octeontx2-af: Disable backpressure between CPT and NIX

NIX can assert backpressure to CPT on the NIX<=>CPT link.
Keep the backpressure disabled for now. NIX block anyways
handles backpressure asserted by MAC due to PFC or flow
control pkts.

Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/marvell/octeontx2/af/mbox.h

@@ -313,6 +313,10 @@ M(NIX_BANDPROF_FREE,	0x801e, nix_bandprof_free, nix_bandprof_free_req,   \
 				msg_rsp)				    \
 M(NIX_BANDPROF_GET_HWINFO, 0x801f, nix_bandprof_get_hwinfo, msg_req,		\
 				nix_bandprof_get_hwinfo_rsp)		    \
+M(NIX_CPT_BP_ENABLE,    0x8020, nix_cpt_bp_enable, nix_bp_cfg_req,	    \
+				nix_bp_cfg_rsp)				    \
+M(NIX_CPT_BP_DISABLE,   0x8021, nix_cpt_bp_disable, nix_bp_cfg_req,	    \
+				msg_rsp)				\
 M(NIX_READ_INLINE_IPSEC_CFG, 0x8023, nix_read_inline_ipsec_cfg,		\
 				msg_req, nix_inline_ipsec_cfg)		\
 M(NIX_MCAST_GRP_CREATE,	0x802b, nix_mcast_grp_create, nix_mcast_grp_create_req,	\

drivers/net/ethernet/marvell/octeontx2/af/rvu_nix.c

@@ -569,9 +569,17 @@ void rvu_nix_flr_free_bpids(struct rvu *rvu, u16 pcifunc)
 	mutex_unlock(&rvu->rsrc_lock);
 }
 
-int rvu_mbox_handler_nix_bp_disable(struct rvu *rvu,
+static u16 nix_get_channel(u16 chan, bool cpt_link)
+{
+	/* CPT channel for a given link channel is always
+	 * assumed to be BIT(11) set in link channel.
+	 */
+	return cpt_link ? chan | BIT(11) : chan;
+}
+
+static int nix_bp_disable(struct rvu *rvu,
 			  struct nix_bp_cfg_req *req,
-				    struct msg_rsp *rsp)
+			  struct msg_rsp *rsp, bool cpt_link)
 {
 	u16 pcifunc = req->hdr.pcifunc;
 	int blkaddr, pf, type, err;
@@ -579,6 +587,7 @@ int rvu_mbox_handler_nix_bp_disable(struct rvu *rvu,
 	struct rvu_pfvf *pfvf;
 	struct nix_hw *nix_hw;
 	struct nix_bp *bp;
+	u16 chan_v;
 	u64 cfg;
 
 	pf = rvu_get_pf(pcifunc);
@@ -589,6 +598,9 @@ int rvu_mbox_handler_nix_bp_disable(struct rvu *rvu,
 	if (is_sdp_pfvf(pcifunc))
 		type = NIX_INTF_TYPE_SDP;
 
+	if (cpt_link && !rvu->hw->cpt_links)
+		return 0;
+
 	pfvf = rvu_get_pfvf(rvu, pcifunc);
 	err = nix_get_struct_ptrs(rvu, pcifunc, &nix_hw, &blkaddr);
 	if (err)
@@ -597,8 +609,9 @@ int rvu_mbox_handler_nix_bp_disable(struct rvu *rvu,
 	bp = &nix_hw->bp;
 	chan_base = pfvf->rx_chan_base + req->chan_base;
 	for (chan = chan_base; chan < (chan_base + req->chan_cnt); chan++) {
-		cfg = rvu_read64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(chan));
+		chan_v = nix_get_channel(chan, cpt_link);
-		rvu_write64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(chan),
+		cfg = rvu_read64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(chan_v));
+		rvu_write64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(chan_v),
 			    cfg & ~BIT_ULL(16));
 
 		if (type == NIX_INTF_TYPE_LBK) {
@@ -617,6 +630,20 @@ int rvu_mbox_handler_nix_bp_disable(struct rvu *rvu,
 	return 0;
 }
 
