1 /* SPDX-License-Identifier: (GPL-2.0 OR MIT) 2 * Google virtual Ethernet (gve) driver 3 * 4 * Copyright (C) 2015-2019 Google, Inc. 5 */ 6 7 /* GVE Transmit Descriptor formats */ 8 9 #ifndef _GVE_DESC_H_ 10 #define _GVE_DESC_H_ 11 12 #include <linux/build_bug.h> 13 14 /* A note on seg_addrs 15 * 16 * Base addresses encoded in seg_addr are not assumed to be physical 17 * addresses. The ring format assumes these come from some linear address 18 * space. This could be physical memory, kernel virtual memory, user virtual 19 * memory. 20 * If raw dma addressing is not supported then gVNIC uses lists of registered 21 * pages. Each queue is assumed to be associated with a single such linear 22 * address space to ensure a consistent meaning for seg_addrs posted to its 23 * rings. 24 */ 25 26 struct gve_tx_pkt_desc { 27 u8 type_flags; /* desc type is lower 4 bits, flags upper */ 28 u8 l4_csum_offset; /* relative offset of L4 csum word */ 29 u8 l4_hdr_offset; /* Offset of start of L4 headers in packet */ 30 u8 desc_cnt; /* Total descriptors for this packet */ 31 __be16 len; /* Total length of this packet (in bytes) */ 32 __be16 seg_len; /* Length of this descriptor's segment */ 33 __be64 seg_addr; /* Base address (see note) of this segment */ 34 } __packed; 35 36 struct gve_tx_mtd_desc { 37 u8 type_flags; /* type is lower 4 bits, subtype upper */ 38 u8 path_state; /* state is lower 4 bits, hash type upper */ 39 __be16 reserved0; 40 __be32 path_hash; 41 __be64 reserved1; 42 } __packed; 43 44 struct gve_tx_seg_desc { 45 u8 type_flags; /* type is lower 4 bits, flags upper */ 46 u8 l3_offset; /* TSO: 2 byte units to start of IPH */ 47 __be16 reserved; 48 __be16 mss; /* TSO MSS */ 49 __be16 seg_len; 50 __be64 seg_addr; 51 } __packed; 52 53 /* GVE Transmit Descriptor Types */ 54 #define GVE_TXD_STD (0x0 << 4) /* Std with Host Address */ 55 #define GVE_TXD_TSO (0x1 << 4) /* TSO with Host Address */ 56 #define GVE_TXD_SEG (0x2 << 4) /* Seg with Host Address */ 57 #define GVE_TXD_MTD (0x3 << 4) /* Metadata */ 58 59 /* GVE Transmit Descriptor Flags for Std Pkts */ 60 #define GVE_TXF_L4CSUM BIT(0) /* Need csum offload */ 61 #define GVE_TXF_TSTAMP BIT(2) /* Timestamp required */ 62 63 /* GVE Transmit Descriptor Flags for TSO Segs */ 64 #define GVE_TXSF_IPV6 BIT(1) /* IPv6 TSO */ 65 66 /* GVE Transmit Descriptor Options for MTD Segs */ 67 #define GVE_MTD_SUBTYPE_PATH 0 68 69 #define GVE_MTD_PATH_STATE_DEFAULT 0 70 #define GVE_MTD_PATH_STATE_TIMEOUT 1 71 #define GVE_MTD_PATH_STATE_CONGESTION 2 72 #define GVE_MTD_PATH_STATE_RETRANSMIT 3 73 74 #define GVE_MTD_PATH_HASH_NONE (0x0 << 4) 75 #define GVE_MTD_PATH_HASH_L4 (0x1 << 4) 76 77 /* GVE Receive Packet Descriptor */ 78 /* The start of an ethernet packet comes 2 bytes into the rx buffer. 79 * gVNIC adds this padding so that both the DMA and the L3/4 protocol header 80 * access is aligned. 81 */ 82 #define GVE_RX_PAD 2 83 84 struct gve_rx_desc { 85 u8 padding[48]; 86 __be32 rss_hash; /* Receive-side scaling hash (Toeplitz for gVNIC) */ 87 __be16 mss; 88 __be16 reserved; /* Reserved to zero */ 89 u8 hdr_len; /* Header length (L2-L4) including padding */ 90 u8 hdr_off; /* 64-byte-scaled offset into RX_DATA entry */ 91 __sum16 csum; /* 1's-complement partial checksum of L3+ bytes */ 92 __be16 len; /* Length of the received packet */ 93 __be16 flags_seq; /* Flags [15:3] and sequence number [2:0] (1-7) */ 94 } __packed; 95 static_assert(sizeof(struct gve_rx_desc) == 64); 96 97 /* If the device supports raw dma addressing then the addr in data slot is 98 * the dma address of the buffer. 99 * If the device only supports registered segments then the addr is a byte 100 * offset into the registered segment (an ordered list of pages) where the 101 * buffer is. 102 */ 103 union gve_rx_data_slot { 104 __be64 qpl_offset; 105 __be64 addr; 106 }; 107 108 /* GVE Receive Packet Descriptor Seq No */ 109 #define GVE_SEQNO(x) (be16_to_cpu(x) & 0x7) 110 111 /* GVE Receive Packet Descriptor Flags */ 112 #define GVE_RXFLG(x) cpu_to_be16(1 << (3 + (x))) 113 #define GVE_RXF_FRAG GVE_RXFLG(3) /* IP Fragment */ 114 #define GVE_RXF_IPV4 GVE_RXFLG(4) /* IPv4 */ 115 #define GVE_RXF_IPV6 GVE_RXFLG(5) /* IPv6 */ 116 #define GVE_RXF_TCP GVE_RXFLG(6) /* TCP Packet */ 117 #define GVE_RXF_UDP GVE_RXFLG(7) /* UDP Packet */ 118 #define GVE_RXF_ERR GVE_RXFLG(8) /* Packet Error Detected */ 119 #define GVE_RXF_PKT_CONT GVE_RXFLG(10) /* Multi Fragment RX packet */ 120 121 /* GVE IRQ */ 122 #define GVE_IRQ_ACK BIT(31) 123 #define GVE_IRQ_MASK BIT(30) 124 #define GVE_IRQ_EVENT BIT(29) 125 126 static inline bool gve_needs_rss(__be16 flag) 127 { 128 if (flag & GVE_RXF_FRAG) 129 return false; 130 if (flag & (GVE_RXF_IPV4 | GVE_RXF_IPV6)) 131 return true; 132 return false; 133 } 134 135 static inline u8 gve_next_seqno(u8 seq) 136 { 137 return (seq + 1) == 8 ? 1 : seq + 1; 138 } 139 #endif /* _GVE_DESC_H_ */ 140