Re: [PATCH 2/2] net: stmmac: tegra: Add MGBE support

[Paolo Abeni <pabeni@redhat.com>]

Hello,

On Fri, 2022-11-18 at 13:27 +0530, Revanth Kumar Uppala wrote:
> diff --git a/drivers/net/ethernet/stmicro/stmmac/Kconfig b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> index 31ff35174034..e9f61bdaf7c4 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/Kconfig
> +++ b/drivers/net/ethernet/stmicro/stmmac/Kconfig
> @@ -235,6 +235,12 @@ config DWMAC_INTEL_PLAT
>  	  the stmmac device driver. This driver is used for the Intel Keem Bay
>  	  SoC.
>  
> +config DWMAC_TEGRA
> +	tristate "NVIDIA Tegra MGBE support"
> +	depends on ARCH_TEGRA || COMPILE_TEST
> +	help
> +	  Support for the MGBE controller found on Tegra SoCs.

Minor nit: checkpatch is complaining for a more descriptive config
option text.

> +static int tegra_mgbe_probe(struct platform_device *pdev)
> +{
> +	struct plat_stmmacenet_data *plat;
> +	struct stmmac_resources res;
> +	struct tegra_mgbe *mgbe;
> +	int irq, err, i;
> +	u32 value;
> +
> +	mgbe = devm_kzalloc(&pdev->dev, sizeof(*mgbe), GFP_KERNEL);
> +	if (!mgbe)
> +		return -ENOMEM;
> +
> +	mgbe->dev = &pdev->dev;
> +
> +	memset(&res, 0, sizeof(res));
> +
> +	irq = platform_get_irq(pdev, 0);
> +	if (irq < 0)
> +		return irq;
> +
> +	mgbe->hv = devm_platform_ioremap_resource_byname(pdev, "hypervisor");
> +	if (IS_ERR(mgbe->hv))
> +		return PTR_ERR(mgbe->hv);
> +
> +	mgbe->regs = devm_platform_ioremap_resource_byname(pdev, "mac");
> +	if (IS_ERR(mgbe->regs))
> +		return PTR_ERR(mgbe->regs);
> +
> +	mgbe->xpcs = devm_platform_ioremap_resource_byname(pdev, "xpcs");
> +	if (IS_ERR(mgbe->xpcs))
> +		return PTR_ERR(mgbe->xpcs);
> +
> +	res.addr = mgbe->regs;
> +	res.irq = irq;
> +
> +	mgbe->clks = devm_kzalloc(&pdev->dev, sizeof(*mgbe->clks), GFP_KERNEL);
> +	if (!mgbe->clks)
> +		return -ENOMEM;
> +
> +	for (i = 0; i <  ARRAY_SIZE(mgbe_clks); i++)
> +		mgbe->clks[i].id = mgbe_clks[i];
> +
> +	err = devm_clk_bulk_get(mgbe->dev, ARRAY_SIZE(mgbe_clks), mgbe->clks);
> +	if (err < 0)
> +		return err;
> +
> +	err = clk_bulk_prepare_enable(ARRAY_SIZE(mgbe_clks), mgbe->clks);
> +	if (err < 0)
> +		return err;
> +
> +	/* Perform MAC reset */
> +	mgbe->rst_mac = devm_reset_control_get(&pdev->dev, "mac");
> +	if (IS_ERR(mgbe->rst_mac)) {
> +		err = PTR_ERR(mgbe->rst_mac);

This triggers a clang warning:

../drivers/net/ethernet/stmicro/stmmac/dwmac-tegra.c:283:6: warning: variable 'plat' is used uninitialized whenever 'if' condition is true [-Wsometimes-uninitialized]

I guess you have to init plat to NULL and explcitly check for NULL
values under the 'remove' label.

Cheers,

Paolo