[U-Boot] [PATCH] pci: tegra: fix DM conversion issues on Tegra20

[Thierry Reding]

On Wed, Apr 20, 2016 at 03:46:50PM -0600, Stephen Warren wrote:
> From: Stephen Warren <swarren at nvidia.com>
> 
> Tegra20's PCIe controller has a couple of quirks. There are workarounds in
> the driver for these, but they don't work after the DM conversion:
> 
> 1) The PCI_CLASS value is wrong in HW.
> 
> This is worked around in pci_tegra_read_config() by patching up the value
> read from that register. Pre-DM, the PCIe core always read this via a
> 16-bit access to the 16-bit offset 0xa. With DM, 32-bit accesses are used,
> so we need to check for offset 0x8 instead. Mask the offset value back to
> 32-bit alignment to make this work in all cases.
> 
> 2) Accessing devices other than dev 1 causes a data abort.
> 
> Pre-DM, this was worked around in pci_skip_dev(), which the PCIe core code
> called during enumeration while iterating over a bus. The DM PCIe core
> doesn't use this function. Instead, enhance tegra_pcie_conf_address() to
> validate the bdf being accessed, and refuse to access invalid devices.
> Since pci_skip_dev() isn't used, delete it.
> 
> I've also validated that both these WARs are only needed for Tegra20, by
> testing on Tegra30/Cardhu and Tegra124/Jetson TKx. So, compile them in
> conditionally.
> 
> Fixes: e81ca88451cf ("dm: tegra: pci: Convert tegra boards to driver model for PCI")
> Signed-off-by: Stephen Warren <swarren at nvidia.com>
> ---
>  drivers/pci/pci_tegra.c | 21 ++++++++++-----------
>  1 file changed, 10 insertions(+), 11 deletions(-)

Neat:

Reviewed-by: Thierry Reding <treding at nvidia.com>
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