ring_mode.c

  1// SPDX-License-Identifier: GPL-2.0-only
  2/*******************************************************************************
  3  Specialised functions for managing Ring mode
  4
  5  Copyright(C) 2011  STMicroelectronics Ltd
  6
  7  It defines all the functions used to handle the normal/enhanced
  8  descriptors in case of the DMA is configured to work in chained or
  9  in ring mode.
 10
 11
 12  Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
 13*******************************************************************************/
 14
 15#include "stmmac.h"
 16
 17static int jumbo_frm(struct stmmac_tx_queue *tx_q, struct sk_buff *skb,
 18		     int csum)
 19{
 20	unsigned int nopaged_len = skb_headlen(skb);
 21	struct stmmac_priv *priv = tx_q->priv_data;
 22	unsigned int entry = tx_q->cur_tx;
 23	unsigned int bmax, len, des2;
 24	struct dma_desc *desc;
 25
 26	if (priv->extend_desc)
 27		desc = (struct dma_desc *)(tx_q->dma_etx + entry);
 28	else
 29		desc = tx_q->dma_tx + entry;
 30
 31	if (priv->plat->enh_desc)
 32		bmax = BUF_SIZE_8KiB;
 33	else
 34		bmax = BUF_SIZE_2KiB;
 35
 36	len = nopaged_len - bmax;
 37
 38	if (nopaged_len > BUF_SIZE_8KiB) {
 39
 40		des2 = dma_map_single(priv->device, skb->data, bmax,
 41				      DMA_TO_DEVICE);
 42		desc->des2 = cpu_to_le32(des2);
 43		if (dma_mapping_error(priv->device, des2))
 44			return -1;
 45
 46		tx_q->tx_skbuff_dma[entry].buf = des2;
 47		tx_q->tx_skbuff_dma[entry].len = bmax;
 48		tx_q->tx_skbuff_dma[entry].is_jumbo = true;
 49
 50		desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
 51		stmmac_prepare_tx_desc(priv, desc, 1, bmax, csum,
 52				STMMAC_RING_MODE, 0, false, skb->len);
 53		tx_q->tx_skbuff[entry] = NULL;
 54		entry = STMMAC_GET_ENTRY(entry, priv->dma_conf.dma_tx_size);
 55
 56		if (priv->extend_desc)
 57			desc = (struct dma_desc *)(tx_q->dma_etx + entry);
 58		else
 59			desc = tx_q->dma_tx + entry;
 60
 61		des2 = dma_map_single(priv->device, skb->data + bmax, len,
 62				      DMA_TO_DEVICE);
 63		desc->des2 = cpu_to_le32(des2);
 64		if (dma_mapping_error(priv->device, des2))
 65			return -1;
 66		tx_q->tx_skbuff_dma[entry].buf = des2;
 67		tx_q->tx_skbuff_dma[entry].len = len;
 68		tx_q->tx_skbuff_dma[entry].is_jumbo = true;
 69
 70		desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
 71		stmmac_prepare_tx_desc(priv, desc, 0, len, csum,
 72				STMMAC_RING_MODE, 1, !skb_is_nonlinear(skb),
 73				skb->len);
 74	} else {
 75		des2 = dma_map_single(priv->device, skb->data,
 76				      nopaged_len, DMA_TO_DEVICE);
 77		desc->des2 = cpu_to_le32(des2);
 78		if (dma_mapping_error(priv->device, des2))
 79			return -1;
 80		tx_q->tx_skbuff_dma[entry].buf = des2;
 81		tx_q->tx_skbuff_dma[entry].len = nopaged_len;
 82		tx_q->tx_skbuff_dma[entry].is_jumbo = true;
 83		desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
 84		stmmac_prepare_tx_desc(priv, desc, 1, nopaged_len, csum,
 85				STMMAC_RING_MODE, 0, !skb_is_nonlinear(skb),
 86				skb->len);
 87	}
 88
 89	tx_q->cur_tx = entry;
 90
 91	return entry;
 92}
 93
 94static bool is_jumbo_frm(unsigned int len, bool enh_desc)
 95{
 96	return len >= BUF_SIZE_4KiB;
 97}
 98
 99static void refill_desc3(struct stmmac_rx_queue *rx_q, struct dma_desc *p)
100{
101	struct stmmac_priv *priv = rx_q->priv_data;
102
103	/* Fill DES3 in case of RING mode */
104	if (priv->dma_conf.dma_buf_sz == BUF_SIZE_16KiB)
105		p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
106}
107
108/* In ring mode we need to fill the desc3 because it is used as buffer */
109static void init_desc3(struct dma_desc *p)
110{
111	p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
112}
113
114static void clean_desc3(struct stmmac_tx_queue *tx_q, struct dma_desc *p)
115{
116	struct stmmac_priv *priv = tx_q->priv_data;
117	unsigned int entry = tx_q->dirty_tx;
118
119	/* des3 is only used for jumbo frames tx or time stamping */
120	if (unlikely(tx_q->tx_skbuff_dma[entry].is_jumbo ||
121		     (tx_q->tx_skbuff_dma[entry].last_segment &&
122		      !priv->extend_desc && priv->hwts_tx_en)))
123		p->des3 = 0;
124}
125
126static int set_16kib_bfsize(int mtu)
127{
128	int ret = 0;
129	if (unlikely(mtu > BUF_SIZE_8KiB))
130		ret = BUF_SIZE_16KiB;
131	return ret;
132}
133
134const struct stmmac_mode_ops ring_mode_ops = {
135	.is_jumbo_frm = is_jumbo_frm,
136	.jumbo_frm = jumbo_frm,
137	.refill_desc3 = refill_desc3,
138	.init_desc3 = init_desc3,
139	.clean_desc3 = clean_desc3,
140	.set_16kib_bfsize = set_16kib_bfsize,
141};