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

   1 /*******************************************************************************
   2   Specialised functions for managing Chained 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 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 entry = priv->cur_tx;
  35         struct dma_desc *desc = priv->dma_tx + entry;
  36         unsigned int nopaged_len = skb_headlen(skb);
  37         unsigned int bmax;
  38         unsigned int i = 1, len;
  39
  40         if (priv->plat->enh_desc)
  41                 bmax = BUF_SIZE_8KiB;
  42         else
  43                 bmax = BUF_SIZE_2KiB;
  44
  45         len = nopaged_len - bmax;
  46
  47         desc->des2 = dma_map_single(priv->device, skb->data,
  48                                     bmax, DMA_TO_DEVICE);
  49         if (dma_mapping_error(priv->device, desc->des2))
  50                 return -1;
  51         priv->tx_skbuff_dma[entry].buf = desc->des2;
  52         priv->tx_skbuff_dma[entry].len = bmax;
  53         priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum, STMMAC_CHAIN_MODE);
  54
  55         while (len != 0) {
  56                 priv->tx_skbuff[entry] = NULL;
  57                 entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
  58                 desc = priv->dma_tx + entry;
  59
  60                 if (len > bmax) {
  61                         desc->des2 = dma_map_single(priv->device,
  62                                                     (skb->data + bmax * i),
  63                                                     bmax, DMA_TO_DEVICE);
  64                         if (dma_mapping_error(priv->device, desc->des2))
  65                                 return -1;
  66                         priv->tx_skbuff_dma[entry].buf = desc->des2;
  67                         priv->tx_skbuff_dma[entry].len = bmax;
  68                         priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
  69                                                         STMMAC_CHAIN_MODE);
  70                         priv->hw->desc->set_tx_owner(desc);
  71                         len -= bmax;
  72                         i++;
  73                 } else {
  74                         desc->des2 = dma_map_single(priv->device,
  75                                                     (skb->data + bmax * i), len,
  76                                                     DMA_TO_DEVICE);
  77                         if (dma_mapping_error(priv->device, desc->des2))
  78                                 return -1;
  79                         priv->tx_skbuff_dma[entry].buf = desc->des2;
  80                         priv->tx_skbuff_dma[entry].len = len;
  81                         priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
  82                                                         STMMAC_CHAIN_MODE);
  83                         priv->hw->desc->set_tx_owner(desc);
  84                         len = 0;
  85                 }
  86         }
  87
  88         priv->cur_tx = entry;
  89
  90         return entry;
  91 }
  92
  93 static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc)
  94 {
  95         unsigned int ret = 0;
  96
  97         if ((enh_desc && (len > BUF_SIZE_8KiB)) ||
  98             (!enh_desc && (len > BUF_SIZE_2KiB))) {
  99                 ret = 1;
 100         }
 101
 102         return ret;
 103 }
 104
 105 static void stmmac_init_dma_chain(void *des, dma_addr_t phy_addr,
 106                                   unsigned int size, unsigned int extend_desc)
 107 {
 108         /*
 109          * In chained mode the des3 points to the next element in the ring.
 110          * The latest element has to point to the head.
 111          */
 112         int i;
 113         dma_addr_t dma_phy = phy_addr;
 114
 115         if (extend_desc) {
 116                 struct dma_extended_desc *p = (struct dma_extended_desc *)des;
 117                 for (i = 0; i < (size - 1); i++) {
 118                         dma_phy += sizeof(struct dma_extended_desc);
 119                         p->basic.des3 = (unsigned int)dma_phy;
 120                         p++;
 121                 }
 122                 p->basic.des3 = (unsigned int)phy_addr;
 123
 124         } else {
 125                 struct dma_desc *p = (struct dma_desc *)des;
 126                 for (i = 0; i < (size - 1); i++) {
 127                         dma_phy += sizeof(struct dma_desc);
 128                         p->des3 = (unsigned int)dma_phy;
 129                         p++;
 130                 }
 131                 p->des3 = (unsigned int)phy_addr;
 132         }
 133 }
 134
 135 static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p)
 136 {
 137         struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
 138
 139         if (priv->hwts_rx_en && !priv->extend_desc)
 140                 /* NOTE: Device will overwrite des3 with timestamp value if
 141                  * 1588-2002 time stamping is enabled, hence reinitialize it
 142                  * to keep explicit chaining in the descriptor.
 143                  */
 144                 p->des3 = (unsigned int)(priv->dma_rx_phy +
 145                                          (((priv->dirty_rx) + 1) %
 146                                           DMA_RX_SIZE) *
 147                                          sizeof(struct dma_desc));
 148 }
 149
 150 static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
 151 {
 152         struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
 153         unsigned int entry = priv->dirty_tx;
 154
 155         if (priv->tx_skbuff_dma[entry].last_segment && !priv->extend_desc &&
 156             priv->hwts_tx_en)
 157                 /* NOTE: Device will overwrite des3 with timestamp value if
 158                  * 1588-2002 time stamping is enabled, hence reinitialize it
 159                  * to keep explicit chaining in the descriptor.
 160                  */
 161                 p->des3 = (unsigned int)((priv->dma_tx_phy +
 162                                           ((priv->dirty_tx + 1) % DMA_TX_SIZE))
 163                                           * sizeof(struct dma_desc));
 164 }
 165
 166 const struct stmmac_mode_ops chain_mode_ops = {
 167         .init = stmmac_init_dma_chain,
 168         .is_jumbo_frm = stmmac_is_jumbo_frm,
 169         .jumbo_frm = stmmac_jumbo_frm,
 170         .refill_desc3 = stmmac_refill_desc3,
 171         .clean_desc3 = stmmac_clean_desc3,
 172 };