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 unsigned int is_jumbo_frm(int len, int enh_desc)
95{
96	unsigned int ret = 0;
97
98	if (len >= BUF_SIZE_4KiB)
99		ret = 1;
100
101	return ret;
102}
103
104static void refill_desc3(struct stmmac_rx_queue *rx_q, struct dma_desc *p)
105{
106	struct stmmac_priv *priv = rx_q->priv_data;
107
108	/* Fill DES3 in case of RING mode */
109	if (priv->dma_conf.dma_buf_sz == BUF_SIZE_16KiB)
110		p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
111}
112
113/* In ring mode we need to fill the desc3 because it is used as buffer */
114static void init_desc3(struct dma_desc *p)
115{
116	p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
117}
118
119static void clean_desc3(struct stmmac_tx_queue *tx_q, struct dma_desc *p)
120{
121	struct stmmac_priv *priv = tx_q->priv_data;
122	unsigned int entry = tx_q->dirty_tx;
123
124	/* des3 is only used for jumbo frames tx or time stamping */
125	if (unlikely(tx_q->tx_skbuff_dma[entry].is_jumbo ||
126		     (tx_q->tx_skbuff_dma[entry].last_segment &&
127		      !priv->extend_desc && priv->hwts_tx_en)))
128		p->des3 = 0;
129}
130
131static int set_16kib_bfsize(int mtu)
132{
133	int ret = 0;
134	if (unlikely(mtu > BUF_SIZE_8KiB))
135		ret = BUF_SIZE_16KiB;
136	return ret;
137}
138
139const struct stmmac_mode_ops ring_mode_ops = {
140	.is_jumbo_frm = is_jumbo_frm,
141	.jumbo_frm = jumbo_frm,
142	.refill_desc3 = refill_desc3,
143	.init_desc3 = init_desc3,
144	.clean_desc3 = clean_desc3,
145	.set_16kib_bfsize = set_16kib_bfsize,
146};
147