[PATCH v2 6/8] pci: Add DW PCIe controller support for iMX8MP SoC

[Marek Vasut]

On 2/26/24 9:04 AM, Sumit Garg wrote:
> pcie_imx doesn't seem to share any useful code for iMX8 SoC and it is
> tied to quite old port of pcie_designware driver from Linux which
> suffices only iMX6 specific needs.

It is probably hand-rolled, but it does suck, that's true.

> But currently we have the common DWC specific bits which alligns pretty
> well with DW PCIe controller on iMX8MP SoC. So lets reuse those common
> bits instead as a new driver for iMX8 SoCs. It should be fairly easy to
> add support for other iMX8 variants to this driver.
> 
> iMX8MP SoC also comes up with standalone PCIe PHY support, so hence we
> can reuse the generic PHY infrastructure to power on PCIe PHY.

[...]

> +static int pcie_dw_imx_of_to_plat(struct udevice *dev)
> +{
> +	struct pcie_dw_imx *priv = dev_get_priv(dev);
> +	ofnode gpr;
> +	int ret;
> +
> +	/* Get the controller base address */
> +	priv->dw.dbi_base = (void *)dev_read_addr_name(dev, "dbi");
> +	if ((fdt_addr_t)priv->dw.dbi_base == FDT_ADDR_T_NONE) {
> +		dev_err(dev, "failed to get dbi_base address\n");
> +		return -EINVAL;
> +	}
> +
> +	/* Get the config space base address and size */
> +	priv->dw.cfg_base = (void *)dev_read_addr_size_name(dev, "config",
> +							    &priv->dw.cfg_size);
> +	if ((fdt_addr_t)priv->dw.cfg_base == FDT_ADDR_T_NONE) {
> +		dev_err(dev, "failed to get cfg_base address\n");
> +		return -EINVAL;
> +	}
> +
> +	ret = clk_get_bulk(dev, &priv->clks);
> +	if (ret) {
> +		dev_err(dev, "failed to get PCIe clks\n");
> +		return ret;
> +	}
> +
> +	ret = reset_get_by_name(dev, "apps", &priv->apps_reset);
> +	if (ret) {
> +		dev_err(dev,
> +			"Failed to get PCIe apps reset control\n");
> +		return ret;
> +	}
> +
> +	ret = gpio_request_by_name(dev, "reset-gpio", 0, &priv->reset_gpio,
> +				   (GPIOD_IS_OUT | GPIOD_IS_OUT_ACTIVE));
> +	if (ret) {
> +		dev_err(dev, "unable to get reset-gpio\n");
> +		return ret;
> +	}
> +
> +	ret = generic_phy_get_by_name(dev, "pcie-phy", &priv->phy);
> +	if (ret) {
> +		dev_err(dev, "failed to get pcie phy\n");
> +		return ret;
> +	}
> +
> +	gpr = ofnode_by_compatible(ofnode_null(), "fsl,imx8mp-iomuxc-gpr");
> +	if (ofnode_equal(gpr, ofnode_null())) {
> +		dev_err(dev, "unable to find GPR node\n");
> +		return -ENODEV;
> +	}

You likely need a fail path here too, to undo allocation and co.