net: thunderx: Configure RED and backpressure levels

This patch enables moving average calculation of Rx pkt's resources
and configures RED and backpressure levels for both CQ and RBDR.
Also initialize SQ's CQ_LIMIT properly.

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

drivers/net/ethernet/cavium/thunder/nic_main.c

@@ -809,6 +809,15 @@ static int nic_config_loopback(struct nicpf *nic, struct set_loopback *lbk)
 
 	bgx_lmac_internal_loopback(nic->node, bgx_idx, lmac_idx, lbk->enable);
 
+	/* Enable moving average calculation.
+	 * Keep the LVL/AVG delay to HW enforced minimum so that, not too many
+	 * packets sneek in between average calculations.
+	 */
+	nic_reg_write(nic, NIC_PF_CQ_AVG_CFG,
+		      (BIT_ULL(20) | 0x2ull << 14 | 0x1));
+	nic_reg_write(nic, NIC_PF_RRM_AVG_CFG,
+		      (BIT_ULL(20) | 0x3ull << 14 | 0x1));
+
 	return 0;
 }
 

drivers/net/ethernet/cavium/thunder/nicvf_queues.c

@@ -544,14 +544,18 @@ static void nicvf_rcv_queue_config(struct nicvf *nic, struct queue_set *qs,
 	nicvf_send_msg_to_pf(nic, &mbx);
 
 	mbx.rq.msg = NIC_MBOX_MSG_RQ_BP_CFG;
-	mbx.rq.cfg = (1ULL << 63) | (1ULL << 62) | (qs->vnic_id << 0);
+	mbx.rq.cfg = BIT_ULL(63) | BIT_ULL(62) |
+		     (RQ_PASS_RBDR_LVL << 16) | (RQ_PASS_CQ_LVL << 8) |
+		     (qs->vnic_id << 0);
 	nicvf_send_msg_to_pf(nic, &mbx);
 
 	/* RQ drop config
 	 * Enable CQ drop to reserve sufficient CQEs for all tx packets
 	 */
 	mbx.rq.msg = NIC_MBOX_MSG_RQ_DROP_CFG;
-	mbx.rq.cfg = (1ULL << 62) | (RQ_CQ_DROP << 8);
+	mbx.rq.cfg = BIT_ULL(63) | BIT_ULL(62) |
+		     (RQ_PASS_RBDR_LVL << 40) | (RQ_DROP_RBDR_LVL << 32) |
+		     (RQ_PASS_CQ_LVL << 16) | (RQ_DROP_CQ_LVL << 8);
 	nicvf_send_msg_to_pf(nic, &mbx);
 
 	if (!nic->sqs_mode && (qidx == 0)) {
@@ -650,6 +654,7 @@ static void nicvf_snd_queue_config(struct nicvf *nic, struct queue_set *qs,
 	sq_cfg.ldwb = 0;
 	sq_cfg.qsize = SND_QSIZE;
 	sq_cfg.tstmp_bgx_intf = 0;
+	sq_cfg.cq_limit = 0;
 	nicvf_queue_reg_write(nic, NIC_QSET_SQ_0_7_CFG, qidx, *(u64 *)&sq_cfg);
 
 	/* Set threshold value for interrupt generation */

drivers/net/ethernet/cavium/thunder/nicvf_queues.h

@@ -85,12 +85,26 @@
 
 #define MAX_CQES_FOR_TX		((SND_QUEUE_LEN / MIN_SQ_DESC_PER_PKT_XMIT) * \
 				 MAX_CQE_PER_PKT_XMIT)
-/* Calculate number of CQEs to reserve for all SQEs.
- * Its 1/256th level of CQ size.
- * '+ 1' to account for pipelining
+
+/* RED and Backpressure levels of CQ for pkt reception
+ * For CQ, level is a measure of emptiness i.e 0x0 means full
+ * eg: For CQ of size 4K, and for pass/drop levels of 128/96
+ * HW accepts pkt if unused CQE >= 2048
+ * RED accepts pkt if unused CQE < 2048 & >= 1536
+ * DROPs pkts if unused CQE < 1536
+ */
+#define RQ_PASS_CQ_LVL		128ULL
+#define RQ_DROP_CQ_LVL		96ULL
+
+/* RED and Backpressure levels of RBDR for pkt reception
+ * For RBDR, level is a measure of fullness i.e 0x0 means empty
+ * eg: For RBDR of size 8K, and for pass/drop levels of 4/0
+ * HW accepts pkt if unused RBs >= 256
+ * RED accepts pkt if unused RBs < 256 & >= 0
+ * DROPs pkts if unused RBs < 0
  */
-#define RQ_CQ_DROP		((256 / (CMP_QUEUE_LEN / \
-				 (CMP_QUEUE_LEN - MAX_CQES_FOR_TX))) + 1)
+#define RQ_PASS_RBDR_LVL	8ULL
+#define RQ_DROP_RBDR_LVL	0ULL
 
 /* Descriptor size in bytes */
 #define SND_QUEUE_DESC_SIZE	16

drivers/net/ethernet/cavium/thunder/q_struct.h

@@ -624,7 +624,9 @@ struct cq_cfg {
 
 struct sq_cfg {
 #if defined(__BIG_ENDIAN_BITFIELD)
-	u64 reserved_20_63:44;
+	u64 reserved_32_63:32;
+	u64 cq_limit:8;
+	u64 reserved_20_23:4;
 	u64 ena:1;
 	u64 reserved_18_18:1;
 	u64 reset:1;
@@ -642,7 +644,9 @@ struct sq_cfg {
 	u64 reset:1;
 	u64 reserved_18_18:1;
 	u64 ena:1;
-	u64 reserved_20_63:44;
+	u64 reserved_20_23:4;
+	u64 cq_limit:8;
+	u64 reserved_32_63:32;
 #endif
 };