/* SPDX-License-Identifier: GPL-2.0-only */
/* Copyright (C) 2024 Intel Corporation */
#ifndef __LIBETH_RX_H
#define __LIBETH_RX_H
#include <linux/if_vlan.h>
#include <net/page_pool/helpers.h>
#include <net/xdp.h>
/* Rx buffer management */
/* Space reserved in front of each frame */
#define LIBETH_SKB_HEADROOM (NET_SKB_PAD + NET_IP_ALIGN)
/* Maximum headroom for worst-case calculations */
#define LIBETH_MAX_HEADROOM LIBETH_SKB_HEADROOM
/* Link layer / L2 overhead: Ethernet, 2 VLAN tags (C + S), FCS */
#define LIBETH_RX_LL_LEN (ETH_HLEN + 2 * VLAN_HLEN + ETH_FCS_LEN)
/* Maximum supported L2-L4 header length */
#define LIBETH_MAX_HEAD roundup_pow_of_two(max(MAX_HEADER, 256))
/* Always use order-0 pages */
#define LIBETH_RX_PAGE_ORDER 0
/* Pick a sane buffer stride and align to a cacheline boundary */
#define LIBETH_RX_BUF_STRIDE SKB_DATA_ALIGN(128)
/* HW-writeable space in one buffer: truesize - headroom/tailroom, aligned */
#define LIBETH_RX_PAGE_LEN(hr) \
ALIGN_DOWN(SKB_MAX_ORDER(hr, LIBETH_RX_PAGE_ORDER), \
LIBETH_RX_BUF_STRIDE)
/**
* struct libeth_fqe - structure representing an Rx buffer (fill queue element)
* @page: page holding the buffer
* @offset: offset from the page start (to the headroom)
* @truesize: total space occupied by the buffer (w/ headroom and tailroom)
*
* Depending on the MTU, API switches between one-page-per-frame and shared
* page model (to conserve memory on bigger-page platforms). In case of the
* former, @offset is always 0 and @truesize is always ```PAGE_SIZE```.
*/
struct libeth_fqe {
struct page *page;
u32 offset;
u32 truesize;
} __aligned_largest;
/**
* enum libeth_fqe_type - enum representing types of Rx buffers
* @LIBETH_FQE_MTU: buffer size is determined by MTU
* @LIBETH_FQE_SHORT: buffer size is smaller than MTU, for short frames
* @LIBETH_FQE_HDR: buffer size is ```LIBETH_MAX_HEAD```-sized, for headers
*/
enum libeth_fqe_type {
LIBETH_FQE_MTU = 0U,
LIBETH_FQE_SHORT,
LIBETH_FQE_HDR,
};
/**
* struct libeth_fq - structure representing a buffer (fill) queue
* @fp: hotpath part of the structure
* @pp: &page_pool for buffer management
* @fqes: array of Rx buffers
* @truesize: size to allocate per buffer, w/overhead
* @count: number of descriptors/buffers the queue has
* @type: type of the buffers this queue has
* @hsplit: flag whether header split is enabled
* @buf_len: HW-writeable length per each buffer
* @nid: ID of the closest NUMA node with memory
*/
struct libeth_fq {
struct_group_tagged(libeth_fq_fp, fp,
struct page_pool *pp;
struct libeth_fqe *fqes;
u32 truesize;
u32 count;
);
/* Cold fields */
enum libeth_fqe_type type:2;
bool hsplit:1;
u32 buf_len;
int nid;
};
int libeth_rx_fq_create(struct libeth_fq *fq, struct napi_struct *napi);
void libeth_rx_fq_destroy(struct libeth_fq *fq);
/**
* libeth_rx_alloc - allocate a new Rx buffer
* @fq: fill queue to allocate for
* @i: index of the buffer within the queue
*
* Return: DMA address to be passed to HW for Rx on successful allocation,
* ```DMA_MAPPING_ERROR``` otherwise.
*/
static inline dma_addr_t libeth_rx_alloc(const struct libeth_fq_fp *fq, u32 i)
{
struct libeth_fqe *buf = &fq->fqes[i];
buf->truesize = fq->truesize;
buf->page = page_pool_dev_alloc(fq->pp, &buf->offset, &buf->truesize);
if (unlikely(!buf->page))
return DMA_MAPPING_ERROR;
return page_pool_get_dma_addr(buf->page) + buf->offset +
fq->pp->p.offset;
}
void libeth_rx_recycle_slow(struct page *page);
/**
* libeth_rx_sync_for_cpu - synchronize or recycle buffer post DMA
* @fqe: buffer to process
* @len: frame length from the descriptor
*
* Process the buffer after it's written by HW. The regular path is to
* synchronize DMA for CPU, but in case of no data it will be immediately
* recycled back to its PP.
*
* Return: true when there's data to process, false otherwise.
