LXR linux/drivers/net/ethernet/stmicro/stmmac/ring

   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  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
  31static unsigned 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 txsize = priv->dma_tx_size;
  35        unsigned int entry = priv->cur_tx % txsize;
  36        struct dma_desc *desc = priv->dma_tx + entry;
  37        unsigned int nopaged_len = skb_headlen(skb);
  38        unsigned int bmax, 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        if (nopaged_len > BUF_SIZE_8KiB) {
  48
  49                desc->des2 = dma_map_single(priv->device, skb->data,
  50                                            bmax, DMA_TO_DEVICE);
  51                desc->des3 = desc->des2 + BUF_SIZE_4KiB;
  52                priv->hw->desc->prepare_tx_desc(desc, 1, bmax,
  53                                                csum);
  54                wmb();
  55                entry = (++priv->cur_tx) % txsize;
  56                desc = priv->dma_tx + entry;
  57
  58                desc->des2 = dma_map_single(priv->device, skb->data + bmax,
  59                                            len, DMA_TO_DEVICE);
  60                desc->des3 = desc->des2 + BUF_SIZE_4KiB;
  61                priv->hw->desc->prepare_tx_desc(desc, 0, len, csum);
  62                wmb();
  63                priv->hw->desc->set_tx_owner(desc);
  64                priv->tx_skbuff[entry] = NULL;
  65        } else {
  66                desc->des2 = dma_map_single(priv->device, skb->data,
  67                                            nopaged_len, DMA_TO_DEVICE);
  68                desc->des3 = desc->des2 + BUF_SIZE_4KiB;
  69                priv->hw->desc->prepare_tx_desc(desc, 1, nopaged_len, csum);
  70        }
  71
  72        return entry;
  73}
  74
  75static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc)
  76{
  77        unsigned int ret = 0;
  78
  79        if (len >= BUF_SIZE_4KiB)
  80                ret = 1;
  81
  82        return ret;
  83}
  84
  85static void stmmac_refill_desc3(int bfsize, struct dma_desc *p)
  86{
  87        /* Fill DES3 in case of RING mode */
  88        if (bfsize >= BUF_SIZE_8KiB)
  89                p->des3 = p->des2 + BUF_SIZE_8KiB;
  90}
  91
  92/* In ring mode we need to fill the desc3 because it is used
  93 * as buffer */
  94static void stmmac_init_desc3(int des3_as_data_buf, struct dma_desc *p)
  95{
  96        if (unlikely(des3_as_data_buf))
  97                p->des3 = p->des2 + BUF_SIZE_8KiB;
  98}
  99
 100static void stmmac_init_dma_chain(struct dma_desc *des, dma_addr_t phy_addr,
 101                                  unsigned int size)
 102{
 103}
 104
 105static void stmmac_clean_desc3(struct dma_desc *p)
 106{
 107        if (unlikely(p->des3))
 108                p->des3 = 0;
 109}
 110
 111static int stmmac_set_16kib_bfsize(int mtu)
 112{
 113        int ret = 0;
 114        if (unlikely(mtu >= BUF_SIZE_8KiB))
 115                ret = BUF_SIZE_16KiB;
 116        return ret;
 117}
 118
 119const struct stmmac_ring_mode_ops ring_mode_ops = {
 120        .is_jumbo_frm = stmmac_is_jumbo_frm,
 121        .jumbo_frm = stmmac_jumbo_frm,
 122        .refill_desc3 = stmmac_refill_desc3,
 123        .init_desc3 = stmmac_init_desc3,
 124        .init_dma_chain = stmmac_init_dma_chain,
 125        .clean_desc3 = stmmac_clean_desc3,
 126        .set_16kib_bfsize = stmmac_set_16kib_bfsize,
 127};
 128