octeontx2-pf: Add egress PFC support

As of now all transmit queues transmit packets out of same scheduler
queue hierarchy. Due to this PFC frames sent by peer are not handled
properly, either all transmit queues are backpressured or none.
To fix this when user enables PFC for a given priority map relavant
transmit queue to a different scheduler queue hierarcy, so that
backpressure is applied only to the traffic egressing out of that TXQ.

Signed-off-by: Suman Ghosh <sumang@marvell.com>
Link: https://lore.kernel.org/r/20220830120304.158060-1-sumang@marvell.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

1 files changed, 300 insertions, 0 deletions

diff --git a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_dcbnl.c b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_dcbnl.c
index 723d2506d309..ccaf97bb1ce0 100644
--- a/drivers/net/ethernet/marvell/octeontx2/nic/otx2_dcbnl.c
+++ b/drivers/net/ethernet/marvell/octeontx2/nic/otx2_dcbnl.c
@@ -7,6 +7,289 @@
 
 #include "otx2_common.h"
 
+static int otx2_check_pfc_config(struct otx2_nic *pfvf)
+{
+	u8 tx_queues = pfvf->hw.tx_queues, prio;
+	u8 pfc_en = pfvf->pfc_en;
+
+	for (prio = 0; prio < NIX_PF_PFC_PRIO_MAX; prio++) {
+		if ((pfc_en & (1 << prio)) &&
+		    prio > tx_queues - 1) {
+			dev_warn(pfvf->dev,
+				 "Increase number of tx queues from %d to %d to support PFC.\n",
+				 tx_queues, prio + 1);
+			return -EINVAL;
+		}
+	}
+
+	return 0;
+}
+
+int otx2_pfc_txschq_config(struct otx2_nic *pfvf)
+{
+	u8 pfc_en, pfc_bit_set;
+	int prio, lvl, err;
+
+	pfc_en = pfvf->pfc_en;
+	for (prio = 0; prio < NIX_PF_PFC_PRIO_MAX; prio++) {
+		pfc_bit_set = pfc_en & (1 << prio);
+
+		/* Either PFC bit is not set
+		 * or tx scheduler is not allocated for the priority
+		 */
+		if (!pfc_bit_set || !pfvf->pfc_alloc_status[prio])
+			continue;
+
+		/* configure the scheduler for the tls*/
+		for (lvl = 0; lvl < NIX_TXSCH_LVL_CNT; lvl++) {
+			err = otx2_txschq_config(pfvf, lvl, prio, true);
+			if (err) {
+				dev_err(pfvf->dev,
+					"%s configure PFC tx schq for lvl:%d, prio:%d failed!\n",
+					__func__, lvl, prio);
+				return err;
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int otx2_pfc_txschq_alloc_one(struct otx2_nic *pfvf, u8 prio)
+{
+	struct nix_txsch_alloc_req *req;
+	struct nix_txsch_alloc_rsp *rsp;
+	int lvl, rc;
+
+	/* Get memory to put this msg */
+	req = otx2_mbox_alloc_msg_nix_txsch_alloc(&pfvf->mbox);
+	if (!req)
+		return -ENOMEM;
+
+	/* Request one schq per level upto max level as configured
+	 * link config level. These rest of the scheduler can be
+	 * same as hw.txschq_list.
+	 */
+	for (lvl = 0; lvl < pfvf->hw.txschq_link_cfg_lvl; lvl++)
+		req->schq[lvl] = 1;
+
+	rc = otx2_sync_mbox_msg(&pfvf->mbox);
+	if (rc)
+		return rc;
+
+	rsp = (struct nix_txsch_alloc_rsp *)
+	      otx2_mbox_get_rsp(&pfvf->mbox.mbox, 0, &req->hdr);
+	if (IS_ERR(rsp))
+		return PTR_ERR(rsp);
+
+	/* Setup transmit scheduler list */
+	for (lvl = 0; lvl < pfvf->hw.txschq_link_cfg_lvl; lvl++) {
+		if (!rsp->schq[lvl])
