octeontx2-pf: Add ucast filter count configurability via devlink.

The existing method of reserving unicast filter count leads to wasted
MCAM entries if the functionality is not used or fewer entries are used.
Furthermore, the amount of MCAM entries differs amongst Octeon SoCs.
We implemented a means to adjust the UC filter count via devlink,
allowing for better use of MCAM entries across Netdev apps.

commands:

To get the current unicast filter count
 # devlink dev param show pci/0002:02:00.0 name unicast_filter_count

To change/set the unicast filter count
 # devlink dev param  set  pci/0002:02:00.0  name unicast_filter_count
 value 5 cmode runtime

Signed-off-by: Sai Krishna <saikrishnag@marvell.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/devlink/octeontx2.rst

@@ -40,3 +40,19 @@ The ``octeontx2 AF`` driver implements the following driver-specific parameters.
      - runtime
      - Use to set the quantum which hardware uses for scheduling among transmit queues.
        Hardware uses weighted DWRR algorithm to schedule among all transmit queues.
+
+The ``octeontx2 PF`` driver implements the following driver-specific parameters.
+
+.. list-table:: Driver-specific parameters implemented
+   :widths: 5 5 5 85
+
+   * - Name
+     - Type
+     - Mode
+     - Description
+   * - ``unicast_filter_count``
+     - u8
+     - runtime
+     - Set the maximum number of unicast filters that can be programmed for
+       the device. This can be used to achieve better device resource
+       utilization, avoiding over consumption of unused MCAM table entries.

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

@@ -346,12 +346,9 @@ struct otx2_flow_config {
 	u16			*def_ent;
 	u16			nr_flows;
 #define OTX2_DEFAULT_FLOWCOUNT		16
-#define OTX2_MAX_UNICAST_FLOWS		8
+#define OTX2_DEFAULT_UNICAST_FLOWS	4
 #define OTX2_MAX_VLAN_FLOWS		1
 #define OTX2_MAX_TC_FLOWS	OTX2_DEFAULT_FLOWCOUNT
-#define OTX2_MCAM_COUNT		(OTX2_DEFAULT_FLOWCOUNT + \
-				 OTX2_MAX_UNICAST_FLOWS + \
-				 OTX2_MAX_VLAN_FLOWS)
 	u16			unicast_offset;
 	u16			rx_vlan_offset;
 	u16			vf_vlan_offset;
@@ -365,6 +362,7 @@ struct otx2_flow_config {
 	u16                     max_flows;
 	refcount_t		mark_flows;
 	struct list_head	flow_list_tc;
+	u8			ucast_flt_cnt;
 	bool			ntuple;
 };
 
@@ -1067,6 +1065,7 @@ int otx2_handle_ntuple_tc_features(struct net_device *netdev,
 int otx2_smq_flush(struct otx2_nic *pfvf, int smq);
 void otx2_free_bufs(struct otx2_nic *pfvf, struct otx2_pool *pool,
 		    u64 iova, int size);
+int otx2_mcam_entry_init(struct otx2_nic *pfvf);
 
 /* tc support */
 int otx2_init_tc(struct otx2_nic *nic);

drivers/net/ethernet/marvell/octeontx2/nic/otx2_devlink.c

@@ -64,9 +64,68 @@ static int otx2_dl_mcam_count_get(struct devlink *devlink, u32 id,
 	return 0;
 }
 