+int rvu_mbox_handler_nix_bp_disable(struct rvu *rvu,
+				    struct nix_bp_cfg_req *req,
+				    struct msg_rsp *rsp)
+{
+	return nix_bp_disable(rvu, req, rsp, false);
+}
+
+int rvu_mbox_handler_nix_cpt_bp_disable(struct rvu *rvu,
+					struct nix_bp_cfg_req *req,
+					struct msg_rsp *rsp)
+{
+	return nix_bp_disable(rvu, req, rsp, true);
+}
+
 static int rvu_nix_get_bpid(struct rvu *rvu, struct nix_bp_cfg_req *req,
 			    int type, int chan_id)
 {
@@ -696,15 +723,17 @@ static int rvu_nix_get_bpid(struct rvu *rvu, struct nix_bp_cfg_req *req,
 	return bpid;
 }
 
-int rvu_mbox_handler_nix_bp_enable(struct rvu *rvu,
+static int nix_bp_enable(struct rvu *rvu,
 			 struct nix_bp_cfg_req *req,
-				   struct nix_bp_cfg_rsp *rsp)
+			 struct nix_bp_cfg_rsp *rsp,
+			 bool cpt_link)
 {
 	int blkaddr, pf, type, chan_id = 0;
 	u16 pcifunc = req->hdr.pcifunc;
 	struct rvu_pfvf *pfvf;
 	u16 chan_base, chan;
 	s16 bpid, bpid_base;
+	u16 chan_v;
 	u64 cfg;
 
 	pf = rvu_get_pf(pcifunc);
@@ -717,6 +746,9 @@ int rvu_mbox_handler_nix_bp_enable(struct rvu *rvu,
 	    type != NIX_INTF_TYPE_SDP)
 		return 0;
 
+	if (cpt_link && !rvu->hw->cpt_links)
+		return 0;
+
 	pfvf = rvu_get_pfvf(rvu, pcifunc);
 	blkaddr = rvu_get_blkaddr(rvu, BLKTYPE_NIX, pcifunc);
 
@@ -730,9 +762,11 @@ int rvu_mbox_handler_nix_bp_enable(struct rvu *rvu,
 			return -EINVAL;
 		}
 
-		cfg = rvu_read64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(chan));
+		chan_v = nix_get_channel(chan, cpt_link);
+
+		cfg = rvu_read64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(chan_v));
 		cfg &= ~GENMASK_ULL(8, 0);
-		rvu_write64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(chan),
+		rvu_write64(rvu, blkaddr, NIX_AF_RX_CHANX_CFG(chan_v),
 			    cfg | (bpid & GENMASK_ULL(8, 0)) | BIT_ULL(16));
 		chan_id++;
 		bpid = rvu_nix_get_bpid(rvu, req, type, chan_id);
@@ -750,6 +784,20 @@ int rvu_mbox_handler_nix_bp_enable(struct rvu *rvu,
 	return 0;
 }
 
+int rvu_mbox_handler_nix_bp_enable(struct rvu *rvu,
+				   struct nix_bp_cfg_req *req,
+				   struct nix_bp_cfg_rsp *rsp)
+{
+	return nix_bp_enable(rvu, req, rsp, false);
+}
+
+int rvu_mbox_handler_nix_cpt_bp_enable(struct rvu *rvu,
+				       struct nix_bp_cfg_req *req,
+				       struct nix_bp_cfg_rsp *rsp)
+{
+	return nix_bp_enable(rvu, req, rsp, true);
+}
+
 static void nix_setup_lso_tso_l3(struct rvu *rvu, int blkaddr,
 				 u64 format, bool v4, u64 *fidx)
 {

drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.c

@@ -17,6 +17,11 @@
 #include "otx2_struct.h"
 #include "cn10k.h"
 
