drivers/net/ethernet/stmicro/stmmac/ring_mode.c

Source file repositories/reference/linux-study-clean/drivers/net/ethernet/stmicro/stmmac/ring_mode.c

File Facts

System
Linux kernel
Corpus path
drivers/net/ethernet/stmicro/stmmac/ring_mode.c
Extension
.c
Size
4054 bytes
Lines
142
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

// SPDX-License-Identifier: GPL-2.0-only
/*******************************************************************************
  Specialised functions for managing Ring mode

  Copyright(C) 2011  STMicroelectronics Ltd

  It defines all the functions used to handle the normal/enhanced
  descriptors in case of the DMA is configured to work in chained or
  in ring mode.


  Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
*******************************************************************************/

#include "stmmac.h"

static int jumbo_frm(struct stmmac_tx_queue *tx_q, struct sk_buff *skb,
		     int csum)
{
	unsigned int nopaged_len = skb_headlen(skb);
	struct stmmac_priv *priv = tx_q->priv_data;
	unsigned int entry = tx_q->cur_tx;
	unsigned int bmax, len, des2;
	struct dma_desc *desc;

	if (priv->extend_desc)
		desc = (struct dma_desc *)(tx_q->dma_etx + entry);
	else
		desc = tx_q->dma_tx + entry;

	if (priv->plat->enh_desc)
		bmax = BUF_SIZE_8KiB;
	else
		bmax = BUF_SIZE_2KiB;

	len = nopaged_len - bmax;

	if (nopaged_len > BUF_SIZE_8KiB) {

		des2 = dma_map_single(priv->device, skb->data, bmax,
				      DMA_TO_DEVICE);
		desc->des2 = cpu_to_le32(des2);
		if (dma_mapping_error(priv->device, des2))
			return -1;

		tx_q->tx_skbuff_dma[entry].buf = des2;
		tx_q->tx_skbuff_dma[entry].len = bmax;
		tx_q->tx_skbuff_dma[entry].is_jumbo = true;

		desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
		stmmac_prepare_tx_desc(priv, desc, 1, bmax, csum,
				STMMAC_RING_MODE, 0, false, skb->len);
		tx_q->tx_skbuff[entry] = NULL;
		entry = STMMAC_NEXT_ENTRY(entry, priv->dma_conf.dma_tx_size);

		if (priv->extend_desc)
			desc = (struct dma_desc *)(tx_q->dma_etx + entry);
		else
			desc = tx_q->dma_tx + entry;

		des2 = dma_map_single(priv->device, skb->data + bmax, len,
				      DMA_TO_DEVICE);
		desc->des2 = cpu_to_le32(des2);
		if (dma_mapping_error(priv->device, des2))
			return -1;
		tx_q->tx_skbuff_dma[entry].buf = des2;
		tx_q->tx_skbuff_dma[entry].len = len;
		tx_q->tx_skbuff_dma[entry].is_jumbo = true;

		desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
		stmmac_prepare_tx_desc(priv, desc, 0, len, csum,
				STMMAC_RING_MODE, 1, !skb_is_nonlinear(skb),
				skb->len);
	} else {
		des2 = dma_map_single(priv->device, skb->data,
				      nopaged_len, DMA_TO_DEVICE);
		desc->des2 = cpu_to_le32(des2);
		if (dma_mapping_error(priv->device, des2))
			return -1;
		tx_q->tx_skbuff_dma[entry].buf = des2;
		tx_q->tx_skbuff_dma[entry].len = nopaged_len;
		tx_q->tx_skbuff_dma[entry].is_jumbo = true;
		desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
		stmmac_prepare_tx_desc(priv, desc, 1, nopaged_len, csum,
				STMMAC_RING_MODE, 0, !skb_is_nonlinear(skb),
				skb->len);
	}

	tx_q->cur_tx = entry;

Annotation

Implementation Notes