mlxsw: spectrum_buffers: Convert mlxsw_sp_port_headroom_init()

Currently mlxsw_sp_port_headroom_init() configures both priomap and buffers
by hand. Additionally, for port buffers, it configures buffer 0 with a size
that it will never again have if PFC configuration is touched.

Rewrite the init code to become a client of the new hdroom code. The only
difference in invocation is that the configuration is forced, so that it is
issued even if the desired configuration happens to match what is contained
in (hitherto not initialized with meaningful values) mlxsw_sp_port->hdroom.

Since now mlxsw_sp_port_headroom_init() initializes all the PG buffers to
meaningful values, mlxsw_sp_hdroom_configure_buffers() can avoid querying
the current configuration, and can fill the whole PBMC itself.

Signed-off-by: Petr Machata <petrm@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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

@@ -286,47 +286,6 @@ static int mlxsw_sp_sb_pm_occ_query(struct mlxsw_sp *mlxsw_sp, u8 local_port,
 				     (unsigned long) pm);
 }
 
-/* 1/4 of a headroom necessary for 100Gbps port and 100m cable. */
-#define MLXSW_SP_PB_HEADROOM 25632
-#define MLXSW_SP_PB_UNUSED 8
-
-static int mlxsw_sp_port_pb_init(struct mlxsw_sp_port *mlxsw_sp_port)
-{
-	const u32 pbs[] = {
-		[0] = MLXSW_SP_PB_HEADROOM * mlxsw_sp_port->mapping.width,
-		[9] = MLXSW_PORT_MAX_MTU,
-	};
-	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
-	char pbmc_pl[MLXSW_REG_PBMC_LEN];
-	int i;
-
-	mlxsw_reg_pbmc_pack(pbmc_pl, mlxsw_sp_port->local_port,
-			    0xffff, 0xffff / 2);
-	for (i = 0; i < ARRAY_SIZE(pbs); i++) {
-		u16 size = mlxsw_sp_bytes_cells(mlxsw_sp, pbs[i]);
-
-		if (i == MLXSW_SP_PB_UNUSED)
-			continue;
-		size = mlxsw_sp_port_headroom_8x_adjust(mlxsw_sp_port, size);
-		mlxsw_reg_pbmc_lossy_buffer_pack(pbmc_pl, i, size);
-	}
-	mlxsw_reg_pbmc_lossy_buffer_pack(pbmc_pl,
-					 MLXSW_REG_PBMC_PORT_SHARED_BUF_IDX, 0);
-	return mlxsw_reg_write(mlxsw_sp->core, MLXSW_REG(pbmc), pbmc_pl);
-}
-
-static int mlxsw_sp_port_pb_prio_init(struct mlxsw_sp_port *mlxsw_sp_port)
-{
-	char pptb_pl[MLXSW_REG_PPTB_LEN];
-	int i;
-
-	mlxsw_reg_pptb_pack(pptb_pl, mlxsw_sp_port->local_port);
-	for (i = 0; i < IEEE_8021QAZ_MAX_TCS; i++)
-		mlxsw_reg_pptb_prio_to_buff_pack(pptb_pl, i, 0);
-	return mlxsw_reg_write(mlxsw_sp_port->mlxsw_sp->core, MLXSW_REG(pptb),
-			       pptb_pl);
-}
-
 void mlxsw_sp_hdroom_prios_reset_buf_idx(struct mlxsw_sp_hdroom *hdroom)
 {
 	int prio;
@@ -422,6 +381,8 @@ void mlxsw_sp_hdroom_bufs_reset_sizes(struct mlxsw_sp_port *mlxsw_sp_port,
 	}
 }
 
+#define MLXSW_SP_PB_UNUSED 8
+
 static int mlxsw_sp_hdroom_configure_buffers(struct mlxsw_sp_port *mlxsw_sp_port,
 					     const struct mlxsw_sp_hdroom *hdroom, bool force)
 {
@@ -435,14 +396,13 @@ static int mlxsw_sp_hdroom_configure_buffers(struct mlxsw_sp_port *mlxsw_sp_port
 	if (!dirty && !force)
 		return 0;
 
-	mlxsw_reg_pbmc_pack(pbmc_pl, mlxsw_sp_port->local_port, 0, 0);
-	err = mlxsw_reg_query(mlxsw_sp->core, MLXSW_REG(pbmc), pbmc_pl);
-	if (err)
-		return err;
-
-	for (i = 0; i < DCBX_MAX_BUFFERS; i++) {
+	mlxsw_reg_pbmc_pack(pbmc_pl, mlxsw_sp_port->local_port, 0xffff, 0xffff / 2);
+	for (i = 0; i < MLXSW_SP_PB_COUNT; i++) {
 		const struct mlxsw_sp_hdroom_buf *buf = &hdroom->bufs.buf[i];
 
+		if (i == MLXSW_SP_PB_UNUSED)
+			continue;
+
 		mlxsw_sp_hdroom_buf_pack(pbmc_pl, i, buf->size_cells, buf->thres_cells, buf->lossy);
 	}
 
@@ -548,12 +508,23 @@ int mlxsw_sp_hdroom_configure(struct mlxsw_sp_port *mlxsw_sp_port,
 
 static int mlxsw_sp_port_headroom_init(struct mlxsw_sp_port *mlxsw_sp_port)
 {
-	int err;
+	struct mlxsw_sp *mlxsw_sp = mlxsw_sp_port->mlxsw_sp;
+	struct mlxsw_sp_hdroom hdroom = {};
+	u32 size9;
+	int prio;
 
-	err = mlxsw_sp_port_pb_init(mlxsw_sp_port);
-	if (err)
-		return err;
-	return mlxsw_sp_port_pb_prio_init(mlxsw_sp_port);
+	hdroom.mtu = mlxsw_sp_port->dev->mtu;
+	for (prio = 0; prio < IEEE_8021QAZ_MAX_TCS; prio++)
+		hdroom.prios.prio[prio].lossy = true;
+
+	mlxsw_sp_hdroom_bufs_reset_lossiness(&hdroom);
+	mlxsw_sp_hdroom_bufs_reset_sizes(mlxsw_sp_port, &hdroom);
+
+	/* Buffer 9 is used for control traffic. */
+	size9 = mlxsw_sp_port_headroom_8x_adjust(mlxsw_sp_port, mlxsw_sp_port->max_mtu);
+	hdroom.bufs.buf[9].size_cells = mlxsw_sp_bytes_cells(mlxsw_sp, size9);
+
+	return __mlxsw_sp_hdroom_configure(mlxsw_sp_port, &hdroom, true);
 }
 
 static int mlxsw_sp_sb_port_init(struct mlxsw_sp *mlxsw_sp,