1 files changed, 392 insertions, 0 deletions
diff --git a/drivers/net/ethernet/sfc/siena/tx.c b/drivers/net/ethernet/sfc/siena/tx.c
new file mode 100644
index 000000000..91e87594e
--- /dev/null
+++ b/drivers/net/ethernet/sfc/siena/tx.c
@@ -0,0 +1,392 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/****************************************************************************
+ * Driver for Solarflare network controllers and boards
+ * Copyright 2005-2006 Fen Systems Ltd.
+ * Copyright 2005-2013 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/cache.h>
+#include "net_driver.h"
+#include "efx.h"
+#include "io.h"
+#include "nic.h"
+#include "tx.h"
+#include "tx_common.h"
+#include "workarounds.h"
+
+static inline u8 *efx_tx_get_copy_buffer(struct efx_tx_queue *tx_queue,
+					 struct efx_tx_buffer *buffer)
+{
+	unsigned int index = efx_tx_queue_get_insert_index(tx_queue);
+	struct efx_buffer *page_buf =
+		&tx_queue->cb_page[index >> (PAGE_SHIFT - EFX_TX_CB_ORDER)];
+	unsigned int offset =
+		((index << EFX_TX_CB_ORDER) + NET_IP_ALIGN) & (PAGE_SIZE - 1);
+
+	if (unlikely(!page_buf->addr) &&
+	    efx_siena_alloc_buffer(tx_queue->efx, page_buf, PAGE_SIZE,
+				   GFP_ATOMIC))
+		return NULL;
+	buffer->dma_addr = page_buf->dma_addr + offset;
+	buffer->unmap_len = 0;
+	return (u8 *)page_buf->addr + offset;
+}
+
+static void efx_tx_maybe_stop_queue(struct efx_tx_queue *txq1)
+{
+	/* We need to consider all queues that the net core sees as one */
+	struct efx_nic *efx = txq1->efx;
+	struct efx_tx_queue *txq2;
+	unsigned int fill_level;
+
+	fill_level = efx_channel_tx_old_fill_level(txq1->channel);
+	if (likely(fill_level < efx->txq_stop_thresh))
+		return;
+
+	/* We used the stale old_read_count above, which gives us a
+	 * pessimistic estimate of the fill level (which may even
+	 * validly be >= efx->txq_entries).  Now try again using
+	 * read_count (more likely to be a cache miss).
+	 *
+	 * If we read read_count and then conditionally stop the
+	 * queue, it is possible for the completion path to race with
+	 * us and complete all outstanding descriptors in the middle,
+	 * after which there will be no more completions to wake it.
+	 * Therefore we stop the queue first, then read read_count
+	 * (with a memory barrier to ensure the ordering), then
+	 * restart the queue if the fill level turns out to be low
+	 * enough.
+	 */
+	netif_tx_stop_queue(txq1->core_txq);
+	smp_mb();
+	efx_for_each_channel_tx_queue(txq2, txq1->channel)
+		txq2->old_read_count = READ_ONCE(txq2->read_count);
+
+	fill_level = efx_channel_tx_old_fill_level(txq1->channel);
+	EFX_WARN_ON_ONCE_PARANOID(fill_level >= efx->txq_entries);
+	if (likely(fill_level < efx->txq_stop_thresh)) {
+		smp_mb();
+		if (likely(!efx->loopback_selftest))
+			netif_tx_start_queue(txq1->core_txq);
+	}
+}
+
+static int efx_enqueue_skb_copy(struct efx_tx_queue *tx_queue,
+				struct sk_buff *skb)
+{
+	unsigned int copy_len = skb->len;
+	struct efx_tx_buffer *buffer;
+	u8 *copy_buffer;
+	int rc;
+
+	EFX_WARN_ON_ONCE_PARANOID(copy_len > EFX_TX_CB_SIZE);
+
+	buffer = efx_tx_queue_get_insert_buffer(tx_queue);
+
+	copy_buffer = efx_tx_get_copy_buffer(tx_queue, buffer);
+	if (unlikely(!copy_buffer))
+		return -ENOMEM;
+
+	rc = skb_copy_bits(skb, 0, copy_buffer, copy_len);
+	EFX_WARN_ON_PARANOID(rc);
+	buffer->len = copy_len;
+
+	buffer->skb = skb;
+	buffer->flags = EFX_TX_BUF_SKB;
+
+	++tx_queue->insert_count;
+	return rc;
+}
+
+/* Send any pending traffic for a channel. xmit_more is shared across all
+ * queues for a channel, so we must check all of them.
