[RFC/RFT PATCH 0/3] Prepwork for non-PCIe NHI/TBT hosts

[Konrad Dybcio <konradybcio@kernel.org>]

Currently, the NHI driver (and other parts of the TBT framework) make
multiple assumptions about the host router being a PCIe device. This
series tries to decouple them by moving the 'struct pci_device' out of
the NHI code and introduce NHI-on-PCIe-specific abstractions where
necessary (with no functional change).

The intended usage of the new nhi_probe_common() is pretty similar to
other bus frameworks (I2C, SPI, USB..), i.e.:

static int foo_bar_probe() {
	// get SoC-specifc resources (clks, regulators..)

	// power things on

	// set some implementation-specific registers

	// register NHI and all the sub-devices
	ret = nhi_probe_common(&my_usb4->nhi)
	...

	// cleanup boilerplate
}

Instead of the previously-suggested aux/fauxbus, the NHI device remains
the same 'struct dev' as the PCIe/platform/[...] device that provides
it. This is in line with some other buses and it makes things easier
from the PM perspective.

Compile-tested only for the PCIe case. The Qualcomm USB4 driver that
leverages this patchset is unfortunately still work in progress and
will be shared at a later time. Nonetheless, we need to get this
non-PCIe topic sorted.

Signed-off-by: Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>
---
Konrad Dybcio (3):
      thunderbolt: Move pci_device out of tb_nhi
      thunderbolt: Separate out common NHI bits
      thunderbolt: Add some more descriptive probe error messages

 drivers/thunderbolt/Makefile    |   2 +-
 drivers/thunderbolt/acpi.c      |  14 +-
 drivers/thunderbolt/ctl.c       |  14 +-
 drivers/thunderbolt/domain.c    |   2 +-
 drivers/thunderbolt/eeprom.c    |   2 +-
 drivers/thunderbolt/icm.c       |  25 +-
 drivers/thunderbolt/nhi.c       | 494 ++++++---------------------------------
 drivers/thunderbolt/nhi.h       |  32 +++
 drivers/thunderbolt/nhi_ops.c   |  31 ++-
 drivers/thunderbolt/nhi_pci.c   | 496 ++++++++++++++++++++++++++++++++++++++++
 drivers/thunderbolt/nhi_pci.h   |  22 ++
 drivers/thunderbolt/switch.c    |  41 +---
 drivers/thunderbolt/tb.c        |  76 +-----
 drivers/thunderbolt/tb.h        |  10 +-
 drivers/thunderbolt/usb4_port.c |   2 +-
 include/linux/thunderbolt.h     |   5 +-
 16 files changed, 699 insertions(+), 569 deletions(-)
---
base-commit: fc7b1a72c6cd5cbbd989c6c32a6486e3e4e3594d
change-id: 20260309-topic-usb4_nonpcie_prepwork-86881f769b8f

Best regards,
-- 
Konrad Dybcio <konrad.dybcio@oss.qualcomm.com>