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