Re: [PATCH V3 2/2] PCI: Add MCFG quirks for Tegra194 host controllers

Thierry Reding
2020-01-17T11:42:53Z

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On Sat, Jan 11, 2020 at 12:45:00AM +0530, Vidya Sagar wrote:
> The PCIe controller in Tegra194 SoC is not completely ECAM-compliant.
> With the current hardware design limitations in place, ECAM can be enabled
> only for one controller (C5 controller to be precise) with bus numbers
> starting from 160 instead of 0. A different approach is taken to avoid this
> abnormal way of enabling ECAM for just one controller but to enable
> configuration space access for all the other controllers. In this approach,
> ops are added through MCFG quirk mechanism which access the configuration
> spaces by dynamically programming iATU (internal AddressTranslation Unit)
> to generate respective configuration accesses just like the way it is
> done in DesignWare core sub-system.
>
> Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
> Reported-by: kbuild test robot <lkp@intel.com>
> ---
> V3:
> * Removed MCFG address hardcoding in pci_mcfg.c file
> * Started using 'dbi_base' for accessing root port's own config space
> * and using 'config_base' for accessing config space of downstream hierarchy
>
> V2:
> * Fixed build issues reported by kbuild test bot
>
> drivers/acpi/pci_mcfg.c | 7 ++
> drivers/pci/controller/dwc/Kconfig | 3 +-
> drivers/pci/controller/dwc/Makefile | 2 +-
> drivers/pci/controller/dwc/pcie-tegra194.c | 102 +++++++++++++++++++++
> include/linux/pci-ecam.h | 1 +
> 5 files changed, 113 insertions(+), 2 deletions(-)

Acked-by: Thierry Reding <treding@nvidia.com>

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