chain_mode.c (4900B)
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 17static int jumbo_frm(void *p, struct sk_buff *skb, int csum) 18{ 19 struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)p; 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_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 86static unsigned int is_jumbo_frm(int len, int enh_desc) 87{ 88 unsigned int ret = 0; 89 90 if ((enh_desc && (len > BUF_SIZE_8KiB)) || 91 (!enh_desc && (len > BUF_SIZE_2KiB))) { 92 ret = 1; 93 } 94 95 return ret; 96} 97 98static void init_dma_chain(void *des, dma_addr_t phy_addr, 99 unsigned int size, unsigned int extend_desc) 100{ 101 /* 102 * In chained mode the des3 points to the next element in the ring. 103 * The latest element has to point to the head. 104 */ 105 int i; 106 dma_addr_t dma_phy = phy_addr; 107 108 if (extend_desc) { 109 struct dma_extended_desc *p = (struct dma_extended_desc *)des; 110 for (i = 0; i < (size - 1); i++) { 111 dma_phy += sizeof(struct dma_extended_desc); 112 p->basic.des3 = cpu_to_le32((unsigned int)dma_phy); 113 p++; 114 } 115 p->basic.des3 = cpu_to_le32((unsigned int)phy_addr); 116 117 } else { 118 struct dma_desc *p = (struct dma_desc *)des; 119 for (i = 0; i < (size - 1); i++) { 120 dma_phy += sizeof(struct dma_desc); 121 p->des3 = cpu_to_le32((unsigned int)dma_phy); 122 p++; 123 } 124 p->des3 = cpu_to_le32((unsigned int)phy_addr); 125 } 126} 127 128static void refill_desc3(void *priv_ptr, struct dma_desc *p) 129{ 130 struct stmmac_rx_queue *rx_q = (struct stmmac_rx_queue *)priv_ptr; 131 struct stmmac_priv *priv = rx_q->priv_data; 132 133 if (priv->hwts_rx_en && !priv->extend_desc) 134 /* NOTE: Device will overwrite des3 with timestamp value if 135 * 1588-2002 time stamping is enabled, hence reinitialize it 136 * to keep explicit chaining in the descriptor. 137 */ 138 p->des3 = cpu_to_le32((unsigned int)(rx_q->dma_rx_phy + 139 (((rx_q->dirty_rx) + 1) % 140 priv->dma_rx_size) * 141 sizeof(struct dma_desc))); 142} 143 144static void clean_desc3(void *priv_ptr, struct dma_desc *p) 145{ 146 struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)priv_ptr; 147 struct stmmac_priv *priv = tx_q->priv_data; 148 unsigned int entry = tx_q->dirty_tx; 149 150 if (tx_q->tx_skbuff_dma[entry].last_segment && !priv->extend_desc && 151 priv->hwts_tx_en) 152 /* NOTE: Device will overwrite des3 with timestamp value if 153 * 1588-2002 time stamping is enabled, hence reinitialize it 154 * to keep explicit chaining in the descriptor. 155 */ 156 p->des3 = cpu_to_le32((unsigned int)((tx_q->dma_tx_phy + 157 ((tx_q->dirty_tx + 1) % 158 priv->dma_tx_size)) 159 * sizeof(struct dma_desc))); 160} 161 162const struct stmmac_mode_ops chain_mode_ops = { 163 .init = init_dma_chain, 164 .is_jumbo_frm = is_jumbo_frm, 165 .jumbo_frm = jumbo_frm, 166 .refill_desc3 = refill_desc3, 167 .clean_desc3 = clean_desc3, 168};