linux.git/drivers/thunderbolt/domain.c, branch for-next

driver core: have match() callback in struct bus_type take a const *

2024-07-03T13:16:54+00:00

In the match() callback, the struct device_driver * should not be
changed, so change the function callback to be a const *.  This is one
step of many towards making the driver core safe to have struct
device_driver in read-only memory.

Because the match() callback is in all busses, all busses are modified
to handle this properly.  This does entail switching some container_of()
calls to container_of_const() to properly handle the constant *.

For some busses, like PCI and USB and HV, the const * is cast away in
the match callback as those busses do want to modify those structures at
this point in time (they have a local lock in the driver structure.)
That will have to be changed in the future if they wish to have their
struct device * in read-only-memory.

Cc: Rafael J. Wysocki 
Reviewed-by: Alex Elder 
Acked-by: Sumit Garg 
Link: https://lore.kernel.org/r/2024070136-wrongdoer-busily-01e8@gregkh
Signed-off-by: Greg Kroah-Hartman

thunderbolt: Constify the struct device_type usage

2024-02-26T07:15:49+00:00

Since commit aed65af1cc2f ("drivers: make device_type const"), the driver
core can properly handle constant struct device_type. Move the
tb_domain_type, tb_retimer_type, tb_switch_type, usb4_port_device_type,
tb_service_type and tb_xdomain_type variables to be constant structures as
well, placing it into read-only memory which can not be modified at
runtime.

Cc: Greg Kroah-Hartman 
Signed-off-by: Ricardo B. Marliere 
Signed-off-by: Mika Westerberg

thunderbolt: Add trace events support for the control channel

2024-02-26T07:12:24+00:00

Sometimes it is useful to see the traffic happening inside the control
channel, especially when debugging a possible problem. This adds
tracepoints close to the hardware which can be enabled dynamically as
needed using the standard Linux trace events facility.

Signed-off-by: Gil Fine 
Co-developed-by: Mika Westerberg 
Signed-off-by: Mika Westerberg

thunderbolt: Reserve released DisplayPort bandwidth for a group for 10 seconds

2024-02-16T10:29:23+00:00

The USB4 spec says that the Connection Manager should reserve the
bandwidth that is released in the same group for 10 seconds before it
can be shared with other groups. Add support for this. We also delay the
symmetric transition by that same 10 seconds to avoid any unnecessary
transitions (i.e if the released bandwidth is used by another
DisplayPort tunnel in the same group the link can stay asymmetric the
whole time).

Signed-off-by: Mika Westerberg

thunderbolt: Remove usage of the deprecated ida_simple_xx() API

2024-01-23T11:30:20+00:00

ida_alloc() and ida_free() should be preferred to the deprecated
ida_simple_get() and ida_simple_remove().

Note that the upper limit of ida_simple_get() is exclusive, but the one of
ida_alloc_range()/ida_alloc_max() is inclusive. So a -1 has been added
when needed.

Signed-off-by: Christophe JAILLET 
Signed-off-by: Mika Westerberg

thunderbolt: Reset topology created by the boot firmware

2024-01-22T11:21:06+00:00

Boot firmware (typically BIOS) might have created tunnels of its own.
The tunnel configuration that it does might be sub-optimal. For instance
it may only support HBR2 monitors so the DisplayPort tunnels it created
may limit Linux graphics drivers. In addition there is an issue on some
AMD based systems where the BIOS does not allocate enough PCIe resources
for future topology extension. By resetting the USB4 topology the PCIe
links will be reset as well allowing Linux to re-allocate.

This aligns the behavior with Windows Connection Manager.

We already issued host router reset for USB4 v2 routers, now extend it
to USB4 v1 routers as well. For pre-USB4 (that's Apple systems) we leave
it as is and continue to discover the existing tunnels.

Suggested-by: Mario Limonciello 
Signed-off-by: Sanath S 
Signed-off-by: Mika Westerberg

thunderbolt: make tb_bus_type const

2023-12-20T07:21:57+00:00

Now that the driver core can properly handle constant struct bus_type,
move the tb_bus_type variable to be a constant structure as well,
placing it into read-only memory which can not be modified at runtime.

Cc: Andreas Noever 
Cc: Michael Jamet 
Cc: Yehezkel Bernat 
Cc:  
Acked-by: Mika Westerberg 
Link: https://lore.kernel.org/r/2023121904-utopia-broadcast-06d1@gregkh
Signed-off-by: Greg Kroah-Hartman

thunderbolt: Convert to use sysfs_emit()/sysfs_emit_at() APIs

2022-09-24T06:22:01+00:00

Follow the advice of the Documentation/filesystems/sysfs.rst and show()
should only use sysfs_emit() or sysfs_emit_at() when formatting the value
to be returned to user space.

While at it, use Elvis operator in some cases.

Signed-off-by: Andy Shevchenko 
Signed-off-by: Mika Westerberg

thunderbolt: test: Use kunit_test_suite() macro

2022-07-11T23:13:21+00:00

The new implementation of kunit_test_suite() for modules no longer
conflicts with module_init, so can now be used by the thunderbolt tests.

Also update the Kconfig entry to enable the test when KUNIT_ALL_TESTS is
enabled.

This means that kunit_tool can now successfully run and parse the test
results with, for example:
	./tools/testing/kunit/kunit.py run --arch=x86_64 \
	--kconfig_add CONFIG_PCI=y --kconfig_add CONFIG_USB4=y \
	'thunderbolt'

Acked-by: Mika Westerberg 
Acked-by: Daniel Latypov 
Acked-by: Brendan Higgins 
Signed-off-by: David Gow 
Signed-off-by: Shuah Khan

thunderbolt: Make iommu_dma_protection more accurate

2022-04-28T08:30:25+00:00

Between me trying to get rid of iommu_present() and Mario wanting to
support the AMD equivalent of DMAR_PLATFORM_OPT_IN, scrutiny has shown
that the iommu_dma_protection attribute is being far too optimistic.
Even if an IOMMU might be present for some PCI segment in the system,
that doesn't necessarily mean it provides translation for the device(s)
we care about. Furthermore, all that DMAR_PLATFORM_OPT_IN really does
is tell us that memory was protected before the kernel was loaded, and
prevent the user from disabling the intel-iommu driver entirely. While
that lets us assume kernel integrity, what matters for actual runtime
DMA protection is whether we trust individual devices, based on the
"external facing" property that we expect firmware to describe for
Thunderbolt ports.

It's proven challenging to determine the appropriate ports accurately
given the variety of possible topologies, so while still not getting a
perfect answer, by putting enough faith in firmware we can at least get
a good bit closer. If we can see that any device near a Thunderbolt NHI
has all the requisites for Kernel DMA Protection, chances are that it
*is* a relevant port, but moreover that implies that firmware is playing
the game overall, so we'll use that to assume that all Thunderbolt ports
should be correctly marked and thus will end up fully protected.

CC: Mario Limonciello 
Reviewed-by: Christoph Hellwig 
Acked-by: Mika Westerberg 
Signed-off-by: Robin Murphy 
Link: https://lore.kernel.org/r/b153f208bc9eafab5105bad0358b77366509d2d4.1650878781.git.robin.murphy@arm.com
Signed-off-by: Joerg Roedel