thunderbolt: Add missing UNSET_INBOUND_SBTX for retimer access

According to USB4 retimer specification, the process of firmware update
sequence requires issuing a SET_INBOUND_SBTX port operation tha

thunderbolt: Add missing UNSET_INBOUND_SBTX for retimer access

According to USB4 retimer specification, the process of firmware update
sequence requires issuing a SET_INBOUND_SBTX port operation that later
shall be followed by UNSET_INBOUND_SBTX port operation. This last step
is not currently issued by the driver but it is necessary to make sure
the retimers are put back to passthrough mode even during enumeration.

If this step is missing the link may not come up properly after
soft-reboot for example.

For this reason issue UNSET_INBOUND_SBTX after SET_INBOUND_SBTX for
enumeration and also when the NVM upgrade is run.

Reported-by: Christian Schaubschläger <christian.schaubschlaeger@gmx.at>
Link: https://lore.kernel.org/linux-usb/b556f5ed-5ee8-9990-9910-afd60db93310@gmx.at/
Cc: stable@vger.kernel.org
Signed-off-by: Gil Fine <gil.fine@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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thunderbolt: Add support for receiver lane margining

USB4 spec defines standard set of registers to be used for receiver lane
margining. This is useful for I/O interface quality and electrical
robus

thunderbolt: Add support for receiver lane margining

USB4 spec defines standard set of registers to be used for receiver lane
margining. This is useful for I/O interface quality and electrical
robustness validation during manufacturing. Expose receiver lane
margining through new debugfs directory "margining" that is added under
each connected USB4 port. Users can then run the margining by writing to
the exposed attributes under that directory.

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

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thunderbolt: Add additional USB4 port operations for retimer access

When accessing retimers when there is no cable connected we are going to
need additional USB4 port operations. First the port need

thunderbolt: Add additional USB4 port operations for retimer access

When accessing retimers when there is no cable connected we are going to
need additional USB4 port operations. First the port needs to be put
into offline mode, and then the sideband channel transactions must be
enabled on the SBTX line. This adds support for these operations.

Signed-off-by: Rajmohan Mani <rajmohan.mani@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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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 fi

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>

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thunderbolt: Implement USB4 port sideband operations for retimer access

USB4 spec specifies standard set of sideband operations that are send
over the low speed link to access either retimers on the

thunderbolt: Implement USB4 port sideband operations for retimer access

USB4 spec specifies standard set of sideband operations that are send
over the low speed link to access either retimers on the link or the
link parter (the other router). The USB4 retimer spec extends these and
adds operations for retimer NVM upgrade.

This implements the retimer access and NVM upgrade USB4 port sideband
operations which we need for retimer support in the patch that follows.

Signed-off-by: Rajmohan Mani <rajmohan.mani@intel.com>
Co-developed-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

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