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linux-zen-server/drivers/net/ethernet/sfc/ef100_tx.c

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// SPDX-License-Identifier: GPL-2.0-only
/****************************************************************************
* Driver for Solarflare network controllers and boards
* Copyright 2018 Solarflare Communications Inc.
* Copyright 2019-2020 Xilinx 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 <net/ip6_checksum.h>
#include "net_driver.h"
#include "tx_common.h"
#include "nic_common.h"
#include "mcdi_functions.h"
#include "ef100_regs.h"
#include "io.h"
#include "ef100_tx.h"
#include "ef100_nic.h"
int ef100_tx_probe(struct efx_tx_queue *tx_queue)
{
/* Allocate an extra descriptor for the QMDA status completion entry */
return efx_nic_alloc_buffer(tx_queue->efx, &tx_queue->txd.buf,
(tx_queue->ptr_mask + 2) *
sizeof(efx_oword_t),
GFP_KERNEL);
}
void ef100_tx_init(struct efx_tx_queue *tx_queue)
{
/* must be the inverse of lookup in efx_get_tx_channel */
tx_queue->core_txq =
netdev_get_tx_queue(tx_queue->efx->net_dev,
tx_queue->channel->channel -
tx_queue->efx->tx_channel_offset);
/* This value is purely documentational; as EF100 never passes through
* the switch statement in tx.c:__efx_enqueue_skb(), that switch does
* not handle case 3. EF100's TSOv3 descriptors are generated by
* ef100_make_tso_desc().
* Meanwhile, all efx_mcdi_tx_init() cares about is that it's not 2.
*/
tx_queue->tso_version = 3;
if (efx_mcdi_tx_init(tx_queue))
netdev_WARN(tx_queue->efx->net_dev,
"failed to initialise TXQ %d\n", tx_queue->queue);
}
static bool ef100_tx_can_tso(struct efx_tx_queue *tx_queue, struct sk_buff *skb)
{
struct efx_nic *efx = tx_queue->efx;
struct ef100_nic_data *nic_data;
struct efx_tx_buffer *buffer;
size_t header_len;
u32 mss;
nic_data = efx->nic_data;
if (!skb_is_gso_tcp(skb))
return false;
if (!(efx->net_dev->features & NETIF_F_TSO))
return false;
mss = skb_shinfo(skb)->gso_size;
if (unlikely(mss < 4)) {
WARN_ONCE(1, "MSS of %u is too small for TSO\n", mss);
return false;
}
header_len = efx_tx_tso_header_length(skb);
if (header_len > nic_data->tso_max_hdr_len)
return false;
if (skb_shinfo(skb)->gso_segs > nic_data->tso_max_payload_num_segs) {
/* net_dev->gso_max_segs should've caught this */
WARN_ON_ONCE(1);
return false;
}
if (skb->data_len / mss > nic_data->tso_max_frames)
return false;
/* net_dev->gso_max_size should've caught this */
if (WARN_ON_ONCE(skb->data_len > nic_data->tso_max_payload_len))
return false;
/* Reserve an empty buffer for the TSO V3 descriptor.
* Convey the length of the header since we already know it.
*/
buffer = efx_tx_queue_get_insert_buffer(tx_queue);
buffer->flags = EFX_TX_BUF_TSO_V3 | EFX_TX_BUF_CONT;
buffer->len = header_len;
buffer->unmap_len = 0;
buffer->skb = skb;
++tx_queue->insert_count;
return true;
}
static efx_oword_t *ef100_tx_desc(struct efx_tx_queue *tx_queue, unsigned int index)
{
if (likely(tx_queue->txd.buf.addr))
return ((efx_oword_t *)tx_queue->txd.buf.addr) + index;
else
return NULL;
}
static void ef100_notify_tx_desc(struct efx_tx_queue *tx_queue)
{
unsigned int write_ptr;
efx_dword_t reg;
tx_queue->xmit_pending = false;
if (unlikely(tx_queue->notify_count == tx_queue->write_count))
return;
write_ptr = tx_queue->write_count & tx_queue->ptr_mask;
/* The write pointer goes into the high word */
EFX_POPULATE_DWORD_1(reg, ERF_GZ_TX_RING_PIDX, write_ptr);
efx_writed_page(tx_queue->efx, &reg,
ER_GZ_TX_RING_DOORBELL, tx_queue->queue);
tx_queue->notify_count = tx_queue->write_count;
}
static void ef100_tx_push_buffers(struct efx_tx_queue *tx_queue)
{
ef100_notify_tx_desc(tx_queue);
++tx_queue->pushes;
}
static void ef100_set_tx_csum_partial(const struct sk_buff *skb,
struct efx_tx_buffer *buffer, efx_oword_t *txd)
{
efx_oword_t csum;
int csum_start;
if (!skb || skb->ip_summed != CHECKSUM_PARTIAL)
return;
/* skb->csum_start has the offset from head, but we need the offset
* from data.
