1/* SPDX-License-Identifier: (GPL-2.0 OR MIT) 2 * Google virtual Ethernet (gve) driver 3 * 4 * Copyright (C) 2015-2021 Google, Inc. 5 */ 6 7/* GVE DQO Descriptor formats */ 8 9#ifndef _GVE_DESC_DQO_H_ 10#define _GVE_DESC_DQO_H_ 11 12#include <linux/build_bug.h> 13 14#define GVE_TX_MAX_HDR_SIZE_DQO 255 15#define GVE_TX_MIN_TSO_MSS_DQO 88 16 17#ifndef __LITTLE_ENDIAN_BITFIELD 18#error "Only little endian supported" 19#endif 20 21/* Basic TX descriptor (DTYPE 0x0C) */ 22struct gve_tx_pkt_desc_dqo { 23 __le64 buf_addr; 24 25 /* Must be GVE_TX_PKT_DESC_DTYPE_DQO (0xc) */ 26 u8 dtype: 5; 27 28 /* Denotes the last descriptor of a packet. */ 29 u8 end_of_packet: 1; 30 u8 checksum_offload_enable: 1; 31 32 /* If set, will generate a descriptor completion for this descriptor. */ 33 u8 report_event: 1; 34 u8 reserved0; 35 __le16 reserved1; 36 37 /* The TX completion associated with this packet will contain this tag. 38 */ 39 __le16 compl_tag; 40 u16 buf_size: 14; 41 u16 reserved2: 2; 42} __packed; 43static_assert(sizeof(struct gve_tx_pkt_desc_dqo) == 16); 44 45#define GVE_TX_PKT_DESC_DTYPE_DQO 0xc 46#define GVE_TX_MAX_BUF_SIZE_DQO ((16 * 1024) - 1) 47 48/* Maximum number of data descriptors allowed per packet, or per-TSO segment. */ 49#define GVE_TX_MAX_DATA_DESCS 10 50 51/* Min gap between tail and head to avoid cacheline overlap */ 52#define GVE_TX_MIN_DESC_PREVENT_CACHE_OVERLAP 4 53 54/* "report_event" on TX packet descriptors may only be reported on the last 55 * descriptor of a TX packet, and they must be spaced apart with at least this 56 * value. 57 */ 58#define GVE_TX_MIN_RE_INTERVAL 32 59 60struct gve_tx_context_cmd_dtype { 61 u8 dtype: 5; 62 u8 tso: 1; 63 u8 reserved1: 2; 64 65 u8 reserved2; 66}; 67 68static_assert(sizeof(struct gve_tx_context_cmd_dtype) == 2); 69 70/* TX Native TSO Context DTYPE (0x05) 71 * 72 * "flex" fields allow the driver to send additional packet context to HW. 73 */ 74struct gve_tx_tso_context_desc_dqo { 75 /* The L4 payload bytes that should be segmented. */ 76 u32 tso_total_len: 24; 77 u32 flex10: 8; 78 79 /* Max segment size in TSO excluding headers. */ 80 u16 mss: 14; 81 u16 reserved: 2; 82 83 u8 header_len; /* Header length to use for TSO offload */ 84 u8 flex11; 85 struct gve_tx_context_cmd_dtype cmd_dtype; 86 u8 flex0; 87 u8 flex5; 88 u8 flex6; 89 u8 flex7; 90 u8 flex8; 91 u8 flex9; 92} __packed; 93static_assert(sizeof(struct gve_tx_tso_context_desc_dqo) == 16); 94 95#define GVE_TX_TSO_CTX_DESC_DTYPE_DQO 0x5 96 97/* General context descriptor for sending metadata. */ 98struct gve_tx_general_context_desc_dqo { 99 u8 flex4; 100 u8 flex5; 101 u8 flex6; 102 u8 flex7; 103 u8 flex8; 104 u8 flex9; 105 u8 flex10; 106 u8 flex11; 107 struct gve_tx_context_cmd_dtype cmd_dtype; 108 u16 reserved; 109 u8 flex0; 110 u8 flex1; 111 u8 flex2; 112 u8 flex3; 113} __packed; 114static_assert(sizeof(struct gve_tx_general_context_desc_dqo) == 16); 115 116#define GVE_TX_GENERAL_CTX_DESC_DTYPE_DQO 0x4 117 118/* Logical structure of metadata which is packed into context descriptor flex 119 * fields. 120 */ 121struct gve_tx_metadata_dqo { 122 union { 123 struct { 124 u8 version; 125 126 /* If `skb->l4_hash` is set, this value should be 127 * derived from `skb->hash`. 128 * 129 * A zero value means no l4_hash was associated with the 130 * skb. 131 */ 132 u16 path_hash: 15; 133 134 /* Should be set to 1 if the flow associated with the 135 * skb had a rehash from the TCP stack. 