drivers/net/ethernet/stmicro/stmmac/chain_mode.c

   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 };