*/
static inline bool libeth_rx_sync_for_cpu(const struct libeth_fqe *fqe,
u32 len)
{
struct page *page = fqe->page;
/* Very rare, but possible case. The most common reason:
* the last fragment contained FCS only, which was then
* stripped by the HW.
*/
if (unlikely(!len)) {
libeth_rx_recycle_slow(page);
return false;
}
page_pool_dma_sync_for_cpu(page->pp, page, fqe->offset, len);
return true;
}
/* Converting abstract packet type numbers into a software structure with
* the packet parameters to do O(1) lookup on Rx.
*/
enum {
LIBETH_RX_PT_OUTER_L2 = 0U,
LIBETH_RX_PT_OUTER_IPV4,
LIBETH_RX_PT_OUTER_IPV6,
};
enum {
LIBETH_RX_PT_NOT_FRAG = 0U,
LIBETH_RX_PT_FRAG,
};
enum {
LIBETH_RX_PT_TUNNEL_IP_NONE = 0U,
LIBETH_RX_PT_TUNNEL_IP_IP,
LIBETH_RX_PT_TUNNEL_IP_GRENAT,
LIBETH_RX_PT_TUNNEL_IP_GRENAT_MAC,
LIBETH_RX_PT_TUNNEL_IP_GRENAT_MAC_VLAN,
};
enum {
LIBETH_RX_PT_TUNNEL_END_NONE = 0U,
LIBETH_RX_PT_TUNNEL_END_IPV4,
LIBETH_RX_PT_TUNNEL_END_IPV6,
};
enum {
LIBETH_RX_PT_INNER_NONE = 0U,
LIBETH_RX_PT_INNER_UDP,
LIBETH_RX_PT_INNER_TCP,
LIBETH_RX_PT_INNER_SCTP,
LIBETH_RX_PT_INNER_ICMP,
LIBETH_RX_PT_INNER_TIMESYNC,
};
#define LIBETH_RX_PT_PAYLOAD_NONE PKT_HASH_TYPE_NONE
#define LIBETH_RX_PT_PAYLOAD_L2 PKT_HASH_TYPE_L2
#define LIBETH_RX_PT_PAYLOAD_L3 PKT_HASH_TYPE_L3
#define LIBETH_RX_PT_PAYLOAD_L4 PKT_HASH_TYPE_L4
struct libeth_rx_pt {
u32 outer_ip:2;
u32 outer_frag:1;
u32 tunnel_type:3;
u32 tunnel_end_prot:2;
u32 tunnel_end_frag:1;
u32 inner_prot:3;
enum pkt_hash_types payload_layer:2;
u32 pad:2;
enum xdp_rss_hash_type hash_type:16;
};
void libeth_rx_pt_gen_hash_type(struct libeth_rx_pt *pt);
/**
* libeth_rx_pt_get_ip_ver - get IP version from a packet type structure
* @pt: packet type params
*
* Wrapper to compile out the IPv6 code from the drivers when not supported
* by the kernel.
*
* Return: @pt.outer_ip or stub for IPv6 when not compiled-in.
*/
static inline u32 libeth_rx_pt_get_ip_ver(struct libeth_rx_pt pt)
{
#if !IS_ENABLED(CONFIG_IPV6)
switch (pt.outer_ip) {
case LIBETH_RX_PT_OUTER_IPV4:
return LIBETH_RX_PT_OUTER_IPV4;
default:
return LIBETH_RX_PT_OUTER_L2;
}
#else
return pt.outer_ip;
#endif
}
/* libeth_has_*() can be used to quickly check whether the HW metadata is
* available to avoid further expensive processing such as descriptor reads.
* They already check for the corresponding netdev feature to be enabled,
* thus can be used as drop-in replacements.
*/
static inline bool libeth_rx_pt_has_checksum(const struct net_device *dev,
struct libeth_rx_pt pt)
{
/* Non-zero _INNER* is only possible when _OUTER_IPV* is set,
* it is enough to check only for the L4 type.
*/
return likely(pt.inner_prot > LIBETH_RX_PT_INNER_NONE &&
(dev->features & NETIF_F_RXCSUM));
}
static inline bool libeth_rx_pt_has_hash(const struct net_device *dev,
struct libeth_rx_pt pt)
{
return likely(pt.payload_layer > LIBETH_RX_PT_PAYLOAD_NONE &&
(dev->features & NETIF_F_RXHASH));
}
/**
* libeth_rx_pt_set_hash - fill in skb hash value basing on the PT
* @skb: skb to fill the hash in
* @hash: 32-bit hash value from the descriptor
* @pt: packet type
*/
static inline void libeth_rx_pt_set_hash(struct sk_buff *skb, u32 hash,
struct libeth_rx_pt pt)
{
skb_set_hash(skb, hash, pt.payload_layer);
}
#endif /* __LIBETH_RX_H */
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