*/
csum_start = skb_checksum_start_offset(skb);
EFX_POPULATE_OWORD_3(csum,
ESF_GZ_TX_SEND_CSO_PARTIAL_EN, 1,
ESF_GZ_TX_SEND_CSO_PARTIAL_START_W,
csum_start >> 1,
ESF_GZ_TX_SEND_CSO_PARTIAL_CSUM_W,
skb->csum_offset >> 1);
EFX_OR_OWORD(*txd, *txd, csum);
}
static void ef100_set_tx_hw_vlan(const struct sk_buff *skb, efx_oword_t *txd)
{
u16 vlan_tci = skb_vlan_tag_get(skb);
efx_oword_t vlan;
EFX_POPULATE_OWORD_2(vlan,
ESF_GZ_TX_SEND_VLAN_INSERT_EN, 1,
ESF_GZ_TX_SEND_VLAN_INSERT_TCI, vlan_tci);
EFX_OR_OWORD(*txd, *txd, vlan);
}
static void ef100_make_send_desc(struct efx_nic *efx,
const struct sk_buff *skb,
struct efx_tx_buffer *buffer, efx_oword_t *txd,
unsigned int segment_count)
{
/* TX send descriptor */
EFX_POPULATE_OWORD_3(*txd,
ESF_GZ_TX_SEND_NUM_SEGS, segment_count,
ESF_GZ_TX_SEND_LEN, buffer->len,
ESF_GZ_TX_SEND_ADDR, buffer->dma_addr);
if (likely(efx->net_dev->features & NETIF_F_HW_CSUM))
ef100_set_tx_csum_partial(skb, buffer, txd);
if (efx->net_dev->features & NETIF_F_HW_VLAN_CTAG_TX &&
skb && skb_vlan_tag_present(skb))
ef100_set_tx_hw_vlan(skb, txd);
}
static void ef100_make_tso_desc(struct efx_nic *efx,
const struct sk_buff *skb,
struct efx_tx_buffer *buffer, efx_oword_t *txd,
unsigned int segment_count)
{
bool gso_partial = skb_shinfo(skb)->gso_type & SKB_GSO_PARTIAL;
unsigned int len, ip_offset, tcp_offset, payload_segs;
u32 mangleid = ESE_GZ_TX_DESC_IP4_ID_INC_MOD16;
unsigned int outer_ip_offset, outer_l4_offset;
u16 vlan_tci = skb_vlan_tag_get(skb);
u32 mss = skb_shinfo(skb)->gso_size;
bool encap = skb->encapsulation;
bool udp_encap = false;
u16 vlan_enable = 0;
struct tcphdr *tcp;
bool outer_csum;
u32 paylen;
if (skb_shinfo(skb)->gso_type & SKB_GSO_TCP_FIXEDID)
mangleid = ESE_GZ_TX_DESC_IP4_ID_NO_OP;
if (efx->net_dev->features & NETIF_F_HW_VLAN_CTAG_TX)
vlan_enable = skb_vlan_tag_present(skb);
len = skb->len - buffer->len;
/* We use 1 for the TSO descriptor and 1 for the header */
payload_segs = segment_count - 2;
if (encap) {
outer_ip_offset = skb_network_offset(skb);
outer_l4_offset = skb_transport_offset(skb);
ip_offset = skb_inner_network_offset(skb);
tcp_offset = skb_inner_transport_offset(skb);
if (skb_shinfo(skb)->gso_type &
(SKB_GSO_UDP_TUNNEL | SKB_GSO_UDP_TUNNEL_CSUM))
udp_encap = true;
} else {
ip_offset = skb_network_offset(skb);
tcp_offset = skb_transport_offset(skb);
outer_ip_offset = outer_l4_offset = 0;
}
outer_csum = skb_shinfo(skb)->gso_type & SKB_GSO_UDP_TUNNEL_CSUM;
/* subtract TCP payload length from inner checksum */
tcp = (void *)skb->data + tcp_offset;
paylen = skb->len - tcp_offset;
