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>
We are going to reuse some of this functionality to implement retimer
NVM upgrade so move common NVM functionality into its own file. We also
rename the structure from tb_switch_nvm to tb_nvm to make it clear that
it is not just for switches.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
USB3 supports both isochronous and non-isochronous traffic. The former
requires guaranteed bandwidth and can take up to 90% of the total
bandwidth. With USB4 USB3 is tunneled over USB4 fabric which means that
we need to make sure there is enough bandwidth allocated for the USB3
tunnels in addition to DisplayPort tunnels.
Whereas DisplayPort bandwidth management is static and done before the
DP tunnel is established, the USB3 bandwidth management is dynamic and
allows increasing and decreasing the allocated bandwidth according to
what is currently consumed. This is done through host router USB3
downstream adapter registers.
This adds USB3 bandwidth management to the software connection manager
so that we always try to allocate maximum bandwidth for DP tunnels and
what is left is allocated for USB3.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
We need to call this from tb.c when we improve the bandwidth management
to take USB3 into account.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Each host router USB3 downstream adapter has a set of registers that are
used to negotiate bandwidth between the connection manager and the
internal xHCI controller. These registers allow dynamic bandwidth
management for USB3 isochronous traffic based on what is actually
consumed vs. allocated at any given time.
Implement these USB3 bandwidth negotiation routines to allow the
software connection manager take advantage of these.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
USB3 tunneling is possible only over USB4 link so don't create USB3
tunnels if that's not the case.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Currently we have only supported paths that follow daisy-chain topology
but USB4 also allows to build trees of devices. For this reason increase
maximum path length we use for discovery to be from the lowest level to
the host router and back to the same level.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
With USB4, topologies are not limited to daisy-chains anymore so when
calculating how many hops are between two ports we need to walk the
whole path instead.
Add helper function tb_for_each_port_on_path() that can be used to walk
over each port on a path and make tb_path_alloc() to use it.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
USB4 added a capability to tunnel USB 3.x protocol over the USB4
fabric. USB4 device routers may include integrated SuperSpeed HUB or a
function or both. USB tunneling follows PCIe so that the tunnel is
created between the parent and the child router from USB3 downstream
adapter port to USB3 upstream adapter port over a single USB4 link.
This adds support for USB 3.x tunneling and also capability to discover
existing USB 3.x tunnels (for example created by connection manager in
boot firmware).
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>
Link: https://lore.kernel.org/r/20191217123345.31850-9-mika.westerberg@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Time Management Unit (TMU) is included in each USB4 router. It is used
to synchronize time across the USB4 fabric. By default when USB4 router
is plugged to the domain, its TMU is turned off. This differs from
Thunderbolt (1, 2 and 3) devices whose TMU is by default configured to
bi-directional HiFi mode. Since time synchronization is needed for
proper Display Port tunneling this means we need to configure the TMU on
USB4 compliant devices.
The USB4 spec allows some flexibility on how the TMU can be configured.
This makes it possible to enable link power management states (CLx) in
certain topologies, where for example DP tunneling is not used. TMU can
also be re-configured dynamicaly depending on types of tunnels created
over the USB4 fabric.
In this patch we simply configure the TMU to be in bi-directional HiFi
mode. This way we can tunnel any kind of traffic without need to perform
complex steps to re-configure the domain dynamically. We can add more
fine-grained TMU configuration later on when we start enabling CLx
states.
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>
Link: https://lore.kernel.org/r/20191217123345.31850-8-mika.westerberg@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We need to find switch capabilities in order to implement TMU support so
make it available to other files as well.
Signed-off-by: Rajmohan Mani <rajmohan.mani@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20191217123345.31850-7-mika.westerberg@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB4 is the public specification based on Thunderbolt 3 protocol. There
are some differences in register layouts and flows. In addition to PCIe
and DP tunneling, USB4 supports tunneling of USB 3.x. USB4 is also
backward compatible with Thunderbolt 3 (and older generations but the
spec only talks about 3rd generation). USB4 compliant devices can be
identified by checking USB4 version field in router configuration space.
This patch adds initial support for USB4 compliant hosts and devices
which enables following features provided by the existing functionality
in the driver:
- PCIe tunneling
- Display Port tunneling
- Host and device NVM firmware upgrade
- P2P networking
This brings the USB4 support to the same level that we already have for
Thunderbolt 1, 2 and 3 devices.
