drivers/dma/dmaengine.h

Source file repositories/reference/linux-study-clean/drivers/dma/dmaengine.h

File Facts

System
Linux kernel
Corpus path
drivers/dma/dmaengine.h
Extension
.h
Size
5350 bytes
Lines
202
Domain
Driver Families
Bucket
drivers/dma
Inferred role
Driver Families: implementation source
Status
source 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

struct dmaengine_desc_callback {
	dma_async_tx_callback callback;
	dma_async_tx_callback_result callback_result;
	void *callback_param;
};

/**
 * dmaengine_desc_get_callback - get the passed in callback function
 * @tx: tx descriptor
 * @cb: temp struct to hold the callback info
 *
 * Fill the passed in cb struct with what's available in the passed in
 * tx descriptor struct
 * No locking is required.
 */
static inline void
dmaengine_desc_get_callback(struct dma_async_tx_descriptor *tx,
			    struct dmaengine_desc_callback *cb)
{
	cb->callback = tx->callback;
	cb->callback_result = tx->callback_result;
	cb->callback_param = tx->callback_param;
}

/**
 * dmaengine_desc_callback_invoke - call the callback function in cb struct
 * @cb: temp struct that is holding the callback info
 * @result: transaction result
 *
 * Call the callback function provided in the cb struct with the parameter
 * in the cb struct.
 * Locking is dependent on the driver.
 */
static inline void
dmaengine_desc_callback_invoke(struct dmaengine_desc_callback *cb,
			       const struct dmaengine_result *result)
{
	struct dmaengine_result dummy_result = {
		.result = DMA_TRANS_NOERROR,
		.residue = 0
	};

	if (cb->callback_result) {
		if (!result)
			result = &dummy_result;
		cb->callback_result(cb->callback_param, result);
	} else if (cb->callback) {
		cb->callback(cb->callback_param);
	}
}

/**
 * dmaengine_desc_get_callback_invoke - get the callback in tx descriptor and
 * 					then immediately call the callback.
 * @tx: dma async tx descriptor
 * @result: transaction result
 *
 * Call dmaengine_desc_get_callback() and dmaengine_desc_callback_invoke()
 * in a single function since no work is necessary in between for the driver.
 * Locking is dependent on the driver.
 */
static inline void
dmaengine_desc_get_callback_invoke(struct dma_async_tx_descriptor *tx,
				   const struct dmaengine_result *result)
{
	struct dmaengine_desc_callback cb;

	dmaengine_desc_get_callback(tx, &cb);
	dmaengine_desc_callback_invoke(&cb, result);
}

/**
 * dmaengine_desc_callback_valid - verify the callback is valid in cb
 * @cb: callback info struct
 *
 * Return a bool that verifies whether callback in cb is valid or not.
 * No locking is required.
 */
static inline bool
dmaengine_desc_callback_valid(struct dmaengine_desc_callback *cb)
{
	return cb->callback || cb->callback_result;
}

struct dma_chan *dma_get_slave_channel(struct dma_chan *chan);
struct dma_chan *dma_get_any_slave_channel(struct dma_device *device);

#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>

Annotation

Implementation Notes