[PATCH u-boot 1/3] pci: mpc85xx: Do not access PCI BARs registers of BDF address 00:00.0

[Heiko Schocher]

Hello Pali,

On 20.04.23 21:44, Pali Rohár wrote:
> At BDF address 00:00.0 is fictional device which PCI configuration header
> is for configuring mpc85xx PCI controller itself. PCI config space of this
> device has ATMU inbound registers on position of PCI BARs. Trying to do PCI
> auto configuration of this device cause rewriting ATMU inbound registers.
> To avoid it, do not allow overwriting registers at BARs positions. And
> because this device does not have any PCI memory, return zeros when trying
> to read PCI BARs config space registers. It signals to auto configuration
> tool to not allocate any PCI memory for this device.
> 
> This information is taken from MPC8544E Reference Manual, sections
> 17.3.1.3, 17.3.1.1.1, 17.3.2 and 17.3.2.11. Available at NXP website:
> https://www.nxp.com/docs/en/reference-manual/MPC8544ERM.pdf
> 
> Signed-off-by: Pali Rohár <pali at kernel.org>
> ---
>  drivers/pci/pci_mpc85xx.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)

Reviewed-by: Heiko Schocher <hs at denx.de>
Tested-by: Heiko Schocher <hs at denx.de>

Tested on the socrates board, it fixes the problem:

PCI: Failed autoconfig bar 18
PCI: Failed autoconfig bar 20

Thanks!

bye,
Heiko
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