1 files changed, 448 insertions, 0 deletions

diff --git a/drivers/net/ethernet/sfc/tx_tso.c b/drivers/net/ethernet/sfc/tx_tso.c
new file mode 100644
index 000000000..d381d8164
--- /dev/null
+++ b/drivers/net/ethernet/sfc/tx_tso.c
@@ -0,0 +1,448 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/****************************************************************************
+ * Driver for Solarflare network controllers and boards
+ * Copyright 2005-2006 Fen Systems Ltd.
+ * Copyright 2005-2015 Solarflare Communications Inc.
+ */
+
+#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_WARN_ON_ONCE_PARANOID(len <= 0);
+
+	while (1) {
+		buffer = efx_tx_queue_get_insert_buffer(tx_queue);
+		++tx_queue->insert_count;
+
+		EFX_WARN_ON_ONCE_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_WARN_ON_ONCE_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_WARN_ON_ONCE_PARANOID(((struct ethhdr *)skb->data)->h_proto !=
+				  protocol);
+	if (protocol == htons(ETH_P_8021Q)) {
+		struct vlan_ethhdr *veh = skb_vlan_eth_hdr(skb);
+
+		protocol = veh->h_vlan_encapsulated_proto;
+	}
+
+	if (protocol == htons(ETH_P_IP)) {
+		EFX_WARN_ON_ONCE_PARANOID(ip_hdr(skb)->protocol != IPPROTO_TCP);
+	} else {
+		EFX_WARN_ON_ONCE_PARANOID(protocol != htons(ETH_P_IPV6));
+		EFX_WARN_ON_ONCE_PARANOID(ipv6_hdr(skb)->nexthdr != NEXTHDR_TCP);
+	}
+	EFX_WARN_ON_ONCE_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_WARN_ON_ONCE_PARANOID(tcp_hdr(skb)->urg);
+	EFX_WARN_ON_ONCE_PARANOID(tcp_hdr(skb)->syn);
+	EFX_WARN_ON_ONCE_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_WARN_ON_ONCE_PARANOID(st->in_len <= 0);
+	EFX_WARN_ON_ONCE_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_WARN_ON_ONCE_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_WARN_ON_ONCE_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;
+}