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_seg_desc { 37 u8 type_flags; /* type is lower 4 bits, flags upper */ 38 u8 l3_offset; /* TSO: 2 byte units to start of IPH */ 39 __be16 reserved; 40 __be16 mss; /* TSO MSS */ 41 __be16 seg_len; 42 __be64 seg_addr; 43 } __packed; 44 45 /* GVE Transmit Descriptor Types */ 46 #define GVE_TXD_STD (0x0 << 4) /* Std with Host Address */ 47 #define GVE_TXD_TSO (0x1 << 4) /* TSO with Host Address */ 48 #define GVE_TXD_SEG (0x2 << 4) /* Seg with Host Address */ 49 50 /* GVE Transmit Descriptor Flags for Std Pkts */ 51 #define GVE_TXF_L4CSUM BIT(0) /* Need csum offload */ 52 #define GVE_TXF_TSTAMP BIT(2) /* Timestamp required */ 53 54 /* GVE Transmit Descriptor Flags for TSO Segs */ 55 #define GVE_TXSF_IPV6 BIT(1) /* IPv6 TSO */ 56 57 /* GVE Receive Packet Descriptor */ 58 /* The start of an ethernet packet comes 2 bytes into the rx buffer. 59 * gVNIC adds this padding so that both the DMA and the L3/4 protocol header 60 * access is aligned. 61 */ 62 #define GVE_RX_PAD 2 63 64 struct gve_rx_desc { 65 u8 padding[48]; 66 __be32 rss_hash; /* Receive-side scaling hash (Toeplitz for gVNIC) */ 67 __be16 mss; 68 __be16 reserved; /* Reserved to zero */ 69 u8 hdr_len; /* Header length (L2-L4) including padding */ 70 u8 hdr_off; /* 64-byte-scaled offset into RX_DATA entry */ 71 __sum16 csum; /* 1's-complement partial checksum of L3+ bytes */ 72 __be16 len; /* Length of the received packet */ 73 __be16 flags_seq; /* Flags [15:3] and sequence number [2:0] (1-7) */ 74 } __packed; 75 static_assert(sizeof(struct gve_rx_desc) == 64); 76 77 /* If the device supports raw dma addressing then the addr in data slot is 78 * the dma address of the buffer. 79 * If the device only supports registered segments then the addr is a byte 80 * offset into the registered segment (an ordered list of pages) where the 81 * buffer is. 82 */ 83 union gve_rx_data_slot { 84 __be64 qpl_offset; 85 __be64 addr; 86 }; 87 88 /* GVE Recive Packet Descriptor Seq No */ 89 #define GVE_SEQNO(x) (be16_to_cpu(x) & 0x7) 90 91 /* GVE Recive Packet Descriptor Flags */ 92 #define GVE_RXFLG(x) cpu_to_be16(1 << (3 + (x))) 93 #define GVE_RXF_FRAG GVE_RXFLG(3) /* IP Fragment */ 94 #define GVE_RXF_IPV4 GVE_RXFLG(4) /* IPv4 */ 95 #define GVE_RXF_IPV6 GVE_RXFLG(5) /* IPv6 */ 96 #define GVE_RXF_TCP GVE_RXFLG(6) /* TCP Packet */ 97 #define GVE_RXF_UDP GVE_RXFLG(7) /* UDP Packet */ 98 #define GVE_RXF_ERR GVE_RXFLG(8) /* Packet Error Detected */ 99 100 /* GVE IRQ */ 101 #define GVE_IRQ_ACK BIT(31) 102 #define GVE_IRQ_MASK BIT(30) 103 #define GVE_IRQ_EVENT BIT(29) 104 gve_needs_rss(__be16 flag)105static inline bool gve_needs_rss(__be16 flag) 106 { 107 if (flag & GVE_RXF_FRAG) 108 return false; 109 if (flag & (GVE_RXF_IPV4 | GVE_RXF_IPV6)) 110 return true; 111 return false; 112 } 113 gve_next_seqno(u8 seq)114static inline u8 gve_next_seqno(u8 seq) 115 { 116 return (seq + 1) == 8 ? 1 : seq + 1; 117 } 118 #endif /* _GVE_DESC_H_ */ 119