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 stmmac_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 priv->hw->desc->prepare_tx_desc(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 priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum, 72 STMMAC_CHAIN_MODE, 1, 73 false, skb->len); 74 len -= bmax; 75 i++; 76 } else { 77 des2 = dma_map_single(priv->device, 78 (skb->data + bmax * i), len, 79 DMA_TO_DEVICE); 80 desc->des2 = cpu_to_le32(des2); 81 if (dma_mapping_error(priv->device, des2)) 82 return -1; 83 tx_q->tx_skbuff_dma[entry].buf = des2; 84 tx_q->tx_skbuff_dma[entry].len = len; 85 /* last descriptor can be set now */ 86 priv->hw->desc->prepare_tx_desc(desc, 0, len, csum, 87 STMMAC_CHAIN_MODE, 1, 88 true, skb->len); 89 len = 0; 90 } 91 } 92 93 tx_q->cur_tx = entry; 94 95 return entry; 96 } 97 98 static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc) 99 { 100 unsigned int ret = 0; 101 102 if ((enh_desc && (len > BUF_SIZE_8KiB)) || 103 (!enh_desc && (len > BUF_SIZE_2KiB))) { 104 ret = 1; 105 } 106 107 return ret; 108 } 109 110 static void stmmac_init_dma_chain(void *des, dma_addr_t phy_addr, 111 unsigned int size, unsigned int extend_desc) 112 { 113 /* 114 * In chained mode the des3 points to the next element in the ring. 115 * The latest element has to point to the head. 116 */ 117 int i; 118 dma_addr_t dma_phy = phy_addr; 119 120 if (extend_desc) { 121 struct dma_extended_desc *p = (struct dma_extended_desc *)des; 122 for (i = 0; i < (size - 1); i++) { 123 dma_phy += sizeof(struct dma_extended_desc); 124 p->basic.des3 = cpu_to_le32((unsigned int)dma_phy); 125 p++; 126 } 127 p->basic.des3 = cpu_to_le32((unsigned int)phy_addr); 128 129 } else { 130 struct dma_desc *p = (struct dma_desc *)des; 131 for (i = 0; i < (size - 1); i++) { 132 dma_phy += sizeof(struct dma_desc); 133 p->des3 = cpu_to_le32((unsigned int)dma_phy); 134 p++; 135 } 136 p->des3 = cpu_to_le32((unsigned int)phy_addr); 137 } 138 } 139 140 static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p) 141 { 142 struct stmmac_rx_queue *rx_q = (struct stmmac_rx_queue *)priv_ptr; 143 struct stmmac_priv *priv = rx_q->priv_data; 144 145 if (priv->hwts_rx_en && !priv->extend_desc) 146 /* NOTE: Device will overwrite des3 with timestamp value if 147 * 1588-2002 time stamping is enabled, hence reinitialize it 148 * to keep explicit chaining in the descriptor. 149 */ 150 p->des3 = cpu_to_le32((unsigned int)(rx_q->dma_rx_phy + 151 (((rx_q->dirty_rx) + 1) % 152 DMA_RX_SIZE) * 153 sizeof(struct dma_desc))); 154 } 155 156 static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p) 157 { 158 struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)priv_ptr; 159 struct stmmac_priv *priv = tx_q->priv_data; 160 unsigned int entry = tx_q->dirty_tx; 161 162 if (tx_q->tx_skbuff_dma[entry].last_segment && !priv->extend_desc && 163 priv->hwts_tx_en) 164 /* NOTE: Device will overwrite des3 with timestamp value if 165 * 1588-2002 time stamping is enabled, hence reinitialize it 166 * to keep explicit chaining in the descriptor. 167 */ 168 p->des3 = cpu_to_le32((unsigned int)((tx_q->dma_tx_phy + 169 ((tx_q->dirty_tx + 1) % DMA_TX_SIZE)) 170 * sizeof(struct dma_desc))); 171 } 172 173 const struct stmmac_mode_ops chain_mode_ops = { 174 .init = stmmac_init_dma_chain, 175 .is_jumbo_frm = stmmac_is_jumbo_frm, 176 .jumbo_frm = stmmac_jumbo_frm, 177 .refill_desc3 = stmmac_refill_desc3, 178 .clean_desc3 = stmmac_clean_desc3, 179 }; 180