drivers/dma/of-dma.c

Source file repositories/reference/linux-study-clean/drivers/dma/of-dma.c

File Facts

System
Linux kernel
Corpus path
drivers/dma/of-dma.c
Extension
.c
Size
10543 bytes
Lines
372
Domain
Driver Families
Bucket
drivers/dma
Inferred role
Driver Families: exported/initcall integration point
Status
integration implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

if (ret) {
			dma_release_channel(chan);
			chan = ERR_PTR(ret);
		}
	}

err:
	/*
	 * Need to put the node back since the ofdma->of_dma_route_allocate
	 * has taken it for generating the new, translated dma_spec
	 */
	of_node_put(dma_spec_target.np);
	return chan;
}

/**
 * of_dma_controller_register - Register a DMA controller to DT DMA helpers
 * @np:			device node of DMA controller
 * @of_dma_xlate:	translation function which converts a phandle
 *			arguments list into a dma_chan structure
 * @data:		pointer to controller specific data to be used by
 *			translation function
 *
 * Returns 0 on success or appropriate errno value on error.
 *
 * Allocated memory should be freed with appropriate of_dma_controller_free()
 * call.
 */
int of_dma_controller_register(struct device_node *np,
				struct dma_chan *(*of_dma_xlate)
				(struct of_phandle_args *, struct of_dma *),
				void *data)
{
	struct of_dma	*ofdma;

	if (!np || !of_dma_xlate) {
		pr_err("%s: not enough information provided\n", __func__);
		return -EINVAL;
	}

	ofdma = kzalloc_obj(*ofdma);
	if (!ofdma)
		return -ENOMEM;

	ofdma->of_node = np;
	ofdma->of_dma_xlate = of_dma_xlate;
	ofdma->of_dma_data = data;

	/* Now queue of_dma controller structure in list */
	mutex_lock(&of_dma_lock);
	list_add_tail(&ofdma->of_dma_controllers, &of_dma_list);
	mutex_unlock(&of_dma_lock);

	return 0;
}
EXPORT_SYMBOL_GPL(of_dma_controller_register);

/**
 * of_dma_controller_free - Remove a DMA controller from DT DMA helpers list
 * @np:		device node of DMA controller
 *
 * Memory allocated by of_dma_controller_register() is freed here.
 */
void of_dma_controller_free(struct device_node *np)
{
	struct of_dma *ofdma;

	mutex_lock(&of_dma_lock);

	list_for_each_entry(ofdma, &of_dma_list, of_dma_controllers)
		if (ofdma->of_node == np) {
			list_del(&ofdma->of_dma_controllers);
			kfree(ofdma);
			break;
		}

	mutex_unlock(&of_dma_lock);
}
EXPORT_SYMBOL_GPL(of_dma_controller_free);

/**
 * of_dma_router_register - Register a DMA router to DT DMA helpers as a
 *			    controller
 * @np:				device node of DMA router
 * @of_dma_route_allocate:	setup function for the router which need to
 *				modify the dma_spec for the DMA controller to
 *				use and to set up the requested route.
 * @dma_router:			pointer to dma_router structure to be used when
 *				the route need to be free up.
 *

Annotation

Implementation Notes