// SPDX-License-Identifier: GPL-2.0-only
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/****************************************************************************
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* Driver for Solarflare network controllers and boards
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* Copyright 2005-2006 Fen Systems Ltd.
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* Copyright 2005-2015 Solarflare Communications Inc.
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*/
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#include <linux/pci.h>
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#include <linux/tcp.h>
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#include <linux/ip.h>
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#include <linux/in.h>
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#include <linux/ipv6.h>
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#include <linux/slab.h>
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#include <net/ipv6.h>
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#include <linux/if_ether.h>
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#include <linux/highmem.h>
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#include <linux/moduleparam.h>
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#include <linux/cache.h>
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#include "net_driver.h"
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#include "efx.h"
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#include "io.h"
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#include "nic.h"
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#include "tx.h"
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#include "workarounds.h"
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#include "ef10_regs.h"
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/* Efx legacy TCP segmentation acceleration.
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*
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* Utilises firmware support to go faster than GSO (but not as fast as TSOv2).
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*
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* Requires TX checksum offload support.
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*/
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#define PTR_DIFF(p1, p2) ((u8 *)(p1) - (u8 *)(p2))
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/**
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* struct tso_state - TSO state for an SKB
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* @out_len: Remaining length in current segment
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* @seqnum: Current sequence number
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* @ipv4_id: Current IPv4 ID, host endian
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* @packet_space: Remaining space in current packet
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* @dma_addr: DMA address of current position
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* @in_len: Remaining length in current SKB fragment
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* @unmap_len: Length of SKB fragment
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* @unmap_addr: DMA address of SKB fragment
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* @protocol: Network protocol (after any VLAN header)
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* @ip_off: Offset of IP header
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* @tcp_off: Offset of TCP header
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* @header_len: Number of bytes of header
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* @ip_base_len: IPv4 tot_len or IPv6 payload_len, before TCP payload
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* @header_dma_addr: Header DMA address
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* @header_unmap_len: Header DMA mapped length
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*
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* The state used during segmentation. It is put into this data structure
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* just to make it easy to pass into inline functions.
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*/
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struct tso_state {
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/* Output position */
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unsigned int out_len;
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unsigned int seqnum;
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u16 ipv4_id;
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unsigned int packet_space;
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/* Input position */
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dma_addr_t dma_addr;
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unsigned int in_len;
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unsigned int unmap_len;
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dma_addr_t unmap_addr;
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__be16 protocol;
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unsigned int ip_off;
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unsigned int tcp_off;
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unsigned int header_len;
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unsigned int ip_base_len;
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dma_addr_t header_dma_addr;
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unsigned int header_unmap_len;
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};
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static inline void prefetch_ptr(struct efx_tx_queue *tx_queue)
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{
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unsigned int insert_ptr = efx_tx_queue_get_insert_index(tx_queue);
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char *ptr;
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ptr = (char *) (tx_queue->buffer + insert_ptr);
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prefetch(ptr);
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prefetch(ptr + 0x80);
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ptr = (char *) (((efx_qword_t *)tx_queue->txd.buf.addr) + insert_ptr);
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prefetch(ptr);
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prefetch(ptr + 0x80);
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}
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/**
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* efx_tx_queue_insert - push descriptors onto the TX queue
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* @tx_queue: Efx TX queue
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* @dma_addr: DMA address of fragment
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* @len: Length of fragment
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* @final_buffer: The final buffer inserted into the queue
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*
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* Push descriptors onto the TX queue.
