From a339329727ac99e26dd7da30910f39839d7b17fd Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Tue, 16 Dec 2025 18:21:43 +0530 Subject: [PATCH 1/2] FROMLIST: PCI: qcom: Parse PERST# from all PCIe bridge nodes Devicetree schema allows the PERST# GPIO to be present in all PCIe bridge nodes, not just in Root Port node. But the current logic parses PERST# only from the Root Port nodes. Though it is not causing any issue on the current platforms, the upcoming platforms will have PERST# in PCIe switch downstream ports also. So this requires parsing all the PCIe bridge nodes for the PERST# GPIO. Hence, rework the parsing logic to extend to all PCIe bridge nodes starting from the Root Port node. If the 'reset-gpios' property is found for a PCI bridge node, the GPIO descriptor will be stored in qcom_pcie_perst::desc and added to the qcom_pcie_port::perst list. It should be noted that if more than one bridge node has the same GPIO for PERST# (shared PERST#), the driver will error out. This is due to the limitation in the GPIOLIB subsystem that allows only exclusive (non-shared) access to GPIOs from consumers. But this is soon going to get fixed. Once that happens, it will get incorporated in this driver. So for now, PERST# sharing is not supported. Tested-by: Chen-Yu Tsai Signed-off-by: Manivannan Sadhasivam Link: https://lore.kernel.org/all/20251216-pci-pwrctrl-rework-v2-1-745a563b9be6@oss.qualcomm.com/ --- drivers/pci/controller/dwc/pcie-qcom.c | 103 +++++++++++++++++++++---- 1 file changed, 86 insertions(+), 17 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c index 5e88513247b4c..95314330eb8ee 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -269,10 +269,15 @@ struct qcom_pcie_cfg { bool no_l0s; }; +struct qcom_pcie_perst { + struct list_head list; + struct gpio_desc *desc; +}; + struct qcom_pcie_port { struct list_head list; - struct gpio_desc *reset; struct phy *phy; + struct list_head perst; }; struct qcom_pcie { @@ -292,11 +297,14 @@ struct qcom_pcie { static void __qcom_pcie_perst_assert(struct qcom_pcie *pcie, bool assert) { + struct qcom_pcie_perst *perst; struct qcom_pcie_port *port; int val = assert ? 1 : 0; - list_for_each_entry(port, &pcie->ports, list) - gpiod_set_value_cansleep(port->reset, val); + list_for_each_entry(port, &pcie->ports, list) { + list_for_each_entry(perst, &port->perst, list) + gpiod_set_value_cansleep(perst->desc, val); + } usleep_range(PERST_DELAY_US, PERST_DELAY_US + 500); } @@ -1762,18 +1770,58 @@ static const struct pci_ecam_ops pci_qcom_ecam_ops = { } }; -static int qcom_pcie_parse_port(struct qcom_pcie *pcie, struct device_node *node) +/* Parse PERST# from all nodes in depth first manner starting from @np */ +static int qcom_pcie_parse_perst(struct qcom_pcie *pcie, + struct qcom_pcie_port *port, + struct device_node *np) { struct device *dev = pcie->pci->dev; - struct qcom_pcie_port *port; + struct qcom_pcie_perst *perst; struct gpio_desc *reset; - struct phy *phy; int ret; - reset = devm_fwnode_gpiod_get(dev, of_fwnode_handle(node), - "reset", GPIOD_OUT_HIGH, "PERST#"); - if (IS_ERR(reset)) + if (!of_find_property(np, "reset-gpios", NULL)) + goto parse_child_node; + + reset = devm_fwnode_gpiod_get(dev, of_fwnode_handle(np), "reset", + GPIOD_OUT_HIGH, "PERST#"); + if (IS_ERR(reset)) { + /* + * FIXME: GPIOLIB currently supports exclusive GPIO access only. + * Non exclusive access is broken. But shared PERST# requires + * non-exclusive access. So once GPIOLIB properly supports it, + * implement it here. + */ + if (PTR_ERR(reset) == -EBUSY) + dev_err(dev, "Shared PERST# is not supported\n"); + return PTR_ERR(reset); + } + + perst = devm_kzalloc(dev, sizeof(*perst), GFP_KERNEL); + if (!perst) + return -ENOMEM; + + INIT_LIST_HEAD(&perst->list); + perst->desc = reset; + list_add_tail(&perst->list, &port->perst); + +parse_child_node: + for_each_available_child_of_node_scoped(np, child) { + ret = qcom_pcie_parse_perst(pcie, port, child); + if (ret) + return ret; + } + + return 0; +} + +static int qcom_pcie_parse_port(struct qcom_pcie *pcie, struct device_node *node) +{ + struct device *dev = pcie->pci->dev; + struct qcom_pcie_port *port; + struct phy *phy; + int ret; phy = devm_of_phy_get(dev, node, NULL); if (IS_ERR(phy)) @@ -1787,7 +1835,12 @@ static int qcom_pcie_parse_port(struct qcom_pcie *pcie, struct device_node *node if (ret) return ret; - port->reset = reset; + INIT_LIST_HEAD(&port->perst); + + ret = qcom_pcie_parse_perst(pcie, port, node); + if (ret) + return ret; + port->phy = phy; INIT_LIST_HEAD(&port->list); list_add_tail(&port->list, &pcie->ports); @@ -1797,9 +1850,10 @@ static int qcom_pcie_parse_port(struct qcom_pcie *pcie, struct device_node *node