/* 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. 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_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 */
|
|
/* 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 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);
|
|
/* As with the Tx ring format, the qpl_offset entries below are offsets into an
|
* ordered list of registered pages.
|
*/
|
struct gve_rx_data_slot {
|
/* byte offset into the rx registered segment of this slot */
|
__be64 qpl_offset;
|
};
|
|
/* 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 */
|
|
/* 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_ */
|