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*/
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static void efx_tx_queue_insert(struct efx_tx_queue *tx_queue,
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dma_addr_t dma_addr, unsigned int len,
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struct efx_tx_buffer **final_buffer)
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{
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struct efx_tx_buffer *buffer;
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unsigned int dma_len;
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EFX_WARN_ON_ONCE_PARANOID(len <= 0);
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while (1) {
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buffer = efx_tx_queue_get_insert_buffer(tx_queue);
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++tx_queue->insert_count;
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EFX_WARN_ON_ONCE_PARANOID(tx_queue->insert_count -
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tx_queue->read_count >=
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tx_queue->efx->txq_entries);
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buffer->dma_addr = dma_addr;
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dma_len = tx_queue->efx->type->tx_limit_len(tx_queue,
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dma_addr, len);
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/* If there's space for everything this is our last buffer. */
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if (dma_len >= len)
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break;
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buffer->len = dma_len;
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buffer->flags = EFX_TX_BUF_CONT;
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dma_addr += dma_len;
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len -= dma_len;
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}
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EFX_WARN_ON_ONCE_PARANOID(!len);
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buffer->len = len;
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*final_buffer = buffer;
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}
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/*
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* Verify that our various assumptions about sk_buffs and the conditions
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* under which TSO will be attempted hold true. Return the protocol number.
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*/
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static __be16 efx_tso_check_protocol(struct sk_buff *skb)
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{
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__be16 protocol = skb->protocol;
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EFX_WARN_ON_ONCE_PARANOID(((struct ethhdr *)skb->data)->h_proto !=
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protocol);
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if (protocol == htons(ETH_P_8021Q)) {
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struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;
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protocol = veh->h_vlan_encapsulated_proto;
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}
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if (protocol == htons(ETH_P_IP)) {
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EFX_WARN_ON_ONCE_PARANOID(ip_hdr(skb)->protocol != IPPROTO_TCP);
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} else {
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EFX_WARN_ON_ONCE_PARANOID(protocol != htons(ETH_P_IPV6));
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EFX_WARN_ON_ONCE_PARANOID(ipv6_hdr(skb)->nexthdr != NEXTHDR_TCP);
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}
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EFX_WARN_ON_ONCE_PARANOID((PTR_DIFF(tcp_hdr(skb), skb->data) +
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(tcp_hdr(skb)->doff << 2u)) >
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skb_headlen(skb));
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return protocol;
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}
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/* Parse the SKB header and initialise state. */
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static int tso_start(struct tso_state *st, struct efx_nic *efx,
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struct efx_tx_queue *tx_queue,
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const struct sk_buff *skb)
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{
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struct device *dma_dev = &efx->pci_dev->dev;
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unsigned int header_len, in_len;
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dma_addr_t dma_addr;
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st->ip_off = skb_network_header(skb) - skb->data;
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st->tcp_off = skb_transport_header(skb) - skb->data;
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header_len = st->tcp_off + (tcp_hdr(skb)->doff << 2u);
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in_len = skb_headlen(skb) - header_len;
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st->header_len = header_len;
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st->in_len = in_len;
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if (st->protocol == htons(ETH_P_IP)) {
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st->ip_base_len = st->header_len - st->ip_off;
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st->ipv4_id = ntohs(ip_hdr(skb)->id);
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} else {
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st->ip_base_len = st->header_len - st->tcp_off;
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st->ipv4_id = 0;
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}
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st->seqnum = ntohl(tcp_hdr(skb)->seq);
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EFX_WARN_ON_ONCE_PARANOID(tcp_hdr(skb)->urg);
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EFX_WARN_ON_ONCE_PARANOID(tcp_hdr(skb)->syn);
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EFX_WARN_ON_ONCE_PARANOID(tcp_hdr(skb)->rst);
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st->out_len = skb->len - header_len;
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dma_addr = dma_map_single(dma_dev, skb->data,
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skb_headlen(skb), DMA_TO_DEVICE);
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st->header_dma_addr = dma_addr;
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st->header_unmap_len = skb_headlen(skb);
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st->dma_addr = dma_addr + header_len;
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st->unmap_len = 0;
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return unlikely(dma_mapping_error(dma_dev, dma_addr)) ? -ENOMEM : 0;
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}
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static int tso_get_fragment(struct tso_state *st, struct efx_nic *efx,
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skb_frag_t *frag)
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{
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st->unmap_addr = skb_frag_dma_map(&efx->pci_dev->dev, frag, 0,
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skb_frag_size(frag), DMA_TO_DEVICE);
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if (likely(!dma_mapping_error(&efx->pci_dev->dev, st->unmap_addr))) {
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st->unmap_len = skb_frag_size(frag);
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st->in_len = skb_frag_size(frag);
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st->dma_addr = st->unmap_addr;
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return 0;
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}
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return -ENOMEM;
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}
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/**
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* tso_fill_packet_with_fragment - form descriptors for the current fragment
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* @tx_queue: Efx TX queue
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* @skb: Socket buffer
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* @st: TSO state
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*
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* Form descriptors for the current fragment, until we reach the end
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* of fragment or end-of-packet.
