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

[Tom Warren <TWarren@nvidia.com>]

I'll add it to u-boot-tegra/master for the next PR.

> -----Original Message-----
> From: Stephen Warren [mailto:swarren at wwwdotorg.org]
> Sent: Wednesday, May 04, 2016 12:00 PM
> To: Tom Warren <TWarren@nvidia.com>
> Cc: u-boot at lists.denx.de; Simon Glass <sjg@chromium.org>; Stephen Warren
> <swarren@nvidia.com>
> Subject: Re: [U-Boot] [PATCH] pci: tegra: fix DM conversion issues on Tegra20
> 
> On 04/20/2016 03:46 PM, Stephen Warren wrote:
> > From: Stephen Warren <swarren@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@nvidia.com>
> 
> TomW, I'd like to make sure this one gets into the upcoming release, since it's a
> functional bug-fix.
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