thunderbolt: Introduce tb_port_reset()

Introduce a function that issues Downstream Port Reset to a USB4 port.
This supports Thunderbolt 2, 3 and USB4 routers.

Signed-off-by: Sanath S <Sanath.S@amd.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Add internal xHCI connect flows for Thunderbolt 3 devices

Both Alpine Ridge and Titan Ridge require special flows in order to
activate the internal xHCI controller when there is USB device connected
to the downstream type-C port. This implements the missing flows for
both.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Enable CL0s for Intel Titan Ridge

Low power link states (called collectively CLx) are used to reduce
transmitter and receiver power when a high-speed lane is idle. The
simplest one being called CL0s. Follow what we already do for USB4
device routers and enable CL0s for Intel Titan Ridge device router too.
This allows better thermal management.

Signed-off-by: Gil Fine <gil.fine@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Add wake from DisplayPort

Latest USB4 spec added a new wake bit for DisplayPort so add this to the
driver when runtime suspending. This way wake up the domain when a new
monitor is plugged in to any of the device routers.

Also do the same for pre-USB4 devices through the link controller
registers as documented in chapter 13 of the USB4 spec.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Start lane initialization after sleep

USB4 spec says that for TBT3 compatible device routers the connection
manager needs to set SLI (Start Lane Initialization) to get the lanes
that were not connected back to functional state after sleep. Same needs
to be done if the link was XDomain.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Yehezkel Bernat <YehezkelShB@gmail.com>

thunderbolt: Enable wakes from system suspend

In order for the router and the whole domain to wake up from system
suspend states we need to enable wakes for the connected routers. For
device routers we enable wakes from PCIe and USB 3.x. This allows
devices such as keyboards connected to USB 3.x hub that is tunneled to
wake the system up as expected. For all routers we enabled wake on USB4
for each connected ports. This is used to propagate the wake from router
to another.

Do the same for legacy routers through link controller vendor specific
registers as documented in USB4 spec chapter 13.

While there correct kernel-doc of usb4_switch_set_sleep() -- it does not
enable wakes instead there is a separate function (usb4_switch_set_wake())
that does.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Configure port for XDomain

When the port is connected to another host it should be marked as such
in the USB4 port capability. This information is used by the router
during sleep and wakeup.

Also do the same for legacy switches via link controller vendor specific
registers.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Set port configured for both ends of the link

Both ends of the link needs to have this set. Otherwise the link is not
re-established properly after sleep. Now since it is possible to have
mixed USB4 and Thunderbolt 1, 2 and 3 devices we need to split the link
configuration functionality to happen per port so we can pick the
correct implementation.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Configure link after lane bonding is enabled

During testing it was noticed that the link is not properly restored
after the domain exits sleep if the link configured bits are set before
lane bonding is enabled. The USB4 spec does not say in which order these
need to be set but setting link configured afterwards makes the link
restoration work so we do that instead.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Add support for authenticate on disconnect

Some external devices can support completing thunderbolt authentication
when they are unplugged. For this to work though, the link controller must
remain operational.

The only device known to support this right now is the Dell WD19TB, so add
a quirk for this.

Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Add Display Port adapter pairing and resource management

To perform proper Display Port tunneling for Thunderbolt 3 devices we
need to allocate DP resources for DP IN port before they can be used.
The reason for this is that the user can also connect a monitor directly
to the Type-C ports in which case the Thunderbolt controller acts as
re-driver for Display Port (no tunneling takes place) taking the DP
sinks away from the connection manager. This allocation is done using
special sink allocation registers available through the link controller.

We can pair DP IN to DP OUT only if

* DP IN has sink allocated via link controller
* DP OUT port receives hotplug event

For DP IN adapters (only for the host router) we first query whether
there is DP resource available (it may be the previous instance of the
driver for example already allocated it) and if it is we add it to the
list. We then update the list when after each plug/unplug event to a DP
IN/OUT adapter. Each time the list is updated we try to find additional
DP IN <-> DP OUT pairs for tunnel establishment. This strategy also
makes it possible to establish another tunnel in case there are 3
monitors connected and one gets unplugged releasing the DP IN adapter
for the new tunnel.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Add support for lane bonding

Lane bonding allows aggregating two 10/20 Gb/s (depending on the
generation) lanes into a single 20/40 Gb/s bonded link. This allows
sharing the full bandwidth more efficiently. In order to establish lane
bonding we need to check that lane bonding is possible through link
controller and that both ends of the link actually supports 2x widths.
This also means that all the paths should be established through the
primary port so update tb_path_alloc() to handle this as well.

Lane bonding is supported starting from Falcon Ridge (2nd generation)
controllers.

We also expose the current speed and number of lanes under each device
except the host router following similar attribute naming than USB bus.
Expose speed and number of lanes for both directions to allow possibility
of asymmetric link in the future.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Introduce tb_switch_is_icm()

We currently differentiate between SW CM (Software Connection Manager,
sometimes also called External Connection Manager) and ICM (Firmware
based Connection Manager, Internal Connection Manager) by looking
directly at the sw->config.enabled field which may be rather hard to
understand for the casual reader. For this reason introduce a wrapper
function with documentation that should make the intention more clear.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Set sleep bit when suspending switch

Thunderbolt 2 devices and beyond link controller needs to be notified
when a switch is going to be suspended by setting bit 31 in LC_SX_CTRL
register. Add this functionality to the software connection manager.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Configure lanes when switch is initialized

Thunderbolt 2 devices and beyond need to have additional bits set in
link controller specific registers. This includes two bits in LC_SX_CTRL
that tell the link controller which lane is connected and whether it is
upstream facing or not.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

thunderbolt: Move LC specific functionality into a separate file

We will be adding more link controller functionality in subsequent
patches and it does not make sense to keep all that in switch.c, so
separate LC functionality into its own file.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>