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*/
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static void tso_fill_packet_with_fragment(struct efx_tx_queue *tx_queue,
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const struct sk_buff *skb,
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struct tso_state *st)
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{
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struct efx_tx_buffer *buffer;
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int n;
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if (st->in_len == 0)
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return;
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if (st->packet_space == 0)
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return;
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EFX_WARN_ON_ONCE_PARANOID(st->in_len <= 0);
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EFX_WARN_ON_ONCE_PARANOID(st->packet_space <= 0);
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n = min(st->in_len, st->packet_space);
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st->packet_space -= n;
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st->out_len -= n;
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st->in_len -= n;
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efx_tx_queue_insert(tx_queue, st->dma_addr, n, &buffer);
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if (st->out_len == 0) {
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/* Transfer ownership of the skb */
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buffer->skb = skb;
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buffer->flags = EFX_TX_BUF_SKB;
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} else if (st->packet_space != 0) {
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buffer->flags = EFX_TX_BUF_CONT;
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}
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if (st->in_len == 0) {
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/* Transfer ownership of the DMA mapping */
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buffer->unmap_len = st->unmap_len;
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buffer->dma_offset = buffer->unmap_len - buffer->len;
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st->unmap_len = 0;
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}
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st->dma_addr += n;
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}
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#define TCP_FLAGS_OFFSET 13
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/**
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* tso_start_new_packet - generate a new header and prepare for the new packet
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* @tx_queue: Efx TX queue
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* @skb: Socket buffer
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* @st: TSO state
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*
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* Generate a new header and prepare for the new packet. Return 0 on
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* success, or -%ENOMEM if failed to alloc header, or other negative error.
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*/
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static int tso_start_new_packet(struct efx_tx_queue *tx_queue,
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const struct sk_buff *skb,
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struct tso_state *st)
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{
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struct efx_tx_buffer *buffer =
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efx_tx_queue_get_insert_buffer(tx_queue);
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bool is_last = st->out_len <= skb_shinfo(skb)->gso_size;
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u8 tcp_flags_mask, tcp_flags;
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if (!is_last) {
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st->packet_space = skb_shinfo(skb)->gso_size;
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tcp_flags_mask = 0x09; /* mask out FIN and PSH */
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} else {
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st->packet_space = st->out_len;
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tcp_flags_mask = 0x00;
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}
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if (WARN_ON(!st->header_unmap_len))
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return -EINVAL;
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/* Send the original headers with a TSO option descriptor
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* in front
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*/
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tcp_flags = ((u8 *)tcp_hdr(skb))[TCP_FLAGS_OFFSET] & ~tcp_flags_mask;
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buffer->flags = EFX_TX_BUF_OPTION;
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buffer->len = 0;
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buffer->unmap_len = 0;
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EFX_POPULATE_QWORD_5(buffer->option,
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ESF_DZ_TX_DESC_IS_OPT, 1,
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ESF_DZ_TX_OPTION_TYPE,
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ESE_DZ_TX_OPTION_DESC_TSO,
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ESF_DZ_TX_TSO_TCP_FLAGS, tcp_flags,
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ESF_DZ_TX_TSO_IP_ID, st->ipv4_id,
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ESF_DZ_TX_TSO_TCP_SEQNO, st->seqnum);
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++tx_queue->insert_count;
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/* We mapped the headers in tso_start(). Unmap them
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* when the last segment is completed.
