bnxt_en: Increase maximum RX ring size if jumbo ring is not used

The current maximum RX ring size is defined assuming the RX jumbo ring
(aka aggregation ring) is used.  The RX jumbo ring is automicatically used
when the MTU exceeds a threshold or when rx-gro-hw/lro is enabled.  The RX
jumbo ring is automatically sized up to 4 times the size of the RX ring
size.

The BNXT_MAX_RX_DESC_CNT constant is the upper limit on the size of the
RX ring whether or not the RX jumbo ring is used.  Obviously, the
maximum amount of RX buffer space is significantly less when the RX jumbo
ring is not used.

To increase flexibility for the user who does not use the RX jumbo ring,
we now define a bigger maximum RX ring size when the RX jumbo ring is not
used.  The maximum RX ring size is now up to 8K when the RX jumbo ring
is not used.  The maximum completion ring size also needs to be scaled
up to accomodate the larger maximum RX ring size.

Note that when the RX jumbo ring is re-enabled, the RX ring size will
automatically drop if it exceeds the maximum.
Reviewed-by: Edwin Peer <edwin.peer@broadcom.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/broadcom/bnxt/bnxt.c

@@ -3710,9 +3710,15 @@ void bnxt_set_ring_params(struct bnxt *bp)
 		if (jumbo_factor > agg_factor)
 			agg_factor = jumbo_factor;
 	}
-	agg_ring_size = ring_size * agg_factor;
+	if (agg_factor) {
+		if (ring_size > BNXT_MAX_RX_DESC_CNT_JUM_ENA) {
+			ring_size = BNXT_MAX_RX_DESC_CNT_JUM_ENA;
+			netdev_warn(bp->dev, "RX ring size reduced from %d to %d because the jumbo ring is now enabled\n",
+				    bp->rx_ring_size, ring_size);
+			bp->rx_ring_size = ring_size;
+		}
+		agg_ring_size = ring_size * agg_factor;
 
-	if (agg_ring_size) {
 		bp->rx_agg_nr_pages = bnxt_calc_nr_ring_pages(agg_ring_size,
 							RX_DESC_CNT);
 		if (bp->rx_agg_nr_pages > MAX_RX_AGG_PAGES) {

drivers/net/ethernet/broadcom/bnxt/bnxt.h

@@ -596,15 +596,17 @@ struct nqe_cn {
 #define MAX_TPA_SEGS_P5	0x3f
 
 #if (BNXT_PAGE_SHIFT == 16)
-#define MAX_RX_PAGES	1
+#define MAX_RX_PAGES_AGG_ENA	1
+#define MAX_RX_PAGES	4
 #define MAX_RX_AGG_PAGES	4
 #define MAX_TX_PAGES	1
-#define MAX_CP_PAGES	8
+#define MAX_CP_PAGES	16
 #else
-#define MAX_RX_PAGES	8
+#define MAX_RX_PAGES_AGG_ENA	8
+#define MAX_RX_PAGES	32
 #define MAX_RX_AGG_PAGES	32
 #define MAX_TX_PAGES	8
-#define MAX_CP_PAGES	64
+#define MAX_CP_PAGES	128
 #endif
 
 #define RX_DESC_CNT (BNXT_PAGE_SIZE / sizeof(struct rx_bd))
@@ -622,6 +624,7 @@ struct nqe_cn {
 #define HW_CMPD_RING_SIZE (sizeof(struct tx_cmp) * CP_DESC_CNT)
 
 #define BNXT_MAX_RX_DESC_CNT		(RX_DESC_CNT * MAX_RX_PAGES - 1)
+#define BNXT_MAX_RX_DESC_CNT_JUM_ENA	(RX_DESC_CNT * MAX_RX_PAGES_AGG_ENA - 1)
 #define BNXT_MAX_RX_JUM_DESC_CNT	(RX_DESC_CNT * MAX_RX_AGG_PAGES - 1)
 #define BNXT_MAX_TX_DESC_CNT		(TX_DESC_CNT * MAX_TX_PAGES - 1)
 

drivers/net/ethernet/broadcom/bnxt/bnxt_ethtool.c

@@ -768,8 +768,13 @@ static void bnxt_get_ringparam(struct net_device *dev,
 {
 	struct bnxt *bp = netdev_priv(dev);
 
-	ering->rx_max_pending = BNXT_MAX_RX_DESC_CNT;
-	ering->rx_jumbo_max_pending = BNXT_MAX_RX_JUM_DESC_CNT;
+	if (bp->flags & BNXT_FLAG_AGG_RINGS) {
+		ering->rx_max_pending = BNXT_MAX_RX_DESC_CNT_JUM_ENA;
+		ering->rx_jumbo_max_pending = BNXT_MAX_RX_JUM_DESC_CNT;
+	} else {
+		ering->rx_max_pending = BNXT_MAX_RX_DESC_CNT;
+		ering->rx_jumbo_max_pending = 0;
+	}
 	ering->tx_max_pending = BNXT_MAX_TX_DESC_CNT;
 
 	ering->rx_pending = bp->rx_ring_size;