mlxsw: spectrum_router: Encode adjacency group size ranges in an array

The device supports a fixed set of adjacency group sizes. Encode these
sizes in an array, so that the next patch will be able to split it
between Spectrum-1 and Spectrum-{2,3}, which support different size
ranges.
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Petr Machata <petrm@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c

@@ -3559,34 +3559,57 @@ mlxsw_sp_nexthop_fib_entries_update(struct mlxsw_sp *mlxsw_sp,
 	return 0;
 }
 
+struct mlxsw_sp_adj_grp_size_range {
+	u16 start; /* Inclusive */
+	u16 end; /* Inclusive */
+};
+
+/* Ordered by range start value */
+static const struct mlxsw_sp_adj_grp_size_range
+mlxsw_sp_adj_grp_size_ranges[] = {
+	{ .start = 1, .end = 64 },
+	{ .start = 512, .end = 512 },
+	{ .start = 1024, .end = 1024 },
+	{ .start = 2048, .end = 2048 },
+	{ .start = 4096, .end = 4096 },
+};
+
 static void mlxsw_sp_adj_grp_size_round_up(u16 *p_adj_grp_size)
 {
-	/* Valid sizes for an adjacency group are:
-	 * 1-64, 512, 1024, 2048 and 4096.
-	 */
-	if (*p_adj_grp_size <= 64)
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(mlxsw_sp_adj_grp_size_ranges); i++) {
+		const struct mlxsw_sp_adj_grp_size_range *size_range;
+
+		size_range = &mlxsw_sp_adj_grp_size_ranges[i];
+
+		if (*p_adj_grp_size >= size_range->start &&
+		    *p_adj_grp_size <= size_range->end)
 			return;
-	else if (*p_adj_grp_size <= 512)
-		*p_adj_grp_size = 512;
-	else if (*p_adj_grp_size <= 1024)
-		*p_adj_grp_size = 1024;
-	else if (*p_adj_grp_size <= 2048)
-		*p_adj_grp_size = 2048;
-	else
-		*p_adj_grp_size = 4096;
+
+		if (*p_adj_grp_size <= size_range->end) {
+			*p_adj_grp_size = size_range->end;
+			return;
+		}
+	}
 }
 
 static void mlxsw_sp_adj_grp_size_round_down(u16 *p_adj_grp_size,
 					     unsigned int alloc_size)
 {
-	if (alloc_size >= 4096)
-		*p_adj_grp_size = 4096;
-	else if (alloc_size >= 2048)
-		*p_adj_grp_size = 2048;
-	else if (alloc_size >= 1024)
-		*p_adj_grp_size = 1024;
-	else if (alloc_size >= 512)
-		*p_adj_grp_size = 512;
+	size_t arr_size = ARRAY_SIZE(mlxsw_sp_adj_grp_size_ranges);
+	int i;
+
+	for (i = arr_size - 1; i >= 0; i--) {
+		const struct mlxsw_sp_adj_grp_size_range *size_range;
+
+		size_range = &mlxsw_sp_adj_grp_size_ranges[i];
+
+		if (alloc_size >= size_range->end) {
+			*p_adj_grp_size = size_range->end;
+			return;
+		}
+	}
 }
 
 static int mlxsw_sp_fix_adj_grp_size(struct mlxsw_sp *mlxsw_sp,