int dma_async_device_register()

in dmaengine.c [1139:1307]

• 127 lines of code
• 35 McCabe index (conditional complexity)

int dma_async_device_register(struct dma_device *device)
{
	int rc;
	struct dma_chan* chan;

	if (!device)
		return -ENODEV;

	/* validate device routines */
	if (!device->dev) {
		pr_err("DMAdevice must have dev\n");
		return -EIO;
	}

	device->owner = device->dev->driver->owner;

	if (dma_has_cap(DMA_MEMCPY, device->cap_mask) && !device->device_prep_dma_memcpy) {
		dev_err(device->dev,
			"Device claims capability %s, but op is not defined\n",
			"DMA_MEMCPY");
		return -EIO;
	}

	if (dma_has_cap(DMA_MEMCPY_SG, device->cap_mask) && !device->device_prep_dma_memcpy_sg) {
		dev_err(device->dev,
			"Device claims capability %s, but op is not defined\n",
			"DMA_MEMCPY_SG");
		return -EIO;
	}

	if (dma_has_cap(DMA_XOR, device->cap_mask) && !device->device_prep_dma_xor) {
		dev_err(device->dev,
			"Device claims capability %s, but op is not defined\n",
			"DMA_XOR");
		return -EIO;
	}

	if (dma_has_cap(DMA_XOR_VAL, device->cap_mask) && !device->device_prep_dma_xor_val) {
		dev_err(device->dev,
			"Device claims capability %s, but op is not defined\n",
			"DMA_XOR_VAL");
		return -EIO;
	}

	if (dma_has_cap(DMA_PQ, device->cap_mask) && !device->device_prep_dma_pq) {
		dev_err(device->dev,
			"Device claims capability %s, but op is not defined\n",
			"DMA_PQ");
		return -EIO;
	}

	if (dma_has_cap(DMA_PQ_VAL, device->cap_mask) && !device->device_prep_dma_pq_val) {
		dev_err(device->dev,
			"Device claims capability %s, but op is not defined\n",
			"DMA_PQ_VAL");
		return -EIO;
	}

	if (dma_has_cap(DMA_MEMSET, device->cap_mask) && !device->device_prep_dma_memset) {
		dev_err(device->dev,
			"Device claims capability %s, but op is not defined\n",
			"DMA_MEMSET");
		return -EIO;
	}

	if (dma_has_cap(DMA_INTERRUPT, device->cap_mask) && !device->device_prep_dma_interrupt) {
		dev_err(device->dev,
			"Device claims capability %s, but op is not defined\n",
			"DMA_INTERRUPT");
		return -EIO;
	}

	if (dma_has_cap(DMA_CYCLIC, device->cap_mask) && !device->device_prep_dma_cyclic) {
		dev_err(device->dev,
			"Device claims capability %s, but op is not defined\n",
			"DMA_CYCLIC");
		return -EIO;
	}

	if (dma_has_cap(DMA_INTERLEAVE, device->cap_mask) && !device->device_prep_interleaved_dma) {
		dev_err(device->dev,
			"Device claims capability %s, but op is not defined\n",
			"DMA_INTERLEAVE");
		return -EIO;
	}


	if (!device->device_tx_status) {
		dev_err(device->dev, "Device tx_status is not defined\n");
		return -EIO;
	}


	if (!device->device_issue_pending) {
		dev_err(device->dev, "Device issue_pending is not defined\n");
		return -EIO;
	}

	if (!device->device_release)
		dev_dbg(device->dev,
			 "WARN: Device release is not defined so it is not safe to unbind this driver while in use\n");

	kref_init(&device->ref);

	/* note: this only matters in the
	 * CONFIG_ASYNC_TX_ENABLE_CHANNEL_SWITCH=n case
	 */
	if (device_has_all_tx_types(device))
		dma_cap_set(DMA_ASYNC_TX, device->cap_mask);

	rc = get_dma_id(device);
	if (rc != 0)
		return rc;

	mutex_init(&device->chan_mutex);
	ida_init(&device->chan_ida);

	/* represent channels in sysfs. Probably want devs too */
	list_for_each_entry(chan, &device->channels, device_node) {
		rc = __dma_async_device_channel_register(device, chan);
		if (rc < 0)
			goto err_out;
	}

	mutex_lock(&dma_list_mutex);
	/* take references on public channels */
	if (dmaengine_ref_count && !dma_has_cap(DMA_PRIVATE, device->cap_mask))
		list_for_each_entry(chan, &device->channels, device_node) {
			/* if clients are already waiting for channels we need
			 * to take references on their behalf
			 */
			if (dma_chan_get(chan) == -ENODEV) {
				/* note we can only get here for the first
				 * channel as the remaining channels are
				 * guaranteed to get a reference
				 */
				rc = -ENODEV;
				mutex_unlock(&dma_list_mutex);
				goto err_out;
			}
		}
	list_add_tail_rcu(&device->global_node, &dma_device_list);
	if (dma_has_cap(DMA_PRIVATE, device->cap_mask))
		device->privatecnt++;	/* Always private */
	dma_channel_rebalance();
	mutex_unlock(&dma_list_mutex);

	dmaengine_debug_register(device);

	return 0;

err_out:
	/* if we never registered a channel just release the idr */
	if (!device->chancnt) {
		ida_free(&dma_ida, device->dev_id);
		return rc;
	}

	list_for_each_entry(chan, &device->channels, device_node) {
		if (chan->local == NULL)
			continue;
		mutex_lock(&dma_list_mutex);
		chan->dev->chan = NULL;
		mutex_unlock(&dma_list_mutex);
		device_unregister(&chan->dev->device);
		free_percpu(chan->local);
	}
	return rc;
}