octeontx2-af: Add devlink option to adjust mcam high prio zone entries

The NPC MCAM entries are currently divided into three priority zones
in AF driver: high, mid, and low. The high priority zone and low priority
zone take up 1/8th (each) of the available MCAM entries, and remaining
going to the mid priority zone.

The current allocation scheme may not meet certain requirements, such
as when a requester needs more high priority zone entries than are
reserved. This patch adds a devlink configurable option to increase the
number of high priority zone entries that can be allocated by requester.
The max number of entries that can be reserved for high priority usage
is 100% of available MCAM entries.

Usage:
1) Change high priority zone percentage to 75%:
devlink -p dev param set pci/0002:01:00.0 name npc_mcam_high_zone_percent \
value 75 cmode runtime

2) Read high priority zone percentage:
devlink -p dev param show pci/0002:01:00.0 name npc_mcam_high_zone_percent

The devlink set configuration is only permitted when no MCAM entries
are assigned, i.e., all MCAM entries are free, indicating that no PF/VF
driver is loaded. So user must unload/unbind PF/VF driver/devices before
modifying the high priority zone percentage.
Signed-off-by: Naveen Mamindlapalli <naveenm@marvell.com>
Signed-off-by: Sunil Goutham <sgoutham@marvell.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -1438,6 +1438,7 @@ enum rvu_af_dl_param_id {
 	RVU_AF_DEVLINK_PARAM_ID_BASE = DEVLINK_PARAM_GENERIC_ID_MAX,
 	RVU_AF_DEVLINK_PARAM_ID_DWRR_MTU,
 	RVU_AF_DEVLINK_PARAM_ID_NPC_EXACT_FEATURE_DISABLE,
+	RVU_AF_DEVLINK_PARAM_ID_NPC_MCAM_ZONE_PERCENT,
 };
 
 static int rvu_af_npc_exact_feature_get(struct devlink *devlink, u32 id,
@@ -1494,6 +1495,67 @@ static int rvu_af_npc_exact_feature_validate(struct devlink *devlink, u32 id,
 	return -EFAULT;
 }
 
+static int rvu_af_dl_npc_mcam_high_zone_percent_get(struct devlink *devlink, u32 id,
+						    struct devlink_param_gset_ctx *ctx)
+{
+	struct rvu_devlink *rvu_dl = devlink_priv(devlink);
+	struct rvu *rvu = rvu_dl->rvu;
+	struct npc_mcam *mcam;
+	u32 percent;
+
+	mcam = &rvu->hw->mcam;
+	percent = (mcam->hprio_count * 100) / mcam->bmap_entries;
+	ctx->val.vu8 = (u8)percent;
+
+	return 0;
+}
+
+static int rvu_af_dl_npc_mcam_high_zone_percent_set(struct devlink *devlink, u32 id,
+						    struct devlink_param_gset_ctx *ctx)
+{
+	struct rvu_devlink *rvu_dl = devlink_priv(devlink);
+	struct rvu *rvu = rvu_dl->rvu;
+	struct npc_mcam *mcam;
+	u32 percent;
+
+	percent = ctx->val.vu8;
+	mcam = &rvu->hw->mcam;
+	mcam->hprio_count = (mcam->bmap_entries * percent) / 100;
+	mcam->hprio_end = mcam->hprio_count;
+	mcam->lprio_count = (mcam->bmap_entries - mcam->hprio_count) / 2;
+	mcam->lprio_start = mcam->bmap_entries - mcam->lprio_count;
+
+	return 0;
+}
+
+static int rvu_af_dl_npc_mcam_high_zone_percent_validate(struct devlink *devlink, u32 id,
+							 union devlink_param_value val,
+							 struct netlink_ext_ack *extack)
+{
+	struct rvu_devlink *rvu_dl = devlink_priv(devlink);
+	struct rvu *rvu = rvu_dl->rvu;
+	struct npc_mcam *mcam;
+
+	/* The percent of high prio zone must range from 12% to 100% of unreserved mcam space */
+	if (val.vu8 < 12 || val.vu8 > 100) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "mcam high zone percent must be between 12% to 100%");
+		return -EINVAL;
+	}
+
+	/* Do not allow user to modify the high priority zone entries while mcam entries
+	 * have already been assigned.
+	 */
+	mcam = &rvu->hw->mcam;
+	if (mcam->bmap_fcnt < mcam->bmap_entries) {
+		NL_SET_ERR_MSG_MOD(extack,
+				   "mcam entries have already been assigned, can't resize");
+		return -EPERM;
+	}
+
+	return 0;
+}
+
 static const struct devlink_param rvu_af_dl_params[] = {
 	DEVLINK_PARAM_DRIVER(RVU_AF_DEVLINK_PARAM_ID_DWRR_MTU,
 			     "dwrr_mtu", DEVLINK_PARAM_TYPE_U32,
@@ -1509,6 +1571,12 @@ static const struct devlink_param rvu_af_dl_param_exact_match[] = {
 			     rvu_af_npc_exact_feature_get,
 			     rvu_af_npc_exact_feature_disable,
 			     rvu_af_npc_exact_feature_validate),
+	DEVLINK_PARAM_DRIVER(RVU_AF_DEVLINK_PARAM_ID_NPC_MCAM_ZONE_PERCENT,
+			     "npc_mcam_high_zone_percent", DEVLINK_PARAM_TYPE_U8,
+			     BIT(DEVLINK_PARAM_CMODE_RUNTIME),
+			     rvu_af_dl_npc_mcam_high_zone_percent_get,
+			     rvu_af_dl_npc_mcam_high_zone_percent_set,
+			     rvu_af_dl_npc_mcam_high_zone_percent_validate),
 };
 
 /* Devlink switch mode */