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 unsigned 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 txsize = priv->dma_tx_size;
  35         unsigned int entry = priv->cur_tx % txsize;
  36         struct dma_desc *desc = priv->dma_tx + entry;
  37         unsigned int nopaged_len = skb_headlen(skb);
  38         unsigned int bmax;
  39         unsigned int i = 1, len;
  40
  41         if (priv->plat->enh_desc)
  42                 bmax = BUF_SIZE_8KiB;
  43         else
  44                 bmax = BUF_SIZE_2KiB;
  45
  46         len = nopaged_len - bmax;
  47
  48         desc->des2 = dma_map_single(priv->device, skb->data,
  49                                     bmax, DMA_TO_DEVICE);
  50         priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum, STMMAC_CHAIN_MODE);
  51
  52         while (len != 0) {
  53                 entry = (++priv->cur_tx) % txsize;
  54                 desc = priv->dma_tx + entry;
  55
  56                 if (len > bmax) {
  57                         desc->des2 = dma_map_single(priv->device,
  58                                                     (skb->data + bmax * i),
  59                                                     bmax, DMA_TO_DEVICE);
  60                         priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
  61                                                         STMMAC_CHAIN_MODE);
  62                         priv->hw->desc->set_tx_owner(desc);
  63                         priv->tx_skbuff[entry] = NULL;
  64                         len -= bmax;
  65                         i++;
  66                 } else {
  67                         desc->des2 = dma_map_single(priv->device,
  68                                                     (skb->data + bmax * i), len,
  69                                                     DMA_TO_DEVICE);
  70                         priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
  71                                                         STMMAC_CHAIN_MODE);
  72                         priv->hw->desc->set_tx_owner(desc);
  73                         priv->tx_skbuff[entry] = NULL;
  74                         len = 0;
  75                 }
  76         }
  77         return entry;
  78 }
  79
  80 static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc)
  81 {
  82         unsigned int ret = 0;
  83
  84         if ((enh_desc && (len > BUF_SIZE_8KiB)) ||
  85             (!enh_desc && (len > BUF_SIZE_2KiB))) {
  86                 ret = 1;
  87         }
  88
  89         return ret;
  90 }
  91
  92 static void stmmac_init_dma_chain(void *des, dma_addr_t phy_addr,
  93                                   unsigned int size, unsigned int extend_desc)
  94 {
  95         /*
  96          * In chained mode the des3 points to the next element in the ring.
  97          * The latest element has to point to the head.
  98          */
  99         int i;
 100         dma_addr_t dma_phy = phy_addr;
 101
 102         if (extend_desc) {
 103                 struct dma_extended_desc *p = (struct dma_extended_desc *) des;
 104                 for (i = 0; i < (size - 1); i++) {
 105                         dma_phy += sizeof(struct dma_extended_desc);
 106                         p->basic.des3 = (unsigned int)dma_phy;
 107                         p++;
 108                 }
 109                 p->basic.des3 = (unsigned int)phy_addr;
 110
 111         } else {
 112                 struct dma_desc *p = (struct dma_desc *) des;
 113                 for (i = 0; i < (size - 1); i++) {
 114                         dma_phy += sizeof(struct dma_desc);
 115                         p->des3 = (unsigned int)dma_phy;
 116                         p++;
 117                 }
 118                 p->des3 = (unsigned int)phy_addr;
 119         }
 120 }
 121
 122 const struct stmmac_chain_mode_ops chain_mode_ops = {
 123         .init = stmmac_init_dma_chain,
 124         .is_jumbo_frm = stmmac_is_jumbo_frm,
 125         .jumbo_frm = stmmac_jumbo_frm,
 126 };