drivers/dma/uniphier-xdmac.c

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

File Facts

System
Linux kernel
Corpus path
drivers/dma/uniphier-xdmac.c
Extension
.c
Size
16394 bytes
Lines
617
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 uniphier_xdmac_desc_node {
	dma_addr_t src;
	dma_addr_t dst;
	u32 burst_size;
	u32 nr_burst;
};

struct uniphier_xdmac_desc {
	struct virt_dma_desc vd;

	unsigned int nr_node;
	unsigned int cur_node;
	enum dma_transfer_direction dir;
	struct uniphier_xdmac_desc_node nodes[] __counted_by(nr_node);
};

struct uniphier_xdmac_chan {
	struct virt_dma_chan vc;
	struct uniphier_xdmac_device *xdev;
	struct uniphier_xdmac_desc *xd;
	void __iomem *reg_ch_base;
	struct dma_slave_config	sconfig;
	int id;
	unsigned int req_factor;
};

struct uniphier_xdmac_device {
	struct dma_device ddev;
	void __iomem *reg_base;
	int nr_chans;
	struct uniphier_xdmac_chan channels[] __counted_by(nr_chans);
};

static struct uniphier_xdmac_chan *
to_uniphier_xdmac_chan(struct virt_dma_chan *vc)
{
	return container_of(vc, struct uniphier_xdmac_chan, vc);
}

static struct uniphier_xdmac_desc *
to_uniphier_xdmac_desc(struct virt_dma_desc *vd)
{
	return container_of(vd, struct uniphier_xdmac_desc, vd);
}

/* xc->vc.lock must be held by caller */
static struct uniphier_xdmac_desc *
uniphier_xdmac_next_desc(struct uniphier_xdmac_chan *xc)
{
	struct virt_dma_desc *vd;

	vd = vchan_next_desc(&xc->vc);
	if (!vd)
		return NULL;

	list_del(&vd->node);

	return to_uniphier_xdmac_desc(vd);
}

/* xc->vc.lock must be held by caller */
static void uniphier_xdmac_chan_start(struct uniphier_xdmac_chan *xc,
				      struct uniphier_xdmac_desc *xd)
{
	u32 src_mode, src_width;
	u32 dst_mode, dst_width;
	dma_addr_t src_addr, dst_addr;
	u32 val, its, tnum;
	enum dma_slave_buswidth buswidth;

	src_addr = xd->nodes[xd->cur_node].src;
	dst_addr = xd->nodes[xd->cur_node].dst;
	its      = xd->nodes[xd->cur_node].burst_size;
	tnum     = xd->nodes[xd->cur_node].nr_burst;

	/*
	 * The width of MEM side must be 4 or 8 bytes, that does not
	 * affect that of DEV side and transfer size.
	 */
	if (xd->dir == DMA_DEV_TO_MEM) {
		src_mode = XDMAC_SADM_SAM_FIXED;
		buswidth = xc->sconfig.src_addr_width;
	} else {
		src_mode = XDMAC_SADM_SAM_INC;
		buswidth = DMA_SLAVE_BUSWIDTH_8_BYTES;
	}
	src_width = FIELD_PREP(XDMAC_SADM_STW_MASK, __ffs(buswidth));

	if (xd->dir == DMA_MEM_TO_DEV) {
		dst_mode = XDMAC_DADM_DAM_FIXED;

Annotation

Implementation Notes