+			return -ENOSPC;
+
+		pfvf->pfc_schq_list[lvl][prio] = rsp->schq_list[lvl][0];
+	}
+
+	/* Set the Tx schedulers for rest of the levels same as
+	 * hw.txschq_list as those will be common for all.
+	 */
+	for (; lvl < NIX_TXSCH_LVL_CNT; lvl++)
+		pfvf->pfc_schq_list[lvl][prio] = pfvf->hw.txschq_list[lvl][0];
+
+	pfvf->pfc_alloc_status[prio] = true;
+	return 0;
+}
+
+int otx2_pfc_txschq_alloc(struct otx2_nic *pfvf)
+{
+	u8 pfc_en = pfvf->pfc_en;
+	u8 pfc_bit_set;
+	int err, prio;
+
+	for (prio = 0; prio < NIX_PF_PFC_PRIO_MAX; prio++) {
+		pfc_bit_set = pfc_en & (1 << prio);
+
+		if (!pfc_bit_set || pfvf->pfc_alloc_status[prio])
+			continue;
+
+		/* Add new scheduler to the priority */
+		err = otx2_pfc_txschq_alloc_one(pfvf, prio);
+		if (err) {
+			dev_err(pfvf->dev, "%s failed to allocate PFC TX schedulers\n", __func__);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
+static int otx2_pfc_txschq_stop_one(struct otx2_nic *pfvf, u8 prio)
+{
+	struct nix_txsch_free_req *free_req;
+
+	mutex_lock(&pfvf->mbox.lock);
+	/* free PFC TLx nodes */
+	free_req = otx2_mbox_alloc_msg_nix_txsch_free(&pfvf->mbox);
+	if (!free_req) {
+		mutex_unlock(&pfvf->mbox.lock);
+		return -ENOMEM;
+	}
+
+	free_req->flags = TXSCHQ_FREE_ALL;
+	otx2_sync_mbox_msg(&pfvf->mbox);
+	mutex_unlock(&pfvf->mbox.lock);
+
+	pfvf->pfc_alloc_status[prio] = false;
+	return 0;
+}
+
+static int otx2_pfc_update_sq_smq_mapping(struct otx2_nic *pfvf, int prio)
+{
+	struct nix_cn10k_aq_enq_req *cn10k_sq_aq;
+	struct net_device *dev = pfvf->netdev;
+	bool if_up = netif_running(dev);
+	struct nix_aq_enq_req *sq_aq;
+
+	if (if_up) {
+		if (pfvf->pfc_alloc_status[prio])
+			netif_tx_stop_all_queues(pfvf->netdev);
+		else
+			netif_tx_stop_queue(netdev_get_tx_queue(dev, prio));
+	}
+
+	if (test_bit(CN10K_LMTST, &pfvf->hw.cap_flag)) {
+		cn10k_sq_aq = otx2_mbox_alloc_msg_nix_cn10k_aq_enq(&pfvf->mbox);
+		if (!cn10k_sq_aq)
+			return -ENOMEM;
+
+		/* Fill AQ info */
+		cn10k_sq_aq->qidx = prio;
+		cn10k_sq_aq->ctype = NIX_AQ_CTYPE_SQ;
+		cn10k_sq_aq->op = NIX_AQ_INSTOP_WRITE;
+
+		/* Fill fields to update */
+		cn10k_sq_aq->sq.ena = 1;
+		cn10k_sq_aq->sq_mask.ena = 1;
+		cn10k_sq_aq->sq_mask.smq = GENMASK(9, 0);
+		cn10k_sq_aq->sq.smq = otx2_get_smq_idx(pfvf, prio);
+	} else {
+		sq_aq = otx2_mbox_alloc_msg_nix_aq_enq(&pfvf->mbox);
+		if (!sq_aq)
+			return -ENOMEM;
+
+		/* Fill AQ info */
+		sq_aq->qidx = prio;
+		sq_aq->ctype = NIX_AQ_CTYPE_SQ;
+		sq_aq->op = NIX_AQ_INSTOP_WRITE;
+
+		/* Fill fields to update */
+		sq_aq->sq.ena = 1;
+		sq_aq->sq_mask.ena = 1;
+		sq_aq->sq_mask.smq = GENMASK(8, 0);
+		sq_aq->sq.smq = otx2_get_smq_idx(pfvf, prio);
+	}
+
+	otx2_sync_mbox_msg(&pfvf->mbox);
+
+	if (if_up) {
+		if (pfvf->pfc_alloc_status[prio])
+			netif_tx_start_all_queues(pfvf->netdev);
+		else
+			netif_tx_start_queue(netdev_get_tx_queue(dev, prio));
+	}
+
+	return 0;
+}
+
+int otx2_pfc_txschq_update(struct otx2_nic *pfvf)
+{
+	bool if_up = netif_running(pfvf->netdev);
+	u8 pfc_en = pfvf->pfc_en, pfc_bit_set;