csum_replace_by_diff(&tcp->check, (__force __wsum)htonl(paylen));
EFX_POPULATE_OWORD_19(*txd,
ESF_GZ_TX_DESC_TYPE, ESE_GZ_TX_DESC_TYPE_TSO,
ESF_GZ_TX_TSO_MSS, mss,
ESF_GZ_TX_TSO_HDR_NUM_SEGS, 1,
ESF_GZ_TX_TSO_PAYLOAD_NUM_SEGS, payload_segs,
ESF_GZ_TX_TSO_HDR_LEN_W, buffer->len >> 1,
ESF_GZ_TX_TSO_PAYLOAD_LEN, len,
ESF_GZ_TX_TSO_CSO_OUTER_L4, outer_csum,
ESF_GZ_TX_TSO_CSO_INNER_L4, 1,
ESF_GZ_TX_TSO_INNER_L3_OFF_W, ip_offset >> 1,
ESF_GZ_TX_TSO_INNER_L4_OFF_W, tcp_offset >> 1,
ESF_GZ_TX_TSO_ED_INNER_IP4_ID, mangleid,
ESF_GZ_TX_TSO_ED_INNER_IP_LEN, 1,
ESF_GZ_TX_TSO_OUTER_L3_OFF_W, outer_ip_offset >> 1,
ESF_GZ_TX_TSO_OUTER_L4_OFF_W, outer_l4_offset >> 1,
ESF_GZ_TX_TSO_ED_OUTER_UDP_LEN, udp_encap && !gso_partial,
ESF_GZ_TX_TSO_ED_OUTER_IP_LEN, encap && !gso_partial,
ESF_GZ_TX_TSO_ED_OUTER_IP4_ID, encap ? mangleid :
ESE_GZ_TX_DESC_IP4_ID_NO_OP,
ESF_GZ_TX_TSO_VLAN_INSERT_EN, vlan_enable,
ESF_GZ_TX_TSO_VLAN_INSERT_TCI, vlan_tci
);
}
static void ef100_tx_make_descriptors(struct efx_tx_queue *tx_queue,
const struct sk_buff *skb,
unsigned int segment_count,
struct efx_rep *efv)
{
unsigned int old_write_count = tx_queue->write_count;
unsigned int new_write_count = old_write_count;
struct efx_tx_buffer *buffer;
unsigned int next_desc_type;
unsigned int write_ptr;
efx_oword_t *txd;
unsigned int nr_descs = tx_queue->insert_count - old_write_count;
if (unlikely(nr_descs == 0))
return;
if (segment_count)
next_desc_type = ESE_GZ_TX_DESC_TYPE_TSO;
else
next_desc_type = ESE_GZ_TX_DESC_TYPE_SEND;
if (unlikely(efv)) {
/* Create TX override descriptor */
write_ptr = new_write_count & tx_queue->ptr_mask;
txd = ef100_tx_desc(tx_queue, write_ptr);
++new_write_count;
tx_queue->packet_write_count = new_write_count;
EFX_POPULATE_OWORD_3(*txd,
ESF_GZ_TX_DESC_TYPE, ESE_GZ_TX_DESC_TYPE_PREFIX,
ESF_GZ_TX_PREFIX_EGRESS_MPORT, efv->mport,
ESF_GZ_TX_PREFIX_EGRESS_MPORT_EN, 1);
nr_descs--;
}
/* if it's a raw write (such as XDP) then always SEND single frames */
if (!skb)
nr_descs = 1;
do {
write_ptr = new_write_count & tx_queue->ptr_mask;
buffer = &tx_queue->buffer[write_ptr];
txd = ef100_tx_desc(tx_queue, write_ptr);
++new_write_count;
/* Create TX descriptor ring entry */
tx_queue->packet_write_count = new_write_count;
switch (next_desc_type) {
case ESE_GZ_TX_DESC_TYPE_SEND:
ef100_make_send_desc(tx_queue->efx, skb,
buffer, txd, nr_descs);
break;
case ESE_GZ_TX_DESC_TYPE_TSO:
/* TX TSO descriptor */
WARN_ON_ONCE(!(buffer->flags & EFX_TX_BUF_TSO_V3));
ef100_make_tso_desc(tx_queue->efx, skb,
buffer, txd, nr_descs);
break;
default:
/* TX segment descriptor */