+static int otx2_dl_ucast_flt_cnt_set(struct devlink *devlink, u32 id,
+				     struct devlink_param_gset_ctx *ctx,
+				     struct netlink_ext_ack *extack)
+{
+	struct otx2_devlink *otx2_dl = devlink_priv(devlink);
+	struct otx2_nic *pfvf = otx2_dl->pfvf;
+	int err;
+
+	pfvf->flow_cfg->ucast_flt_cnt = ctx->val.vu8;
+
+	otx2_mcam_flow_del(pfvf);
+	err = otx2_mcam_entry_init(pfvf);
+	if (err)
+		return err;
+
+	return 0;
+}
+
+static int otx2_dl_ucast_flt_cnt_get(struct devlink *devlink, u32 id,
+				     struct devlink_param_gset_ctx *ctx)
+{
+	struct otx2_devlink *otx2_dl = devlink_priv(devlink);
+	struct otx2_nic *pfvf = otx2_dl->pfvf;
+
+	ctx->val.vu8 = pfvf->flow_cfg ? pfvf->flow_cfg->ucast_flt_cnt : 0;
+
+	return 0;
+}
+
+static int otx2_dl_ucast_flt_cnt_validate(struct devlink *devlink, u32 id,
+					  union devlink_param_value val,
+					  struct netlink_ext_ack *extack)
+{
+	struct otx2_devlink *otx2_dl = devlink_priv(devlink);
+	struct otx2_nic *pfvf = otx2_dl->pfvf;
+
+	/* Check for UNICAST filter support*/
+	if (!(pfvf->flags & OTX2_FLAG_UCAST_FLTR_SUPPORT)) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Unicast filter not enabled");
+		return -EINVAL;
+	}
+
+	if (!pfvf->flow_cfg) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "pfvf->flow_cfg not initialized");
+		return -EINVAL;
+	}
+
+	if (pfvf->flow_cfg->nr_flows) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "Cannot modify count when there are active rules");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 enum otx2_dl_param_id {
 	OTX2_DEVLINK_PARAM_ID_BASE = DEVLINK_PARAM_GENERIC_ID_MAX,
 	OTX2_DEVLINK_PARAM_ID_MCAM_COUNT,
+	OTX2_DEVLINK_PARAM_ID_UCAST_FLT_CNT,
 };
 
 static const struct devlink_param otx2_dl_params[] = {
@@ -75,6 +134,11 @@ static const struct devlink_param otx2_dl_params[] = {
 			     BIT(DEVLINK_PARAM_CMODE_RUNTIME),
 			     otx2_dl_mcam_count_get, otx2_dl_mcam_count_set,
 			     otx2_dl_mcam_count_validate),
+	DEVLINK_PARAM_DRIVER(OTX2_DEVLINK_PARAM_ID_UCAST_FLT_CNT,
+			     "unicast_filter_count", DEVLINK_PARAM_TYPE_U8,
+			     BIT(DEVLINK_PARAM_CMODE_RUNTIME),
+			     otx2_dl_ucast_flt_cnt_get, otx2_dl_ucast_flt_cnt_set,
+			     otx2_dl_ucast_flt_cnt_validate),
 };
 
 static const struct devlink_ops otx2_devlink_ops = {

drivers/net/ethernet/marvell/octeontx2/nic/otx2_flows.c

@@ -12,8 +12,6 @@
 
 #define OTX2_DEFAULT_ACTION	0x1
 
-static int otx2_mcam_entry_init(struct otx2_nic *pfvf);
-
 struct otx2_flow {
 	struct ethtool_rx_flow_spec flow_spec;
 	struct list_head list;
@@ -161,7 +159,7 @@ int otx2_alloc_mcam_entries(struct otx2_nic *pfvf, u16 count)
 }
 EXPORT_SYMBOL(otx2_alloc_mcam_entries);
 
-static int otx2_mcam_entry_init(struct otx2_nic *pfvf)
+int otx2_mcam_entry_init(struct otx2_nic *pfvf)
 {
 	struct otx2_flow_config *flow_cfg = pfvf->flow_cfg;
 	struct npc_get_field_status_req *freq;
@@ -172,7 +170,7 @@ static int otx2_mcam_entry_init(struct otx2_nic *pfvf)
 	int ent, count;
 
 	vf_vlan_max_flows = pfvf->total_vfs * OTX2_PER_VF_VLAN_FLOWS;
-	count = OTX2_MAX_UNICAST_FLOWS +
+	count = flow_cfg->ucast_flt_cnt +
 			OTX2_MAX_VLAN_FLOWS + vf_vlan_max_flows;
 
 	flow_cfg->def_ent = devm_kmalloc_array(pfvf->dev, count,
@@ -214,7 +212,7 @@ static int otx2_mcam_entry_init(struct otx2_nic *pfvf)
 	flow_cfg->vf_vlan_offset = 0;
 	flow_cfg->unicast_offset = vf_vlan_max_flows;
 	flow_cfg->rx_vlan_offset = flow_cfg->unicast_offset +
-					OTX2_MAX_UNICAST_FLOWS;
+					flow_cfg->ucast_flt_cnt;
 	pfvf->flags |= OTX2_FLAG_UCAST_FLTR_SUPPORT;
 
