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   You should have received a copy of the GNU General Public License along with
  20   this program; if not, write to the Free Software Foundation, Inc.,
  21   51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  22
  23   The full GNU General Public License is included in this distribution in
  24   the file called "COPYING".
  25
  26   Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
  27 *******************************************************************************/
  28
  29 #include "stmmac.h"
  30
  31 static int stmmac_jumbo_frm(void *p, struct sk_buff *skb, int csum)
  32 {
  33         struct stmmac_priv *priv = (struct stmmac_priv *)p;
  34         unsigned int entry = priv->cur_tx;
  35         struct dma_desc *desc = priv->dma_tx + entry;
  36         unsigned int nopaged_len = skb_headlen(skb);
  37         unsigned int bmax;
  38         unsigned int i = 1, len;
  39
  40         if (priv->plat->enh_desc)
  41                 bmax = BUF_SIZE_8KiB;
  42         else
  43                 bmax = BUF_SIZE_2KiB;
  44
  45         len = nopaged_len - bmax;
  46
  47         desc->des2 = dma_map_single(priv->device, skb->data,
  48                                     bmax, DMA_TO_DEVICE);
  49         if (dma_mapping_error(priv->device, desc->des2))
  50                 return -1;
  51         priv->tx_skbuff_dma[entry].buf = desc->des2;
  52         priv->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);
  56
  57         while (len != 0) {
  58                 priv->tx_skbuff[entry] = NULL;
  59                 entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
  60                 desc = priv->dma_tx + entry;
  61
  62                 if (len > bmax) {
  63                         desc->des2 = dma_map_single(priv->device,
  64                                                     (skb->data + bmax * i),
  65                                                     bmax, DMA_TO_DEVICE);
  66                         if (dma_mapping_error(priv->device, desc->des2))
  67                                 return -1;
  68                         priv->tx_skbuff_dma[entry].buf = desc->des2;
  69                         priv->tx_skbuff_dma[entry].len = bmax;
  70                         priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
  71                                                         STMMAC_CHAIN_MODE, 1,
  72                                                         false);
  73                         len -= bmax;
  74                         i++;
  75                 } else {
  76                         desc->des2 = dma_map_single(priv->device,
  77                                                     (skb->data + bmax * i), len,
  78                                                     DMA_TO_DEVICE);
  79                         if (dma_mapping_error(priv->device, desc->des2))
  80                                 return -1;
  81                         priv->tx_skbuff_dma[entry].buf = desc->des2;
  82                         priv->tx_skbuff_dma[entry].len = len;
  83                         /* last descriptor can be set now */
  84                         priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
  85                                                         STMMAC_CHAIN_MODE, 1,
  86                                                         true);
  87                         len = 0;
  88                 }
  89         }
  90
  91         priv->cur_tx = entry;
  92
  93         return entry;
  94 }
  95
  96 static unsigned int stmmac_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 stmmac_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 = (unsigned int)dma_phy;
 123                         p++;
 124                 }
 125                 p->basic.des3 = (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 = (unsigned int)dma_phy;
 132                         p++;
 133                 }
 134                 p->des3 = (unsigned int)phy_addr;
 135         }
 136 }
 137
 138 static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p)
 139 {
 140         struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
 141
 142         if (priv->hwts_rx_en && !priv->extend_desc)
 143                 /* NOTE: Device will overwrite des3 with timestamp value if
 144                  * 1588-2002 time stamping is enabled, hence reinitialize it
 145                  * to keep explicit chaining in the descriptor.
 146                  */
 147                 p->des3 = (unsigned int)(priv->dma_rx_phy +
 148                                          (((priv->dirty_rx) + 1) %
 149                                           DMA_RX_SIZE) *
 150                                          sizeof(struct dma_desc));
 151 }
 152
 153 static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
 154 {
 155         struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
 156         unsigned int entry = priv->dirty_tx;
 157
 158         if (priv->tx_skbuff_dma[entry].last_segment && !priv->extend_desc &&
 159             priv->hwts_tx_en)
 160                 /* NOTE: Device will overwrite des3 with timestamp value if
 161                  * 1588-2002 time stamping is enabled, hence reinitialize it
 162                  * to keep explicit chaining in the descriptor.
 163                  */
 164                 p->des3 = (unsigned int)((priv->dma_tx_phy +
 165                                           ((priv->dirty_tx + 1) % DMA_TX_SIZE))
 166                                           * sizeof(struct dma_desc));
 167 }
 168
 169 const struct stmmac_mode_ops chain_mode_ops = {
 170         .init = stmmac_init_dma_chain,
 171         .is_jumbo_frm = stmmac_is_jumbo_frm,
 172         .jumbo_frm = stmmac_jumbo_frm,
 173         .refill_desc3 = stmmac_refill_desc3,
 174         .clean_desc3 = stmmac_clean_desc3,
 175 };