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, 15 insertions, 0 deletions

diff --git a/drivers/net/ethernet/sfc/farch.c b/drivers/net/ethernet/sfc/farch.c
index 4762ec444cb8..3d5b91bc4ce6 100644
--- a/drivers/net/ethernet/sfc/farch.c
+++ b/drivers/net/ethernet/sfc/farch.c
@@ -356,6 +356,21 @@ void efx_farch_tx_write(struct efx_tx_queue *tx_queue)
 	}
 }
 
+unsigned int efx_farch_tx_limit_len(struct efx_tx_queue *tx_queue,
+				    dma_addr_t dma_addr, unsigned int len)
+{
+	/* Don't cross 4K boundaries with descriptors. */
+	unsigned int limit = (~dma_addr & (EFX_PAGE_SIZE - 1)) + 1;
+
+	len = min(limit, len);
+
+	if (EFX_WORKAROUND_5391(tx_queue->efx) && (dma_addr & 0xf))
+		len = min_t(unsigned int, len, 512 - (dma_addr & 0xf));
+
+	return len;
+}
+
+
 /* Allocate hardware resources for a TX queue */
 int efx_farch_tx_probe(struct efx_tx_queue *tx_queue)
 {