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_rx_queue *rx_q = priv_ptr;
 118         struct stmmac_priv *priv = rx_q->priv_data;
 119
 120         /* Fill DES3 in case of RING mode */
 121         if (priv->dma_buf_sz == BUF_SIZE_16KiB)
 122                 p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
 123 }
 124
 125 /* In ring mode we need to fill the desc3 because it is used as buffer */
 126 static void stmmac_init_desc3(struct dma_desc *p)
 127 {
 128         p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
 129 }
 130
 131 static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
 132 {
 133         struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)priv_ptr;
 134         struct stmmac_priv *priv = tx_q->priv_data;
 135         unsigned int entry = tx_q->dirty_tx;
 136
 137         /* des3 is only used for jumbo frames tx or time stamping */
 138         if (unlikely(tx_q->tx_skbuff_dma[entry].is_jumbo ||
 139                      (tx_q->tx_skbuff_dma[entry].last_segment &&
 140                       !priv->extend_desc && priv->hwts_tx_en)))
 141                 p->des3 = 0;
 142 }
 143
 144 static int stmmac_set_16kib_bfsize(int mtu)
 145 {
 146         int ret = 0;
 147         if (unlikely(mtu > BUF_SIZE_8KiB))
 148                 ret = BUF_SIZE_16KiB;
 149         return ret;
 150 }
 151
 152 const struct stmmac_mode_ops ring_mode_ops = {
 153         .is_jumbo_frm = stmmac_is_jumbo_frm,
 154         .jumbo_frm = stmmac_jumbo_frm,
 155         .refill_desc3 = stmmac_refill_desc3,
 156         .init_desc3 = stmmac_init_desc3,
 157         .clean_desc3 = stmmac_clean_desc3,
 158         .set_16kib_bfsize = stmmac_set_16kib_bfsize,
 159 };