+static bool otx2_is_pfc_enabled(struct otx2_nic *pfvf)
+{
+	return IS_ENABLED(CONFIG_DCB) && !!pfvf->pfc_en;
+}
+
 static void otx2_nix_rq_op_stats(struct queue_stats *stats,
 				 struct otx2_nic *pfvf, int qidx)
 {
@@ -1723,18 +1728,43 @@ int otx2_nix_config_bp(struct otx2_nic *pfvf, bool enable)
 		return -ENOMEM;
 
 	req->chan_base = 0;
-#ifdef CONFIG_DCB
+	if (otx2_is_pfc_enabled(pfvf)) {
-	req->chan_cnt = pfvf->pfc_en ? IEEE_8021QAZ_MAX_TCS : 1;
+		req->chan_cnt = IEEE_8021QAZ_MAX_TCS;
-	req->bpid_per_chan = pfvf->pfc_en ? 1 : 0;
+		req->bpid_per_chan = 1;
-#else
+	} else {
 		req->chan_cnt = 1;
 		req->bpid_per_chan = 0;
-#endif
+	}
 
 	return otx2_sync_mbox_msg(&pfvf->mbox);
 }
 EXPORT_SYMBOL(otx2_nix_config_bp);
 
+int otx2_nix_cpt_config_bp(struct otx2_nic *pfvf, bool enable)
+{
+	struct nix_bp_cfg_req *req;
+
+	if (enable)
+		req = otx2_mbox_alloc_msg_nix_cpt_bp_enable(&pfvf->mbox);
+	else
+		req = otx2_mbox_alloc_msg_nix_cpt_bp_disable(&pfvf->mbox);
+
+	if (!req)
+		return -ENOMEM;
+
+	req->chan_base = 0;
+	if (otx2_is_pfc_enabled(pfvf)) {
+		req->chan_cnt = IEEE_8021QAZ_MAX_TCS;
+		req->bpid_per_chan = 1;
+	} else {
+		req->chan_cnt = 1;
+		req->bpid_per_chan = 0;
+	}
+
+	return otx2_sync_mbox_msg(&pfvf->mbox);
+}
+EXPORT_SYMBOL(otx2_nix_cpt_config_bp);
+
 /* Mbox message handlers */
 void mbox_handler_cgx_stats(struct otx2_nic *pfvf,
 			    struct cgx_stats_rsp *rsp)

drivers/net/ethernet/marvell/octeontx2/nic/otx2_common.h

@@ -985,6 +985,7 @@ int otx2_alloc_rbuf(struct otx2_nic *pfvf, struct otx2_pool *pool,
 int otx2_rxtx_enable(struct otx2_nic *pfvf, bool enable);
 void otx2_ctx_disable(struct mbox *mbox, int type, bool npa);
 int otx2_nix_config_bp(struct otx2_nic *pfvf, bool enable);
+int otx2_nix_cpt_config_bp(struct otx2_nic *pfvf, bool enable);
 void otx2_cleanup_rx_cqes(struct otx2_nic *pfvf, struct otx2_cq_queue *cq, int qidx);
 void otx2_cleanup_tx_cqes(struct otx2_nic *pfvf, struct otx2_cq_queue *cq);
 int otx2_sq_init(struct otx2_nic *pfvf, u16 qidx, u16 sqb_aura);

drivers/net/ethernet/marvell/octeontx2/nic/otx2_dcbnl.c

@@ -435,6 +435,9 @@ process_pfc:
 		return err;
 	}
 
+	/* Default disable backpressure on NIX-CPT */
+	otx2_nix_cpt_config_bp(pfvf, false);
+
 	/* Request Per channel Bpids */
 	if (pfc->pfc_en)
 		otx2_nix_config_bp(pfvf, true);

drivers/net/ethernet/marvell/octeontx2/nic/otx2_pf.c

@@ -1551,6 +1551,9 @@ int otx2_init_hw_resources(struct otx2_nic *pf)
 	if (err)
 		goto err_free_npa_lf;
 
+	/* Default disable backpressure on NIX-CPT */
+	otx2_nix_cpt_config_bp(pf, false);
+
 	/* Enable backpressure for CGX mapped PF/VFs */
 	if (!is_otx2_lbkvf(pf->pdev))
 		otx2_nix_config_bp(pf, true);