Note the spec talks about host and device "routers" but in the driver we
still use term "switch" in most places. Both can be used interchangeably.
Co-developed-by: Rajmohan Mani <rajmohan.mani@intel.com>
Signed-off-by: Rajmohan Mani <rajmohan.mani@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20191217123345.31850-5-mika.westerberg@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
We will be needing this when adding initial USB4 support so make it
available to other files in the driver as well. We also rename it to
tb_switch_find_port() to follow conventions used in switch.c.
No functional changes.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Link: https://lore.kernel.org/r/20191217123345.31850-2-mika.westerberg@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Titan Ridge supports Display Port 1.4 which adds HBR3 (High Bit Rate)
rates that may be up to 8.1 Gb/s over 4 lanes. This translates to
effective data bandwidth of 25.92 Gb/s (as 8/10 encoding is removed by
the DP adapters when going over Thunderbolt fabric). If another high
rate monitor is connected we may need to reduce the bandwidth it
consumes so that it fits into the total 40 Gb/s available on the
Thunderbolt fabric.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
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>
In order to keep PCIe hierarchies consistent across hotplugs, add
hard-coded PCIe downstream port to Thunderbolt port for Alpine Ridge and
Titan Ridge as well.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
For a casual reader tb_switch_is_cr() does not tell much so instead
spell out the full controller name in the function name. For example
tb_switch_is_cr() becomes tb_switch_is_cactus_ridge() which is easier
to understand.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
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>
There are quite many places in the driver where we iterate over each
port in the switch. To make it bit more convenient, add a macro that can
be used to iterate over each port and convert existing call sites to use it.
This is based on code by Lukas Wunner.
No functional changes.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
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>
When a device is authorized from userspace by writing to authorized
attribute we first take the domain lock and then runtime resume the
device in question. There are two issues with this.
First is that the device connected notifications are blocked during this
time which means we get them only after the authorization operation is
complete. Because of this the authorization needed flag from the
firmware notification is not reflecting the real authorization status
anymore. So what happens is that the "authorized" keeps returning 0 even
if the device was already authorized properly.
Second issue is that each time the controller is runtime resumed the
connection_id field of device connected notification may be different
than in the previous resume. We need to use the latest connection_id
otherwise the firmware rejects the authorization command.
Fix these by moving runtime resume operations to happen before the
domain lock is taken, and waiting for the updated device connected
notification from the firmware before we allow runtime resume of a
device to complete.
While there add missing locking to tb_switch_nvm_read().
Fixes: 09f11b6c99 ("thunderbolt: Take domain lock in switch sysfs attribute callbacks")
Reported-by: Pengfei Xu <pengfei.xu@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Clang warns:
drivers/thunderbolt/tunnel.c:504:17: warning: implicit truncation from
'int' to bit-field changes value from 5 to -3
[-Wbitfield-constant-conversion]
path->priority = 5;
^ ~
1 warning generated.
The priority member in struct tb_path is only ever assigned a positive
number:
$ rg -n priority drivers/thunderbolt/path.c
drivers/thunderbolt/tunnel.c:99: path->priority = 3;
drivers/thunderbolt/tunnel.c:308: path->priority = 2;
drivers/thunderbolt/tunnel.c:323: path->priority = 1;
drivers/thunderbolt/tunnel.c:504: path->priority = 5;
Furthermore, that value is only assigned to an unsigned integer in
tb_path_activate (the priority member in struct tb_regs_hop).
Fixes: 44242d6c97 ("thunderbolt: Add support for DMA tunnels")
Link: https://github.com/ClangBuiltLinux/linux/issues/454
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
The printing macros do not modify the passed object so make them
const. While there make tb_route() to take const parameter as well.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
In addition to PCIe and Display Port tunnels it is also possible to
create tunnels that forward DMA traffic from the host interface adapter
(NHI) to a NULL port that is connected to another domain through a
Thunderbolt cable. These tunnels can be used to carry software messages
such as networking packets.
To support this we introduce another tunnel type (TB_TUNNEL_DMA) that
supports paths from NHI to NULL port and back.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
We run all XDomain requests during discovery in tb->wq and since it only
runs one work at the time it means that sending back reply to the other
domain may be delayed too much depending whether there is an active
XDomain discovery request running.