+ */
+static void efx_tx_send_pending(struct efx_channel *channel)
+{
+	struct efx_tx_queue *q;
+
+	efx_for_each_channel_tx_queue(q, channel) {
+		if (q->xmit_pending)
+			efx_nic_push_buffers(q);
+	}
+}
+
+/*
+ * Add a socket buffer to a TX queue
+ *
+ * This maps all fragments of a socket buffer for DMA and adds them to
+ * the TX queue.  The queue's insert pointer will be incremented by
+ * the number of fragments in the socket buffer.
+ *
+ * If any DMA mapping fails, any mapped fragments will be unmapped,
+ * the queue's insert pointer will be restored to its original value.
+ *
+ * This function is split out from efx_siena_hard_start_xmit to allow the
+ * loopback test to direct packets via specific TX queues.
+ *
+ * Returns NETDEV_TX_OK.
+ * You must hold netif_tx_lock() to call this function.
+ */
+netdev_tx_t __efx_siena_enqueue_skb(struct efx_tx_queue *tx_queue,
+				    struct sk_buff *skb)
+{
+	unsigned int old_insert_count = tx_queue->insert_count;
+	bool xmit_more = netdev_xmit_more();
+	bool data_mapped = false;
+	unsigned int segments;
+	unsigned int skb_len;
+	int rc;
+
+	skb_len = skb->len;
+	segments = skb_is_gso(skb) ? skb_shinfo(skb)->gso_segs : 0;
+	if (segments == 1)
+		segments = 0; /* Don't use TSO for a single segment. */
+
+	/* Handle TSO first - it's *possible* (although unlikely) that we might
+	 * be passed a packet to segment that's smaller than the copybreak/PIO
+	 * size limit.
+	 */
+	if (segments) {
+		rc = efx_siena_tx_tso_fallback(tx_queue, skb);
+		tx_queue->tso_fallbacks++;
+		if (rc == 0)
+			return 0;
+		goto err;
+	} else if (skb->data_len && skb_len <= EFX_TX_CB_SIZE) {
+		/* Pad short packets or coalesce short fragmented packets. */
+		if (efx_enqueue_skb_copy(tx_queue, skb))
+			goto err;
+		tx_queue->cb_packets++;
+		data_mapped = true;
+	}
+
+	/* Map for DMA and create descriptors if we haven't done so already. */
+	if (!data_mapped && (efx_siena_tx_map_data(tx_queue, skb, segments)))
+		goto err;
+
+	efx_tx_maybe_stop_queue(tx_queue);
+
+	tx_queue->xmit_pending = true;
+
+	/* Pass off to hardware */
+	if (__netdev_tx_sent_queue(tx_queue->core_txq, skb_len, xmit_more))
+		efx_tx_send_pending(tx_queue->channel);
+
+	tx_queue->tx_packets++;
+	return NETDEV_TX_OK;
+
+
+err:
+	efx_siena_enqueue_unwind(tx_queue, old_insert_count);
+	dev_kfree_skb_any(skb);
+
+	/* If we're not expecting another transmit and we had something to push
+	 * on this queue or a partner queue then we need to push here to get the
+	 * previous packets out.
