linux-kernel - Re: [PATCH V4 02/11] PCI: host-generic: Add common helpers for parsing Root Port properties

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <aYoMb89MeP44xV8N@lizhi-Precision-Tower-5810>
Date: Mon, 9 Feb 2026 11:33:51 -0500
From: Frank Li <Frank.li@....com>
To: Sherry Sun <sherry.sun@....com>
Cc: hongxing.zhu@....com, l.stach@...gutronix.de, bhelgaas@...gle.com,
	lpieralisi@...nel.org, kwilczynski@...nel.org, mani@...nel.org,
	robh@...nel.org, krzk+dt@...nel.org, conor+dt@...nel.org,
	s.hauer@...gutronix.de, festevam@...il.com, will@...nel.org,
	imx@...ts.linux.dev, kernel@...gutronix.de,
	linux-pci@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	devicetree@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH V4 02/11] PCI: host-generic: Add common helpers for
 parsing Root Port properties

On Mon, Feb 09, 2026 at 04:24:45PM +0800, Sherry Sun wrote:
> Introduce generic helper functions to parse Root Port device tree nodes
> and extract common properties like reset GPIOs. This allows multiple
> PCI host controller drivers to share the same parsing logic.
>
> Define struct pci_host_port to hold common Root Port properties and add
> pci_host_common_parse_ports() to parse Root Port nodes from device tree,
> pci_host_common_delete_ports() to cleanup the port lists.
>
> Signed-off-by: Sherry Sun <sherry.sun@....com>
> ---
>  drivers/pci/controller/pci-host-common.c | 75 ++++++++++++++++++++++++
>  drivers/pci/controller/pci-host-common.h | 17 ++++++
>  2 files changed, 92 insertions(+)
>
> diff --git a/drivers/pci/controller/pci-host-common.c b/drivers/pci/controller/pci-host-common.c
> index c473e7c03bac..287e92df0092 100644
> --- a/drivers/pci/controller/pci-host-common.c
> +++ b/drivers/pci/controller/pci-host-common.c
> @@ -9,6 +9,7 @@
>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
> +#include <linux/gpio/consumer.h>
>  #include <linux/of.h>
>  #include <linux/of_address.h>
>  #include <linux/of_pci.h>
> @@ -17,6 +18,80 @@
>
>  #include "pci-host-common.h"
>
> +/**
> + * pci_host_common_delete_ports - Cleanup function for port list
> + * @data: Pointer to the port list head
> + */
> +void pci_host_common_delete_ports(void *data)
> +{
> +	struct list_head *ports = data;
> +	struct pci_host_port *port, *tmp;
> +
> +	list_for_each_entry_safe(port, tmp, ports, list)
> +		list_del(&port->list);
> +}
> +EXPORT_SYMBOL_GPL(pci_host_common_delete_ports);
> +
> +/**
> + * pci_host_common_parse_port - Parse a single Root Port node
> + * @dev: Device pointer
> + * @node: Device tree node of the Root Port
> + * @ports: List head to add the parsed port to
> + *
> + * Returns: 0 on success, negative error code on failure
> + */
> +static int pci_host_common_parse_port(struct device *dev,
> +				      struct device_node *node,
> +				      struct list_head *ports)
> +{
> +	struct pci_host_port *port;
> +	struct gpio_desc *reset;
> +
> +	reset = devm_fwnode_gpiod_get(dev, of_fwnode_handle(node),
> +				      "reset", GPIOD_OUT_HIGH, "PERST#");
> +	if (IS_ERR(reset))
> +		return PTR_ERR(reset);
> +
> +	port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
> +	if (!port)
> +		return -ENOMEM;
> +
> +	port->reset = reset;
> +	INIT_LIST_HEAD(&port->list);
> +	list_add_tail(&port->list, ports);

Suppose need spin_lock for link list.

> +
> +	return 0;
> +}
> +
> +/**
> + * pci_host_common_parse_ports - Parse Root Port nodes from device tree
> + * @dev: Device pointer
> + * @ports: List head to store parsed ports
> + *
> + * This function iterates through child nodes of the host bridge and parses
> + * Root Port properties (currently only reset GPIO).
> + *
> + * Returns: 0 on success, -ENOENT if no ports found, other negative error codes
> + * on failure
> + */
> +int pci_host_common_parse_ports(struct device *dev, struct list_head *ports)
> +{
> +	int ret = -ENOENT;
> +
> +	for_each_available_child_of_node_scoped(dev->of_node, of_port) {
> +		if (!of_node_is_type(of_port, "pci"))
> +			continue;
> +		ret = pci_host_common_parse_port(dev, of_port, ports);
> +		if (ret) {
> +			pci_host_common_delete_ports(ports);
> +			return ret;
> +		}
> +	}
> +
> +	return ret;
> +}
> +EXPORT_SYMBOL_GPL(pci_host_common_parse_ports);
> +
>  static void gen_pci_unmap_cfg(void *ptr)
>  {
>  	pci_ecam_free((struct pci_config_window *)ptr);
> diff --git a/drivers/pci/controller/pci-host-common.h b/drivers/pci/controller/pci-host-common.h
> index b5075d4bd7eb..2c8df230886f 100644
> --- a/drivers/pci/controller/pci-host-common.h
> +++ b/drivers/pci/controller/pci-host-common.h
> @@ -12,6 +12,23 @@
>
>  struct pci_ecam_ops;
>
> +/**
> + * struct pci_host_port - Generic Root Port properties
> + * @list: List node for linking multiple ports
> + * @reset: GPIO descriptor for PERST# signal
> + *
> + * This structure contains common properties that can be parsed from
> + * Root Port device tree nodes.
> + */
> +struct pci_host_port {
> +	struct list_head	list;
> +	struct gpio_desc	*reset;
> +};

I think it should be include/linux/pci.h

struct pci_host_bridge {
	...
	struct list_head ports_header;
}

So all API should pass down struct pci_host_bridge *.

Frank
> +
> +void pci_host_common_delete_ports(void *data);
> +int pci_host_common_parse_ports(struct device *dev,
> +				struct list_head *ports);
> +
>  int pci_host_common_probe(struct platform_device *pdev);
>  int pci_host_common_init(struct platform_device *pdev,
>  			 struct pci_host_bridge *bridge,
> --
> 2.37.1
>