To make sure we can send reply to the other domain as soon as possible
run tb_xdp_handle_request() in system workqueue instead. Since the
device can be hot-removed in the middle we need to make sure the domain
structure is still around when the function is run so increase reference
count before we schedule the reply work.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Display Port tunnels are somewhat more complex than PCIe tunnels as it
requires 3 tunnels (AUX Rx/Tx and Video). In addition we are not
supposed to create the tunnels immediately when a DP OUT is enumerated.
Instead we need to wait until we get hotplug event to that adapter port
or check if the port has HPD set before tunnels can be established. This
adds Display Port tunneling support to the software connection manager.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
We will be needing these routines to find Display Port adapters as well
so modify them to take port type as the second parameter.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
The only way to expand Thunderbolt topology is through the NULL adapter
ports (typically ports 1, 2, 3 and 4). There is no point handling
Thunderbolt hotplug events on any other port.
Add a helper function (tb_port_is_null()) that can be used to determine
if the port is NULL port, and use it in software connection manager code
when hotplug event is handled.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Currently the software connection manager (tb.c) has only supported
creating a single PCIe tunnel, no PCIe device daisy chaining has been
supported so far. This updates the software connection manager so that
it now can create PCIe tunnels for full chain of six devices.
Because PCIe allows DMA and opens possibility for DMA attacks we change
security level to "user" meaning that PCIe tunneling requires that the
userspace authorizes the devices first. This makes it possible to block
PCIe tunneling completely while still allowing other types of tunnels to
be automatically created.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
In Apple Macs the boot firmware (EFI) connects all devices automatically
when the system is started, before it hands over to the OS. Instead of
ignoring we discover all those PCIe tunnels and record them using our
internal structures, just like we do when a device is connected after
the OS is already up.
By doing this we can properly tear down tunnels when devices are
disconnected. Also this allows us to resume the existing tunnels after
system suspend/resume cycle.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Now that we can allocate hop IDs per port on a path, we can take
advantage of this and create tunnels covering longer paths than just
between two adjacent switches. PCIe actually does not need this as it
is typically a daisy chain between two adjacent switches but this way we
do not need to hard-code creation of the tunnel.
While there add name to struct tb_path to make debugging easier, and
update kernel-doc comments.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
We need to be able to walk from one port to another when we are creating
paths where there are multiple switches between two ports. For this
reason introduce a new function tb_next_port_on_path().
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
Currently the driver only assigns remote port for the primary port if in
case of dual link. This makes things such as walking from one port to
another more complex than necessary because the code needs to change
from secondary to primary port if the path that is established is
created using secondary links.
In order to always assign both remote pointers we need to prevent the
scanning code from following the secondary link. Failing to do that
might cause problems as the same switch may be enumerated twice (or
removed in case of unplug). Handle that properly by introducing a new
function tb_port_has_remote() that returns true only for the primary
port. We also update tb_is_upstream_port() to support both dual link
ports, make it take const port pointer and move it below
tb_upstream_port() to keep similar functions close.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Each port has a separate path configuration space that is used for
finding the next hop (switch) in the path. HopID is an index to this
configuration space. HopIDs 0 - 7 are reserved by the protocol.
In order to get next available HopID for each direction we provide two
pairs of helper functions that can be used to allocate and release
HopIDs for a given port.
While there remove obsolete TODO comment.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
To be able to tunnel non-PCIe traffic, separate tunnel functionality
into generic and PCIe specific parts. Rename struct tb_pci_tunnel to
tb_tunnel, and make it hold an array of paths instead of just two.
Update all the tunneling functions to take this structure as parameter.
We also move tb_pci_port_active() to switch.c (and rename it) where we
will be keeping all port and switch related functions.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
The adapter specific capability either is there or not if the port does
not hold an adapter. Instead of always finding it on-demand we read the
offset just once when the port is initialized.
While there we update the struct port documentation to follow kernel-doc
format.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
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 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>
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>
Light Ridge and Eagle Ridge both need to have TMU access enabled before
port space can be fully accessed so make sure it happens on those. This
allows us to get rid of the offset quirk in tb_port_find_cap().
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Maximum depth in Thunderbolt topology is 6 so make sure it is not
possible to allocate switches that exceed the depth limit.
While at it update tb_switch_alloc() to use upper/lower_32_bits()
following tb_switch_alloc_safe_mode().
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
switch_lock was introduced because it allowed serialization of device
authorization requests from userspace without need to take the big
domain lock (tb->lock). This was fine because device authorization with
ICM is just one command that is sent to the firmware. Now that we start
to handle all tunneling in the driver switch_lock is not enough because
we need to walk over the topology to establish paths.
