[PATCH] PCI: dw-rockchip: Disable BAR 0 and BAR 1 for RC mode

[Manivannan Sadhasivam]

On Wed, Dec 24, 2025 at 06:01:01PM +0800, Shawn Lin wrote:
> To slitence the useless bar allocation error log of RC when
> scanning bus, as RC doesn't need BARs at all.

It is not RC, but Root Port. It is OK to disable the Root Port BARs if they
don't serve any purpose, but I think the issue is that the BAR size is bogus.
Both BARs report 1GiB of size, which I don't think it makes sense for a Root
Port.

Can I reword the commit message as:

Some Rockchip PCIe Root Port report bogus size of 1GiB for the BAR memories and
they cause below resource allocation issue during probe. Since there is no use
of the Root Port BAR memories, disable both of them.

- Mani

> 
>   pci 0000:00:00.0: [1d87:3588] type 01 class 0x060400 PCIe Root Port
>   pci 0000:00:00.0: BAR 0 [mem 0x00000000-0x3fffffff]
>   pci 0000:00:00.0: BAR 1 [mem 0x00000000-0x3fffffff]
>   pci 0000:00:00.0: ROM [mem 0x00000000-0x0000ffff pref]
> 	...
>   pci 0000:00:00.0: BAR 0 [mem 0x900000000-0x93fffffff]: assigned
>   pci 0000:00:00.0: BAR 1 [mem size 0x40000000]: can't assign; no space
>   pci 0000:00:00.0: BAR 1 [mem size 0x40000000]: failed to assign
>   pci 0000:00:00.0: ROM [mem 0xf0200000-0xf020ffff pref]: assigned
>   pci 0000:00:00.0: BAR 0 [mem 0x900000000-0x93fffffff]: releasing
>   pci 0000:00:00.0: ROM [mem 0xf0200000-0xf020ffff pref]: releasing
>   pci 0000:00:00.0: BAR 0 [mem 0x900000000-0x93fffffff]: assigned
>   pci 0000:00:00.0: BAR 1 [mem size 0x40000000]: can't assign; no space
>   pci 0000:00:00.0: BAR 1 [mem size 0x40000000]: failed to assign
> 
> Signed-off-by: Shawn Lin <shawn.lin at rock-chips.com>
> ---
> 
>  drivers/pci/controller/dwc/pcie-dw-rockchip.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> index f8605fe..e421fa0 100644
> --- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> +++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
> @@ -80,6 +80,8 @@
>  #define  PCIE_LINKUP_MASK		GENMASK(17, 16)
>  #define  PCIE_LTSSM_STATUS_MASK		GENMASK(5, 0)
>  
> +#define PCIE_TYPE0_HDR_DBI2_OFFSET      0x100000
> +
>  struct rockchip_pcie {
>  	struct dw_pcie pci;
>  	void __iomem *apb_base;
> @@ -292,6 +294,8 @@ static int rockchip_pcie_host_init(struct dw_pcie_rp *pp)
>  	if (irq < 0)
>  		return irq;
>  
> +	pci->dbi_base2 = pci->dbi_base + PCIE_TYPE0_HDR_DBI2_OFFSET;
> +
>  	ret = rockchip_pcie_init_irq_domain(rockchip);
>  	if (ret < 0)
>  		dev_err(dev, "failed to init irq domain\n");
> @@ -302,6 +306,10 @@ static int rockchip_pcie_host_init(struct dw_pcie_rp *pp)
>  	rockchip_pcie_configure_l1ss(pci);
>  	rockchip_pcie_enable_l0s(pci);
>  
> +	/* Disable RC's BAR0 and BAR1 */
> +	dw_pcie_writel_dbi2(pci, PCI_BASE_ADDRESS_0, 0x0);
> +	dw_pcie_writel_dbi2(pci, PCI_BASE_ADDRESS_1, 0x0);
> +
>  	return 0;
>  }
>  
> -- 
> 2.7.4
> 
> 

-- 
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