net: thunderx: Support for page recycling

Adds support for page recycling for allocating receive buffers
to reduce cost of refilling RBDR ring. Also got rid of using
compound pages when pagesize is 4K, only order-0 pages now.

Only page is recycled, DMA mappings still needs to be done for
every receive buffer allocated due to following constraints
- Cannot have just one receive buffer per 64KB page.
- There is just one buffer ring shared across 8 Rx queues, so
  buffers of same page can go to any Rx queue.
- HW gives buffer address where packet has been DMA'ed and not
  the index into buffer ring.
This makes it not possible to resue DMA mapping info. So unfortunately
have to go through costly mapping route for every buffer.

Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/net/ethernet/cavium/thunder/nicvf_queues.h b/drivers/net/ethernet/cavium/thunder/nicvf_queues.h
index 10cb4b84625b..da4836601d8c 100644
--- a/drivers/net/ethernet/cavium/thunder/nicvf_queues.h
+++ b/drivers/net/ethernet/cavium/thunder/nicvf_queues.h
@@ -213,6 +213,11 @@ struct q_desc_mem {
 	void		*unalign_base;
 };
 
+struct pgcache {
+	struct page	*page;
+	u64		dma_addr;
+};
+
 struct rbdr {
 	bool		enable;
 	u32		dma_size;
@@ -222,6 +227,12 @@ struct rbdr {
 	u32		head;
 	u32		tail;
 	struct q_desc_mem   dmem;
+
+	/* For page recycling */
+	int		pgidx;
+	int		pgcnt;
+	int		pgalloc;
+	struct pgcache	*pgcache;
 } ____cacheline_aligned_in_smp;
 
 struct rcv_queue {