thunderbolt: Add support for on-board retimers

USB4 spec specifies standard access to retimers (both on-board and
cable) through USB4 port sideband access. This makes it possible to
upgrade their firmware in the same way than we already do with the
routers.

This enumerates on-board retimers under each USB4 port when the link
comes up and adds them to the bus under the router the retimer belongs
to. Retimers are exposed in sysfs with name like <device>:<port>.<index>
where device is the router the retimer belongs to, port is the USB4 port
the retimer is connected to and index is the retimer index under that
port (starting from 1). This applies to the upstream USB4 port as well
so if there is on-board retimer between the port and the router it is
also added accordingly.

At this time we do not add cable retimers but there is no techincal
restriction to do so in the future if needed. It is not clear whether it
makes sense to upgrade their firmwares and at least Thunderbolt 3 cables
it has not been done outside of lab environments.

The sysfs interface is made to follow the router NVM upgrade to make it
easy to extend the existing userspace (fwupd) to handle these as well.

Signed-off-by: Kranthi Kuntala <kranthi.kuntala@intel.com>
Co-developed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
index 8f840148378a..736d1589c31e 100644
--- a/drivers/thunderbolt/tb.h
+++ b/drivers/thunderbolt/tb.h
@@ -211,6 +211,28 @@ struct tb_port {
 };
 
 /**
+ * tb_retimer: Thunderbolt retimer
+ * @dev: Device for the retimer
+ * @tb: Pointer to the domain the retimer belongs to
+ * @index: Retimer index facing the router USB4 port
+ * @vendor: Vendor ID of the retimer
+ * @device: Device ID of the retimer
+ * @port: Pointer to the lane 0 adapter
+ * @nvm: Pointer to the NVM if the retimer has one (%NULL otherwise)
+ * @auth_status: Status of last NVM authentication
+ */
+struct tb_retimer {
+	struct device dev;
+	struct tb *tb;
+	u8 index;
+	u32 vendor;
+	u32 device;
+	struct tb_port *port;
+	struct tb_nvm *nvm;
+	u32 auth_status;
+};
+
+/**
  * struct tb_path_hop - routing information for a tb_path
  * @in_port: Ingress port of a switch
  * @out_port: Egress port of a switch where the packet is routed out
@@ -553,6 +575,7 @@ struct tb *icm_probe(struct tb_nhi *nhi);
 struct tb *tb_probe(struct tb_nhi *nhi);
 
 extern struct device_type tb_domain_type;
+extern struct device_type tb_retimer_type;
 extern struct device_type tb_switch_type;
 
 int tb_domain_init(void);
@@ -853,6 +876,21 @@ void tb_xdomain_remove(struct tb_xdomain *xd);
 struct tb_xdomain *tb_xdomain_find_by_link_depth(struct tb *tb, u8 link,
 						 u8 depth);
 
+int tb_retimer_scan(struct tb_port *port);
+void tb_retimer_remove_all(struct tb_port *port);
+
+static inline bool tb_is_retimer(const struct device *dev)
+{
+	return dev->type == &tb_retimer_type;
+}
+
+static inline struct tb_retimer *tb_to_retimer(struct device *dev)
+{
+	if (tb_is_retimer(dev))
+		return container_of(dev, struct tb_retimer, dev);
+	return NULL;
+}
+
 int usb4_switch_setup(struct tb_switch *sw);
 int usb4_switch_read_uid(struct tb_switch *sw, u64 *uid);
 int usb4_switch_drom_read(struct tb_switch *sw, unsigned int address, void *buf,