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 
31 static 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 
88 static 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 
100 static 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 
130 static 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 
145 static 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 
160 const 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