); +} + +/** + * devm_iio_hw_consumer_alloc - Resource-managed iio_hw_consumer_alloc() + * @dev: Pointer to consumer device. + * + * Managed iio_hw_consumer_alloc. iio_hw_consumer allocated with this function + * is automatically freed on driver detach. + * + * returns pointer to allocated iio_hw_consumer on success, NULL on failure. + */ +struct iio_hw_consumer *devm_iio_hw_consumer_alloc(struct device *dev) +{ + struct iio_hw_consumer *iio_hwc; + int ret; + + iio_hwc = iio_hw_consumer_alloc(dev); + if (IS_ERR(iio_hwc)) + return iio_hwc; + + ret = devm_add_action_or_reset(dev, devm_iio_hw_consumer_release, + iio_hwc); + if (ret) + return ERR_PTR(ret); + + return iio_hwc; +} +EXPORT_SYMBOL_GPL(devm_iio_hw_consumer_alloc); + +/** + * iio_hw_consumer_enable() - Enable IIO hardware consumer + * @hwc: iio_hw_consumer to enable. + * + * Returns 0 on success. + */ +int iio_hw_consumer_enable(struct iio_hw_consumer *hwc) +{ + struct hw_consumer_buffer *buf; + int ret; + + list_for_each_entry(buf, &hwc->buffers, head) { + ret = iio_update_buffers(buf->indio_dev, &buf->buffer, NULL); + if (ret) + goto err_disable_buffers; + } + + return 0; + +err_disable_buffers: + list_for_each_entry_continue_reverse(buf, &hwc->buffers, head) + iio_update_buffers(buf->indio_dev, NULL, &buf->buffer); + return ret; +} +EXPORT_SYMBOL_GPL(iio_hw_consumer_enable); + +/** + * iio_hw_consumer_disable() - Disable IIO hardware consumer + * @hwc: iio_hw_consumer to disable. + */ +void iio_hw_consumer_disable(struct iio_hw_consumer *hwc) +{ + struct hw_consumer_buffer *buf; + + list_for_each_entry(buf, &hwc->buffers, head) + iio_update_buffers(buf->indio_dev, NULL, &buf->buffer); +} +EXPORT_SYMBOL_GPL(iio_hw_consumer_disable); + +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); +MODULE_DESCRIPTION("Hardware consumer buffer the IIO framework"); +MODULE_LICENSE("GPL v2"); +MODULE_IMPORT_NS("IIO_CONSUMER"); diff --git a/drivers/iio/buffer/industrialio-triggered-buffer.c b/drivers/iio/buffer/industrialio-triggered-buffer.c new file mode 100644 index 000000000..9bf75dee7 --- /dev/null +++ b/drivers/iio/buffer/industrialio-triggered-buffer.c @@ -0,0 +1,139 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2012 Analog Devices, Inc. + * Author: Lars-Peter Clausen <lars@metafoo.de> + */ + +#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/buffer_impl.h> +#include <linux/iio/kfifo_buf.h> +#include <linux/iio/triggered_buffer.h> +#include <linux/iio/trigger_consumer.h> + +/** + * iio_triggered_buffer_setup_ext() - Setup triggered buffer and pollfunc + * @indio_dev: IIO device structure + * @h: Function which will be used as pollfunc top half + * @thread: Function which will be used as pollfunc bottom half + * @direction: Direction of the data stream (in/out). + * @setup_ops: Buffer setup functions to use for this device. + * If NULL the default setup functions for triggered + * buffers will be used. + * @buffer_attrs: Extra sysfs buffer attributes for this IIO buffer + * + * This function combines some common tasks which will normally be performed + * when setting up a triggered buffer. It will allocate the buffer and the + * pollfunc. + * + * 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_ext(struct iio_dev *indio_dev, + irqreturn_t (*h)(int irq, void *p), + irqreturn_t (*thread)(int irq, void *p), + enum iio_buffer_direction direction, + const struct iio_buffer_setup_ops *setup_ops, + const struct iio_dev_attr **buffer_attrs) +{ + struct iio_buffer *buffer; + int ret; + + /* + * iio_triggered_buffer_cleanup() assumes that the buffer allocated here + * is assigned to indio_dev->buffer but this is only the case if this + * function is the first caller to iio_device_attach_buffer(). If + * indio_dev->buffer is already set then we can't proceed otherwise the + * cleanup function will try to free a buffer that was not allocated here. + */ + if (indio_dev->buffer) + return -EADDRINUSE; + + buffer = iio_kfifo_allocate(); + if (!buffer) { + ret = -ENOMEM; + goto error_ret; + } + + indio_dev->pollfunc = iio_alloc_pollfunc(h, + thread, + IRQF_ONESHOT, + indio_dev, + "%s_consumer%d", + indio_dev->name, + iio_device_id(indio_dev)); + if (indio_dev->pollfunc == NULL) { + ret = -ENOMEM; + goto error_kfifo_free; + } + + /* Ring buffer functions - here trigger setup related */ + indio_dev->setup_ops = setup_ops; + + /* Flag that polled ring buffering is possible */ + indio_dev->modes |= INDIO_BUFFER_TRIGGERED; + + buffer->direction = direction; + buffer->attrs = buffer_attrs; + + ret = iio_device_attach_buffer(indio_dev, buffer); + if (ret < 0) + goto error_dealloc_pollfunc; + + return 0; + +error_dealloc_pollfunc: + iio_dealloc_pollfunc(indio_dev->pollfunc); +error_kfifo_free: + iio_kfifo_free(buffer); +error_ret: + return ret; +} +EXPORT_SYMBOL(iio_triggered_buffer_setup_ext); + +/** + * iio_triggered_buffer_cleanup() - Free resources allocated by iio_triggered_buffer_setup_ext() + * @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); + +static void devm_iio_triggered_buffer_clean(void *indio_dev) +{ + iio_triggered_buffer_cleanup(indio_dev); +} + +int devm_iio_triggered_buffer_setup_ext(struct device *dev, + struct iio_dev *indio_dev, + irqreturn_t (*h)(int irq, void *p), + irqreturn_t (*thread)(int irq, void *p), + enum iio_buffer_direction direction, + const struct iio_buffer_setup_ops *ops, + const struct iio_dev_attr **buffer_attrs) +{ + int ret; + + ret = iio_triggered_buffer_setup_ext(indio_dev, h, thread, direction, + ops, buffer_attrs); + if (ret) + return ret; + + return devm_add_action_or_reset(dev, devm_iio_triggered_buffer_clean, + indio_dev); +} +EXPORT_SYMBOL_GPL(devm_iio_triggered_buffer_setup_ext); + +MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); +MODULE_DESCRIPTION("IIO helper functions for setting up triggered buffers"); +MODULE_LICENSE("GPL"); diff --git a/drivers/iio/buffer/kfifo_buf.c b/drivers/iio/buffer/kfifo_buf.c new file mode 100644 index 000000000..b67ea6468 --- /dev/null +++ b/drivers/iio/buffer/kfifo_buf.c @@ -0,0 +1,272 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/device.h> +#include <linux/workqueue.h> +#include <linux/kfifo.h> +#include <linux/mutex.h> +#include <linux/iio/iio.h> +#include <linux/iio/buffer.h> +#include <linux/iio/kfifo_buf.h> +#include <linux/iio/buffer_impl.h> +#include <linux/sched.h> +#include <linux/poll.h> + +struct iio_kfifo { + struct iio_buffer buffer; + struct kfifo kf; + struct mutex user_lock; + int update_needed; +}; + +#define iio_to_kfifo(r) container_of(r, struct iio_kfifo, buffer) + +static inline int __iio_allocate_kfifo(struct iio_kfifo *buf, + size_t bytes_per_datum, unsigned int length) +{ + if ((length == 0) || (bytes_per_datum == 0)) + return -EINVAL; + + /* + * Make sure we don't overflow an unsigned int after kfifo rounds up to + * the next power of 2. + */ + if (roundup_pow_of_two(length) > UINT_MAX / bytes_per_datum) + return -EINVAL; + + return __kfifo_alloc((struct __kfifo *)&buf->kf, length, + bytes_per_datum, GFP_KERNEL); +} + +static int iio_request_update_kfifo(struct iio_buffer *r) +{ + int ret = 0; + struct iio_kfifo *buf = iio_to_kfifo(r); + + mutex_lock(&buf->user_lock); + if (buf->update_needed) { + kfifo_free(&buf->kf); + ret = __iio_allocate_kfifo(buf, buf->buffer.bytes_per_datum, + buf->buffer.length); + if (ret >= 0) + buf->update_needed = false; + } else { + kfifo_reset_out(&buf->kf); + } + mutex_unlock(&buf->user_lock); + + return ret; +} + +static int iio_mark_update_needed_kfifo(struct iio_buffer *r) +{ + struct iio_kfifo *kf = iio_to_kfifo(r); + kf->update_needed = true; + return 0; +} + +static int iio_set_bytes_per_datum_kfifo(struct iio_buffer *r, size_t bpd) +{ + if (r->bytes_per_datum != bpd) { + r->bytes_per_datum = bpd; + iio_mark_update_needed_kfifo(r); + } + return 0; +} + +static int iio_set_length_kfifo(struct iio_buffer *r, unsigned int length) +{ + /* Avoid an invalid state */ + if (length < 2) + length = 2; + if (r->length != length) { + r->length = length; + iio_mark_update_needed_kfifo(r); + } + return 0; +} + +static int iio_store_to_kfifo(struct iio_buffer *r, + const void *data) +{ + int ret; + struct iio_kfifo *kf = iio_to_kfifo(r); + ret = kfifo_in(&kf->kf, data, 1); + if (ret != 1) + return -EBUSY; + return 0; +} + +static int iio_read_kfifo(struct iio_buffer *r, size_t n, char __user *buf) +{ + int ret, copied; + struct iio_kfifo *kf = iio_to_kfifo(r); + + if (mutex_lock_interruptible(&kf->user_lock)) + return -ERESTARTSYS; + + if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf)) + ret = -EINVAL; + else + ret = kfifo_to_user(&kf->kf, buf, n, &copied); + mutex_unlock(&kf->user_lock); + if (ret < 0) + return ret; + + return copied; +} + +static size_t iio_kfifo_buf_data_available(struct iio_buffer *r) +{ + struct iio_kfifo *kf = iio_to_kfifo(r); + size_t samples; + + mutex_lock(&kf->user_lock); + samples = kfifo_len(&kf->kf); + mutex_unlock(&kf->user_lock); + + return samples; +} + +static void iio_kfifo_buffer_release(struct iio_buffer *buffer) +{ + struct iio_kfifo *kf = iio_to_kfifo(buffer); + + mutex_destroy(&kf->user_lock); + kfifo_free(&kf->kf); + kfree(kf); +} + +static size_t iio_kfifo_buf_space_available(struct iio_buffer *r) +{ + struct iio_kfifo *kf = iio_to_kfifo(r); + size_t avail; + + mutex_lock(&kf->user_lock); + avail = kfifo_avail(&kf->kf); + mutex_unlock(&kf->user_lock); + + return avail; +} + +static int iio_kfifo_remove_from(struct iio_buffer *r, void *data) +{ + int ret; + struct iio_kfifo *kf = iio_to_kfifo(r); + + if (kfifo_size(&kf->kf) < 1) + return -EBUSY; + + ret = kfifo_out(&kf->kf, data, 1); + if (ret != 1) + return -EBUSY; + + wake_up_interruptible_poll(&r->pollq, EPOLLOUT | EPOLLWRNORM); + + return 0; +} + +static int iio_kfifo_write(struct iio_buffer *r, size_t n, + const char __user *buf) +{ + struct iio_kfifo *kf = iio_to_kfifo(r); + int ret, copied; + + mutex_lock(&kf->user_lock); + if (!kfifo_initialized(&kf->kf) || n < kfifo_esize(&kf->kf)) + ret = -EINVAL; + else + ret = kfifo_from_user(&kf->kf, buf, n, &copied); + mutex_unlock(&kf->user_lock); + if (ret) + return ret; + + return copied; +} + +static const struct iio_buffer_access_funcs kfifo_access_funcs = { + .store_to = &iio_store_to_kfifo, + .read = &iio_read_kfifo, + .data_available = iio_kfifo_buf_data_available, + .remove_from = &iio_kfifo_remove_from, + .write = &iio_kfifo_write, + .space_available = &iio_kfifo_buf_space_available, + .request_update = &iio_request_update_kfifo, + .set_bytes_per_datum = &iio_set_bytes_per_datum_kfifo, + .set_length = &iio_set_length_kfifo, + .release = &iio_kfifo_buffer_release, + + .modes = INDIO_BUFFER_SOFTWARE | INDIO_BUFFER_TRIGGERED, +}; + +struct iio_buffer *iio_kfifo_allocate(void) +{ + struct iio_kfifo *kf; + + kf = kzalloc_obj(*kf); + if (!kf) + return NULL; + + kf->update_needed = true; + iio_buffer_init(&kf->buffer); + kf->buffer.access = &kfifo_access_funcs; + kf->buffer.length = 2; + mutex_init(&kf->user_lock); + + return &kf->buffer; +} +EXPORT_SYMBOL(iio_kfifo_allocate); + +void iio_kfifo_free(struct iio_buffer *r) +{ + iio_buffer_put(r); +} +EXPORT_SYMBOL(iio_kfifo_free); + +static void devm_iio_kfifo_release(void *buffer) +{ + iio_kfifo_free(buffer); +} + +/** + * devm_iio_kfifo_buffer_setup_ext - Allocate a kfifo buffer & attach it to an IIO device + * @dev: Device object to which to attach the life-time of this kfifo buffer + * @indio_dev: The device the buffer should be attached to + * @setup_ops: The setup_ops required to configure the HW part of the buffer (optional) + * @buffer_attrs: Extra sysfs buffer attributes for this IIO buffer + * + * This function allocates a kfifo buffer via iio_kfifo_allocate() and + * attaches it to the IIO device via iio_device_attach_buffer(). + * This is meant to be a bit of a short-hand/helper function as there are a few + * drivers that seem to do this. + * + * Return: 0 on success, negative error code on failure. + */ +int devm_iio_kfifo_buffer_setup_ext(struct device *dev, + struct iio_dev *indio_dev, + const struct iio_buffer_setup_ops *setup_ops, + const struct iio_dev_attr **buffer_attrs) +{ + struct iio_buffer *buffer; + int ret; + + buffer = iio_kfifo_allocate(); + if (!buffer) + return -ENOMEM; + + ret = devm_add_action_or_reset(dev, devm_iio_kfifo_release, buffer); + if (ret) + return ret; + + indio_dev->modes |= INDIO_BUFFER_SOFTWARE; + indio_dev->setup_ops = setup_ops; + + buffer->attrs = buffer_attrs; + + return iio_device_attach_buffer(indio_dev, buffer); +} +EXPORT_SYMBOL_GPL(devm_iio_kfifo_buffer_setup_ext); + +MODULE_DESCRIPTION("Industrial I/O buffering based on kfifo"); +MODULE_LICENSE("GPL"); |