Re: [PATCH 2/3] PCI: dwc: Improve msg_atu_index error handling

[Frank Li <Frank.li@nxp.com>]

On Thu, Jan 22, 2026 at 03:54:13PM +0100, Niklas Cassel wrote:
> Only try to dedicate an outbound iATU to MSG TLP if use_atu_msg is set.
> If use_atu_msg is not set, it is completely useless to bump the index.
>
> Additionally, if use_atu_msg is set, and there is no available outbound
> iatu available, return an error.
>
> Fixes: e1a4ec1a9520 ("PCI: dwc: Add generic MSG TLP support for sending PME_Turn_Off when system suspend")
> Signed-off-by: Niklas Cassel <cassel@kernel.org>
> ---

Reviewed-by: Frank Li <Frank.Li@nxp.com>
>  drivers/pci/controller/dwc/pcie-designware-host.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
> index cca5fc886409..991fe5b9a7b3 100644
> --- a/drivers/pci/controller/dwc/pcie-designware-host.c
> +++ b/drivers/pci/controller/dwc/pcie-designware-host.c
> @@ -982,7 +982,14 @@ 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;
> +	if (pp->use_atu_msg) {
> +		if (pci->num_ob_windows > ++i) {
> +			pp->msg_atu_index = i;
> +		} else {
> +			dev_err(pci->dev, "Cannot add outbound window for MSG TLP\n");
> +			return -ENOMEM;
> +		}
> +	}
>
>  	i = 0;
>  	resource_list_for_each_entry(entry, &pp->bridge->dma_ranges) {
> --
> 2.52.0
>