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 
17 static int jumbo_frm(void *p, struct sk_buff *skb, int csum)
18 {
19 	struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)p;
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_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 
94 static 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 
104 static void refill_desc3(void *priv_ptr, struct dma_desc *p)
105 {
106 	struct stmmac_rx_queue *rx_q = priv_ptr;
107 	struct stmmac_priv *priv = rx_q->priv_data;
108 
109 	/* Fill DES3 in case of RING mode */
110 	if (priv->dma_buf_sz == BUF_SIZE_16KiB)
111 		p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
112 }
113 
114 /* In ring mode we need to fill the desc3 because it is used as buffer */
115 static void init_desc3(struct dma_desc *p)
116 {
117 	p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
118 }
119 
120 static void clean_desc3(void *priv_ptr, struct dma_desc *p)
121 {
122 	struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)priv_ptr;
123 	struct stmmac_priv *priv = tx_q->priv_data;
124 	unsigned int entry = tx_q->dirty_tx;
125 
126 	/* des3 is only used for jumbo frames tx or time stamping */
127 	if (unlikely(tx_q->tx_skbuff_dma[entry].is_jumbo ||
128 		     (tx_q->tx_skbuff_dma[entry].last_segment &&
129 		      !priv->extend_desc && priv->hwts_tx_en)))
130 		p->des3 = 0;
131 }
132 
133 static int set_16kib_bfsize(int mtu)
134 {
135 	int ret = 0;
136 	if (unlikely(mtu > BUF_SIZE_8KiB))
137 		ret = BUF_SIZE_16KiB;
138 	return ret;
139 }
140 
141 const struct stmmac_mode_ops ring_mode_ops = {
142 	.is_jumbo_frm = is_jumbo_frm,
143 	.jumbo_frm = jumbo_frm,
144 	.refill_desc3 = refill_desc3,
145 	.init_desc3 = init_desc3,
146 	.clean_desc3 = clean_desc3,
147 	.set_16kib_bfsize = set_16kib_bfsize,
148 };
149