EFX_POPULATE_OWORD_3(*txd,
ESF_GZ_TX_DESC_TYPE, ESE_GZ_TX_DESC_TYPE_SEG,
ESF_GZ_TX_SEG_LEN, buffer->len,
ESF_GZ_TX_SEG_ADDR, buffer->dma_addr);
}
/* if it's a raw write (such as XDP) then always SEND */
next_desc_type = skb ? ESE_GZ_TX_DESC_TYPE_SEG :
ESE_GZ_TX_DESC_TYPE_SEND;
/* mark as an EFV buffer if applicable */
if (unlikely(efv))
buffer->flags |= EFX_TX_BUF_EFV;
} while (new_write_count != tx_queue->insert_count);
wmb(); /* Ensure descriptors are written before they are fetched */
tx_queue->write_count = new_write_count;
/* The write_count above must be updated before reading
* channel->holdoff_doorbell to avoid a race with the
* completion path, so ensure these operations are not
* re-ordered. This also flushes the update of write_count
* back into the cache.
*/
smp_mb();
}
void ef100_tx_write(struct efx_tx_queue *tx_queue)
{
ef100_tx_make_descriptors(tx_queue, NULL, 0, NULL);
ef100_tx_push_buffers(tx_queue);
}
void ef100_ev_tx(struct efx_channel *channel, const efx_qword_t *p_event)
{
unsigned int tx_done =
EFX_QWORD_FIELD(*p_event, ESF_GZ_EV_TXCMPL_NUM_DESC);
unsigned int qlabel =
EFX_QWORD_FIELD(*p_event, ESF_GZ_EV_TXCMPL_Q_LABEL);
struct efx_tx_queue *tx_queue =
efx_channel_get_tx_queue(channel, qlabel);
unsigned int tx_index = (tx_queue->read_count + tx_done - 1) &
tx_queue->ptr_mask;
efx_xmit_done(tx_queue, tx_index);
}
/* Add a socket buffer to a TX queue
*
* You must hold netif_tx_lock() to call this function.
*
* Returns 0 on success, error code otherwise. In case of an error this
* function will free the SKB.
*/
netdev_tx_t ef100_enqueue_skb(struct efx_tx_queue *tx_queue,
struct sk_buff *skb)
{
return __ef100_enqueue_skb(tx_queue, skb, NULL);
}
int __ef100_enqueue_skb(struct efx_tx_queue *tx_queue, struct sk_buff *skb,
struct efx_rep *efv)
{
unsigned int old_insert_count = tx_queue->insert_count;
struct efx_nic *efx = tx_queue->efx;
bool xmit_more = netdev_xmit_more();
unsigned int fill_level;
unsigned int segments;
int rc;
if (!tx_queue->buffer || !tx_queue->ptr_mask) {
netif_stop_queue(efx->net_dev);
dev_kfree_skb_any(skb);
return -ENODEV;
}
segments = skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 0;
if (segments == 1)
segments = 0; /* Don't use TSO/GSO for a single segment. */
if (segments && !ef100_tx_can_tso(tx_queue, skb)) {
rc = efx_tx_tso_fallback(tx_queue, skb);
tx_queue->tso_fallbacks++;
if (rc)
goto err;
else
return 0;
}
if (unlikely(efv)) {
struct efx_tx_buffer *buffer = __efx_tx_queue_get_insert_buffer(tx_queue);
/* Drop representor packets if the queue is stopped.
