drivers/net/ethernet/sfc/tx.c

Source file repositories/reference/linux-study-clean/drivers/net/ethernet/sfc/tx.c

File Facts

System
Linux kernel
Corpus path
drivers/net/ethernet/sfc/tx.c
Extension
.c
Size
17264 bytes
Lines
601
Domain
Driver Families
Bucket
drivers/net
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 efx_short_copy_buffer {
	int used;
	u8 buf[L1_CACHE_BYTES];
};

/* Copy to PIO, respecting that writes to PIO buffers must be dword aligned.
 * Advances piobuf pointer. Leaves additional data in the copy buffer.
 */
static void efx_memcpy_toio_aligned(struct efx_nic *efx, u8 __iomem **piobuf,
				    u8 *data, int len,
				    struct efx_short_copy_buffer *copy_buf)
{
	int block_len = len & ~(sizeof(copy_buf->buf) - 1);

	__iowrite64_copy(*piobuf, data, block_len >> 3);
	*piobuf += block_len;
	len -= block_len;

	if (len) {
		data += block_len;
		BUG_ON(copy_buf->used);
		BUG_ON(len > sizeof(copy_buf->buf));
		memcpy(copy_buf->buf, data, len);
		copy_buf->used = len;
	}
}

/* Copy to PIO, respecting dword alignment, popping data from copy buffer first.
 * Advances piobuf pointer. Leaves additional data in the copy buffer.
 */
static void efx_memcpy_toio_aligned_cb(struct efx_nic *efx, u8 __iomem **piobuf,
				       u8 *data, int len,
				       struct efx_short_copy_buffer *copy_buf)
{
	if (copy_buf->used) {
		/* if the copy buffer is partially full, fill it up and write */
		int copy_to_buf =
			min_t(int, sizeof(copy_buf->buf) - copy_buf->used, len);

		memcpy(copy_buf->buf + copy_buf->used, data, copy_to_buf);
		copy_buf->used += copy_to_buf;

		/* if we didn't fill it up then we're done for now */
		if (copy_buf->used < sizeof(copy_buf->buf))
			return;

		__iowrite64_copy(*piobuf, copy_buf->buf,
				 sizeof(copy_buf->buf) >> 3);
		*piobuf += sizeof(copy_buf->buf);
		data += copy_to_buf;
		len -= copy_to_buf;
		copy_buf->used = 0;
	}

	efx_memcpy_toio_aligned(efx, piobuf, data, len, copy_buf);
}

static void efx_flush_copy_buffer(struct efx_nic *efx, u8 __iomem *piobuf,
				  struct efx_short_copy_buffer *copy_buf)
{
	/* if there's anything in it, write the whole buffer, including junk */
	if (copy_buf->used)
		__iowrite64_copy(piobuf, copy_buf->buf,
				 sizeof(copy_buf->buf) >> 3);
}

/* Traverse skb structure and copy fragments in to PIO buffer.
 * Advances piobuf pointer.
 */
static void efx_skb_copy_bits_to_pio(struct efx_nic *efx, struct sk_buff *skb,
				     u8 __iomem **piobuf,
				     struct efx_short_copy_buffer *copy_buf)
{
	int i;

	efx_memcpy_toio_aligned(efx, piobuf, skb->data, skb_headlen(skb),
				copy_buf);

	for (i = 0; i < skb_shinfo(skb)->nr_frags; ++i) {
		skb_frag_t *f = &skb_shinfo(skb)->frags[i];
		u8 *vaddr;

		vaddr = kmap_local_page(skb_frag_page(f));

		efx_memcpy_toio_aligned_cb(efx, piobuf, vaddr + skb_frag_off(f),
					   skb_frag_size(f), copy_buf);
		kunmap_local(vaddr);
	}

	EFX_WARN_ON_ONCE_PARANOID(skb_shinfo(skb)->frag_list);

Annotation

Implementation Notes