PCI: Add enable_device() and disable_device() callbacks for bridges

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Some PCI host bridges require special handling when enabling or
disabling PCI devices. For example, the i.MX95 platform has a lookup
table to map Requester IDs to StreamIDs, which the SMMU and MSI
controller use to identify the source of DMA accesses.

Without this mapping, DMA accesses may target unintended memory, which
would corrupt memory or read the wrong data.

Add a host bridge enable_device() hook the imx6 driver can use to
configure the Requester ID to StreamID mapping. The hardware table isn't
big enough to map all possible Requester IDs, so this hook may fail if
no table space is available. In that case, return failure from
pci_enable_device().

It might make more sense to make pci_set_master() decline to enable bus
mastering and return failure, but it currently doesn't have a way to return
failure.

Link: https://lore.kernel.org/r/20250114-imx95_lut-v9-1-39f58dbed03a@nxp.com
Tested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
[kwilczynski: commit log]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Acked-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>

...

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Frank Li 2025-01-14 15:37:08 -05:00 • committed by Krzysztof Wilczyński

parent 40384c840e

commit a3751212a8

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2 changed files with 37 additions and 1 deletions

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36

drivers/pci/pci.c

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2

include/linux/pci.h

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