136 */ 137 u16 rehash_event: 1; 138 } __packed; 139 u8 bytes[12]; 140 }; 141} __packed; 142static_assert(sizeof(struct gve_tx_metadata_dqo) == 12); 143 144#define GVE_TX_METADATA_VERSION_DQO 0 145 146/* TX completion descriptor */ 147struct gve_tx_compl_desc { 148 /* For types 0-4 this is the TX queue ID associated with this 149 * completion. 150 */ 151 u16 id: 11; 152 153 /* See: GVE_COMPL_TYPE_DQO* */ 154 u16 type: 3; 155 u16 reserved0: 1; 156 157 /* Flipped by HW to notify the descriptor is populated. */ 158 u16 generation: 1; 159 union { 160 /* For descriptor completions, this is the last index fetched 161 * by HW + 1. 162 */ 163 __le16 tx_head; 164 165 /* For packet completions, this is the completion tag set on the 166 * TX packet descriptors. 167 */ 168 __le16 completion_tag; 169 }; 170 __le32 reserved1; 171} __packed; 172static_assert(sizeof(struct gve_tx_compl_desc) == 8); 173 174#define GVE_COMPL_TYPE_DQO_PKT 0x2 /* Packet completion */ 175#define GVE_COMPL_TYPE_DQO_DESC 0x4 /* Descriptor completion */ 176#define GVE_COMPL_TYPE_DQO_MISS 0x1 /* Miss path completion */ 177#define GVE_COMPL_TYPE_DQO_REINJECTION 0x3 /* Re-injection completion */ 178 179/* The most significant bit in the completion tag can change the completion 180 * type from packet completion to miss path completion. 181 */ 182#define GVE_ALT_MISS_COMPL_BIT BIT(15) 183 184/* Descriptor to post buffers to HW on buffer queue. */ 185struct gve_rx_desc_dqo { 186 __le16 buf_id; /* ID returned in Rx completion descriptor */ 187 __le16 reserved0; 188 __le32 reserved1; 189 __le64 buf_addr; /* DMA address of the buffer */ 190 __le64 header_buf_addr; 191 __le64 reserved2; 192} __packed; 193static_assert(sizeof(struct gve_rx_desc_dqo) == 32); 194 195/* Descriptor for HW to notify SW of new packets received on RX queue. */ 196struct gve_rx_compl_desc_dqo { 197 /* Must be 1 */ 198 u8 rxdid: 4; 199 u8 reserved0: 4; 200 201 /* Packet originated from this system rather than the network. */ 202 u8 loopback: 1; 203 /* Set when IPv6 packet contains a destination options header or routing 204 * header. 205 */ 206 u8 ipv6_ex_add: 1; 207 /* Invalid packet was received. */ 208 u8 rx_error: 1; 209 u8 reserved1: 5; 210 211 u16 packet_type: 10; 212 u16 ip_hdr_err: 1; 213 u16 udp_len_err: 1; 214 u16 raw_cs_invalid: 1; 215 u16 reserved2: 3; 216 217 u16 packet_len: 14; 218 /* Flipped by HW to notify the descriptor is populated. */ 219 u16 generation: 1; 220 /* Should be zero. */ 221 u16 buffer_queue_id: 1; 222 223 u16 header_len: 10; 224 u16 rsc: 1; 225 u16 split_header: 1; 226 u16 reserved3: 4; 227 228 u8 descriptor_done: 1; 229 u8 end_of_packet: 1; 230 u8 header_buffer_overflow: 1; 231 u8 l3_l4_processed: 1; 232 u8 csum_ip_err: 1; 233 u8 csum_l4_err: 1; 234 u8 csum_external_ip_err: 1; 235 u8 csum_external_udp_err: 1; 236 237 u8 status_error1; 238 239 __le16 reserved5; 240 __le16 buf_id; /* Buffer ID which was sent on the buffer queue. */ 241 242 union { 243 /* Packet checksum. */ 244 __le16 raw_cs; 245 /* Segment length for RSC packets. */ 246 __le16 rsc_seg_len; 247 }; 248 __le32 hash; 249 __le32 reserved6; 250 __le64 reserved7; 251} __packed; 252 253static_assert(sizeof(struct gve_rx_compl_desc_dqo) == 32); 254 255/* Ringing the doorbell too often can hurt performance. 256 * 257 * HW requires this value to be at least 8. 258 */ 259#define GVE_RX_BUF_THRESH_DQO 32 260 261#endif /* _GVE_DESC_DQO_H_ */ 262