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

   1 /*******************************************************************************
   2   Specialised functions for managing Ring 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;
  37         unsigned int nopaged_len = skb_headlen(skb);
  38         unsigned int bmax, len;
  39
  40         if (priv->extend_desc)
  41                 desc = (struct dma_desc *)(priv->dma_etx + entry);
  42         else
  43                 desc = priv->dma_tx + entry;
  44
  45         if (priv->plat->enh_desc)
  46                 bmax = BUF_SIZE_8KiB;
  47         else
  48                 bmax = BUF_SIZE_2KiB;
  49
  50         len = nopaged_len - bmax;
  51
  52         if (nopaged_len > BUF_SIZE_8KiB) {
  53
  54                 desc->des2 = dma_map_single(priv->device, skb->data,
  55                                             bmax, DMA_TO_DEVICE);
  56                 priv->tx_skbuff_dma[entry] = desc->des2;
  57                 desc->des3 = desc->des2 + BUF_SIZE_4KiB;
  58                 priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum,
  59                                                 STMMAC_RING_MODE);
  60                 wmb();
  61                 priv->tx_skbuff[entry] = NULL;
  62                 entry = (++priv->cur_tx) % txsize;
  63
  64                 if (priv->extend_desc)
  65                         desc = (struct dma_desc *)(priv->dma_etx + entry);
  66                 else
  67                         desc = priv->dma_tx + entry;
  68
  69                 desc->des2 = dma_map_single(priv->device, skb->data + bmax,
  70                                             len, DMA_TO_DEVICE);
  71                 priv->tx_skbuff_dma[entry] = desc->des2;
  72                 desc->des3 = desc->des2 + BUF_SIZE_4KiB;
  73                 priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
  74                                                 STMMAC_RING_MODE);
  75                 wmb();
  76                 priv->hw->desc->set_tx_owner(desc);
  77         } else {
  78                 desc->des2 = dma_map_single(priv->device, skb->data,
  79                                             nopaged_len, DMA_TO_DEVICE);
  80                 priv->tx_skbuff_dma[entry] = desc->des2;
  81                 desc->des3 = desc->des2 + BUF_SIZE_4KiB;
  82                 priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len, csum,
  83                                                 STMMAC_RING_MODE);
  84         }
  85
  86         return entry;
  87 }
  88
  89 static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc)
  90 {
  91         unsigned int ret = 0;
  92
  93         if (len >= BUF_SIZE_4KiB)
  94                 ret = 1;
  95
  96         return ret;
  97 }
  98
  99 static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p)
 100 {
 101         struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
 102
 103         /* Fill DES3 in case of RING mode */
 104         if (priv->dma_buf_sz >= BUF_SIZE_8KiB)
 105                 p->des3 = p->des2 + BUF_SIZE_8KiB;
 106 }
 107
 108 /* In ring mode we need to fill the desc3 because it is used as buffer */
 109 static void stmmac_init_desc3(struct dma_desc *p)
 110 {
 111         p->des3 = p->des2 + BUF_SIZE_8KiB;
 112 }
 113
 114 static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
 115 {
 116         if (unlikely(p->des3))
 117                 p->des3 = 0;
 118 }
 119
 120 static int stmmac_set_16kib_bfsize(int mtu)
 121 {
 122         int ret = 0;
 123         if (unlikely(mtu >= BUF_SIZE_8KiB))
 124                 ret = BUF_SIZE_16KiB;
 125         return ret;
 126 }
 127
 128 const struct stmmac_mode_ops ring_mode_ops = {
 129         .is_jumbo_frm = stmmac_is_jumbo_frm,
 130         .jumbo_frm = stmmac_jumbo_frm,
 131         .refill_desc3 = stmmac_refill_desc3,
 132         .init_desc3 = stmmac_init_desc3,
 133         .clean_desc3 = stmmac_clean_desc3,
 134         .set_16kib_bfsize = stmmac_set_16kib_bfsize,
 135 };