dmaengine.c

来自「linux 内核源代码」· C语言 代码 · 共 607 行 · 第 1/2 页

	if (!client)
		return;

	mutex_lock(&dma_list_mutex);
	/* free all channels the client is holding */
	list_for_each_entry(device, &dma_device_list, global_node)
		list_for_each_entry(chan, &device->channels, device_node) {
			ack = client->event_callback(client, chan,
				DMA_RESOURCE_REMOVED);

			if (ack == DMA_ACK)
				dma_chan_put(chan);
		}

	list_del(&client->global_node);
	mutex_unlock(&dma_list_mutex);
}
EXPORT_SYMBOL(dma_async_client_unregister);

/**
 * dma_async_client_chan_request - send all available channels to the
 * client that satisfy the capability mask
 * @client - requester
 */
void dma_async_client_chan_request(struct dma_client *client)
{
	mutex_lock(&dma_list_mutex);
	dma_client_chan_alloc(client);
	mutex_unlock(&dma_list_mutex);
}
EXPORT_SYMBOL(dma_async_client_chan_request);

/**
 * dma_async_device_register - registers DMA devices found
 * @device: &dma_device
 */
int dma_async_device_register(struct dma_device *device)
{
	static int id;
	int chancnt = 0, rc;
	struct dma_chan* chan;

	if (!device)
		return -ENODEV;

	/* validate device routines */
	BUG_ON(dma_has_cap(DMA_MEMCPY, device->cap_mask) &&
		!device->device_prep_dma_memcpy);
	BUG_ON(dma_has_cap(DMA_XOR, device->cap_mask) &&
		!device->device_prep_dma_xor);
	BUG_ON(dma_has_cap(DMA_ZERO_SUM, device->cap_mask) &&
		!device->device_prep_dma_zero_sum);
	BUG_ON(dma_has_cap(DMA_MEMSET, device->cap_mask) &&
		!device->device_prep_dma_memset);
	BUG_ON(dma_has_cap(DMA_ZERO_SUM, device->cap_mask) &&
		!device->device_prep_dma_interrupt);

	BUG_ON(!device->device_alloc_chan_resources);
	BUG_ON(!device->device_free_chan_resources);
	BUG_ON(!device->device_dependency_added);
	BUG_ON(!device->device_is_tx_complete);
	BUG_ON(!device->device_issue_pending);
	BUG_ON(!device->dev);

	init_completion(&device->done);
	kref_init(&device->refcount);
	device->dev_id = id++;

	/* represent channels in sysfs. Probably want devs too */
	list_for_each_entry(chan, &device->channels, device_node) {
		chan->local = alloc_percpu(typeof(*chan->local));
		if (chan->local == NULL)
			continue;

		chan->chan_id = chancnt++;
		chan->class_dev.class = &dma_devclass;
		chan->class_dev.dev = NULL;
		snprintf(chan->class_dev.class_id, BUS_ID_SIZE, "dma%dchan%d",
		         device->dev_id, chan->chan_id);

		rc = class_device_register(&chan->class_dev);
		if (rc) {
			chancnt--;
			free_percpu(chan->local);
			chan->local = NULL;
			goto err_out;
		}

		/* One for the channel, one of the class device */
		kref_get(&device->refcount);
		kref_get(&device->refcount);
		kref_init(&chan->refcount);
		chan->slow_ref = 0;
		INIT_RCU_HEAD(&chan->rcu);
	}

	mutex_lock(&dma_list_mutex);
	list_add_tail(&device->global_node, &dma_device_list);
	mutex_unlock(&dma_list_mutex);

	dma_clients_notify_available();

	return 0;

err_out:
	list_for_each_entry(chan, &device->channels, device_node) {
		if (chan->local == NULL)
			continue;
		kref_put(&device->refcount, dma_async_device_cleanup);
		class_device_unregister(&chan->class_dev);
		chancnt--;
		free_percpu(chan->local);
	}
	return rc;
}
EXPORT_SYMBOL(dma_async_device_register);

/**
 * dma_async_device_cleanup - function called when all references are released
 * @kref: kernel reference object
 */
static void dma_async_device_cleanup(struct kref *kref)
{
	struct dma_device *device;

	device = container_of(kref, struct dma_device, refcount);
	complete(&device->done);
}

/**
 * dma_async_device_unregister - unregisters DMA devices
 * @device: &dma_device
 */
void dma_async_device_unregister(struct dma_device *device)
{
	struct dma_chan *chan;

	mutex_lock(&dma_list_mutex);
	list_del(&device->global_node);
	mutex_unlock(&dma_list_mutex);

	list_for_each_entry(chan, &device->channels, device_node) {
		dma_clients_notify_removed(chan);
		class_device_unregister(&chan->class_dev);
		dma_chan_release(chan);
	}

	kref_put(&device->refcount, dma_async_device_cleanup);
	wait_for_completion(&device->done);
}
EXPORT_SYMBOL(dma_async_device_unregister);

