drivers/dma/virt-dma.h

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

File Facts

System
Linux kernel
Corpus path
drivers/dma/virt-dma.h
Extension
.h
Size
6214 bytes
Lines
238
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 virt_dma_desc {
	struct dma_async_tx_descriptor tx;
	struct dmaengine_result tx_result;
	/* protected by vc.lock */
	struct list_head node;
};

struct virt_dma_chan {
	struct dma_chan	chan;
	struct tasklet_struct task;
	void (*desc_free)(struct virt_dma_desc *);

	spinlock_t lock;

	/* protected by vc.lock */
	struct list_head desc_allocated;
	struct list_head desc_submitted;
	struct list_head desc_issued;
	struct list_head desc_completed;
	struct list_head desc_terminated;

	struct virt_dma_desc *cyclic;
};

static inline struct virt_dma_chan *to_virt_chan(struct dma_chan *chan)
{
	return container_of(chan, struct virt_dma_chan, chan);
}

void vchan_dma_desc_free_list(struct virt_dma_chan *vc, struct list_head *head);
void vchan_init(struct virt_dma_chan *vc, struct dma_device *dmadev);
struct virt_dma_desc *vchan_find_desc(struct virt_dma_chan *, dma_cookie_t);
extern dma_cookie_t vchan_tx_submit(struct dma_async_tx_descriptor *);
extern int vchan_tx_desc_free(struct dma_async_tx_descriptor *);

/**
 * vchan_tx_prep - prepare a descriptor
 * @vc: virtual channel allocating this descriptor
 * @vd: virtual descriptor to prepare
 * @tx_flags: flags argument passed in to prepare function
 */
static inline struct dma_async_tx_descriptor *vchan_tx_prep(struct virt_dma_chan *vc,
	struct virt_dma_desc *vd, unsigned long tx_flags)
{
	unsigned long flags;

	dma_async_tx_descriptor_init(&vd->tx, &vc->chan);
	vd->tx.flags = tx_flags;
	vd->tx.tx_submit = vchan_tx_submit;
	vd->tx.desc_free = vchan_tx_desc_free;

	vd->tx_result.result = DMA_TRANS_NOERROR;
	vd->tx_result.residue = 0;

	spin_lock_irqsave(&vc->lock, flags);
	list_add_tail(&vd->node, &vc->desc_allocated);
	spin_unlock_irqrestore(&vc->lock, flags);

	return &vd->tx;
}

/**
 * vchan_issue_pending - move submitted descriptors to issued list
 * @vc: virtual channel to update
 *
 * vc.lock must be held by caller
 */
static inline bool vchan_issue_pending(struct virt_dma_chan *vc)
{
	lockdep_assert_held(&vc->lock);

	list_splice_tail_init(&vc->desc_submitted, &vc->desc_issued);
	return !list_empty(&vc->desc_issued);
}

/**
 * vchan_cookie_complete - report completion of a descriptor
 * @vd: virtual descriptor to update
 *
 * vc.lock must be held by caller
 */
static inline void vchan_cookie_complete(struct virt_dma_desc *vd)
{
	struct virt_dma_chan *vc = to_virt_chan(vd->tx.chan);
	dma_cookie_t cookie;

	lockdep_assert_held(&vc->lock);

	cookie = vd->tx.cookie;
	dma_cookie_complete(&vd->tx);

Annotation

Implementation Notes