[U-Boot] [PATCH 3/8] RFC: dm: pci: Set up the SDRAM mapping correctly

[Stephen Warren <swarren@wwwdotorg.org>]

On 10/17/2015 11:50 AM, Simon Glass wrote:
> SDRAM doesn't always start at 0. Adjust the region mapping so that it works
> on platforms where SDRAM is somewhere else.
>
> This needs testing on other platforms.

> diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c

> @@ -729,8 +729,11 @@ static int decode_regions(struct pci_controller *hose, const void *blob,
>   	addr = gd->ram_size;
>   	if (gd->pci_ram_top && gd->pci_ram_top < addr)
>   		addr = gd->pci_ram_top;
> -	pci_set_region(hose->regions + hose->region_count++, 0, 0, addr,
> -		       PCI_REGION_MEM | PCI_REGION_SYS_MEMORY);
> +#ifdef CONFIG_SYS_SDRAM_BASE
> +	base = CONFIG_SYS_SDRAM_BASE;
> +#endif
> +	pci_set_region(hose->regions + hose->region_count++, base, base,
> +		       addr, PCI_REGION_MEM | PCI_REGION_SYS_MEMORY);

The variable naming here is extremely misleading; "addr" is actually the 
size of the region not its address. I think it'd be a good idea to 
rename the addr variable while you're fixing this bug, and also 
pci_ram_top too since that's really pci_ram_size.

FWIW, on Tegra210 when I set gd->pci_ram_top = 0x80000000 (coupled with 
SDRAM_BASE being 0x80000000) this function seems to do the right thing; 
at least a PCIe NIC works OK.