/drivers/net/ethernet/stmicro/stmmac/chain_mode.c
http://github.com/mirrors/linux · C · 167 lines · 119 code · 21 blank · 27 comment · 19 complexity · bd929b74203ffb0a81f976248422e8b0 MD5 · raw file
- // SPDX-License-Identifier: GPL-2.0-only
- /*******************************************************************************
- Specialised functions for managing Chained mode
- Copyright(C) 2011 STMicroelectronics Ltd
- It defines all the functions used to handle the normal/enhanced
- descriptors in case of the DMA is configured to work in chained or
- in ring mode.
- Author: Giuseppe Cavallaro <peppe.cavallaro@st.com>
- *******************************************************************************/
- #include "stmmac.h"
- static int jumbo_frm(void *p, struct sk_buff *skb, int csum)
- {
- struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)p;
- unsigned int nopaged_len = skb_headlen(skb);
- struct stmmac_priv *priv = tx_q->priv_data;
- unsigned int entry = tx_q->cur_tx;
- unsigned int bmax, des2;
- unsigned int i = 1, len;
- struct dma_desc *desc;
- desc = tx_q->dma_tx + entry;
- if (priv->plat->enh_desc)
- bmax = BUF_SIZE_8KiB;
- else
- bmax = BUF_SIZE_2KiB;
- len = nopaged_len - bmax;
- des2 = dma_map_single(priv->device, skb->data,
- bmax, DMA_TO_DEVICE);
- desc->des2 = cpu_to_le32(des2);
- if (dma_mapping_error(priv->device, des2))
- return -1;
- tx_q->tx_skbuff_dma[entry].buf = des2;
- tx_q->tx_skbuff_dma[entry].len = bmax;
- /* do not close the descriptor and do not set own bit */
- stmmac_prepare_tx_desc(priv, desc, 1, bmax, csum, STMMAC_CHAIN_MODE,
- 0, false, skb->len);
- while (len != 0) {
- tx_q->tx_skbuff[entry] = NULL;
- entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
- desc = tx_q->dma_tx + entry;
- if (len > bmax) {
- des2 = dma_map_single(priv->device,
- (skb->data + bmax * i),
- bmax, DMA_TO_DEVICE);
- desc->des2 = cpu_to_le32(des2);
- if (dma_mapping_error(priv->device, des2))
- return -1;
- tx_q->tx_skbuff_dma[entry].buf = des2;
- tx_q->tx_skbuff_dma[entry].len = bmax;
- stmmac_prepare_tx_desc(priv, desc, 0, bmax, csum,
- STMMAC_CHAIN_MODE, 1, false, skb->len);
- len -= bmax;
- i++;
- } else {
- des2 = dma_map_single(priv->device,
- (skb->data + bmax * i), len,
- DMA_TO_DEVICE);
- desc->des2 = cpu_to_le32(des2);
- if (dma_mapping_error(priv->device, des2))
- return -1;
- tx_q->tx_skbuff_dma[entry].buf = des2;
- tx_q->tx_skbuff_dma[entry].len = len;
- /* last descriptor can be set now */
- stmmac_prepare_tx_desc(priv, desc, 0, len, csum,
- STMMAC_CHAIN_MODE, 1, true, skb->len);
- len = 0;
- }
- }
- tx_q->cur_tx = entry;
- return entry;
- }
- static unsigned int is_jumbo_frm(int len, int enh_desc)
- {
- unsigned int ret = 0;
- if ((enh_desc && (len > BUF_SIZE_8KiB)) ||
- (!enh_desc && (len > BUF_SIZE_2KiB))) {
- ret = 1;
- }
- return ret;
- }
- static void init_dma_chain(void *des, dma_addr_t phy_addr,
- unsigned int size, unsigned int extend_desc)
- {
- /*
- * In chained mode the des3 points to the next element in the ring.
- * The latest element has to point to the head.
- */
- int i;
- dma_addr_t dma_phy = phy_addr;
- if (extend_desc) {
- struct dma_extended_desc *p = (struct dma_extended_desc *)des;
- for (i = 0; i < (size - 1); i++) {
- dma_phy += sizeof(struct dma_extended_desc);
- p->basic.des3 = cpu_to_le32((unsigned int)dma_phy);
- p++;
- }
- p->basic.des3 = cpu_to_le32((unsigned int)phy_addr);
- } else {
- struct dma_desc *p = (struct dma_desc *)des;
- for (i = 0; i < (size - 1); i++) {
- dma_phy += sizeof(struct dma_desc);
- p->des3 = cpu_to_le32((unsigned int)dma_phy);
- p++;
- }
- p->des3 = cpu_to_le32((unsigned int)phy_addr);
- }
- }
- static void refill_desc3(void *priv_ptr, struct dma_desc *p)
- {
- struct stmmac_rx_queue *rx_q = (struct stmmac_rx_queue *)priv_ptr;
- struct stmmac_priv *priv = rx_q->priv_data;
- if (priv->hwts_rx_en && !priv->extend_desc)
- /* NOTE: Device will overwrite des3 with timestamp value if
- * 1588-2002 time stamping is enabled, hence reinitialize it
- * to keep explicit chaining in the descriptor.
- */
- p->des3 = cpu_to_le32((unsigned int)(rx_q->dma_rx_phy +
- (((rx_q->dirty_rx) + 1) %
- DMA_RX_SIZE) *
- sizeof(struct dma_desc)));
- }
- static void clean_desc3(void *priv_ptr, struct dma_desc *p)
- {
- struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)priv_ptr;
- struct stmmac_priv *priv = tx_q->priv_data;
- unsigned int entry = tx_q->dirty_tx;
- if (tx_q->tx_skbuff_dma[entry].last_segment && !priv->extend_desc &&
- priv->hwts_tx_en)
- /* NOTE: Device will overwrite des3 with timestamp value if
- * 1588-2002 time stamping is enabled, hence reinitialize it
- * to keep explicit chaining in the descriptor.
- */
- p->des3 = cpu_to_le32((unsigned int)((tx_q->dma_tx_phy +
- ((tx_q->dirty_tx + 1) % DMA_TX_SIZE))
- * sizeof(struct dma_desc)));
- }
- const struct stmmac_mode_ops chain_mode_ops = {
- .init = init_dma_chain,
- .is_jumbo_frm = is_jumbo_frm,
- .jumbo_frm = jumbo_frm,
- .refill_desc3 = refill_desc3,
- .clean_desc3 = clean_desc3,
- };