For this reason drop switch_lock from the driver completely in favour of
big domain lock.
There is one complication, though. If userspace is waiting for the lock
in tb_switch_set_authorized(), it keeps the device_del() from removing
the sysfs attribute because it waits for active users to release the
attribute first which leads into following splat:
INFO: task kworker/u8:3:73 blocked for more than 61 seconds.
Tainted: G W 5.1.0-rc1+ #244
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u8:3 D12976 73 2 0x80000000
Workqueue: thunderbolt0 tb_handle_hotplug [thunderbolt]
Call Trace:
? __schedule+0x2e5/0x740
? _raw_spin_lock_irqsave+0x12/0x40
? prepare_to_wait_event+0xc5/0x160
schedule+0x2d/0x80
__kernfs_remove.part.17+0x183/0x1f0
? finish_wait+0x80/0x80
kernfs_remove_by_name_ns+0x4a/0x90
remove_files.isra.1+0x2b/0x60
sysfs_remove_group+0x38/0x80
sysfs_remove_groups+0x24/0x40
device_remove_attrs+0x3d/0x70
device_del+0x14c/0x360
device_unregister+0x15/0x50
tb_switch_remove+0x9e/0x1d0 [thunderbolt]
tb_handle_hotplug+0x119/0x5a0 [thunderbolt]
? process_one_work+0x1b7/0x420
process_one_work+0x1b7/0x420
worker_thread+0x37/0x380
? _raw_spin_unlock_irqrestore+0xf/0x30
? process_one_work+0x420/0x420
kthread+0x118/0x130
? kthread_create_on_node+0x60/0x60
ret_from_fork+0x35/0x40
We deal this by following what network stack did for some of their
attributes and use mutex_trylock() with restart_syscall(). This makes
userspace release the attribute allowing sysfs attribute removal to
progress before the write is restarted and eventually fail when the
attribute is removed.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
If switch is already disconnected there is no point sending it commands
and waiting for timeout. Instead in that case return error immediately.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
tb_switch_find_by_route() does the same already so use it instead and
remove duplicated get_switch_at_route().
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Lukas Wunner <lukas@wunner.de>
This field is not used anywhere so remove it.
Reported-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Intel has done pretty major changes to the driver and we continue to do
so in the future as well. Add Intel as copyright holder of the files we
have done changes.
While there drop "Cactus Ridge" from the headers because this driver
works also with other Thunderbolt controllers.
No functional changes intended.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Yehezkel Bernat <yehezkelshb@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Currently the driver logs quite a lot to the system message buffer even
when doing normal operations. This information is not useful for
ordinary users and might even annoy some.
For this reason convert most of the logs at info level to happen at
debug level instead. The nice output formatting is untouched.
Logging can be easily re-enabled by passing "thunderbolt.dyndbg" in the
kernel command line (or using the corresponding control file runtime).
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Yehezkel Bernat <yehezkelshb@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
When Thunderbolt host controller is set to RTD3 mode (Runtime D3) it is
present all the time. Because of this it is important to runtime suspend
the controller whenever possible. In case of ICM we have following rules
which all needs to be true before the host controller can be put to D3:
- The controller firmware reports to support RTD3
- All the connected devices announce support for RTD3
- There is no active XDomain connection
Implement this using standard Linux runtime PM APIs so that when all the
children devices are runtime suspended, the Thunderbolt host controller
PCI device is runtime suspended as well. The ICM firmware then starts
powering down power domains towards RTD3 but it can prevent this if it
detects that there is an active Display Port stream (this is not visible
to the software, though).
The Thunderbolt host controller will be runtime resumed either when
there is a remote wake event (device is connected or disconnected), or
when there is access from userspace that requires hardware access.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Preboot ACL is a mechanism that allows connecting Thunderbolt devices
boot time in more secure way than the legacy Thunderbolt boot support.
As with the legacy boot option, this also needs to be enabled from the
BIOS before booting is allowed. Difference to the legacy mode is that
the userspace software explicitly adds device UUIDs by sending a special
message to the ICM firmware. Only the devices listed in the boot ACL are
connected automatically during the boot. This works in both "user" and
"secure" security levels.
We implement this in Linux by exposing a new sysfs attribute (boot_acl)
below each Thunderbolt domain. The userspace software can then update
the full list as needed.
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Rajmohan Mani