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
31static 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		if (dma_mapping_error(priv->device, desc->des2))
57			return -1;
58
59		priv->tx_skbuff_dma[entry].buf = desc->des2;
60		desc->des3 = desc->des2 + BUF_SIZE_4KiB;
61		priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum,
62						STMMAC_RING_MODE);
63		wmb();
64		priv->tx_skbuff[entry] = NULL;
65		entry = (++priv->cur_tx) % txsize;
66
67		if (priv->extend_desc)
68			desc = (struct dma_desc *)(priv->dma_etx + entry);
69		else
70			desc = priv->dma_tx + entry;
71
72		desc->des2 = dma_map_single(priv->device, skb->data + bmax,
73					    len, DMA_TO_DEVICE);
74		if (dma_mapping_error(priv->device, desc->des2))
75			return -1;
76		priv->tx_skbuff_dma[entry].buf = desc->des2;
77		desc->des3 = desc->des2 + BUF_SIZE_4KiB;
78		priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
79						STMMAC_RING_MODE);
80		wmb();
81		priv->hw->desc->set_tx_owner(desc);
82	} else {
83		desc->des2 = dma_map_single(priv->device, skb->data,
84					    nopaged_len, DMA_TO_DEVICE);
85		if (dma_mapping_error(priv->device, desc->des2))
86			return -1;
87		priv->tx_skbuff_dma[entry].buf = desc->des2;
88		desc->des3 = desc->des2 + BUF_SIZE_4KiB;
89		priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len, csum,
90						STMMAC_RING_MODE);
91	}
92
93	return entry;
94}
95
96static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc)
97{
98	unsigned int ret = 0;
99
100	if (len >= BUF_SIZE_4KiB)
101		ret = 1;
102
103	return ret;
104}
105
106static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p)
107{
108	struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
109
110	/* Fill DES3 in case of RING mode */
111	if (priv->dma_buf_sz >= BUF_SIZE_8KiB)
112		p->des3 = p->des2 + BUF_SIZE_8KiB;
113}
114
115/* In ring mode we need to fill the desc3 because it is used as buffer */
116static void stmmac_init_desc3(struct dma_desc *p)
117{
118	p->des3 = p->des2 + BUF_SIZE_8KiB;
119}
120
121static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
122{
123	if (unlikely(p->des3))
124		p->des3 = 0;
125}
126
127static int stmmac_set_16kib_bfsize(int mtu)
128{
129	int ret = 0;
130	if (unlikely(mtu >= BUF_SIZE_8KiB))
131		ret = BUF_SIZE_16KiB;
132	return ret;
133}
134
135const struct stmmac_mode_ops ring_mode_ops = {
136	.is_jumbo_frm = stmmac_is_jumbo_frm,
137	.jumbo_frm = stmmac_jumbo_frm,
138	.refill_desc3 = stmmac_refill_desc3,
139	.init_desc3 = stmmac_init_desc3,
140	.clean_desc3 = stmmac_clean_desc3,
141	.set_16kib_bfsize = stmmac_set_16kib_bfsize,
142};
143