1/*******************************************************************************
2  Specialised functions for managing Chained 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 = priv->dma_tx + entry;
37	unsigned int nopaged_len = skb_headlen(skb);
38	unsigned int bmax;
39	unsigned int i = 1, len;
40
41	if (priv->plat->enh_desc)
42		bmax = BUF_SIZE_8KiB;
43	else
44		bmax = BUF_SIZE_2KiB;
45
46	len = nopaged_len - bmax;
47
48	desc->des2 = dma_map_single(priv->device, skb->data,
49				    bmax, DMA_TO_DEVICE);
50	if (dma_mapping_error(priv->device, desc->des2))
51		return -1;
52	priv->tx_skbuff_dma[entry].buf = desc->des2;
53	priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum, STMMAC_CHAIN_MODE);
54
55	while (len != 0) {
56		priv->tx_skbuff[entry] = NULL;
57		entry = (++priv->cur_tx) % txsize;
58		desc = priv->dma_tx + entry;
59
60		if (len > bmax) {
61			desc->des2 = dma_map_single(priv->device,
62						    (skb->data + bmax * i),
63						    bmax, DMA_TO_DEVICE);
64			if (dma_mapping_error(priv->device, desc->des2))
65				return -1;
66			priv->tx_skbuff_dma[entry].buf = desc->des2;
67			priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
68							STMMAC_CHAIN_MODE);
69			priv->hw->desc->set_tx_owner(desc);
70			len -= bmax;
71			i++;
72		} else {
73			desc->des2 = dma_map_single(priv->device,
74						    (skb->data + bmax * i), len,
75						    DMA_TO_DEVICE);
76			if (dma_mapping_error(priv->device, desc->des2))
77				return -1;
78			priv->tx_skbuff_dma[entry].buf = desc->des2;
79			priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
80							STMMAC_CHAIN_MODE);
81			priv->hw->desc->set_tx_owner(desc);
82			len = 0;
83		}
84	}
85	return entry;
86}
87
88static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc)
89{
90	unsigned int ret = 0;
91
92	if ((enh_desc && (len > BUF_SIZE_8KiB)) ||
93	    (!enh_desc && (len > BUF_SIZE_2KiB))) {
94		ret = 1;
95	}
96
97	return ret;
98}
99
100static void stmmac_init_dma_chain(void *des, dma_addr_t phy_addr,
101				  unsigned int size, unsigned int extend_desc)
102{
103	/*
104	 * In chained mode the des3 points to the next element in the ring.
105	 * The latest element has to point to the head.
106	 */
107	int i;
108	dma_addr_t dma_phy = phy_addr;
109
110	if (extend_desc) {
111		struct dma_extended_desc *p = (struct dma_extended_desc *)des;
112		for (i = 0; i < (size - 1); i++) {
113			dma_phy += sizeof(struct dma_extended_desc);
114			p->basic.des3 = (unsigned int)dma_phy;
115			p++;
116		}
117		p->basic.des3 = (unsigned int)phy_addr;
118
119	} else {
120		struct dma_desc *p = (struct dma_desc *)des;
121		for (i = 0; i < (size - 1); i++) {
122			dma_phy += sizeof(struct dma_desc);
123			p->des3 = (unsigned int)dma_phy;
124			p++;
125		}
126		p->des3 = (unsigned int)phy_addr;
127	}
128}
129
130static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p)
131{
132	struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
133
134	if (priv->hwts_rx_en && !priv->extend_desc)
135		/* NOTE: Device will overwrite des3 with timestamp value if
136		 * 1588-2002 time stamping is enabled, hence reinitialize it
137		 * to keep explicit chaining in the descriptor.
138		 */
139		p->des3 = (unsigned int)(priv->dma_rx_phy +
140					 (((priv->dirty_rx) + 1) %
141					  priv->dma_rx_size) *
142					 sizeof(struct dma_desc));
143}
144
145static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
146{
147	struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
148
149	if (priv->hw->desc->get_tx_ls(p) && !priv->extend_desc)
150		/* NOTE: Device will overwrite des3 with timestamp value if
151		 * 1588-2002 time stamping is enabled, hence reinitialize it
152		 * to keep explicit chaining in the descriptor.
153		 */
154		p->des3 = (unsigned int)(priv->dma_tx_phy +
155					 (((priv->dirty_tx + 1) %
156					   priv->dma_tx_size) *
157					  sizeof(struct dma_desc)));
158}
159
160const struct stmmac_mode_ops chain_mode_ops = {
161	.init = stmmac_init_dma_chain,
162	.is_jumbo_frm = stmmac_is_jumbo_frm,
163	.jumbo_frm = stmmac_jumbo_frm,
164	.refill_desc3 = stmmac_refill_desc3,
165	.clean_desc3 = stmmac_clean_desc3,
166};
167