+	struct mbox *mbox = &pfvf->mbox;
+	int err, prio;
+
+	mutex_lock(&mbox->lock);
+	for (prio = 0; prio < NIX_PF_PFC_PRIO_MAX; prio++) {
+		pfc_bit_set = pfc_en & (1 << prio);
+
+		/* tx scheduler was created but user wants to disable now */
+		if (!pfc_bit_set && pfvf->pfc_alloc_status[prio]) {
+			mutex_unlock(&mbox->lock);
+			if (if_up)
+				netif_tx_stop_all_queues(pfvf->netdev);
+
+			otx2_smq_flush(pfvf, pfvf->pfc_schq_list[NIX_TXSCH_LVL_SMQ][prio]);
+			if (if_up)
+				netif_tx_start_all_queues(pfvf->netdev);
+
+			/* delete the schq */
+			err = otx2_pfc_txschq_stop_one(pfvf, prio);
+			if (err) {
+				dev_err(pfvf->dev,
+					"%s failed to stop PFC tx schedulers for priority: %d\n",
+					__func__, prio);
+				return err;
+			}
+
+			mutex_lock(&mbox->lock);
+			goto update_sq_smq_map;
+		}
+
+		/* Either PFC bit is not set
+		 * or Tx scheduler is already mapped for the priority
+		 */
+		if (!pfc_bit_set || pfvf->pfc_alloc_status[prio])
+			continue;
+
+		/* Add new scheduler to the priority */
+		err = otx2_pfc_txschq_alloc_one(pfvf, prio);
+		if (err) {
+			mutex_unlock(&mbox->lock);
+			dev_err(pfvf->dev,
+				"%s failed to allocate PFC tx schedulers for priority: %d\n",
+				__func__, prio);
+			return err;
+		}
+
+update_sq_smq_map:
+		err = otx2_pfc_update_sq_smq_mapping(pfvf, prio);
+		if (err) {
+			mutex_unlock(&mbox->lock);
+			dev_err(pfvf->dev, "%s failed PFC Tx schq sq:%d mapping", __func__, prio);
+			return err;
+		}
+	}
+
+	err = otx2_pfc_txschq_config(pfvf);
+	mutex_unlock(&mbox->lock);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+int otx2_pfc_txschq_stop(struct otx2_nic *pfvf)
+{
+	u8 pfc_en, pfc_bit_set;
+	int prio, err;
+
+	pfc_en = pfvf->pfc_en;
+	for (prio = 0; prio < NIX_PF_PFC_PRIO_MAX; prio++) {
+		pfc_bit_set = pfc_en & (1 << prio);
+		if (!pfc_bit_set || !pfvf->pfc_alloc_status[prio])
+			continue;
+
+		/* Delete the existing scheduler */
+		err = otx2_pfc_txschq_stop_one(pfvf, prio);
+		if (err) {
+			dev_err(pfvf->dev, "%s failed to stop PFC TX schedulers\n", __func__);
+			return err;
+		}
+	}
+
+	return 0;
+}
+
 int otx2_config_priority_flow_ctrl(struct otx2_nic *pfvf)
 {
 	struct cgx_pfc_cfg *req;
@@ -128,6 +411,17 @@ static int otx2_dcbnl_ieee_setpfc(struct net_device *dev, struct ieee_pfc *pfc)
 	/* Save PFC configuration to interface */
 	pfvf->pfc_en = pfc->pfc_en;
 
+	if (pfvf->hw.tx_queues >= NIX_PF_PFC_PRIO_MAX)
+		goto process_pfc;
+
+	/* Check if the PFC configuration can be
+	 * supported by the tx queue configuration
+	 */
+	err = otx2_check_pfc_config(pfvf);
+	if (err)
+		return err;
+
+process_pfc:
 	err = otx2_config_priority_flow_ctrl(pfvf);
 	if (err)
 		return err;
@@ -136,6 +430,12 @@ static int otx2_dcbnl_ieee_setpfc(struct net_device *dev, struct ieee_pfc *pfc)
 	if (pfc->pfc_en)
 		otx2_nix_config_bp(pfvf, true);
 
+	err = otx2_pfc_txschq_update(pfvf);
+	if (err) {
+		dev_err(pfvf->dev, "%s failed to update TX schedulers\n", __func__);
+		return err;
+	}
+
 	return 0;
 }