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*/
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buffer = efx_tx_queue_get_insert_buffer(tx_queue);
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buffer->dma_addr = st->header_dma_addr;
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buffer->len = st->header_len;
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if (is_last) {
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buffer->flags = EFX_TX_BUF_CONT | EFX_TX_BUF_MAP_SINGLE;
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buffer->unmap_len = st->header_unmap_len;
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buffer->dma_offset = 0;
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/* Ensure we only unmap them once in case of a
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* later DMA mapping error and rollback
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*/
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st->header_unmap_len = 0;
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} else {
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buffer->flags = EFX_TX_BUF_CONT;
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buffer->unmap_len = 0;
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}
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++tx_queue->insert_count;
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st->seqnum += skb_shinfo(skb)->gso_size;
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/* Linux leaves suitable gaps in the IP ID space for us to fill. */
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++st->ipv4_id;
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return 0;
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}
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/**
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* efx_enqueue_skb_tso - segment and transmit a TSO socket buffer
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* @tx_queue: Efx TX queue
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* @skb: Socket buffer
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* @data_mapped: Did we map the data? Always set to true
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* by this on success.
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*
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* Context: You must hold netif_tx_lock() to call this function.
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*
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* Add socket buffer @skb to @tx_queue, doing TSO or return != 0 if
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* @skb was not enqueued. @skb is consumed unless return value is
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* %EINVAL.
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*/
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int efx_enqueue_skb_tso(struct efx_tx_queue *tx_queue,
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struct sk_buff *skb,
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bool *data_mapped)
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{
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struct efx_nic *efx = tx_queue->efx;
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int frag_i, rc;
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struct tso_state state;
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if (tx_queue->tso_version != 1)
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return -EINVAL;
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prefetch(skb->data);
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/* Find the packet protocol and sanity-check it */
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state.protocol = efx_tso_check_protocol(skb);
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EFX_WARN_ON_ONCE_PARANOID(tx_queue->write_count != tx_queue->insert_count);
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rc = tso_start(&state, efx, tx_queue, skb);
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if (rc)
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goto fail;
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if (likely(state.in_len == 0)) {
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/* Grab the first payload fragment. */
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EFX_WARN_ON_ONCE_PARANOID(skb_shinfo(skb)->nr_frags < 1);
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frag_i = 0;
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rc = tso_get_fragment(&state, efx,
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skb_shinfo(skb)->frags + frag_i);
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if (rc)
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goto fail;
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} else {
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/* Payload starts in the header area. */
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frag_i = -1;
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}
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rc = tso_start_new_packet(tx_queue, skb, &state);
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if (rc)
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goto fail;
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prefetch_ptr(tx_queue);
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while (1) {
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tso_fill_packet_with_fragment(tx_queue, skb, &state);
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/* Move onto the next fragment? */
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if (state.in_len == 0) {
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if (++frag_i >= skb_shinfo(skb)->nr_frags)
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/* End of payload reached. */
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break;
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rc = tso_get_fragment(&state, efx,
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skb_shinfo(skb)->frags + frag_i);
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if (rc)
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goto fail;
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}
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/* Start at new packet? */
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if (state.packet_space == 0) {
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rc = tso_start_new_packet(tx_queue, skb, &state);
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if (rc)
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goto fail;
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}
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}
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*data_mapped = true;
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return 0;
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fail:
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if (rc == -ENOMEM)
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netif_err(efx, tx_err, efx->net_dev,
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"Out of memory for TSO headers, or DMA mapping error\n");
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else
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netif_err(efx, tx_err, efx->net_dev, "TSO failed, rc = %d\n", rc);
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/* Free the DMA mapping we were in the process of writing out */
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if (state.unmap_len) {
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dma_unmap_page(&efx->pci_dev->dev, state.unmap_addr,
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state.unmap_len, DMA_TO_DEVICE);
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}
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/* Free the header DMA mapping */
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if (state.header_unmap_len)
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dma_unmap_single(&efx->pci_dev->dev, state.header_dma_addr,
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state.header_unmap_len, DMA_TO_DEVICE);
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return rc;
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}
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