Re: [PATCH v11 2/4] PCI: mediatek: Add new method to get shared pcie-cfg base address and parse node

[Bjorn Helgaas <helgaas@kernel.org>]

On Mon, Jul 19, 2021 at 03:34:54PM +0800, Chuanjia Liu wrote:
> For the new dts format, add a new method to get
> shared pcie-cfg base address and parse node.

This commit log doesn't seem to really cover what's going on here.  It
looks like:

  - You added a check for "mediatek,generic-pciecfg" (I guess this is
    the "shared pcie-cfg base address" part).  Probably could have
    been its own patch.

  - You added checks for "interrupt-names" and "pcie_irq".  Not
    explained in commit log; probably could have been its own patch,
    too.

  - You now look for "linux,pci-domain" (via of_get_pci_domain_nr()).
    If present, you parse only one port instead of looking for all the
    children of the node.

    That's sort of weird behavior -- why should the presence of
    "linux,pci-domain" determine whether the node can have children?
    Is that really what you intend?

    Should be explained in the commit log and could have been its own
    patch, too.

> Signed-off-by: Chuanjia Liu <chuanjia.liu@mediatek.com>
> Acked-by: Ryder Lee <ryder.lee@mediatek.com>
> ---
>  drivers/pci/controller/pcie-mediatek.c | 52 +++++++++++++++++++-------
>  1 file changed, 39 insertions(+), 13 deletions(-)
> 
> diff --git a/drivers/pci/controller/pcie-mediatek.c b/drivers/pci/controller/pcie-mediatek.c
> index 25bee693834f..928e0983a900 100644
> --- a/drivers/pci/controller/pcie-mediatek.c
> +++ b/drivers/pci/controller/pcie-mediatek.c
> @@ -14,6 +14,7 @@
>  #include <linux/irqchip/chained_irq.h>
>  #include <linux/irqdomain.h>
>  #include <linux/kernel.h>
> +#include <linux/mfd/syscon.h>
>  #include <linux/msi.h>
>  #include <linux/module.h>
>  #include <linux/of_address.h>
> @@ -23,6 +24,7 @@
>  #include <linux/phy/phy.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
>  #include <linux/reset.h>
>  
>  #include "../pci.h"
> @@ -207,6 +209,7 @@ struct mtk_pcie_port {
>   * struct mtk_pcie - PCIe host information
>   * @dev: pointer to PCIe device
>   * @base: IO mapped register base
> + * @cfg: IO mapped register map for PCIe config
>   * @free_ck: free-run reference clock
>   * @mem: non-prefetchable memory resource
>   * @ports: pointer to PCIe port information
> @@ -215,6 +218,7 @@ struct mtk_pcie_port {
>  struct mtk_pcie {
>  	struct device *dev;
>  	void __iomem *base;
> +	struct regmap *cfg;
>  	struct clk *free_ck;
>  
>  	struct list_head ports;
> @@ -650,7 +654,11 @@ static int mtk_pcie_setup_irq(struct mtk_pcie_port *port,
>  		return err;
>  	}
>  
> -	port->irq = platform_get_irq(pdev, port->slot);
> +	if (of_find_property(dev->of_node, "interrupt-names", NULL))
> +		port->irq = platform_get_irq_byname(pdev, "pcie_irq");
> +	else
> +		port->irq = platform_get_irq(pdev, port->slot);
> +
>  	if (port->irq < 0)
>  		return port->irq;
>  
> @@ -682,6 +690,10 @@ static int mtk_pcie_startup_port_v2(struct mtk_pcie_port *port)
>  		val |= PCIE_CSR_LTSSM_EN(port->slot) |
>  		       PCIE_CSR_ASPM_L1_EN(port->slot);
>  		writel(val, pcie->base + PCIE_SYS_CFG_V2);
> +	} else if (pcie->cfg) {
> +		val = PCIE_CSR_LTSSM_EN(port->slot) |
> +		      PCIE_CSR_ASPM_L1_EN(port->slot);
> +		regmap_update_bits(pcie->cfg, PCIE_SYS_CFG_V2, val, val);
>  	}
>  
>  	/* Assert all reset signals */
> @@ -985,6 +997,7 @@ static int mtk_pcie_subsys_powerup(struct mtk_pcie *pcie)
>  	struct device *dev = pcie->dev;
>  	struct platform_device *pdev = to_platform_device(dev);
>  	struct resource *regs;
> +	struct device_node *cfg_node;
>  	int err;
>  
>  	/* get shared registers, which are optional */
> @@ -995,6 +1008,14 @@ static int mtk_pcie_subsys_powerup(struct mtk_pcie *pcie)
>  			return PTR_ERR(pcie->base);
>  	}
>  
> +	cfg_node = of_find_compatible_node(NULL, NULL,
> +					   "mediatek,generic-pciecfg");
> +	if (cfg_node) {
> +		pcie->cfg = syscon_node_to_regmap(cfg_node);
> +		if (IS_ERR(pcie->cfg))
> +			return PTR_ERR(pcie->cfg);
> +	}
> +
>  	pcie->free_ck = devm_clk_get(dev, "free_ck");
>  	if (IS_ERR(pcie->free_ck)) {
>  		if (PTR_ERR(pcie->free_ck) == -EPROBE_DEFER)
> @@ -1027,22 +1048,27 @@ static int mtk_pcie_setup(struct mtk_pcie *pcie)
>  	struct device *dev = pcie->dev;
>  	struct device_node *node = dev->of_node, *child;
>  	struct mtk_pcie_port *port, *tmp;
> -	int err;
> +	int err, slot;
> +
> +	slot = of_get_pci_domain_nr(dev->of_node);
> +	if (slot < 0) {
> +		for_each_available_child_of_node(node, child) {
> +			err = of_pci_get_devfn(child);
> +			if (err < 0) {
> +				dev_err(dev, "failed to get devfn: %d\n", err);
> +				goto error_put_node;
> +			}
>  
> -	for_each_available_child_of_node(node, child) {
> -		int slot;
> +			slot = PCI_SLOT(err);
>  
> -		err = of_pci_get_devfn(child);
> -		if (err < 0) {
> -			dev_err(dev, "failed to parse devfn: %d\n", err);
> -			goto error_put_node;
> +			err = mtk_pcie_parse_port(pcie, child, slot);
> +			if (err)
> +				goto error_put_node;
>  		}
> -
> -		slot = PCI_SLOT(err);
> -
> -		err = mtk_pcie_parse_port(pcie, child, slot);
> +	} else {
> +		err = mtk_pcie_parse_port(pcie, node, slot);
>  		if (err)
> -			goto error_put_node;
> +			return err;
>  	}
>  
>  	err = mtk_pcie_subsys_powerup(pcie);
> -- 
> 2.18.0
>