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  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
  27static 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, 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, 0, true, skb->len);
  95        }
  96
  97        tx_q->cur_tx = entry;
  98
  99        return entry;
 100}
 101
 102static 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
 112static 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 */
 122static void init_desc3(struct dma_desc *p)
 123{
 124        p->des3 = cpu_to_le32(le32_to_cpu(p->des2) + BUF_SIZE_8KiB);
 125}
 126
 127static 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
 140static 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
 148const 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};
 156