PCI/CXL: Add 'cxl_bus' reset method for devices below CXL Ports

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By default Secondary Bus Reset (SBR) is masked for CXL Ports (see CXL r3.1,
sec 8.1.5.2).

Add cxl_reset_bus_function() (method "cxl_bus") to set the "Unmask SBR" bit
in the upstream CXL Port before performing the bus reset and restore the
original value afterwards.

This method allows the user to perform a bus reset on a CXL device without
needing to set the "Unmask SBR" bit via a user tool.

Link: https://lore.kernel.org/r/20240502165851.1948523-5-dave.jiang@intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
[bhelgaas: simplify commit log, invert condition to avoid negation]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>

...

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Dave Jiang 2024-05-02 09:57:33 -07:00 • committed by Bjorn Helgaas

parent b1956e2d07

commit 53c49b6e6d

2 changed files with 40 additions and 1 deletions

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39

drivers/pci/pci.c

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2

include/linux/pci.h

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