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 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 };