1 // SPDX-License-Identifier: GPL-2.0-only 2 /******************************************************************************* 3 Specialised functions for managing Chained mode 4 5 Copyright(C) 2011 STMicroelectronics Ltd 6 7 It defines all the functions used to handle the normal/enhanced 8 descriptors in case of the DMA is configured to work in chained or 9 in ring mode. 10 11 12 Author: Giuseppe Cavallaro <peppe.cavallaro@st.com> 13 *******************************************************************************/ 14 15 #include "stmmac.h" 16 17 static int jumbo_frm(struct stmmac_tx_queue *tx_q, struct sk_buff *skb, 18 int csum) 19 { 20 unsigned int nopaged_len = skb_headlen(skb); 21 struct stmmac_priv *priv = tx_q->priv_data; 22 unsigned int entry = tx_q->cur_tx; 23 unsigned int bmax, des2; 24 unsigned int i = 1, len; 25 struct dma_desc *desc; 26 27 desc = tx_q->dma_tx + entry; 28 29 if (priv->plat->enh_desc) 30 bmax = BUF_SIZE_8KiB; 31 else 32 bmax = BUF_SIZE_2KiB; 33 34 len = nopaged_len - bmax; 35 36 des2 = dma_map_single(priv->device, skb->data, 37 bmax, DMA_TO_DEVICE); 38 desc->des2 = cpu_to_le32(des2); 39 if (dma_mapping_error(priv->device, des2)) 40 return -1; 41 tx_q->tx_skbuff_dma[entry].buf = des2; 42 tx_q->tx_skbuff_dma[entry].len = bmax; 43 /* do not close the descriptor and do not set own bit */ 44 stmmac_prepare_tx_desc(priv, desc, 1, bmax, csum, STMMAC_CHAIN_MODE, 45 0, false, skb->len); 46 47 while (len != 0) { 48 tx_q->tx_skbuff[entry] = NULL; 49 entry = STMMAC_GET_ENTRY(entry, priv->dma_conf.dma_tx_size); 50 desc = tx_q->dma_tx + entry; 51 52 if (len > bmax) { 53 des2 = dma_map_single(priv->device, 54 (skb->data + bmax * i), 55 bmax, DMA_TO_DEVICE); 56 desc->des2 = cpu_to_le32(des2); 57 if (dma_mapping_error(priv->device, des2)) 58 return -1; 59 tx_q->tx_skbuff_dma[entry].buf = des2; 60 tx_q->tx_skbuff_dma[entry].len = bmax; 61 stmmac_prepare_tx_desc(priv, desc, 0, bmax, csum, 62 STMMAC_CHAIN_MODE, 1, false, skb->len); 63 len -= bmax; 64 i++; 65 } else { 66 des2 = dma_map_single(priv->device, 67 (skb->data + bmax * i), len, 68 DMA_TO_DEVICE); 69 desc->des2 = cpu_to_le32(des2); 70 if (dma_mapping_error(priv->device, des2)) 71 return -1; 72 tx_q->tx_skbuff_dma[entry].buf = des2; 73 tx_q->tx_skbuff_dma[entry].len = len; 74 /* last descriptor can be set now */ 75 stmmac_prepare_tx_desc(priv, desc, 0, len, csum, 76 STMMAC_CHAIN_MODE, 1, true, skb->len); 77 len = 0; 78 } 79 } 80 81 tx_q->cur_tx = entry; 82 83 return entry; 84 } 85 86 static bool is_jumbo_frm(unsigned int len, bool enh_desc) 87 { 88 bool ret = false; 89 90 if ((enh_desc && (len > BUF_SIZE_8KiB)) || 91 (!enh_desc && (len > BUF_SIZE_2KiB))) 92 ret = true; 93 94 return ret; 95 } 96 97 static void init_dma_chain(void *des, dma_addr_t phy_addr, 98 unsigned int size, unsigned int extend_desc) 99 { 100 /* 101 * In chained mode the des3 points to the next element in the ring. 102 * The latest element has to point to the head. 103 */ 104 int i; 105 dma_addr_t dma_phy = phy_addr; 106 107 if (extend_desc) { 108 struct dma_extended_desc *p = (struct dma_extended_desc *)des; 109 for (i = 0; i < (size - 1); i++) { 110 dma_phy += sizeof(struct dma_extended_desc); 111 p->basic.des3 = cpu_to_le32((unsigned int)dma_phy); 112 p++; 113 } 114 p->basic.des3 = cpu_to_le32((unsigned int)phy_addr); 115 116 } else { 117 struct dma_desc *p = (struct dma_desc *)des; 118 for (i = 0; i < (size - 1); i++) { 119 dma_phy += sizeof(struct dma_desc); 120 p->des3 = cpu_to_le32((unsigned int)dma_phy); 121 p++; 122 } 123 p->des3 = cpu_to_le32((unsigned int)phy_addr); 124 } 125 } 126 127 static void refill_desc3(struct stmmac_rx_queue *rx_q, struct dma_desc *p) 128 { 129 struct stmmac_priv *priv = rx_q->priv_data; 130 131 if (priv->hwts_rx_en && !priv->extend_desc) 132 /* NOTE: Device will overwrite des3 with timestamp value if 133 * 1588-2002 time stamping is enabled, hence reinitialize it 134 * to keep explicit chaining in the descriptor. 135 */ 136 p->des3 = cpu_to_le32((unsigned int)(rx_q->dma_rx_phy + 137 (((rx_q->dirty_rx) + 1) % 138 priv->dma_conf.dma_rx_size) * 139 sizeof(struct dma_desc))); 140 } 141 142 static void clean_desc3(struct stmmac_tx_queue *tx_q, struct dma_desc *p) 143 { 144 struct stmmac_priv *priv = tx_q->priv_data; 145 unsigned int entry = tx_q->dirty_tx; 146 147 if (tx_q->tx_skbuff_dma[entry].last_segment && !priv->extend_desc && 148 priv->hwts_tx_en) 149 /* NOTE: Device will overwrite des3 with timestamp value if 150 * 1588-2002 time stamping is enabled, hence reinitialize it 151 * to keep explicit chaining in the descriptor. 152 */ 153 p->des3 = cpu_to_le32((unsigned int)((tx_q->dma_tx_phy + 154 ((tx_q->dirty_tx + 1) % 155 priv->dma_conf.dma_tx_size)) 156 * sizeof(struct dma_desc))); 157 } 158 159 const struct stmmac_mode_ops chain_mode_ops = { 160 .init = init_dma_chain, 161 .is_jumbo_frm = is_jumbo_frm, 162 .jumbo_frm = jumbo_frm, 163 .refill_desc3 = refill_desc3, 164 .clean_desc3 = clean_desc3, 165 }; 166