+	 */
+	if (!xmit_more)
+		efx_tx_send_pending(tx_queue->channel);
+
+	return NETDEV_TX_OK;
+}
+
+/* Transmit a packet from an XDP buffer
+ *
+ * Returns number of packets sent on success, error code otherwise.
+ * Runs in NAPI context, either in our poll (for XDP TX) or a different NIC
+ * (for XDP redirect).
+ */
+int efx_siena_xdp_tx_buffers(struct efx_nic *efx, int n, struct xdp_frame **xdpfs,
+			     bool flush)
+{
+	struct efx_tx_buffer *tx_buffer;
+	struct efx_tx_queue *tx_queue;
+	struct xdp_frame *xdpf;
+	dma_addr_t dma_addr;
+	unsigned int len;
+	int space;
+	int cpu;
+	int i = 0;
+
+	if (unlikely(n && !xdpfs))
+		return -EINVAL;
+	if (unlikely(!n))
+		return 0;
+
+	cpu = raw_smp_processor_id();
+	if (unlikely(cpu >= efx->xdp_tx_queue_count))
+		return -EINVAL;
+
+	tx_queue = efx->xdp_tx_queues[cpu];
+	if (unlikely(!tx_queue))
+		return -EINVAL;
+
+	if (!tx_queue->initialised)
+		return -EINVAL;
+
+	if (efx->xdp_txq_queues_mode != EFX_XDP_TX_QUEUES_DEDICATED)
+		HARD_TX_LOCK(efx->net_dev, tx_queue->core_txq, cpu);
+
+	/* If we're borrowing net stack queues we have to handle stop-restart
+	 * or we might block the queue and it will be considered as frozen
+	 */
+	if (efx->xdp_txq_queues_mode == EFX_XDP_TX_QUEUES_BORROWED) {
+		if (netif_tx_queue_stopped(tx_queue->core_txq))
+			goto unlock;
+		efx_tx_maybe_stop_queue(tx_queue);
+	}
+
+	/* Check for available space. We should never need multiple
+	 * descriptors per frame.
+	 */
+	space = efx->txq_entries +
+		tx_queue->read_count - tx_queue->insert_count;
+
+	for (i = 0; i < n; i++) {
+		xdpf = xdpfs[i];
+
+		if (i >= space)
+			break;
+
+		/* We'll want a descriptor for this tx. */
+		prefetchw(__efx_tx_queue_get_insert_buffer(tx_queue));
+
+		len = xdpf->len;
+
+		/* Map for DMA. */
+		dma_addr = dma_map_single(&efx->pci_dev->dev,
+					  xdpf->data, len,
+					  DMA_TO_DEVICE);
+		if (dma_mapping_error(&efx->pci_dev->dev, dma_addr))
+			break;
+
+		/*  Create descriptor and set up for unmapping DMA. */
+		tx_buffer = efx_siena_tx_map_chunk(tx_queue, dma_addr, len);
+		tx_buffer->xdpf = xdpf;
+		tx_buffer->flags = EFX_TX_BUF_XDP |
+				   EFX_TX_BUF_MAP_SINGLE;
+		tx_buffer->dma_offset = 0;
+		tx_buffer->unmap_len = len;
+		tx_queue->tx_packets++;
+	}
+
+	/* Pass mapped frames to hardware. */
+	if (flush && i > 0)
+		efx_nic_push_buffers(tx_queue);
+
+unlock:
+	if (efx->xdp_txq_queues_mode != EFX_XDP_TX_QUEUES_DEDICATED)
+		HARD_TX_UNLOCK(efx->net_dev, tx_queue->core_txq);
+
+	return i == 0 ? -EIO : i;
+}
+
+/* Initiate a packet transmission.  We use one channel per CPU
+ * (sharing when we have more CPUs than channels).
+ *
+ * Context: non-blocking.
+ * Should always return NETDEV_TX_OK and consume the skb.
