mlx4_core: Save/restore default port IB capability mask

Commit 7ff93f8b ("mlx4_core: Multiple port type support") introduced
support for different port types. As part of that support, SET_PORT
is invoked to set the port type during driver startup. However, as a
side-effect, for IB ports the invocation of this command also sets the
port's capability mask to zero (losing the default value set by FW).

To fix this, get the default ib port capabilities (via a MAD_IFC Port
Info query) during driver startup, and save them for use in the
mlx4_SET_PORT command when setting the port-type to Infiniband.

This patch fixes problems with subnet manager (SM) failover such as
<https://bugs.openfabrics.org/show_bug.cgi?id=1183>, which occurred
because the IsTrapSupported bit in the capability mask was zeroed.

Signed-off-by: Jack Morgenstein <[e-mail]>
Signed-off-by: Roland Dreier <[e-mail]>

drivers/net/mlx4/main.c

···
 	struct mlx4_priv *priv = mlx4_priv(dev);
 	int err;
 	int port;
+	__be32 ib_port_default_caps;
 
 	err = mlx4_init_uar_table(dev);
 	if (err) {
···
 	}
 
 	for (port = 1; port <= dev->caps.num_ports; port++) {
+		ib_port_default_caps = 0;
+		err = mlx4_get_port_ib_caps(dev, port, &ib_port_default_caps);
+		if (err)
+			mlx4_warn(dev, "failed to get port %d default "
+				  "ib capabilities (%d). Continuing with "
+				  "caps = 0\n", port, err);
+		dev->caps.ib_port_def_cap[port] = ib_port_default_caps;
 		err = mlx4_SET_PORT(dev, port);
 		if (err) {
 			mlx4_err(dev, "Failed to set port %d, aborting\n",

drivers/net/mlx4/mlx4.h

···
 void mlx4_init_vlan_table(struct mlx4_dev *dev, struct mlx4_vlan_table *table);
 
 int mlx4_SET_PORT(struct mlx4_dev *dev, u8 port);
+int mlx4_get_port_ib_caps(struct mlx4_dev *dev, u8 port, __be32 *caps);
 
 #endif /* MLX4_H */

drivers/net/mlx4/port.c

···
 }
 EXPORT_SYMBOL_GPL(mlx4_unregister_vlan);
 
+int mlx4_get_port_ib_caps(struct mlx4_dev *dev, u8 port, __be32 *caps)
+{
+	struct mlx4_cmd_mailbox *inmailbox, *outmailbox;
+	u8 *inbuf, *outbuf;
+	int err;
+
+	inmailbox = mlx4_alloc_cmd_mailbox(dev);
+	if (IS_ERR(inmailbox))
+		return PTR_ERR(inmailbox);
+
+	outmailbox = mlx4_alloc_cmd_mailbox(dev);
+	if (IS_ERR(outmailbox)) {
+		mlx4_free_cmd_mailbox(dev, inmailbox);
+		return PTR_ERR(outmailbox);
+	}
+
+	inbuf = inmailbox->buf;
+	outbuf = outmailbox->buf;
+	memset(inbuf, 0, 256);
+	memset(outbuf, 0, 256);
+	inbuf[0] = 1;
+	inbuf[1] = 1;
+	inbuf[2] = 1;
+	inbuf[3] = 1;
+	*(__be16 *) (&inbuf[16]) = cpu_to_be16(0x0015);
+	*(__be32 *) (&inbuf[20]) = cpu_to_be32(port);
+
+	err = mlx4_cmd_box(dev, inmailbox->dma, outmailbox->dma, port, 3,
+			   MLX4_CMD_MAD_IFC, MLX4_CMD_TIME_CLASS_C);
+	if (!err)
+		*caps = *(__be32 *) (outbuf + 84);
+	mlx4_free_cmd_mailbox(dev, inmailbox);
+	mlx4_free_cmd_mailbox(dev, outmailbox);
+	return err;
+}
+
 int mlx4_SET_PORT(struct mlx4_dev *dev, u8 port)
 {
 	struct mlx4_cmd_mailbox *mailbox;
···
 		((u8 *) mailbox->buf)[3] = 6;
 		((__be16 *) mailbox->buf)[4] = cpu_to_be16(1 << 15);
 		((__be16 *) mailbox->buf)[6] = cpu_to_be16(1 << 15);
-	}
+	} else
+		((__be32 *) mailbox->buf)[1] = dev->caps.ib_port_def_cap[port];
 	err = mlx4_cmd(dev, mailbox->dma, port, is_eth, MLX4_CMD_SET_PORT,
 		       MLX4_CMD_TIME_CLASS_B);
 

include/linux/mlx4/device.h

···
 	int			num_ports;
 	int			vl_cap[MLX4_MAX_PORTS + 1];
 	int			ib_mtu_cap[MLX4_MAX_PORTS + 1];
+	__be32			ib_port_def_cap[MLX4_MAX_PORTS + 1];
 	u64			def_mac[MLX4_MAX_PORTS + 1];
 	int			eth_mtu_cap[MLX4_MAX_PORTS + 1];
 	int			gid_table_len[MLX4_MAX_PORTS + 1];