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/* SPDX-License-Identifier: (GPL-2.0 OR MIT)
* Google virtual Ethernet (gve) driver
*
* Copyright (C) 2015-2019 Google, Inc.
*/
/* GVE Transmit Descriptor formats */
#ifndef _GVE_DESC_H_
#define _GVE_DESC_H_
#include <linux/build_bug.h>
/* A note on seg_addrs
*
* Base addresses encoded in seg_addr are not assumed to be physical
* addresses. The ring format assumes these come from some linear address
* space. This could be physical memory, kernel virtual memory, user virtual
* memory.
* If raw dma addressing is not supported then gVNIC uses lists of registered
* pages. Each queue is assumed to be associated with a single such linear
* address space to ensure a consistent meaning for seg_addrs posted to its
* rings.
*/
struct gve_tx_pkt_desc {
u8 type_flags; /* desc type is lower 4 bits, flags upper */
u8 l4_csum_offset; /* relative offset of L4 csum word */
u8 l4_hdr_offset; /* Offset of start of L4 headers in packet */
u8 desc_cnt; /* Total descriptors for this packet */
__be16 len; /* Total length of this packet (in bytes) */
__be16 seg_len; /* Length of this descriptor's segment */
__be64 seg_addr; /* Base address (see note) of this segment */
} __packed;
struct gve_tx_mtd_desc {
u8 type_flags; /* type is lower 4 bits, subtype upper */
u8 path_state; /* state is lower 4 bits, hash type upper */
__be16 reserved0;
__be32 path_hash;
__be64 reserved1;
} __packed;
struct gve_tx_seg_desc {
u8 type_flags; /* type is lower 4 bits, flags upper */
u8 l3_offset; /* TSO: 2 byte units to start of IPH */
__be16 reserved;
__be16 mss; /* TSO MSS */
__be16 seg_len;
__be64 seg_addr;
} __packed;
/* GVE Transmit Descriptor Types */
#define GVE_TXD_STD (0x0 << 4) /* Std with Host Address */
#define GVE_TXD_TSO (0x1 << 4) /* TSO with Host Address */
#define GVE_TXD_SEG (0x2 << 4) /* Seg with Host Address */
#define GVE_TXD_MTD (0x3 << 4) /* Metadata */
/* GVE Transmit Descriptor Flags for Std Pkts */
#define GVE_TXF_L4CSUM BIT(0) /* Need csum offload */
#define GVE_TXF_TSTAMP BIT(2) /* Timestamp required */
/* GVE Transmit Descriptor Flags for TSO Segs */
#define GVE_TXSF_IPV6 BIT(1) /* IPv6 TSO */
/* GVE Transmit Descriptor Options for MTD Segs */
#define GVE_MTD_SUBTYPE_PATH 0
#define GVE_MTD_PATH_STATE_DEFAULT 0
#define GVE_MTD_PATH_STATE_TIMEOUT 1
#define GVE_MTD_PATH_STATE_CONGESTION 2
#define GVE_MTD_PATH_STATE_RETRANSMIT 3
#define GVE_MTD_PATH_HASH_NONE (0x0 << 4)
#define GVE_MTD_PATH_HASH_L4 (0x1 << 4)
/* GVE Receive Packet Descriptor */
/* The start of an ethernet packet comes 2 bytes into the rx buffer.
* gVNIC adds this padding so that both the DMA and the L3/4 protocol header
* access is aligned.
*/
#define GVE_RX_PAD 2
struct gve_rx_desc {
u8 padding[48];
__be32 rss_hash; /* Receive-side scaling hash (Toeplitz for gVNIC) */
__be16 mss;
__be16 reserved; /* Reserved to zero */
u8 hdr_len; /* Header length (L2-L4) including padding */
u8 hdr_off; /* 64-byte-scaled offset into RX_DATA entry */
__sum16 csum; /* 1's-complement partial checksum of L3+ bytes */
__be16 len; /* Length of the received packet */
__be16 flags_seq; /* Flags [15:3] and sequence number [2:0] (1-7) */
} __packed;
static_assert(sizeof(struct gve_rx_desc) == 64);
/* If the device supports raw dma addressing then the addr in data slot is
* the dma address of the buffer.
* If the device only supports registered segments then the addr is a byte
* offset into the registered segment (an ordered list of pages) where the
* buffer is.
*/
union gve_rx_data_slot {
__be64 qpl_offset;
__be64 addr;
};
/* GVE Recive Packet Descriptor Seq No */
#define GVE_SEQNO(x) (be16_to_cpu(x) & 0x7)
/* GVE Recive Packet Descriptor Flags */
#define GVE_RXFLG(x) cpu_to_be16(1 << (3 + (x)))
#define GVE_RXF_FRAG GVE_RXFLG(3) /* IP Fragment */
#define GVE_RXF_IPV4 GVE_RXFLG(4) /* IPv4 */
#define GVE_RXF_IPV6 GVE_RXFLG(5) /* IPv6 */
#define GVE_RXF_TCP GVE_RXFLG(6) /* TCP Packet */
#define GVE_RXF_UDP GVE_RXFLG(7) /* UDP Packet */
#define GVE_RXF_ERR GVE_RXFLG(8) /* Packet Error Detected */
#define GVE_RXF_PKT_CONT GVE_RXFLG(10) /* Multi Fragment RX packet */
/* GVE IRQ */
#define GVE_IRQ_ACK BIT(31)
#define GVE_IRQ_MASK BIT(30)
#define GVE_IRQ_EVENT BIT(29)
static inline bool gve_needs_rss(__be16 flag)
{
if (flag & GVE_RXF_FRAG)
return false;
if (flag & (GVE_RXF_IPV4 | GVE_RXF_IPV6))
return true;
return false;
}
static inline u8 gve_next_seqno(u8 seq)
{
return (seq + 1) == 8 ? 1 : seq + 1;
}
#endif /* _GVE_DESC_H_ */
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