thunderbolt: Do not fail adding switch if some port is not implemented

There are two ways to mark a port as unimplemented. Typical way is to
return port type as TB_TYPE_INACTIVE when its config space is read.
Alternatively if the port is not physically present (such as ports 10
and 11 in ICL) reading from port config space returns
TB_CFG_ERROR_INVALID_CONFIG_SPACE instead. Currently the driver bails
out from adding the switch if it receives any error during port
inititialization which is wrong.

Handle this properly and just leave the port as TB_TYPE_INACTIVE before
continuing to the next port.

This also allows us to get rid of special casing for Light Ridge port 5
in eeprom.c.

Signed-off-by: Mika Westerberg <[email protected]>
Reviewed-by: Yehezkel Bernat <[email protected]>
Tested-by: Mario Limonciello <[email protected]>

drivers/thunderbolt/ctl.c

@@ -930,6 +930,23 @@ struct tb_cfg_result tb_cfg_write_raw(struct tb_ctl *ctl, const void *buffer,
 	return res;
 }
 
+static int tb_cfg_get_error(struct tb_ctl *ctl, enum tb_cfg_space space,
+			    const struct tb_cfg_result *res)
+{
+	/*
+	 * For unimplemented ports access to port config space may return
+	 * TB_CFG_ERROR_INVALID_CONFIG_SPACE (alternatively their type is
+	 * set to TB_TYPE_INACTIVE). In the former case return -ENODEV so
+	 * that the caller can mark the port as disabled.
+	 */
+	if (space == TB_CFG_PORT &&
+	    res->tb_error == TB_CFG_ERROR_INVALID_CONFIG_SPACE)
+		return -ENODEV;
+
+	tb_cfg_print_error(ctl, res);
+	return -EIO;
+}
+
 int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
 		enum tb_cfg_space space, u32 offset, u32 length)
 {
@@ -942,8 +959,7 @@ int tb_cfg_read(struct tb_ctl *ctl, void *buffer, u64 route, u32 port,
 
 	case 1:
 		/* Thunderbolt error, tb_error holds the actual number */
-		tb_cfg_print_error(ctl, &res);
-		return -EIO;
+		return tb_cfg_get_error(ctl, space, &res);
 
 	case -ETIMEDOUT:
 		tb_ctl_warn(ctl, "timeout reading config space %u from %#x\n",
@@ -969,8 +985,7 @@ int tb_cfg_write(struct tb_ctl *ctl, const void *buffer, u64 route, u32 port,
 
 	case 1:
 		/* Thunderbolt error, tb_error holds the actual number */
-		tb_cfg_print_error(ctl, &res);
-		return -EIO;
+		return tb_cfg_get_error(ctl, space, &res);
 
 	case -ETIMEDOUT:
 		tb_ctl_warn(ctl, "timeout writing config space %u to %#x\n",

drivers/thunderbolt/eeprom.c

@@ -525,10 +525,6 @@ int tb_drom_read(struct tb_switch *sw)
 		sw->ports[3].dual_link_port = &sw->ports[4];
 		sw->ports[4].dual_link_port = &sw->ports[3];
 
-		/* Port 5 is inaccessible on this gen 1 controller */
-		if (sw->config.device_id == PCI_DEVICE_ID_INTEL_LIGHT_RIDGE)
-			sw->ports[5].disabled = true;
-
 		return 0;
 	}
 

drivers/thunderbolt/switch.c

@@ -611,8 +611,14 @@ static int tb_init_port(struct tb_port *port)
 	int cap;
 
 	res = tb_port_read(port, &port->config, TB_CFG_PORT, 0, 8);
-	if (res)
+	if (res) {
+		if (res == -ENODEV) {
+			tb_dbg(port->sw->tb, " Port %d: not implemented\n",
+			       port->port);
+			return 0;
+		}
 		return res;
+	}
 
 	/* Port 0 is the switch itself and has no PHY. */
 	if (port->config.type == TB_TYPE_PORT && port->port != 0) {