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, des2;
  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         des2 = dma_map_single(priv->device, skb->data,
  48                               bmax, DMA_TO_DEVICE);
  49         desc->des2 = cpu_to_le32(des2);
  50         if (dma_mapping_error(priv->device, des2))
  51                 return -1;
  52         priv->tx_skbuff_dma[entry].buf = des2;
  53         priv->tx_skbuff_dma[entry].len = bmax;
  54         /* do not close the descriptor and do not set own bit */
  55         priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum, STMMAC_CHAIN_MODE,
  56                                         0, false);
  57
  58         while (len != 0) {
  59                 priv->tx_skbuff[entry] = NULL;
  60                 entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
  61                 desc = priv->dma_tx + entry;
  62
  63                 if (len > bmax) {
  64                         des2 = dma_map_single(priv->device,
  65                                               (skb->data + bmax * i),
  66                                               bmax, DMA_TO_DEVICE);
  67                         desc->des2 = cpu_to_le32(des2);
  68                         if (dma_mapping_error(priv->device, des2))
  69                                 return -1;
  70                         priv->tx_skbuff_dma[entry].buf = des2;
  71                         priv->tx_skbuff_dma[entry].len = bmax;
  72                         priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
  73                                                         STMMAC_CHAIN_MODE, 1,
  74                                                         false);
  75                         len -= bmax;
  76                         i++;
  77                 } else {
  78                         des2 = dma_map_single(priv->device,
  79                                               (skb->data + bmax * i), len,
  80                                               DMA_TO_DEVICE);
  81                         desc->des2 = cpu_to_le32(des2);
  82                         if (dma_mapping_error(priv->device, des2))
  83                                 return -1;
  84                         priv->tx_skbuff_dma[entry].buf = des2;
  85                         priv->tx_skbuff_dma[entry].len = len;
  86                         /* last descriptor can be set now */
  87                         priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
  88                                                         STMMAC_CHAIN_MODE, 1,
  89                                                         true);
  90                         len = 0;
  91                 }
  92         }
  93
  94         priv->cur_tx = entry;
  95
  96         return entry;
  97 }
  98
  99 static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc)
 100 {
 101         unsigned int ret = 0;
 102
 103         if ((enh_desc && (len > BUF_SIZE_8KiB)) ||
 104             (!enh_desc && (len > BUF_SIZE_2KiB))) {
 105                 ret = 1;
 106         }
 107
 108         return ret;
 109 }
 110
 111 static void stmmac_init_dma_chain(void *des, dma_addr_t phy_addr,
 112                                   unsigned int size, unsigned int extend_desc)
 113 {
 114         /*
 115          * In chained mode the des3 points to the next element in the ring.
 116          * The latest element has to point to the head.
 117          */
 118         int i;
 119         dma_addr_t dma_phy = phy_addr;
 120
 121         if (extend_desc) {
 122                 struct dma_extended_desc *p = (struct dma_extended_desc *)des;
 123                 for (i = 0; i < (size - 1); i++) {
 124                         dma_phy += sizeof(struct dma_extended_desc);
 125                         p->basic.des3 = cpu_to_le32((unsigned int)dma_phy);
 126                         p++;
 127                 }
 128                 p->basic.des3 = cpu_to_le32((unsigned int)phy_addr);
 129
 130         } else {
 131                 struct dma_desc *p = (struct dma_desc *)des;
 132                 for (i = 0; i < (size - 1); i++) {
 133                         dma_phy += sizeof(struct dma_desc);
 134                         p->des3 = cpu_to_le32((unsigned int)dma_phy);
 135                         p++;
 136                 }
 137                 p->des3 = cpu_to_le32((unsigned int)phy_addr);
 138         }
 139 }
 140
 141 static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p)
 142 {
 143         struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
 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)(priv->dma_rx_phy +
 151                                       (((priv->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_priv *priv = (struct stmmac_priv *)priv_ptr;
 159         unsigned int entry = priv->dirty_tx;
 160
 161         if (priv->tx_skbuff_dma[entry].last_segment && !priv->extend_desc &&
 162             priv->hwts_tx_en)
 163                 /* NOTE: Device will overwrite des3 with timestamp value if
 164                  * 1588-2002 time stamping is enabled, hence reinitialize it
 165                  * to keep explicit chaining in the descriptor.
 166                  */
 167                 p->des3 = cpu_to_le32((unsigned int)((priv->dma_tx_phy +
 168                                       ((priv->dirty_tx + 1) % DMA_TX_SIZE))
 169                                       * sizeof(struct dma_desc)));
 170 }
 171
 172 const struct stmmac_mode_ops chain_mode_ops = {
 173         .init = stmmac_init_dma_chain,
 174         .is_jumbo_frm = stmmac_is_jumbo_frm,
 175         .jumbo_frm = stmmac_jumbo_frm,
 176         .refill_desc3 = stmmac_refill_desc3,
 177         .clean_desc3 = stmmac_clean_desc3,
 178 };