Add missing free_page() call for the memory allocated by
validate_and_copy_from_user().

Fixes: 6d241fa00159 ("thunderbolt: Add sideband register access to debugfs")
Signed-off-by: Aapo Vienamo <aapo.vienamo@linux.intel.com>
Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Use the FIELD_GET() macro instead of open coding the masks and shifts.
This makes the code more compact and improves readability as it avoids
the need to wrap excessively long lines.

Signed-off-by: Aapo Vienamo <aapo.vienamo@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Yehezkel Bernat <YehezkelShB@gmail.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Retimers support lane margining as well so make this available through
debugfs in the same way as we do for the USB4 ports. When this is
enabled we also expose retimers on the other side of the cable because
typically margining is implemented only on direction towards the cable.
However, for the retimers on the other side of the cable we do not allow
NVM upgrade to avoid confusing the existing userspace (the same retimer
may now appear twice with different name) and is probably not a good
idea anyway.

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

In order to add lane margining support for retimers make the margining
functions take sideband target and retimer index as parameters. This
makes it possible to access both router and retimer sideband using the
same functions.

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

We are going to expand lane margining support for retimers too so split
out the generic margining functionality out of being specific to USB4
ports.

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

This makes it possible to read and write USB4 port and retimer sideband
registers through debugfs which is useful for debugging and manufacturing
purposes. We add "sb_regs" debugfs attribute under each USB4 port and
retimer that is used to access the sideband.

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

The margin debugfs node controls the "Enable Margin Test" field of the
lane margining operations. This field selects between either low or high
voltage margin values for voltage margin test or left or right timing
margin values for timing margin test.

According to the USB4 specification, whether or not the "Enable Margin
Test" control applies, depends on the values of the "Independent
High/Low Voltage Margin" or "Independent Left/Right Timing Margin"
capability fields for voltage and timing margin tests respectively. The
pre-existing condition enabled the debugfs node also in the case where
both low/high or left/right margins are returned, which is incorrect.
This change only enables the debugfs node in question, if the specific
required capability values are met.

Signed-off-by: Aapo Vienamo <aapo.vienamo@linux.intel.com>
Fixes: d0f1e0c2a699 ("thunderbolt: Add support for receiver lane margining")
Cc: stable@vger.kernel.org
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

Intel pre-USB4 routers only have ROUTER_CS_0 up to ROUTER_CS_4 and it
immediately follows the TMU router registers. Correct this accordingly.

Reported-by: Rajaram Regupathy <rajaram.regupathy@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

The dentry returned by debugfs_lookup() needs to be released by calling
dput() which is missing in margining_port_remove(). Fix this by calling
debugfs_lookup_and_remove() that combines both and avoids the memory leak.

Fixes: d0f1e0c2a699 ("thunderbolt: Add support for receiver lane margining")
Cc: stable@vger.kernel.org
Signed-off-by: Yaxiong Tian <tianyaxiong@kylinos.cn>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>

For USB4 v2 routers, the PCIe adapter capability length is longer.
Display the correct capability length in the debugfs register dump.

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