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, 0, 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, !skb_is_nonlinear(skb),
  83                                 skb->len);
  84         } else {
  85                 des2 = dma_map_single(priv->device, skb->data,
  86                                       nopaged_len, DMA_TO_DEVICE);
  87                 desc->des2 = cpu_to_le32(des2);
  88                 if (dma_mapping_error(priv->device, des2))
  89                         return -1;
  90                 tx_q->tx_skbuff_dma[entry].buf = des2;
  91                 tx_q->tx_skbuff_dma[entry].len = nopaged_len;
  92                 tx_q->tx_skbuff_dma[entry].is_jumbo = true;
  93                 desc->des3 = cpu_to_le32(des2 + BUF_SIZE_4KiB);
  94                 stmmac_prepare_tx_desc(priv, desc, 1, nopaged_len, csum,
  95                                 STMMAC_RING_MODE, 0, !skb_is_nonlinear(skb),
  96                                 skb->len);
  97         }
  98
  99         tx_q->cur_tx = entry;
 100
 101         return entry;
 102 }
 103
 104 static unsigned int is_jumbo_frm(int len, int enh_desc)
 105 {
 106         unsigned int ret = 0;
 107
 108         if (len >= BUF_SIZE_4KiB)
 109                 ret = 1;
 110
 111         return ret;
 112 }
 113
 114 static void refill_desc3(void *priv_ptr, struct dma_desc *p)
 115 {
 116         struct stmmac_rx_queue *rx_q = priv_ptr;
 117         struct stmmac_priv *priv = rx_q->priv_data;
 118
 119         /* Fill DES3 in case of RING mode */
 120         if (priv->dma_buf_sz == BUF_SIZE_16KiB)
 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 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 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 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 = is_jumbo_frm,
 153         .jumbo_frm = jumbo_frm,
 154         .refill_desc3 = refill_desc3,
 155         .init_desc3 = init_desc3,
 156         .clean_desc3 = clean_desc3,
 157         .set_16kib_bfsize = set_16kib_bfsize,
 158 };