[PATCH] pci: Disable I/O forwarding during autoconfiguration if unsupported

[Stefan Roese]

On 11/25/21 11:32, Pali Rohár wrote:
> If U-Boot does not have any I/O resource for assignment then disable I/O
> forwarding in PCI bridge autoconfiguration code. Default initial state of
> PCI bridge IO registers is unspecified, therefore they can be in enabled if
> U-Boot does not touch them.
> 
> Signed-off-by: Pali Rohár <pali at kernel.org>
>
> ---
>   drivers/pci/pci_auto.c | 8 ++++++++
>   1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/pci/pci_auto.c b/drivers/pci/pci_auto.c
> index 7e6ee54be087..6e5ed194f247 100644
> --- a/drivers/pci/pci_auto.c
> +++ b/drivers/pci/pci_auto.c
> @@ -265,6 +265,14 @@ void dm_pciauto_prescan_setup_bridge(struct udevice *dev, int sub_bus)
>   				      (pci_io->bus_lower & 0xffff0000) >> 16);
>   
>   		cmdstat |= PCI_COMMAND_IO;
> +	} else {
> +		/* Disable I/O if unsupported */
> +		dm_pci_write_config8(dev, PCI_IO_BASE, 0xf0 | io_32);
> +		dm_pci_write_config8(dev, PCI_IO_LIMIT, 0x0 | io_32);

Does it perhaps make sense to add / use a macro for this 0xf0 above?

Other than this:

Reviewed-by: Stefan Roese <sr at denx.de>

Thanks,
Stefan


> +		if (io_32 == PCI_IO_RANGE_TYPE_32) {
> +			dm_pci_write_config16(dev, PCI_IO_BASE_UPPER16, 0x0);
> +			dm_pci_write_config16(dev, PCI_IO_LIMIT_UPPER16, 0x0);
> +		}
>   	}
>   
>   	/* Enable memory and I/O accesses, enable bus master */
> 

Viele Grüße,
Stefan Roese

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