Re: [PATCH] powerpc: fsl_pci: Fix PCI/PCI-X regression

[Scott Wood <scottwood@freescale.com>]

On Wed, 2014-08-20 at 18:51 -0500, Aaron Sierra wrote:
> @@ -520,9 +520,22 @@ int fsl_add_bridge(struct platform_device *pdev, int is_primary)
>  			goto no_bridge;
>  
>  	} else {
> -		/* For PCI read PROG to identify controller mode */
> -		early_read_config_byte(hose, 0, 0, PCI_CLASS_PROG, &progif);
> -		if ((progif & 1) == 1)
> +		u16 master;
> +
> +		/*
> +		 * If the controller is PCI-X, then Host mode refers to a
> +		 * bridge that drives the PCI-X initialization pattern to
> +		 * indicate bus operating mode/frequency to devices on the bus.
> +		 * Some hardware (specifically PrPMC modules) are Agents, since
> +		 * the mezzanine carrier is responsible for driving the
> +		 * pattern, but they still may perform bus enumeration.
> +		 *
> +		 * Allow the bridge to be used for enumeration, if hardware
> +		 * strapping (Host mode) or firmware (Agent mode) has enabled
> +		 * bus mastering.
> +		 */
> +		early_read_config_word(hose, 0, 0, PCI_COMMAND, &master);
> +		if (!(master & PCI_COMMAND_MASTER))
>  			goto no_bridge;
>  	}

Why wouldn't a normal PCI agent be able to bus master?

-Scott