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   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 stmmac_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, len, des2;
  34         struct dma_desc *desc;
  35
  36         if (priv->extend_desc)
  37                 desc = (struct dma_desc *)(tx_q->dma_etx + entry);
  38         else
  39                 desc = tx_q->dma_tx + entry;
  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         if (nopaged_len > BUF_SIZE_8KiB) {
  49
  50                 des2 = dma_map_single(priv->device, skb->data, bmax,
  51                                       DMA_TO_DEVICE);
  52                 desc->des2 = cpu_to_le32(des2);
  53                 if (dma_mapping_error(priv->device, des2))
  54                         return -1;
  55
  56                 tx_q->tx_skbuff_dma[entry].buf = des2;
  57                 tx_q->tx_skbuff_dma[entry].len = bmax;
  58                 tx_q->tx_skbuff_dma[entry].is_jumbo = true;
  59
  60                 desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
  61                 priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum,
  62                                                 STMMAC_RING_MODE, 0,
  63                                                 false, skb->len);
  64                 tx_q->tx_skbuff[entry] = NULL;
  65                 entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
  66
  67                 if (priv->extend_desc)
  68                         desc = (struct dma_desc *)(tx_q->dma_etx + entry);
  69                 else
  70                         desc = tx_q->dma_tx + entry;
  71
  72                 des2 = dma_map_single(priv->device, skb->data + bmax, len,
  73                                       DMA_TO_DEVICE);
  74                 desc->des2 = cpu_to_le32(des2);
  75                 if (dma_mapping_error(priv->device, des2))
  76                         return -1;
  77                 tx_q->tx_skbuff_dma[entry].buf = des2;
  78                 tx_q->tx_skbuff_dma[entry].len = len;
  79                 tx_q->tx_skbuff_dma[entry].is_jumbo = true;
  80
  81                 desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
  82                 priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
  83                                                 STMMAC_RING_MODE, 1,
  84                                                 true, skb->len);
  85         } else {
  86                 des2 = dma_map_single(priv->device, skb->data,
  87                                       nopaged_len, DMA_TO_DEVICE);
  88                 desc->des2 = cpu_to_le32(des2);
  89                 if (dma_mapping_error(priv->device, des2))
  90                         return -1;
  91                 tx_q->tx_skbuff_dma[entry].buf = des2;
  92                 tx_q->tx_skbuff_dma[entry].len = nopaged_len;
  93                 tx_q->tx_skbuff_dma[entry].is_jumbo = true;
  94                 desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
  95                 priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len, csum,
  96                                                 STMMAC_RING_MODE, 0,
  97                                                 true, skb->len);
  98         }
  99
 100         tx_q->cur_tx = entry;
 101
 102         return entry;
 103 }
 104
 105 static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc)
 106 {
 107         unsigned int ret = 0;
 108
 109         if (len >= BUF_SIZE_4KiB)
 110                 ret = 1;
 111
 112         return ret;
 113 }
 114
 115 static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p)
 116 {
 117         struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
 118
 119         /* Fill DES3 in case of RING mode */
 120         if (priv->dma_buf_sz >= BUF_SIZE_8KiB)
 121                 p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
 122 }
 123
 124 /* In ring mode we need to fill the desc3 because it is used as buffer */
 125 static void stmmac_init_desc3(struct dma_desc *p)
 126 {
 127         p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
 128 }
 129
 130 static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
 131 {
 132         struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)priv_ptr;
 133         struct stmmac_priv *priv = tx_q->priv_data;
 134         unsigned int entry = tx_q->dirty_tx;
 135
 136         /* des3 is only used for jumbo frames tx or time stamping */
 137         if (unlikely(tx_q->tx_skbuff_dma[entry].is_jumbo ||
 138                      (tx_q->tx_skbuff_dma[entry].last_segment &&
 139                       !priv->extend_desc && priv->hwts_tx_en)))
 140                 p->des3 = 0;
 141 }
 142
 143 static int stmmac_set_16kib_bfsize(int mtu)
 144 {
 145         int ret = 0;
 146         if (unlikely(mtu >= BUF_SIZE_8KiB))
 147                 ret = BUF_SIZE_16KiB;
 148         return ret;
 149 }
 150
 151 const struct stmmac_mode_ops ring_mode_ops = {
 152         .is_jumbo_frm = stmmac_is_jumbo_frm,
 153         .jumbo_frm = stmmac_jumbo_frm,
 154         .refill_desc3 = stmmac_refill_desc3,
 155         .init_desc3 = stmmac_init_desc3,
 156         .clean_desc3 = stmmac_clean_desc3,
 157         .set_16kib_bfsize = stmmac_set_16kib_bfsize,
 158 };