Re: [PATCH v4 1/4] PCI: dwc: Fix msg_atu_index assignment

[Damien Le Moal <dlemoal@kernel.org>]

On 2026/01/24 5:28, Niklas Cassel wrote:
> When dw_pcie_iatu_setup() configures outbound address translation
> for both type PCIE_ATU_TYPE_MEM and PCIE_ATU_TYPE_IO, the iATU index
> to use is incremented before calling dw_pcie_prog_outbound_atu().
> 
> However, for msg_atu_index the index is not incremented before use,
> causing the iATU index to be the same as the last configured iATU
> index, which means that it will incorrectly use the same iATU index
> that is already in use, breaking outbound address translation.
> 
> Fixes: e1a4ec1a9520 ("PCI: dwc: Add generic MSG TLP support for sending PME_Turn_Off when system suspend")
> Cc: stable@vger.kernel.org
> Reviewed-by: Frank Li <Frank.Li@nxp.com>
> Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>
> Reviewed-by: Hans Zhang <zhanghuabing@ecosda.com>
> Signed-off-by: Niklas Cassel <cassel@kernel.org>
> ---
>  drivers/pci/controller/dwc/pcie-designware-host.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index b3d6a474fd16..ae5f2d8a3857 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -982,7 +982,7 @@ static int dw_pcie_iatu_setup(struct dw_pcie_rp *pp)
>  		dev_warn(pci->dev, "Ranges exceed outbound iATU size (%d)\n",
>  			 pci->num_ob_windows);
>  
> -	pp->msg_atu_index = i;
> +	pp->msg_atu_index = ++i;

	pp->msg_atu_index = i + 1;

is a lot more readable in my opinion. Changing i itself is useless since it is
reset to 0 below.

>  
>  	i = 0;
>  	resource_list_for_each_entry(entry, &pp->bridge->dma_ranges) {


-- 
Damien Le Moal
Western Digital Research