296 lines
8.5 KiB
C
296 lines
8.5 KiB
C
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// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* Copyright 2014-2015 Analog Devices Inc.
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* Author: Lars-Peter Clausen <lars@metafoo.de>
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*/
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#include <linux/slab.h>
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#include <linux/kernel.h>
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#include <linux/dmaengine.h>
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#include <linux/dma-mapping.h>
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#include <linux/spinlock.h>
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#include <linux/err.h>
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#include <linux/module.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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#include <linux/iio/buffer.h>
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#include <linux/iio/buffer_impl.h>
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#include <linux/iio/buffer-dma.h>
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#include <linux/iio/buffer-dmaengine.h>
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/*
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* The IIO DMAengine buffer combines the generic IIO DMA buffer infrastructure
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* with the DMAengine framework. The generic IIO DMA buffer infrastructure is
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* used to manage the buffer memory and implement the IIO buffer operations
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* while the DMAengine framework is used to perform the DMA transfers. Combined
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* this results in a device independent fully functional DMA buffer
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* implementation that can be used by device drivers for peripherals which are
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* connected to a DMA controller which has a DMAengine driver implementation.
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*/
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struct dmaengine_buffer {
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struct iio_dma_buffer_queue queue;
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struct dma_chan *chan;
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struct list_head active;
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size_t align;
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size_t max_size;
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};
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static struct dmaengine_buffer *iio_buffer_to_dmaengine_buffer(
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struct iio_buffer *buffer)
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{
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return container_of(buffer, struct dmaengine_buffer, queue.buffer);
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}
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static void iio_dmaengine_buffer_block_done(void *data,
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const struct dmaengine_result *result)
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{
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struct iio_dma_buffer_block *block = data;
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unsigned long flags;
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spin_lock_irqsave(&block->queue->list_lock, flags);
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list_del(&block->head);
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spin_unlock_irqrestore(&block->queue->list_lock, flags);
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block->bytes_used -= result->residue;
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iio_dma_buffer_block_done(block);
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}
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static int iio_dmaengine_buffer_submit_block(struct iio_dma_buffer_queue *queue,
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struct iio_dma_buffer_block *block)
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{
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struct dmaengine_buffer *dmaengine_buffer =
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iio_buffer_to_dmaengine_buffer(&queue->buffer);
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struct dma_async_tx_descriptor *desc;
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dma_cookie_t cookie;
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block->bytes_used = min(block->size, dmaengine_buffer->max_size);
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block->bytes_used = round_down(block->bytes_used,
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dmaengine_buffer->align);
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desc = dmaengine_prep_slave_single(dmaengine_buffer->chan,
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block->phys_addr, block->bytes_used, DMA_DEV_TO_MEM,
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DMA_PREP_INTERRUPT);
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if (!desc)
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return -ENOMEM;
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desc->callback_result = iio_dmaengine_buffer_block_done;
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desc->callback_param = block;
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cookie = dmaengine_submit(desc);
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if (dma_submit_error(cookie))
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return dma_submit_error(cookie);
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spin_lock_irq(&dmaengine_buffer->queue.list_lock);
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list_add_tail(&block->head, &dmaengine_buffer->active);
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spin_unlock_irq(&dmaengine_buffer->queue.list_lock);
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dma_async_issue_pending(dmaengine_buffer->chan);
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return 0;
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}
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static void iio_dmaengine_buffer_abort(struct iio_dma_buffer_queue *queue)
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{
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struct dmaengine_buffer *dmaengine_buffer =
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iio_buffer_to_dmaengine_buffer(&queue->buffer);
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dmaengine_terminate_sync(dmaengine_buffer->chan);
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iio_dma_buffer_block_list_abort(queue, &dmaengine_buffer->active);
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}
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static void iio_dmaengine_buffer_release(struct iio_buffer *buf)
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{
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struct dmaengine_buffer *dmaengine_buffer =
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iio_buffer_to_dmaengine_buffer(buf);
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iio_dma_buffer_release(&dmaengine_buffer->queue);
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kfree(dmaengine_buffer);
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}
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static const struct iio_buffer_access_funcs iio_dmaengine_buffer_ops = {
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.read = iio_dma_buffer_read,
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.set_bytes_per_datum = iio_dma_buffer_set_bytes_per_datum,
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.set_length = iio_dma_buffer_set_length,
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.request_update = iio_dma_buffer_request_update,
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.enable = iio_dma_buffer_enable,
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.disable = iio_dma_buffer_disable,
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.data_available = iio_dma_buffer_data_available,
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.release = iio_dmaengine_buffer_release,
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.modes = INDIO_BUFFER_HARDWARE,
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.flags = INDIO_BUFFER_FLAG_FIXED_WATERMARK,
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};
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static const struct iio_dma_buffer_ops iio_dmaengine_default_ops = {
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.submit = iio_dmaengine_buffer_submit_block,
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.abort = iio_dmaengine_buffer_abort,
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};
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static ssize_t iio_dmaengine_buffer_get_length_align(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct iio_buffer *buffer = to_iio_dev_attr(attr)->buffer;
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struct dmaengine_buffer *dmaengine_buffer =
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iio_buffer_to_dmaengine_buffer(buffer);
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return sysfs_emit(buf, "%zu\n", dmaengine_buffer->align);
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}
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static IIO_DEVICE_ATTR(length_align_bytes, 0444,
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iio_dmaengine_buffer_get_length_align, NULL, 0);
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static const struct attribute *iio_dmaengine_buffer_attrs[] = {
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&iio_dev_attr_length_align_bytes.dev_attr.attr,
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NULL,
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};
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/**
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* iio_dmaengine_buffer_alloc() - Allocate new buffer which uses DMAengine
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* @dev: Parent device for the buffer
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* @channel: DMA channel name, typically "rx".
