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  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 stmmac_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, des2;
 34	unsigned int i = 1, len;
 35	struct dma_desc *desc;
 36
 37	desc = tx_q->dma_tx + entry;
 38
 39	if (priv->plat->enh_desc)
 40		bmax = BUF_SIZE_8KiB;
 41	else
 42		bmax = BUF_SIZE_2KiB;
 43
 44	len = nopaged_len - bmax;
 45
 46	des2 = dma_map_single(priv->device, skb->data,
 47			      bmax, DMA_TO_DEVICE);
 48	desc->des2 = cpu_to_le32(des2);
 49	if (dma_mapping_error(priv->device, des2))
 50		return -1;
 51	tx_q->tx_skbuff_dma[entry].buf = des2;
 52	tx_q->tx_skbuff_dma[entry].len = bmax;
 53	/* do not close the descriptor and do not set own bit */
 54	priv->hw->desc->prepare_tx_desc(desc, 1, bmax, csum, STMMAC_CHAIN_MODE,
 55					0, false, skb->len);
 56
 57	while (len != 0) {
 58		tx_q->tx_skbuff[entry] = NULL;
 59		entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
 60		desc = tx_q->dma_tx + entry;
 61
 62		if (len > bmax) {
 63			des2 = dma_map_single(priv->device,
 64					      (skb->data + bmax * i),
 65					      bmax, DMA_TO_DEVICE);
 66			desc->des2 = cpu_to_le32(des2);
 67			if (dma_mapping_error(priv->device, des2))
 68				return -1;
 69			tx_q->tx_skbuff_dma[entry].buf = des2;
 70			tx_q->tx_skbuff_dma[entry].len = bmax;
 71			priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
 72							STMMAC_CHAIN_MODE, 1,
 73							false, skb->len);
 74			len -= bmax;
 75			i++;
 76		} else {
 77			des2 = dma_map_single(priv->device,
 78					      (skb->data + bmax * i), len,
 79					      DMA_TO_DEVICE);
 80			desc->des2 = cpu_to_le32(des2);
 81			if (dma_mapping_error(priv->device, des2))
 82				return -1;
 83			tx_q->tx_skbuff_dma[entry].buf = des2;
 84			tx_q->tx_skbuff_dma[entry].len = len;
 85			/* last descriptor can be set now */
 86			priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
 87							STMMAC_CHAIN_MODE, 1,
 88							true, skb->len);
 89			len = 0;
 90		}
 91	}
 92
 93	tx_q->cur_tx = entry;
 94
 95	return entry;
 96}
 97
 98static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc)
 99{
100	unsigned int ret = 0;
101
102	if ((enh_desc && (len > BUF_SIZE_8KiB)) ||
103	    (!enh_desc && (len > BUF_SIZE_2KiB))) {
104		ret = 1;
105	}
106
107	return ret;
108}
109
110static void stmmac_init_dma_chain(void *des, dma_addr_t phy_addr,
111				  unsigned int size, unsigned int extend_desc)
112{
113	/*
114	 * In chained mode the des3 points to the next element in the ring.
115	 * The latest element has to point to the head.
116	 */
117	int i;
118	dma_addr_t dma_phy = phy_addr;
119
120	if (extend_desc) {
121		struct dma_extended_desc *p = (struct dma_extended_desc *)des;
122		for (i = 0; i < (size - 1); i++) {
123			dma_phy += sizeof(struct dma_extended_desc);
124			p->basic.des3 = cpu_to_le32((unsigned int)dma_phy);
125			p++;
126		}
127		p->basic.des3 = cpu_to_le32((unsigned int)phy_addr);
128
129	} else {
130		struct dma_desc *p = (struct dma_desc *)des;
131		for (i = 0; i < (size - 1); i++) {
132			dma_phy += sizeof(struct dma_desc);
133			p->des3 = cpu_to_le32((unsigned int)dma_phy);
134			p++;
135		}
136		p->des3 = cpu_to_le32((unsigned int)phy_addr);
137	}
138}
139
140static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p)
141{
142	struct stmmac_rx_queue *rx_q = (struct stmmac_rx_queue *)priv_ptr;
143	struct stmmac_priv *priv = rx_q->priv_data;
144
145	if (priv->hwts_rx_en && !priv->extend_desc)
146		/* NOTE: Device will overwrite des3 with timestamp value if
147		 * 1588-2002 time stamping is enabled, hence reinitialize it
148		 * to keep explicit chaining in the descriptor.
149		 */
150		p->des3 = cpu_to_le32((unsigned int)(rx_q->dma_rx_phy +
151				      (((rx_q->dirty_rx) + 1) %
152				       DMA_RX_SIZE) *
153				      sizeof(struct dma_desc)));
154}
155
156static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
157{
158	struct stmmac_tx_queue *tx_q = (struct stmmac_tx_queue *)priv_ptr;
159	struct stmmac_priv *priv = tx_q->priv_data;
160	unsigned int entry = tx_q->dirty_tx;
161
162	if (tx_q->tx_skbuff_dma[entry].last_segment && !priv->extend_desc &&
163	    priv->hwts_tx_en)
164		/* NOTE: Device will overwrite des3 with timestamp value if
165		 * 1588-2002 time stamping is enabled, hence reinitialize it
166		 * to keep explicit chaining in the descriptor.
167		 */
168		p->des3 = cpu_to_le32((unsigned int)((tx_q->dma_tx_phy +
169				      ((tx_q->dirty_tx + 1) % DMA_TX_SIZE))
170				      * sizeof(struct dma_desc)));
171}
172
173const struct stmmac_mode_ops chain_mode_ops = {
174	.init = stmmac_init_dma_chain,
175	.is_jumbo_frm = stmmac_is_jumbo_frm,
176	.jumbo_frm = stmmac_jumbo_frm,
177	.refill_desc3 = stmmac_refill_desc3,
178	.clean_desc3 = stmmac_clean_desc3,
179};