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 The full GNU General Public License is included in this distribution in 20 the file called "COPYING". 21 22 Author: Giuseppe Cavallaro <peppe.cavallaro@st.com> 23 *******************************************************************************/ 24 25 #include "stmmac.h" 26 27 static int jumbo_frm(void *p, struct sk_buff *skb, int csum) 28 { 29 struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)p; 30 unsigned int nopaged_len = skb_headlen(skb); 31 struct stmmac_priv *priv = tx_q->priv_data; 32 unsigned int entry = tx_q->cur_tx; 33 unsigned int bmax, des2; 34 unsigned int i = 1, len; 35 struct dma_desc *desc; 36 37 desc = tx_q->dma_tx + entry; 38 39 if (priv->plat->enh_desc) 40 bmax = BUF_SIZE_8KiB; 41 else 42 bmax = BUF_SIZE_2KiB; 43 44 len = nopaged_len - bmax; 45 46 des2 = dma_map_single(priv->device, skb->data, 47 bmax, DMA_TO_DEVICE); 48 desc->des2 = cpu_to_le32(des2); 49 if (dma_mapping_error(priv->device, des2)) 50 return -1; 51 tx_q->tx_skbuff_dma[entry].buf = des2; 52 tx_q->tx_skbuff_dma[entry].len = bmax; 53 /* do not close the descriptor and do not set own bit */ 54 stmmac_prepare_tx_desc(priv, desc, 1, bmax, csum, STMMAC_CHAIN_MODE, 55 0, false, skb->len); 56 57 while (len != 0) { 58 tx_q->tx_skbuff[entry] = NULL; 59 entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE); 60 desc = tx_q->dma_tx + entry; 61 62 if (len > bmax) { 63 des2 = dma_map_single(priv->device, 64 (skb->data + bmax * i), 65 bmax, DMA_TO_DEVICE); 66 desc->des2 = cpu_to_le32(des2); 67 if (dma_mapping_error(priv->device, des2)) 68 return -1; 69 tx_q->tx_skbuff_dma[entry].buf = des2; 70 tx_q->tx_skbuff_dma[entry].len = bmax; 71 stmmac_prepare_tx_desc(priv, desc, 0, bmax, csum, 72 STMMAC_CHAIN_MODE, 1, false, skb->len); 73 len -= bmax; 74 i++; 75 } else { 76 des2 = dma_map_single(priv->device, 77 (skb->data + bmax * i), len, 78 DMA_TO_DEVICE); 79 desc->des2 = cpu_to_le32(des2); 80 if (dma_mapping_error(priv->device, des2)) 81 return -1; 82 tx_q->tx_skbuff_dma[entry].buf = des2; 83 tx_q->tx_skbuff_dma[entry].len = len; 84 /* last descriptor can be set now */ 85 stmmac_prepare_tx_desc(priv, desc, 0, len, csum, 86 STMMAC_CHAIN_MODE, 1, true, skb->len); 87 len = 0; 88 } 89 } 90 91 tx_q->cur_tx = entry; 92 93 return entry; 94 } 95 96 static unsigned int is_jumbo_frm(int len, int enh_desc) 97 { 98 unsigned int ret = 0; 99 100 if ((enh_desc && (len > BUF_SIZE_8KiB)) || 101 (!enh_desc && (len > BUF_SIZE_2KiB))) { 102 ret = 1; 103 } 104 105 return ret; 106 } 107 108 static void init_dma_chain(void *des, dma_addr_t phy_addr, 109 unsigned int size, unsigned int extend_desc) 110 { 111 /* 112 * In chained mode the des3 points to the next element in the ring. 113 * The latest element has to point to the head. 114 */ 115 int i; 116 dma_addr_t dma_phy = phy_addr; 117 118 if (extend_desc) { 119 struct dma_extended_desc *p = (struct dma_extended_desc *)des; 120 for (i = 0; i < (size - 1); i++) { 121 dma_phy += sizeof(struct dma_extended_desc); 122 p->basic.des3 = cpu_to_le32((unsigned int)dma_phy); 123 p++; 124 } 125 p->basic.des3 = cpu_to_le32((unsigned int)phy_addr); 126 127 } else { 128 struct dma_desc *p = (struct dma_desc *)des; 129 for (i = 0; i < (size - 1); i++) { 130 dma_phy += sizeof(struct dma_desc); 131 p->des3 = cpu_to_le32((unsigned int)dma_phy); 132 p++; 133 } 134 p->des3 = cpu_to_le32((unsigned int)phy_addr); 135 } 136 } 137 138 static void refill_desc3(void *priv_ptr, struct dma_desc *p) 139 { 140 struct stmmac_rx_queue *rx_q = (struct stmmac_rx_queue *)priv_ptr; 141 struct stmmac_priv *priv = rx_q->priv_data; 142 143 if (priv->hwts_rx_en && !priv->extend_desc) 144 /* NOTE: Device will overwrite des3 with timestamp value if 145 * 1588-2002 time stamping is enabled, hence reinitialize it 146 * to keep explicit chaining in the descriptor. 147 */ 148 p->des3 = cpu_to_le32((unsigned int)(rx_q->dma_rx_phy + 149 (((rx_q->dirty_rx) + 1) % 150 DMA_RX_SIZE) * 151 sizeof(struct dma_desc))); 152 } 153 154 static void clean_desc3(void *priv_ptr, struct dma_desc *p) 155 { 156 struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)priv_ptr; 157 struct stmmac_priv *priv = tx_q->priv_data; 158 unsigned int entry = tx_q->dirty_tx; 159 160 if (tx_q->tx_skbuff_dma[entry].last_segment && !priv->extend_desc && 161 priv->hwts_tx_en) 162 /* NOTE: Device will overwrite des3 with timestamp value if 163 * 1588-2002 time stamping is enabled, hence reinitialize it 164 * to keep explicit chaining in the descriptor. 165 */ 166 p->des3 = cpu_to_le32((unsigned int)((tx_q->dma_tx_phy + 167 ((tx_q->dirty_tx + 1) % DMA_TX_SIZE)) 168 * sizeof(struct dma_desc))); 169 } 170 171 const struct stmmac_mode_ops chain_mode_ops = { 172 .init = init_dma_chain, 173 .is_jumbo_frm = is_jumbo_frm, 174 .jumbo_frm = jumbo_frm, 175 .refill_desc3 = refill_desc3, 176 .clean_desc3 = clean_desc3, 177 }; 178