* We currently don't assert backoff to representors so this is
* to make sure representor traffic can't starve the main
* net device.
* And, of course, if there are no TX descriptors left.
*/
if (netif_tx_queue_stopped(tx_queue->core_txq) ||
unlikely(efx_tx_buffer_in_use(buffer))) {
atomic64_inc(&efv->stats.tx_errors);
rc = -ENOSPC;
goto err;
}
/* Also drop representor traffic if it could cause us to
* stop the queue. If we assert backoff and we haven't
* received traffic on the main net device recently then the
* TX watchdog can go off erroneously.
*/
fill_level = efx_channel_tx_old_fill_level(tx_queue->channel);
fill_level += efx_tx_max_skb_descs(efx);
if (fill_level > efx->txq_stop_thresh) {
struct efx_tx_queue *txq2;
/* Refresh cached fill level and re-check */
efx_for_each_channel_tx_queue(txq2, tx_queue->channel)
txq2->old_read_count = READ_ONCE(txq2->read_count);
fill_level = efx_channel_tx_old_fill_level(tx_queue->channel);
fill_level += efx_tx_max_skb_descs(efx);
if (fill_level > efx->txq_stop_thresh) {
atomic64_inc(&efv->stats.tx_errors);
rc = -ENOSPC;
goto err;
}
}
buffer->flags = EFX_TX_BUF_OPTION | EFX_TX_BUF_EFV;
tx_queue->insert_count++;
}
/* Map for DMA and create descriptors */
rc = efx_tx_map_data(tx_queue, skb, segments);
if (rc)
goto err;
ef100_tx_make_descriptors(tx_queue, skb, segments, efv);
fill_level = efx_channel_tx_old_fill_level(tx_queue->channel);
if (fill_level > efx->txq_stop_thresh) {
struct efx_tx_queue *txq2;
/* Because of checks above, representor traffic should
* not be able to stop the queue.
*/
WARN_ON(efv);
netif_tx_stop_queue(tx_queue->core_txq);
/* Re-read after a memory barrier in case we've raced with
* the completion path. Otherwise there's a danger we'll never
* restart the queue if all completions have just happened.
*/
smp_mb();
efx_for_each_channel_tx_queue(txq2, tx_queue->channel)
txq2->old_read_count = READ_ONCE(txq2->read_count);
fill_level = efx_channel_tx_old_fill_level(tx_queue->channel);
if (fill_level < efx->txq_stop_thresh)
netif_tx_start_queue(tx_queue->core_txq);
}
tx_queue->xmit_pending = true;
/* If xmit_more then we don't need to push the doorbell, unless there
* are 256 descriptors already queued in which case we have to push to
* ensure we never push more than 256 at once.
*
* Always push for representor traffic, and don't account it to parent
* PF netdevice's BQL.
*/
if (unlikely(efv) ||
__netdev_tx_sent_queue(tx_queue->core_txq, skb->len, xmit_more) ||
tx_queue->write_count - tx_queue->notify_count > 255)
ef100_tx_push_buffers(tx_queue);
if (segments) {
tx_queue->tso_bursts++;
tx_queue->tso_packets += segments;
tx_queue->tx_packets += segments;
} else {
tx_queue->tx_packets++;
}
return 0;
err:
efx_enqueue_unwind(tx_queue, old_insert_count);
if (!IS_ERR_OR_NULL(skb))
dev_kfree_skb_any(skb);
/* If we're not expecting another transmit and we had something to push
* on this queue then we need to push here to get the previous packets
* out. We only enter this branch from before the xmit_more handling
* above, so xmit_pending still refers to the old state.
*/
if (tx_queue->xmit_pending && !xmit_more)
ef100_tx_push_buffers(tx_queue);
return rc;
}
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