Re: [PATCH net-next RFC v15 11/14] net: stmmac: dwmac-loongson: Add DT-less GMAC PCI-device support

[Simon Horman <horms@kernel.org>]

On Mon, Jul 22, 2024 at 07:01:09PM +0800, Yanteng Si wrote:
> The Loongson GMAC driver currently supports the network controllers
> installed on the LS2K1000 SoC and LS7A1000 chipset, for which the GMAC
> devices are required to be defined in the platform device tree source.
> But Loongson machines may have UEFI (implies ACPI) or PMON/UBOOT
> (implies FDT) as the system bootloaders. In order to have both system
> configurations support let's extend the driver functionality with the
> case of having the Loongson GMAC probed on the PCI bus with no device
> tree node defined for it. That requires to make the device DT-node
> optional, to rely on the IRQ line detected by the PCI core and to
> have the MDIO bus ID calculated using the PCIe Domain+BDF numbers.
> 
> In order to have the device probe() and remove() methods less
> complicated let's move the DT- and ACPI-specific code to the
> respective sub-functions.
> 
> Signed-off-by: Feiyang Chen <chenfeiyang@loongson.cn>
> Signed-off-by: Yinggang Gu <guyinggang@loongson.cn>
> Acked-by: Huacai Chen <chenhuacai@loongson.cn>
> Signed-off-by: Yanteng Si <siyanteng@loongson.cn>
> ---
>  .../ethernet/stmicro/stmmac/dwmac-loongson.c  | 160 +++++++++++-------
>  1 file changed, 101 insertions(+), 59 deletions(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-loongson.c

...

> @@ -90,25 +158,20 @@ static int loongson_dwmac_probe(struct pci_dev *pdev, const struct pci_device_id
>  	if (!plat->mdio_bus_data)
>  		return -ENOMEM;
>  
> -	plat->mdio_node = of_get_child_by_name(np, "mdio");
> -	if (plat->mdio_node) {
> -		dev_info(&pdev->dev, "Found MDIO subnode\n");
> -		plat->mdio_bus_data->needs_reset = true;
> -	}
> -
>  	plat->dma_cfg = devm_kzalloc(&pdev->dev, sizeof(*plat->dma_cfg), GFP_KERNEL);
> -	if (!plat->dma_cfg) {
> -		ret = -ENOMEM;
> -		goto err_put_node;
> -	}
> +	if (!plat->dma_cfg)
> +		return -ENOMEM;
>  
>  	/* Enable pci device */
>  	ret = pci_enable_device(pdev);
>  	if (ret) {
>  		dev_err(&pdev->dev, "%s: ERROR: failed to enable device\n", __func__);
>  		goto err_put_node;
> +		return ret;

This seems incorrect: this line will never be executed.

Flagged by Smatch.

>  	}
>  
> +	pci_set_master(pdev);
> +
>  	/* Get the base address of device */
>  	for (i = 0; i < PCI_STD_NUM_BARS; i++) {
>  		if (pci_resource_len(pdev, i) == 0)

...