/**
 * dma_async_memcpy_buf_to_buf - offloaded copy between virtual addresses
 * @chan: DMA channel to offload copy to
 * @dest: destination address (virtual)
 * @src: source address (virtual)
 * @len: length
 *
 * Both @dest and @src must be mappable to a bus address according to the
 * DMA mapping API rules for streaming mappings.
 * Both @dest and @src must stay memory resident (kernel memory or locked
 * user space pages).
 */
dma_cookie_t
dma_async_memcpy_buf_to_buf(struct dma_chan *chan, void *dest,
			void *src, size_t len)
{
	struct dma_device *dev = chan->device;
	struct dma_async_tx_descriptor *tx;
	dma_addr_t addr;
	dma_cookie_t cookie;
	int cpu;

	tx = dev->device_prep_dma_memcpy(chan, len, 0);
	if (!tx)
		return -ENOMEM;

	tx->ack = 1;
	tx->callback = NULL;
	addr = dma_map_single(dev->dev, src, len, DMA_TO_DEVICE);
	tx->tx_set_src(addr, tx, 0);
	addr = dma_map_single(dev->dev, dest, len, DMA_FROM_DEVICE);
	tx->tx_set_dest(addr, tx, 0);
	cookie = tx->tx_submit(tx);

	cpu = get_cpu();
	per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
	per_cpu_ptr(chan->local, cpu)->memcpy_count++;
	put_cpu();

	return cookie;
}
EXPORT_SYMBOL(dma_async_memcpy_buf_to_buf);

/**
 * dma_async_memcpy_buf_to_pg - offloaded copy from address to page
 * @chan: DMA channel to offload copy to
 * @page: destination page
 * @offset: offset in page to copy to
 * @kdata: source address (virtual)
 * @len: length
 *
 * Both @page/@offset and @kdata must be mappable to a bus address according
 * to the DMA mapping API rules for streaming mappings.
 * Both @page/@offset and @kdata must stay memory resident (kernel memory or
 * locked user space pages)
 */
dma_cookie_t
dma_async_memcpy_buf_to_pg(struct dma_chan *chan, struct page *page,
			unsigned int offset, void *kdata, size_t len)
{
	struct dma_device *dev = chan->device;
	struct dma_async_tx_descriptor *tx;
	dma_addr_t addr;
	dma_cookie_t cookie;
	int cpu;

	tx = dev->device_prep_dma_memcpy(chan, len, 0);
	if (!tx)
		return -ENOMEM;

	tx->ack = 1;
	tx->callback = NULL;
	addr = dma_map_single(dev->dev, kdata, len, DMA_TO_DEVICE);
	tx->tx_set_src(addr, tx, 0);
	addr = dma_map_page(dev->dev, page, offset, len, DMA_FROM_DEVICE);
	tx->tx_set_dest(addr, tx, 0);
	cookie = tx->tx_submit(tx);

	cpu = get_cpu();
	per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
	per_cpu_ptr(chan->local, cpu)->memcpy_count++;
	put_cpu();

	return cookie;
}
EXPORT_SYMBOL(dma_async_memcpy_buf_to_pg);

/**
 * dma_async_memcpy_pg_to_pg - offloaded copy from page to page
 * @chan: DMA channel to offload copy to
 * @dest_pg: destination page
 * @dest_off: offset in page to copy to
 * @src_pg: source page
 * @src_off: offset in page to copy from
 * @len: length
 *
 * Both @dest_page/@dest_off and @src_page/@src_off must be mappable to a bus
 * address according to the DMA mapping API rules for streaming mappings.
 * Both @dest_page/@dest_off and @src_page/@src_off must stay memory resident
 * (kernel memory or locked user space pages).
 */
dma_cookie_t
dma_async_memcpy_pg_to_pg(struct dma_chan *chan, struct page *dest_pg,
	unsigned int dest_off, struct page *src_pg, unsigned int src_off,
	size_t len)
{
	struct dma_device *dev = chan->device;
	struct dma_async_tx_descriptor *tx;
	dma_addr_t addr;
	dma_cookie_t cookie;
	int cpu;

	tx = dev->device_prep_dma_memcpy(chan, len, 0);
	if (!tx)
		return -ENOMEM;

	tx->ack = 1;
	tx->callback = NULL;
	addr = dma_map_page(dev->dev, src_pg, src_off, len, DMA_TO_DEVICE);
	tx->tx_set_src(addr, tx, 0);
	addr = dma_map_page(dev->dev, dest_pg, dest_off, len, DMA_FROM_DEVICE);
	tx->tx_set_dest(addr, tx, 0);
	cookie = tx->tx_submit(tx);

	cpu = get_cpu();
	per_cpu_ptr(chan->local, cpu)->bytes_transferred += len;
	per_cpu_ptr(chan->local, cpu)->memcpy_count++;
	put_cpu();

	return cookie;
}
EXPORT_SYMBOL(dma_async_memcpy_pg_to_pg);

void dma_async_tx_descriptor_init(struct dma_async_tx_descriptor *tx,
	struct dma_chan *chan)
{
	tx->chan = chan;
	spin_lock_init(&tx->lock);
	INIT_LIST_HEAD(&tx->depend_node);
	INIT_LIST_HEAD(&tx->depend_list);
}
EXPORT_SYMBOL(dma_async_tx_descriptor_init);

static int __init dma_bus_init(void)
{
	mutex_init(&dma_list_mutex);
	return class_register(&dma_devclass);
}
subsys_initcall(dma_bus_init);