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*
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* This allocates a new IIO buffer which internally uses the DMAengine framework
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* to perform its transfers. The parent device will be used to request the DMA
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* channel.
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*
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* Once done using the buffer iio_dmaengine_buffer_free() should be used to
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* release it.
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*/
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static struct iio_buffer *iio_dmaengine_buffer_alloc(struct device *dev,
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const char *channel)
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{
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struct dmaengine_buffer *dmaengine_buffer;
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unsigned int width, src_width, dest_width;
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struct dma_slave_caps caps;
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struct dma_chan *chan;
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int ret;
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dmaengine_buffer = kzalloc(sizeof(*dmaengine_buffer), GFP_KERNEL);
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if (!dmaengine_buffer)
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return ERR_PTR(-ENOMEM);
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chan = dma_request_chan(dev, channel);
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if (IS_ERR(chan)) {
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ret = PTR_ERR(chan);
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goto err_free;
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}
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ret = dma_get_slave_caps(chan, &caps);
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if (ret < 0)
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goto err_free;
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/* Needs to be aligned to the maximum of the minimums */
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if (caps.src_addr_widths)
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src_width = __ffs(caps.src_addr_widths);
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else
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src_width = 1;
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if (caps.dst_addr_widths)
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dest_width = __ffs(caps.dst_addr_widths);
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else
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dest_width = 1;
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width = max(src_width, dest_width);
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INIT_LIST_HEAD(&dmaengine_buffer->active);
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dmaengine_buffer->chan = chan;
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dmaengine_buffer->align = width;
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dmaengine_buffer->max_size = dma_get_max_seg_size(chan->device->dev);
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iio_dma_buffer_init(&dmaengine_buffer->queue, chan->device->dev,
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&iio_dmaengine_default_ops);
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dmaengine_buffer->queue.buffer.attrs = iio_dmaengine_buffer_attrs;
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dmaengine_buffer->queue.buffer.access = &iio_dmaengine_buffer_ops;
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return &dmaengine_buffer->queue.buffer;
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err_free:
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kfree(dmaengine_buffer);
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return ERR_PTR(ret);
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}
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/**
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* iio_dmaengine_buffer_free() - Free dmaengine buffer
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* @buffer: Buffer to free
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*
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* Frees a buffer previously allocated with iio_dmaengine_buffer_alloc().
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*/
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static void iio_dmaengine_buffer_free(struct iio_buffer *buffer)
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{
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struct dmaengine_buffer *dmaengine_buffer =
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iio_buffer_to_dmaengine_buffer(buffer);
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iio_dma_buffer_exit(&dmaengine_buffer->queue);
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dma_release_channel(dmaengine_buffer->chan);
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iio_buffer_put(buffer);
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}
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static void __devm_iio_dmaengine_buffer_free(void *buffer)
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{
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iio_dmaengine_buffer_free(buffer);
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}
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/**
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* devm_iio_dmaengine_buffer_alloc() - Resource-managed iio_dmaengine_buffer_alloc()
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* @dev: Parent device for the buffer
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* @channel: DMA channel name, typically "rx".
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*
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* This allocates a new IIO buffer which internally uses the DMAengine framework
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* to perform its transfers. The parent device will be used to request the DMA
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* channel.
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*
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* The buffer will be automatically de-allocated once the device gets destroyed.
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*/
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static struct iio_buffer *devm_iio_dmaengine_buffer_alloc(struct device *dev,
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const char *channel)
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{
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struct iio_buffer *buffer;
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int ret;
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buffer = iio_dmaengine_buffer_alloc(dev, channel);
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if (IS_ERR(buffer))
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return buffer;
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ret = devm_add_action_or_reset(dev, __devm_iio_dmaengine_buffer_free,
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buffer);
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if (ret)
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return ERR_PTR(ret);
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return buffer;
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}
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/**
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* devm_iio_dmaengine_buffer_setup() - Setup a DMA buffer for an IIO device
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* @dev: Parent device for the buffer
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* @indio_dev: IIO device to which to attach this buffer.
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* @channel: DMA channel name, typically "rx".
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*
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* This allocates a new IIO buffer with devm_iio_dmaengine_buffer_alloc()
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* and attaches it to an IIO device with iio_device_attach_buffer().
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* It also appends the INDIO_BUFFER_HARDWARE mode to the supported modes of the
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* IIO device.
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*/
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int devm_iio_dmaengine_buffer_setup(struct device *dev,
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struct iio_dev *indio_dev,
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const char *channel)
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{
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struct iio_buffer *buffer;
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buffer = devm_iio_dmaengine_buffer_alloc(indio_dev->dev.parent,
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channel);
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if (IS_ERR(buffer))
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return PTR_ERR(buffer);
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indio_dev->modes |= INDIO_BUFFER_HARDWARE;
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return iio_device_attach_buffer(indio_dev, buffer);
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}
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EXPORT_SYMBOL_GPL(devm_iio_dmaengine_buffer_setup);
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MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>");
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MODULE_DESCRIPTION("DMA buffer for the IIO framework");
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MODULE_LICENSE("GPL");
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