xref: /dpdk/drivers/net/sfc/sfc_tso.c (revision 89f0711f9ddfb5822da9d34f384b92f72a61c4dc)
1 /* SPDX-License-Identifier: BSD-3-Clause
2  *
3  * Copyright (c) 2016-2018 Solarflare Communications Inc.
4  * All rights reserved.
5  *
6  * This software was jointly developed between OKTET Labs (under contract
7  * for Solarflare) and Solarflare Communications, Inc.
8  */
9 
10 #include <rte_ip.h>
11 #include <rte_tcp.h>
12 
13 #include "sfc.h"
14 #include "sfc_debug.h"
15 #include "sfc_tx.h"
16 #include "sfc_ev.h"
17 
18 /** Standard TSO header length */
19 #define SFC_TSOH_STD_LEN        256
20 
21 /** The number of TSO option descriptors that precede the packet descriptors */
22 #define SFC_TSO_OPDESCS_IDX_SHIFT	2
23 
24 int
25 sfc_efx_tso_alloc_tsoh_objs(struct sfc_efx_tx_sw_desc *sw_ring,
26 			    unsigned int txq_entries, unsigned int socket_id)
27 {
28 	unsigned int i;
29 
30 	for (i = 0; i < txq_entries; ++i) {
31 		sw_ring[i].tsoh = rte_malloc_socket("sfc-efx-txq-tsoh-obj",
32 						    SFC_TSOH_STD_LEN,
33 						    RTE_CACHE_LINE_SIZE,
34 						    socket_id);
35 		if (sw_ring[i].tsoh == NULL)
36 			goto fail_alloc_tsoh_objs;
37 	}
38 
39 	return 0;
40 
41 fail_alloc_tsoh_objs:
42 	while (i > 0)
43 		rte_free(sw_ring[--i].tsoh);
44 
45 	return ENOMEM;
46 }
47 
48 void
49 sfc_efx_tso_free_tsoh_objs(struct sfc_efx_tx_sw_desc *sw_ring,
50 			   unsigned int txq_entries)
51 {
52 	unsigned int i;
53 
54 	for (i = 0; i < txq_entries; ++i) {
55 		rte_free(sw_ring[i].tsoh);
56 		sw_ring[i].tsoh = NULL;
57 	}
58 }
59 
60 static void
61 sfc_efx_tso_prepare_header(struct sfc_efx_txq *txq, struct rte_mbuf **in_seg,
62 			   size_t *in_off, unsigned int idx, size_t bytes_left)
63 {
64 	struct rte_mbuf *m = *in_seg;
65 	size_t bytes_to_copy = 0;
66 	uint8_t *tsoh = txq->sw_ring[idx & txq->ptr_mask].tsoh;
67 
68 	do {
69 		bytes_to_copy = MIN(bytes_left, m->data_len);
70 
71 		rte_memcpy(tsoh, rte_pktmbuf_mtod(m, uint8_t *),
72 			   bytes_to_copy);
73 
74 		bytes_left -= bytes_to_copy;
75 		tsoh += bytes_to_copy;
76 
77 		if (bytes_left > 0) {
78 			m = m->next;
79 			SFC_ASSERT(m != NULL);
80 		}
81 	} while (bytes_left > 0);
82 
83 	if (bytes_to_copy == m->data_len) {
84 		*in_seg = m->next;
85 		*in_off = 0;
86 	} else {
87 		*in_seg = m;
88 		*in_off = bytes_to_copy;
89 	}
90 }
91 
92 int
93 sfc_efx_tso_do(struct sfc_efx_txq *txq, unsigned int idx,
94 	       struct rte_mbuf **in_seg, size_t *in_off, efx_desc_t **pend,
95 	       unsigned int *pkt_descs, size_t *pkt_len)
96 {
97 	uint8_t *tsoh;
98 	const struct tcp_hdr *th;
99 	efsys_dma_addr_t header_paddr;
100 	uint16_t packet_id;
101 	uint32_t sent_seq;
102 	struct rte_mbuf *m = *in_seg;
103 	size_t nh_off = m->l2_len; /* IP header offset */
104 	size_t tcph_off = m->l2_len + m->l3_len; /* TCP header offset */
105 	size_t header_len = m->l2_len + m->l3_len + m->l4_len;
106 	const efx_nic_cfg_t *encp = efx_nic_cfg_get(txq->evq->sa->nic);
107 
108 	idx += SFC_TSO_OPDESCS_IDX_SHIFT;
109 
110 	/* Packets which have too big headers should be discarded */
111 	if (unlikely(header_len > SFC_TSOH_STD_LEN))
112 		return EMSGSIZE;
113 
114 	/*
115 	 * The TCP header must start at most 208 bytes into the frame.
116 	 * If it starts later than this then the NIC won't realise
117 	 * it's a TCP packet and TSO edits won't be applied
118 	 */
119 	if (unlikely(tcph_off > encp->enc_tx_tso_tcp_header_offset_limit))
120 		return EMSGSIZE;
121 
122 	header_paddr = rte_pktmbuf_iova(m);
123 
124 	/*
125 	 * Sometimes headers may be split across multiple mbufs. In such cases
126 	 * we need to glue those pieces and store them in some temporary place.
127 	 * Also, packet headers must be contiguous in memory, so that
128 	 * they can be referred to with a single DMA descriptor. EF10 has no
129 	 * limitations on address boundaries crossing by DMA descriptor data.
130 	 */
131 	if (m->data_len < header_len) {
132 		sfc_efx_tso_prepare_header(txq, in_seg, in_off, idx,
133 					   header_len);
134 		tsoh = txq->sw_ring[idx & txq->ptr_mask].tsoh;
135 
136 		header_paddr = rte_malloc_virt2iova((void *)tsoh);
137 	} else {
138 		if (m->data_len == header_len) {
139 			*in_off = 0;
140 			*in_seg = m->next;
141 		} else {
142 			*in_off = header_len;
143 		}
144 
145 		tsoh = rte_pktmbuf_mtod(m, uint8_t *);
146 	}
147 
148 	/* Handle IP header */
149 	if (m->ol_flags & PKT_TX_IPV4) {
150 		const struct ipv4_hdr *iphe4;
151 
152 		iphe4 = (const struct ipv4_hdr *)(tsoh + nh_off);
153 		rte_memcpy(&packet_id, &iphe4->packet_id, sizeof(uint16_t));
154 		packet_id = rte_be_to_cpu_16(packet_id);
155 	} else if (m->ol_flags & PKT_TX_IPV6) {
156 		packet_id = 0;
157 	} else {
158 		return EINVAL;
159 	}
160 
161 	/* Handle TCP header */
162 	th = (const struct tcp_hdr *)(tsoh + tcph_off);
163 
164 	rte_memcpy(&sent_seq, &th->sent_seq, sizeof(uint32_t));
165 	sent_seq = rte_be_to_cpu_32(sent_seq);
166 
167 	efx_tx_qdesc_tso2_create(txq->common, packet_id, sent_seq, m->tso_segsz,
168 				 *pend, EFX_TX_FATSOV2_OPT_NDESCS);
169 
170 	*pend += EFX_TX_FATSOV2_OPT_NDESCS;
171 	*pkt_descs += EFX_TX_FATSOV2_OPT_NDESCS;
172 
173 	efx_tx_qdesc_dma_create(txq->common, header_paddr, header_len,
174 				B_FALSE, (*pend)++);
175 	(*pkt_descs)++;
176 	*pkt_len -= header_len;
177 
178 	return 0;
179 }
180