stmicro/stmmac/chain_mode.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*******************************************************************************
0003   Specialised functions for managing Chained mode
0004
0005   Copyright(C) 2011  STMicroelectronics Ltd
0006
0007   It defines all the functions used to handle the normal/enhanced
0008   descriptors in case of the DMA is configured to work in chained or
0009   in ring mode.
0010
0011
0012   Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
0013 *******************************************************************************/
0014
0015 #include "stmmac.h"
0016
0017 static int jumbo_frm(void *p, struct sk_buff *skb, int csum)
0018 {
0019     struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)p;
0020     unsigned int nopaged_len = skb_headlen(skb);
0021     struct stmmac_priv *priv = tx_q->priv_data;
0022     unsigned int entry = tx_q->cur_tx;
0023     unsigned int bmax, des2;
0024     unsigned int i = 1, len;
0025     struct dma_desc *desc;
0026
0027     desc = tx_q->dma_tx + entry;
0028
0029     if (priv->plat->enh_desc)
0030         bmax = BUF_SIZE_8KiB;
0031     else
0032         bmax = BUF_SIZE_2KiB;
0033
0034     len = nopaged_len - bmax;
0035
0036     des2 = dma_map_single(priv->device, skb->data,
0037                   bmax, DMA_TO_DEVICE);
0038     desc->des2 = cpu_to_le32(des2);
0039     if (dma_mapping_error(priv->device, des2))
0040         return -1;
0041     tx_q->tx_skbuff_dma[entry].buf = des2;
0042     tx_q->tx_skbuff_dma[entry].len = bmax;
0043     /* do not close the descriptor and do not set own bit */
0044     stmmac_prepare_tx_desc(priv, desc, 1, bmax, csum, STMMAC_CHAIN_MODE,
0045             0, false, skb->len);
0046
0047     while (len != 0) {
0048         tx_q->tx_skbuff[entry] = NULL;
0049         entry = STMMAC_GET_ENTRY(entry, priv->dma_conf.dma_tx_size);
0050         desc = tx_q->dma_tx + entry;
0051
0052         if (len > bmax) {
0053             des2 = dma_map_single(priv->device,
0054                           (skb->data + bmax * i),
0055                           bmax, DMA_TO_DEVICE);
0056             desc->des2 = cpu_to_le32(des2);
0057             if (dma_mapping_error(priv->device, des2))
0058                 return -1;
0059             tx_q->tx_skbuff_dma[entry].buf = des2;
0060             tx_q->tx_skbuff_dma[entry].len = bmax;
0061             stmmac_prepare_tx_desc(priv, desc, 0, bmax, csum,
0062                     STMMAC_CHAIN_MODE, 1, false, skb->len);
0063             len -= bmax;
0064             i++;
0065         } else {
0066             des2 = dma_map_single(priv->device,
0067                           (skb->data + bmax * i), len,
0068                           DMA_TO_DEVICE);
0069             desc->des2 = cpu_to_le32(des2);
0070             if (dma_mapping_error(priv->device, des2))
0071                 return -1;
0072             tx_q->tx_skbuff_dma[entry].buf = des2;
0073             tx_q->tx_skbuff_dma[entry].len = len;
0074             /* last descriptor can be set now */
0075             stmmac_prepare_tx_desc(priv, desc, 0, len, csum,
0076                     STMMAC_CHAIN_MODE, 1, true, skb->len);
0077             len = 0;
0078         }
0079     }
0080
0081     tx_q->cur_tx = entry;
0082
0083     return entry;
0084 }
0085
0086 static unsigned int is_jumbo_frm(int len, int enh_desc)
0087 {
0088     unsigned int ret = 0;
0089
0090     if ((enh_desc && (len > BUF_SIZE_8KiB)) ||
0091         (!enh_desc && (len > BUF_SIZE_2KiB))) {
0092         ret = 1;
0093     }
0094
0095     return ret;
0096 }
0097
0098 static void init_dma_chain(void *des, dma_addr_t phy_addr,
0099                   unsigned int size, unsigned int extend_desc)
0100 {
0101     /*
0102      * In chained mode the des3 points to the next element in the ring.
0103      * The latest element has to point to the head.
0104      */
0105     int i;
0106     dma_addr_t dma_phy = phy_addr;
0107
0108     if (extend_desc) {
0109         struct dma_extended_desc *p = (struct dma_extended_desc *)des;
0110         for (i = 0; i < (size - 1); i++) {
0111             dma_phy += sizeof(struct dma_extended_desc);
0112             p->basic.des3 = cpu_to_le32((unsigned int)dma_phy);
0113             p++;
0114         }
0115         p->basic.des3 = cpu_to_le32((unsigned int)phy_addr);
0116
0117     } else {
0118         struct dma_desc *p = (struct dma_desc *)des;
0119         for (i = 0; i < (size - 1); i++) {
0120             dma_phy += sizeof(struct dma_desc);
0121             p->des3 = cpu_to_le32((unsigned int)dma_phy);
0122             p++;
0123         }
0124         p->des3 = cpu_to_le32((unsigned int)phy_addr);
0125     }
0126 }
0127
0128 static void refill_desc3(void *priv_ptr, struct dma_desc *p)
0129 {
0130     struct stmmac_rx_queue *rx_q = (struct stmmac_rx_queue *)priv_ptr;
0131     struct stmmac_priv *priv = rx_q->priv_data;
0132
0133     if (priv->hwts_rx_en && !priv->extend_desc)
0134         /* NOTE: Device will overwrite des3 with timestamp value if
0135          * 1588-2002 time stamping is enabled, hence reinitialize it
0136          * to keep explicit chaining in the descriptor.
0137          */
0138         p->des3 = cpu_to_le32((unsigned int)(rx_q->dma_rx_phy +
0139                       (((rx_q->dirty_rx) + 1) %
0140                        priv->dma_conf.dma_rx_size) *
0141                       sizeof(struct dma_desc)));
0142 }
0143
0144 static void clean_desc3(void *priv_ptr, struct dma_desc *p)
0145 {
0146     struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)priv_ptr;
0147     struct stmmac_priv *priv = tx_q->priv_data;
0148     unsigned int entry = tx_q->dirty_tx;
0149
0150     if (tx_q->tx_skbuff_dma[entry].last_segment && !priv->extend_desc &&
0151         priv->hwts_tx_en)
0152         /* NOTE: Device will overwrite des3 with timestamp value if
0153          * 1588-2002 time stamping is enabled, hence reinitialize it
0154          * to keep explicit chaining in the descriptor.
0155          */
0156         p->des3 = cpu_to_le32((unsigned int)((tx_q->dma_tx_phy +
0157                       ((tx_q->dirty_tx + 1) %
0158                        priv->dma_conf.dma_tx_size))
0159                       * sizeof(struct dma_desc)));
0160 }
0161
0162 const struct stmmac_mode_ops chain_mode_ops = {
0163     .init = init_dma_chain,
0164     .is_jumbo_frm = is_jumbo_frm,
0165     .jumbo_frm = jumbo_frm,
0166     .refill_desc3 = refill_desc3,
0167     .clean_desc3 = clean_desc3,
0168 };