1 /*******************************************************************************
2   Specialised functions for managing Ring mode
3 
4   Copyright(C) 2011  STMicroelectronics Ltd
5 
6   It defines all the functions used to handle the normal/enhanced
7   descriptors in case of the DMA is configured to work in chained or
8   in ring mode.
9 
10   This program is free software; you can redistribute it and/or modify it
11   under the terms and conditions of the GNU General Public License,
12   version 2, as published by the Free Software Foundation.
13 
14   This program is distributed in the hope it will be useful, but WITHOUT
15   ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
16   FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
17   more details.
18 
19   You should have received a copy of the GNU General Public License along with
20   this program; if not, write to the Free Software Foundation, Inc.,
21   51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
22 
23   The full GNU General Public License is included in this distribution in
24   the file called "COPYING".
25 
26   Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
27 *******************************************************************************/
28 
29 #include "stmmac.h"
30 
31 static unsigned int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
32 {
33 	struct stmmac_priv *priv = (struct stmmac_priv *)p;
34 	unsigned int txsize = priv->dma_tx_size;
35 	unsigned int entry = priv->cur_tx % txsize;
36 	struct dma_desc *desc;
37 	unsigned int nopaged_len = skb_headlen(skb);
38 	unsigned int bmax, len;
39 
40 	if (priv->extend_desc)
41 		desc = (struct dma_desc *)(priv->dma_etx + entry);
42 	else
43 		desc = priv->dma_tx + entry;
44 
45 	if (priv->plat->enh_desc)
46 		bmax = BUF_SIZE_8KiB;
47 	else
48 		bmax = BUF_SIZE_2KiB;
49 
50 	len = nopaged_len - bmax;
51 
52 	if (nopaged_len > BUF_SIZE_8KiB) {
53 
54 		desc->des2 = dma_map_single(priv->device, skb->data,
55 					    bmax, DMA_TO_DEVICE);
56 		priv->tx_skbuff_dma[entry] = desc->des2;
57 		desc->des3 = desc->des2 + BUF_SIZE_4KiB;
58 		priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum,
59 						STMMAC_RING_MODE);
60 		wmb();
61 		priv->tx_skbuff[entry] = NULL;
62 		entry = (++priv->cur_tx) % txsize;
63 
64 		if (priv->extend_desc)
65 			desc = (struct dma_desc *)(priv->dma_etx + entry);
66 		else
67 			desc = priv->dma_tx + entry;
68 
69 		desc->des2 = dma_map_single(priv->device, skb->data + bmax,
70 					    len, DMA_TO_DEVICE);
71 		priv->tx_skbuff_dma[entry] = desc->des2;
72 		desc->des3 = desc->des2 + BUF_SIZE_4KiB;
73 		priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
74 						STMMAC_RING_MODE);
75 		wmb();
76 		priv->hw->desc->set_tx_owner(desc);
77 	} else {
78 		desc->des2 = dma_map_single(priv->device, skb->data,
79 					    nopaged_len, DMA_TO_DEVICE);
80 		priv->tx_skbuff_dma[entry] = desc->des2;
81 		desc->des3 = desc->des2 + BUF_SIZE_4KiB;
82 		priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len, csum,
83 						STMMAC_RING_MODE);
84 	}
85 
86 	return entry;
87 }
88 
89 static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc)
90 {
91 	unsigned int ret = 0;
92 
93 	if (len >= BUF_SIZE_4KiB)
94 		ret = 1;
95 
96 	return ret;
97 }
98 
99 static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p)
100 {
101 	struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
102 
103 	/* Fill DES3 in case of RING mode */
104 	if (priv->dma_buf_sz >= BUF_SIZE_8KiB)
105 		p->des3 = p->des2 + BUF_SIZE_8KiB;
106 }
107 
108 /* In ring mode we need to fill the desc3 because it is used as buffer */
109 static void stmmac_init_desc3(struct dma_desc *p)
110 {
111 	p->des3 = p->des2 + BUF_SIZE_8KiB;
112 }
113 
114 static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
115 {
116 	if (unlikely(p->des3))
117 		p->des3 = 0;
118 }
119 
120 static int stmmac_set_16kib_bfsize(int mtu)
121 {
122 	int ret = 0;
123 	if (unlikely(mtu >= BUF_SIZE_8KiB))
124 		ret = BUF_SIZE_16KiB;
125 	return ret;
126 }
127 
128 const struct stmmac_mode_ops ring_mode_ops = {
129 	.is_jumbo_frm = stmmac_is_jumbo_frm,
130 	.jumbo_frm = stmmac_jumbo_frm,
131 	.refill_desc3 = stmmac_refill_desc3,
132 	.init_desc3 = stmmac_init_desc3,
133 	.clean_desc3 = stmmac_clean_desc3,
134 	.set_16kib_bfsize = stmmac_set_16kib_bfsize,
135 };
136