liquidio: replace info-pointer mode with buffer-pointer-only mode

Each Octeon output ring can DMA packets to host memory in two modes:  info-
pointer mode and buffer-pointer-only mode.  In info-pointer mode, Octeon
takes two buffer pointers for each packet and places the length of the
packet along with specified number of bytes from the beginning of the
packet into one buffer and the rest of the packet in a separate buffer.  In
buffer-pointer-only mode, Octeon takes single buffer pointer and places the
length of the packet at the beginning of the buffer followed by the packet
data.

This patch switches all Octeon output rings from info-pointer mode to
buffer-pointer-only mode.  This results in fewer DMA setups and cache line
snoops.

Signed-off-by: Prasad Kanneganti <pkanneganti@cavium.com>
Signed-off-by: Derek Chickles <derek.chickles@cavium.com>
Signed-off-by: Satanand Burla <satananda.burla@cavium.com>
Signed-off-by: Felix Manlunas <felix.manlunas@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 10 insertions, 27 deletions

diff --git a/drivers/net/ethernet/cavium/liquidio/octeon_droq.c b/drivers/net/ethernet/cavium/liquidio/octeon_droq.c
index d3a6a1c28053..2e190deb2233 100644
--- a/drivers/net/ethernet/cavium/liquidio/octeon_droq.c
+++ b/drivers/net/ethernet/cavium/liquidio/octeon_droq.c
@@ -181,10 +181,7 @@ octeon_droq_setup_ring_buffers(struct octeon_device *oct,
 
 		droq->recv_buf_list[i].buffer = buf;
 		droq->recv_buf_list[i].data = get_rbd(buf);
-		droq->info_list[i].length = 0;
-
-		/* map ring buffers into memory */
-		desc_ring[i].info_ptr = lio_map_ring_info(droq, i);
+		desc_ring[i].info_ptr = 0;
 		desc_ring[i].buffer_ptr =
 			lio_map_ring(droq->recv_buf_list[i].buffer);
 	}
@@ -205,9 +202,6 @@ int octeon_delete_droq(struct octeon_device *oct, u32 q_no)
 	octeon_droq_destroy_ring_buffers(oct, droq);
 	vfree(droq->recv_buf_list);
 
-	if (droq->info_base_addr)
-		lio_free_info_buffer(oct, droq);
-
 	if (droq->desc_ring)
 		lio_dma_free(oct, (droq->max_count * OCT_DROQ_DESC_SIZE),
 			     droq->desc_ring, droq->desc_ring_dma);
@@ -280,14 +274,6 @@ int octeon_init_droq(struct octeon_device *oct,
 	dev_dbg(&oct->pci_dev->dev, "droq[%d]: num_desc: %d\n", q_no,
 		droq->max_count);
 
-	droq->info_list = lio_alloc_info_buffer(oct, droq);
-	if (!droq->info_list) {
-		dev_err(&oct->pci_dev->dev, "Cannot allocate memory for info list.\n");
-		lio_dma_free(oct, (droq->max_count * OCT_DROQ_DESC_SIZE),
-			     droq->desc_ring, droq->desc_ring_dma);
-		return 1;
-	}
-
 	droq->recv_buf_list = (struct octeon_recv_buffer *)
 			      vmalloc_node(droq->max_count *
 						OCT_DROQ_RECVBUF_SIZE,
@@ -357,7 +343,7 @@ static inline struct octeon_recv_info *octeon_create_recv_info(
 	u32 i, bytes_left;
 	struct octeon_skb_page_info *pg_info;
 
-	info = &droq->info_list[idx];
+	info = (struct octeon_droq_info *)droq->recv_buf_list[idx].data;
 
 	recv_info = octeon_alloc_recv_info(sizeof(struct __dispatch));
 	if (!recv_info)
@@ -491,8 +477,6 @@ octeon_droq_refill(struct octeon_device *octeon_dev, struct octeon_droq *droq)
 		desc_ring[droq->refill_idx].buffer_ptr =
 			lio_map_ring(droq->recv_buf_list[
 				     droq->refill_idx].buffer);
-		/* Reset any previous values in the length field. */
-		droq->info_list[droq->refill_idx].length = 0;
 
 		droq->refill_idx = incr_index(droq->refill_idx, 1,
 					      droq->max_count);
@@ -541,11 +525,7 @@ void octeon_droq_check_oom(struct octeon_droq *droq)
 static inline u32
 octeon_droq_get_bufcount(u32 buf_size, u32 total_len)
 {
-	u32 buf_cnt = 0;
-
-	while (total_len > (buf_size * buf_cnt))
-		buf_cnt++;
-	return buf_cnt;
+	return ((total_len + buf_size - 1) / buf_size);
 }
 
 static int
@@ -593,11 +573,12 @@ static inline void octeon_droq_drop_packets(struct octeon_device *oct,
 	struct octeon_droq_info *info;
 
 	for (i = 0; i < cnt; i++) {
-		info = &droq->info_list[droq->read_idx];
+		info = (struct octeon_droq_info *)
+			droq->recv_buf_list[droq->read_idx].data;
 		octeon_swap_8B_data((u64 *)info, 2);
 
 		if (info->length) {
-			info->length -= OCT_RH_SIZE;
+			info->length += OCTNET_FRM_LENGTH_SIZE;
 			droq->stats.bytes_received += info->length;
 			buf_cnt = octeon_droq_get_bufcount(droq->buffer_size,
 							   (u32)info->length);
@@ -629,7 +610,8 @@ octeon_droq_fast_process_packets(struct octeon_device *oct,
 		struct octeon_skb_page_info *pg_info;
 		void *buf;
 
-		info = &droq->info_list[droq->read_idx];
+		info = (struct octeon_droq_info *)
+			droq->recv_buf_list[droq->read_idx].data;
 		octeon_swap_8B_data((u64 *)info, 2);
 
 		if (!info->length) {
@@ -643,9 +625,10 @@ octeon_droq_fast_process_packets(struct octeon_device *oct,
 		}
 
 		/* Len of resp hdr in included in the received data len. */
-		info->length -= OCT_RH_SIZE;
 		rh = &info->rh;
 
+		info->length += OCTNET_FRM_LENGTH_SIZE;
+		rh->r_dh.len += (ROUNDUP8(OCT_DROQ_INFO_SIZE) / sizeof(u64));
 		total_len += (u32)info->length;
 		if (opcode_slow_path(rh)) {
 			u32 buf_cnt;