+ */
+netdev_tx_t efx_siena_hard_start_xmit(struct sk_buff *skb,
+				      struct net_device *net_dev)
+{
+	struct efx_nic *efx = netdev_priv(net_dev);
+	struct efx_tx_queue *tx_queue;
+	unsigned index, type;
+
+	EFX_WARN_ON_PARANOID(!netif_device_present(net_dev));
+
+	index = skb_get_queue_mapping(skb);
+	type = efx_tx_csum_type_skb(skb);
+	if (index >= efx->n_tx_channels) {
+		index -= efx->n_tx_channels;
+		type |= EFX_TXQ_TYPE_HIGHPRI;
+	}
+
+	/* PTP "event" packet */
+	if (unlikely(efx_xmit_with_hwtstamp(skb)) &&
+	    ((efx_siena_ptp_use_mac_tx_timestamps(efx) && efx->ptp_data) ||
+	     unlikely(efx_siena_ptp_is_ptp_tx(efx, skb)))) {
+		/* There may be existing transmits on the channel that are
+		 * waiting for this packet to trigger the doorbell write.
+		 * We need to send the packets at this point.
+		 */
+		efx_tx_send_pending(efx_get_tx_channel(efx, index));
+		return efx_siena_ptp_tx(efx, skb);
+	}
+
+	tx_queue = efx_get_tx_queue(efx, index, type);
+	if (WARN_ON_ONCE(!tx_queue)) {
+		/* We don't have a TXQ of the right type.
+		 * This should never happen, as we don't advertise offload
+		 * features unless we can support them.
+		 */
+		dev_kfree_skb_any(skb);
+		/* If we're not expecting another transmit and we had something to push
+		 * on this queue or a partner queue then we need to push here to get the
+		 * previous packets out.
+		 */
+		if (!netdev_xmit_more())
+			efx_tx_send_pending(efx_get_tx_channel(efx, index));
+		return NETDEV_TX_OK;
+	}
+
+	return __efx_siena_enqueue_skb(tx_queue, skb);
+}
+
+void efx_siena_init_tx_queue_core_txq(struct efx_tx_queue *tx_queue)
+{
+	struct efx_nic *efx = tx_queue->efx;
+
+	/* Must be inverse of queue lookup in efx_siena_hard_start_xmit() */
+	tx_queue->core_txq =
+		netdev_get_tx_queue(efx->net_dev,
+				    tx_queue->channel->channel +
+				    ((tx_queue->type & EFX_TXQ_TYPE_HIGHPRI) ?
+				     efx->n_tx_channels : 0));
+}
+
+int efx_siena_setup_tc(struct net_device *net_dev, enum tc_setup_type type,
+		       void *type_data)
+{
+	struct efx_nic *efx = netdev_priv(net_dev);
+	struct tc_mqprio_qopt *mqprio = type_data;
+	unsigned tc, num_tc;
+
+	if (type != TC_SETUP_QDISC_MQPRIO)
+		return -EOPNOTSUPP;
+
+	/* Only Siena supported highpri queues */
+	if (efx_nic_rev(efx) > EFX_REV_SIENA_A0)
+		return -EOPNOTSUPP;
+
+	num_tc = mqprio->num_tc;
+
+	if (num_tc > EFX_MAX_TX_TC)
+		return -EINVAL;
+
+	mqprio->hw = TC_MQPRIO_HW_OFFLOAD_TCS;
+
+	if (num_tc == net_dev->num_tc)
+		return 0;
+
+	for (tc = 0; tc < num_tc; tc++) {
+		net_dev->tc_to_txq[tc].offset = tc * efx->n_tx_channels;
+		net_dev->tc_to_txq[tc].count = efx->n_tx_channels;
+	}
+
+	net_dev->num_tc = num_tc;
+
+	return netif_set_real_num_tx_queues(net_dev,
+					    max_t(int, num_tc, 1) *
+					    efx->n_tx_channels);
+}