static int qcom_pcie_parse_ports(struct qcom_pcie *pcie) { + struct qcom_pcie_perst *perst, *tmp_perst; + struct qcom_pcie_port *port, *tmp_port; struct device *dev = pcie->pci->dev; - struct qcom_pcie_port *port, *tmp; - int ret = -ENOENT; + int ret = -ENODEV; for_each_available_child_of_node_scoped(dev->of_node, of_port) { if (!of_node_is_type(of_port, "pci")) @@ -1812,7 +1866,9 @@ static int qcom_pcie_parse_ports(struct qcom_pcie *pcie) return ret; err_port_del: - list_for_each_entry_safe(port, tmp, &pcie->ports, list) { + list_for_each_entry_safe(port, tmp_port, &pcie->ports, list) { + list_for_each_entry_safe(perst, tmp_perst, &port->perst, list) + list_del(&perst->list); phy_exit(port->phy); list_del(&port->list); } @@ -1823,6 +1879,7 @@ static int qcom_pcie_parse_ports(struct qcom_pcie *pcie) static int qcom_pcie_parse_legacy_binding(struct qcom_pcie *pcie) { struct device *dev = pcie->pci->dev; + struct qcom_pcie_perst *perst; struct qcom_pcie_port *port; struct gpio_desc *reset; struct phy *phy; @@ -1844,18 +1901,28 @@ static int qcom_pcie_parse_legacy_binding(struct qcom_pcie *pcie) if (!port) return -ENOMEM; - port->reset = reset; + perst = devm_kzalloc(dev, sizeof(*perst), GFP_KERNEL); + if (!perst) + return -ENOMEM; + port->phy = phy; INIT_LIST_HEAD(&port->list); list_add_tail(&port->list, &pcie->ports); + perst->desc = reset; + INIT_LIST_HEAD(&port->perst); + INIT_LIST_HEAD(&perst->list); + list_add_tail(&perst->list, &port->perst); + return 0; } static int qcom_pcie_probe(struct platform_device *pdev) { + struct qcom_pcie_perst *perst, *tmp_perst; + struct qcom_pcie_port *port, *tmp_port; const struct qcom_pcie_cfg *pcie_cfg; - struct qcom_pcie_port *port, *tmp; + unsigned long max_freq = ULONG_MAX; struct device *dev = &pdev->dev; struct qcom_pcie *pcie; struct dw_pcie_rp *pp; @@ -1982,7 +2049,7 @@ static int qcom_pcie_probe(struct platform_device *pdev) ret = qcom_pcie_parse_ports(pcie); if (ret) { - if (ret != -ENOENT) { + if (ret != -ENODEV) { dev_err_probe(pci->dev, ret, "Failed to parse Root Port: %d\n", ret); goto err_pm_runtime_put; @@ -2014,7 +2081,9 @@ static int qcom_pcie_probe(struct platform_device *pdev) return 0; err_phy_exit: - list_for_each_entry_safe(port, tmp, &pcie->ports, list) { + list_for_each_entry_safe(port, tmp_port, &pcie->ports, list) { + list_for_each_entry_safe(perst, tmp_perst, &port->perst, list) + list_del(&perst->list); phy_exit(port->phy); list_del(&port->list); } From e8fbbf36753983209a5fa34b56733d2c933a7309 Mon Sep 17 00:00:00 2001 From: Qiang Yu Date: Tue, 30 Jun 2026 10:20:50 +0800 Subject: [PATCH 2/2] FROMLIST: PCI: qcom: Handle mixed PERST#/PHY DT configuration Some platforms have a mixed DT configuration where PERST# is described in the Root Complex node (using 'perst-gpios') while PHY is described in the PCIe port nodes. The current code only handles the case where PERST# is in the port nodes (via 'reset-gpios'). Handle this mixed configuration by checking for 'perst-gpios' in the Root Complex node first. If found, reuse that GPIO descriptor for all ports instead of parsing 'reset-gpios' from individual port nodes. Emit a warning to indicate that the DT needs to be fixed to use the standard 'reset-gpios' in port nodes. Signed-off-by: Qiang Yu Link: https://lore.kernel.org/all/20260508-mix_perst_phy_dts-v1-1-9eff6ee9b51a@oss.qualcomm.com/ --- drivers/pci/controller/dwc/pcie-qcom.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c index 95314330eb8ee..4c16512a832cb 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -290,6 +290,7 @@ struct qcom_pcie { const struct qcom_pcie_cfg *cfg; struct dentry *debugfs; struct list_head ports; + struct gpio_desc *reset; bool use_pm_opp; }; @@ -1780,6 +1781,11 @@ static int qcom_pcie_parse_perst(struct qcom_pcie *pcie, struct gpio_desc *reset; int ret; + if (pcie->reset) { + reset = pcie->reset; + goto skip_perst_parsing; + } + if (!of_find_property(np, "reset-gpios", NULL)) goto parse_child_node; @@ -1798,6 +1804,7 @@ static int qcom_pcie_parse_perst(struct qcom_pcie *pcie, return PTR_ERR(reset); } +skip_perst_parsing: perst = devm_kzalloc(dev, sizeof(*perst), GFP_KERNEL); if (!perst) return -ENOMEM; @@ -1855,6 +1862,14 @@ static int qcom_pcie_parse_ports(struct qcom_pcie *pcie) struct device *dev = pcie->pci->dev; int ret = -ENODEV; + if (of_find_property(dev->of_node, "perst-gpios", NULL)) { + pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH); + if (IS_ERR(pcie->reset)) + return PTR_ERR(pcie->reset); + + dev_warn(dev, "Reusing PERST# from Root Complex node. DT needs to be fixed!\n"); + } + for_each_available_child_of_node_scoped(dev->of_node, of_port) { if (!of_node_is_type(of_port, "pci")) continue;