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