 	/* Check if NPC_DMAC field is supported
@@ -255,6 +253,7 @@ static int otx2_mcam_entry_init(struct otx2_nic *pfvf)
 	refcount_set(&flow_cfg->mark_flows, 1);
 	return 0;
 }
+EXPORT_SYMBOL(otx2_mcam_entry_init);
 
 /* TODO : revisit on size */
 #define OTX2_DMAC_FLTR_BITMAP_SZ (4 * 2048 + 32)
@@ -302,6 +301,8 @@ int otx2_mcam_flow_init(struct otx2_nic *pf)
 	INIT_LIST_HEAD(&pf->flow_cfg->flow_list);
 	INIT_LIST_HEAD(&pf->flow_cfg->flow_list_tc);
 
+	pf->flow_cfg->ucast_flt_cnt = OTX2_DEFAULT_UNICAST_FLOWS;
+
 	/* Allocate bare minimum number of MCAM entries needed for
 	 * unicast and ntuple filters.
 	 */
@@ -314,7 +315,7 @@ int otx2_mcam_flow_init(struct otx2_nic *pf)
 		return 0;
 
 	pf->mac_table = devm_kzalloc(pf->dev, sizeof(struct otx2_mac_table)
-					* OTX2_MAX_UNICAST_FLOWS, GFP_KERNEL);
+					* pf->flow_cfg->ucast_flt_cnt, GFP_KERNEL);
 	if (!pf->mac_table)
 		return -ENOMEM;
 
@@ -356,7 +357,7 @@ static int otx2_do_add_macfilter(struct otx2_nic *pf, const u8 *mac)
 		return -ENOMEM;
 
 	/* dont have free mcam entries or uc list is greater than alloted */
-	if (netdev_uc_count(pf->netdev) > OTX2_MAX_UNICAST_FLOWS)
+	if (netdev_uc_count(pf->netdev) > pf->flow_cfg->ucast_flt_cnt)
 		return -ENOMEM;
 
 	mutex_lock(&pf->mbox.lock);
@@ -367,7 +368,7 @@ static int otx2_do_add_macfilter(struct otx2_nic *pf, const u8 *mac)
 	}
 
 	/* unicast offset starts with 32 0..31 for ntuple */
-	for (i = 0; i <  OTX2_MAX_UNICAST_FLOWS; i++) {
+	for (i = 0; i <  pf->flow_cfg->ucast_flt_cnt; i++) {
 		if (pf->mac_table[i].inuse)
 			continue;
 		ether_addr_copy(pf->mac_table[i].addr, mac);
@@ -410,7 +411,7 @@ static bool otx2_get_mcamentry_for_mac(struct otx2_nic *pf, const u8 *mac,
 {
 	int i;
 
-	for (i = 0; i < OTX2_MAX_UNICAST_FLOWS; i++) {
+	for (i = 0; i < pf->flow_cfg->ucast_flt_cnt; i++) {
 		if (!pf->mac_table[i].inuse)
 			continue;
 
@@ -1394,6 +1395,7 @@ int otx2_destroy_mcam_flows(struct otx2_nic *pfvf)
 	}
 
 	pfvf->flags &= ~OTX2_FLAG_MCAM_ENTRIES_ALLOC;
+	flow_cfg->max_flows = 0;
 	mutex_unlock(&pfvf->mbox.lock);
 
 	return 0;

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

@@ -1714,7 +1714,7 @@ static void otx2_do_set_rx_mode(struct otx2_nic *pf)
 		return;
 
 	if ((netdev->flags & IFF_PROMISC) ||
-	    (netdev_uc_count(netdev) > OTX2_MAX_UNICAST_FLOWS)) {
+	    (netdev_uc_count(netdev) > pf->flow_cfg->ucast_flt_cnt)) {
 		promisc = true;
 	}