sfc: Firmware-Assisted TSO version 2

Add support for FATSOv2 to the driver. FATSOv2 offloads far more of the task
 of TCP segmentation to the firmware, such that we now just pass a single
 super-packet to the NIC. This means TSO has a great deal in common with a
 normal DMA transmit, apart from adding a couple of option descriptors.
 NIC-specific checks have been moved off the fast path and in to
 initialisation where possible.

This also moves FATSOv1/SWTSO to a new file (tx_tso.c).  The end of transmit
 and some error handling is now outside TSO, since it is common with other
 code.

Signed-off-by: Edward Cree <ecree@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 45 insertions, 2 deletions

diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index fec51c4b2607..2da3e8fb6d71 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -189,13 +189,17 @@ struct efx_tx_buffer {
  * @channel: The associated channel
  * @core_txq: The networking core TX queue structure
  * @buffer: The software buffer ring
- * @tsoh_page: Array of pages of TSO header buffers
+ * @cb_page: Array of pages of copy buffers.  Carved up according to
+ *	%EFX_TX_CB_ORDER into %EFX_TX_CB_SIZE-sized chunks.
  * @txd: The hardware descriptor ring
  * @ptr_mask: The size of the ring minus 1.
  * @piobuf: PIO buffer region for this TX queue (shared with its partner).
  *	Size of the region is efx_piobuf_size.
  * @piobuf_offset: Buffer offset to be specified in PIO descriptors
  * @initialised: Has hardware queue been initialised?
+ * @tx_min_size: Minimum transmit size for this queue. Depends on HW.
+ * @handle_tso: TSO xmit preparation handler.  Sets up the TSO metadata and
+ *	may also map tx data, depending on the nature of the TSO implementation.
  * @read_count: Current read pointer.
  *	This is the number of buffers that have been removed from both rings.
  * @old_write_count: The value of @write_count when last checked.
@@ -224,6 +228,7 @@ struct efx_tx_buffer {
  * @pushes: Number of times the TX push feature has been used
  * @pio_packets: Number of times the TX PIO feature has been used
  * @xmit_more_available: Are any packets waiting to be pushed to the NIC
+ * @cb_packets: Number of times the TX copybreak feature has been used
  * @empty_read_count: If the completion path has seen the queue as empty
  *	and the transmission path has not yet checked this, the value of
  *	@read_count bitwise-added to %EFX_EMPTY_COUNT_VALID; otherwise 0.
@@ -236,12 +241,16 @@ struct efx_tx_queue {
 	struct efx_channel *channel;
 	struct netdev_queue *core_txq;
 	struct efx_tx_buffer *buffer;
-	struct efx_buffer *tsoh_page;
+	struct efx_buffer *cb_page;
 	struct efx_special_buffer txd;
 	unsigned int ptr_mask;
 	void __iomem *piobuf;
 	unsigned int piobuf_offset;
 	bool initialised;
+	unsigned int tx_min_size;
+
+	/* Function pointers used in the fast path. */
+	int (*handle_tso)(struct efx_tx_queue*, struct sk_buff*, bool *);
 
 	/* Members used mainly on the completion path */
 	unsigned int read_count ____cacheline_aligned_in_smp;
@@ -260,6 +269,7 @@ struct efx_tx_queue {
 	unsigned int pushes;
 	unsigned int pio_packets;
 	bool xmit_more_available;
+	unsigned int cb_packets;
 	/* Statistics to supplement MAC stats */
 	unsigned long tx_packets;
 
@@ -269,6 +279,9 @@ struct efx_tx_queue {
 	atomic_t flush_outstanding;
 };
 
+#define EFX_TX_CB_ORDER	7
+#define EFX_TX_CB_SIZE	(1 << EFX_TX_CB_ORDER) - NET_IP_ALIGN
+
 /**
  * struct efx_rx_buffer - An Efx RX data buffer
  * @dma_addr: DMA base address of the buffer
@@ -1288,6 +1301,8 @@ struct efx_nic_type {
 	void (*tx_init)(struct efx_tx_queue *tx_queue);
 	void (*tx_remove)(struct efx_tx_queue *tx_queue);
 	void (*tx_write)(struct efx_tx_queue *tx_queue);
+	unsigned int (*tx_limit_len)(struct efx_tx_queue *tx_queue,
+				     dma_addr_t dma_addr, unsigned int len);
 	int (*rx_push_rss_config)(struct efx_nic *efx, bool user,
 				  const u32 *rx_indir_table);
 	int (*rx_probe)(struct efx_rx_queue *rx_queue);
@@ -1545,4 +1560,32 @@ static inline netdev_features_t efx_supported_features(const struct efx_nic *efx
 	return net_dev->features | net_dev->hw_features;
 }
 
+/* Get the current TX queue insert index. */
+static inline unsigned int
+efx_tx_queue_get_insert_index(const struct efx_tx_queue *tx_queue)
+{
+	return tx_queue->insert_count & tx_queue->ptr_mask;
+}
+
+/* Get a TX buffer. */
+static inline struct efx_tx_buffer *
+__efx_tx_queue_get_insert_buffer(const struct efx_tx_queue *tx_queue)
+{
+	return &tx_queue->buffer[efx_tx_queue_get_insert_index(tx_queue)];
+}
+
+/* Get a TX buffer, checking it's not currently in use. */
+static inline struct efx_tx_buffer *
+efx_tx_queue_get_insert_buffer(const struct efx_tx_queue *tx_queue)
+{
+	struct efx_tx_buffer *buffer =
+		__efx_tx_queue_get_insert_buffer(tx_queue);
+
+	EFX_BUG_ON_PARANOID(buffer->len);
+	EFX_BUG_ON_PARANOID(buffer->flags);
+	EFX_BUG_ON_PARANOID(buffer->unmap_len);
+
+	return buffer;
+}
+
 #endif /* EFX_NET_DRIVER_H */