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  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 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 entry = priv->cur_tx;
 35	struct dma_desc *desc = priv->dma_tx + entry;
 36	unsigned int nopaged_len = skb_headlen(skb);
 37	unsigned int bmax;
 38	unsigned int i = 1, 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	desc->des2 = dma_map_single(priv->device, skb->data,
 48				    bmax, DMA_TO_DEVICE);
 49	if (dma_mapping_error(priv->device, desc->des2))
 50		return -1;
 51	priv->tx_skbuff_dma[entry].buf = desc->des2;
 52	priv->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);
 56
 57	while (len != 0) {
 58		priv->tx_skbuff[entry] = NULL;
 59		entry = STMMAC_GET_ENTRY(entry, DMA_TX_SIZE);
 60		desc = priv->dma_tx + entry;
 61
 62		if (len > bmax) {
 63			desc->des2 = dma_map_single(priv->device,
 64						    (skb->data + bmax * i),
 65						    bmax, DMA_TO_DEVICE);
 66			if (dma_mapping_error(priv->device, desc->des2))
 67				return -1;
 68			priv->tx_skbuff_dma[entry].buf = desc->des2;
 69			priv->tx_skbuff_dma[entry].len = bmax;
 70			priv->hw->desc->prepare_tx_desc(desc, 0, bmax, csum,
 71							STMMAC_CHAIN_MODE, 1,
 72							false);
 73			len -= bmax;
 74			i++;
 75		} else {
 76			desc->des2 = dma_map_single(priv->device,
 77						    (skb->data + bmax * i), len,
 78						    DMA_TO_DEVICE);
 79			if (dma_mapping_error(priv->device, desc->des2))
 80				return -1;
 81			priv->tx_skbuff_dma[entry].buf = desc->des2;
 82			priv->tx_skbuff_dma[entry].len = len;
 83			/* last descriptor can be set now */
 84			priv->hw->desc->prepare_tx_desc(desc, 0, len, csum,
 85							STMMAC_CHAIN_MODE, 1,
 86							true);
 87			len = 0;
 88		}
 89	}
 90
 91	priv->cur_tx = entry;
 92
 93	return entry;
 94}
 95
 96static unsigned int stmmac_is_jumbo_frm(int len, int enh_desc)
 97{
 98	unsigned int ret = 0;
 99
100	if ((enh_desc && (len > BUF_SIZE_8KiB)) ||
101	    (!enh_desc && (len > BUF_SIZE_2KiB))) {
102		ret = 1;
103	}
104
105	return ret;
106}
107
108static void stmmac_init_dma_chain(void *des, dma_addr_t phy_addr,
109				  unsigned int size, unsigned int extend_desc)
110{
111	/*
112	 * In chained mode the des3 points to the next element in the ring.
113	 * The latest element has to point to the head.
114	 */
115	int i;
116	dma_addr_t dma_phy = phy_addr;
117
118	if (extend_desc) {
119		struct dma_extended_desc *p = (struct dma_extended_desc *)des;
120		for (i = 0; i < (size - 1); i++) {
121			dma_phy += sizeof(struct dma_extended_desc);
122			p->basic.des3 = (unsigned int)dma_phy;
123			p++;
124		}
125		p->basic.des3 = (unsigned int)phy_addr;
126
127	} else {
128		struct dma_desc *p = (struct dma_desc *)des;
129		for (i = 0; i < (size - 1); i++) {
130			dma_phy += sizeof(struct dma_desc);
131			p->des3 = (unsigned int)dma_phy;
132			p++;
133		}
134		p->des3 = (unsigned int)phy_addr;
135	}
136}
137
138static void stmmac_refill_desc3(void *priv_ptr, struct dma_desc *p)
139{
140	struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
141
142	if (priv->hwts_rx_en && !priv->extend_desc)
143		/* NOTE: Device will overwrite des3 with timestamp value if
144		 * 1588-2002 time stamping is enabled, hence reinitialize it
145		 * to keep explicit chaining in the descriptor.
146		 */
147		p->des3 = (unsigned int)(priv->dma_rx_phy +
148					 (((priv->dirty_rx) + 1) %
149					  DMA_RX_SIZE) *
150					 sizeof(struct dma_desc));
151}
152
153static void stmmac_clean_desc3(void *priv_ptr, struct dma_desc *p)
154{
155	struct stmmac_priv *priv = (struct stmmac_priv *)priv_ptr;
156	unsigned int entry = priv->dirty_tx;
157
158	if (priv->tx_skbuff_dma[entry].last_segment && !priv->extend_desc &&
159	    priv->hwts_tx_en)
160		/* NOTE: Device will overwrite des3 with timestamp value if
161		 * 1588-2002 time stamping is enabled, hence reinitialize it
162		 * to keep explicit chaining in the descriptor.
163		 */
164		p->des3 = (unsigned int)((priv->dma_tx_phy +
165					  ((priv->dirty_tx + 1) % DMA_TX_SIZE))
166					  * sizeof(struct dma_desc));
167}
168
169const struct stmmac_mode_ops chain_mode_ops = {
170	.init = stmmac_init_dma_chain,
171	.is_jumbo_frm = stmmac_is_jumbo_frm,
172	.jumbo_frm = stmmac_jumbo_frm,
173	.refill_desc3 = stmmac_refill_desc3,
174	.clean_desc3 = stmmac_clean_desc3,
175};