Message-Id: <20250702-perst-v5-2-920b3d1f6ee1@qti.qualcomm.com>
Date: Wed, 02 Jul 2025 16:50:42 +0530
From: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
To: Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Krzysztof Wilczyński <kwilczynski@...nel.org>,
        Manivannan Sadhasivam <mani@...nel.org>, Rob Herring <robh@...nel.org>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Bjorn Andersson <andersson@...nel.org>,
        Konrad Dybcio <konradybcio@...nel.org>,
        cros-qcom-dts-watchers@...omium.org
Cc: linux-arm-msm@...r.kernel.org, linux-pci@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        quic_vbadigan@...cinc.com, quic_mrana@...cinc.com,
        Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
Subject: [PATCH v5 2/2] PCI: qcom: Add support for multi-root port

Move phy, PERST# handling to root port and provide a way to have multi-port
logic.

Currently, QCOM controllers only support single port, and all properties
are present in the host bridge node itself. This is incorrect, as
properties like phys, perst-gpios, etc.. can vary per port and should be
present in the root port node.

To maintain DT backwards compatibility, fallback to the legacy method of
parsing the host bridge node if the port parsing fails.

pci-bus-common.yaml uses reset-gpios property for representing PERST#, use
same property instead of perst-gpios.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@....qualcomm.com>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 178 ++++++++++++++++++++++++++++-----
 1 file changed, 151 insertions(+), 27 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index f7ed1e010eb6607b2e98a42f0051c47e4de2af93..56d04a15edf8f99f6d3b9bfaa037ff922b521888 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -267,6 +267,12 @@ struct qcom_pcie_cfg {
 	bool no_l0s;
 };
 
+struct qcom_pcie_port {
+	struct list_head list;
+	struct gpio_desc *reset;
+	struct phy *phy;
+};
+
 struct qcom_pcie {
 	struct dw_pcie *pci;
 	void __iomem *parf;			/* DT parf */
@@ -279,24 +285,37 @@ struct qcom_pcie {
 	struct icc_path *icc_cpu;
 	const struct qcom_pcie_cfg *cfg;
 	struct dentry *debugfs;
+	struct list_head ports;
 	bool suspended;
 	bool use_pm_opp;
 };
 
 #define to_qcom_pcie(x)		dev_get_drvdata((x)->dev)
 
-static void qcom_ep_reset_assert(struct qcom_pcie *pcie)
+static void qcom_perst_assert(struct qcom_pcie *pcie, bool assert)
 {
-	gpiod_set_value_cansleep(pcie->reset, 1);
+	struct qcom_pcie_port *port;
+	int val = assert ? 1 : 0;
+
+	if (list_empty(&pcie->ports))
+		gpiod_set_value_cansleep(pcie->reset, val);
+	else
+		list_for_each_entry(port, &pcie->ports, list)
+			gpiod_set_value_cansleep(port->reset, val);
+
 	usleep_range(PERST_DELAY_US, PERST_DELAY_US + 500);
 }
 
+static void qcom_ep_reset_assert(struct qcom_pcie *pcie)
+{
+	qcom_perst_assert(pcie, true);
+}
+
 static void qcom_ep_reset_deassert(struct qcom_pcie *pcie)
 {
 	/* Ensure that PERST has been asserted for at least 100 ms */
 	msleep(PCIE_T_PVPERL_MS);
-	gpiod_set_value_cansleep(pcie->reset, 0);
-	usleep_range(PERST_DELAY_US, PERST_DELAY_US + 500);
+	qcom_perst_assert(pcie, false);
 }
 
 static int qcom_pcie_start_link(struct dw_pcie *pci)
@@ -1234,6 +1253,59 @@ static bool qcom_pcie_link_up(struct dw_pcie *pci)
 	return val & PCI_EXP_LNKSTA_DLLLA;
 }
 
+static void qcom_pcie_phy_exit(struct qcom_pcie *pcie)
+{
+	struct qcom_pcie_port *port;
+
+	if (list_empty(&pcie->ports))
+		phy_exit(pcie->phy);
+	else
+		list_for_each_entry(port, &pcie->ports, list)
+			phy_exit(port->phy);
+}
+
+static void qcom_pcie_phy_power_off(struct qcom_pcie *pcie)
+{
+	struct qcom_pcie_port *port;
+
+	if (list_empty(&pcie->ports)) {
+		phy_power_off(pcie->phy);
+	} else {
+		list_for_each_entry(port, &pcie->ports, list)
+			phy_power_off(port->phy);
+	}
+}
+
+static int qcom_pcie_phy_power_on(struct qcom_pcie *pcie)
+{
+	struct qcom_pcie_port *port;
+	int ret = 0;
+
+	if (list_empty(&pcie->ports)) {
+		ret = phy_set_mode_ext(pcie->phy, PHY_MODE_PCIE, PHY_MODE_PCIE_RC);
+		if (ret)
+			return ret;
+
+		ret = phy_power_on(pcie->phy);
+		if (ret)
+			return ret;
+	} else {
+		list_for_each_entry(port, &pcie->ports, list) {
+			ret = phy_set_mode_ext(port->phy, PHY_MODE_PCIE, PHY_MODE_PCIE_RC);
+			if (ret)
+				return ret;
+
+			ret = phy_power_on(port->phy);
+			if (ret) {
+				qcom_pcie_phy_power_off(pcie);
+				return ret;
+			}
+		}
+	}
+
+	return ret;
+}
+
 static int qcom_pcie_host_init(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -1246,11 +1318,7 @@ static int qcom_pcie_host_init(struct dw_pcie_rp *pp)
 	if (ret)
 		return ret;
 
-	ret = phy_set_mode_ext(pcie->phy, PHY_MODE_PCIE, PHY_MODE_PCIE_RC);
-	if (ret)
-		goto err_deinit;
-
-	ret = phy_power_on(pcie->phy);
+	ret = qcom_pcie_phy_power_on(pcie);
 	if (ret)
 		goto err_deinit;
 
@@ -1273,7 +1341,7 @@ static int qcom_pcie_host_init(struct dw_pcie_rp *pp)
 err_assert_reset:
 	qcom_ep_reset_assert(pcie);
 err_disable_phy:
-	phy_power_off(pcie->phy);
+	qcom_pcie_phy_power_off(pcie);
 err_deinit:
 	pcie->cfg->ops->deinit(pcie);
 
@@ -1286,7 +1354,7 @@ static void qcom_pcie_host_deinit(struct dw_pcie_rp *pp)
 	struct qcom_pcie *pcie = to_qcom_pcie(pci);
 
 	qcom_ep_reset_assert(pcie);
-	phy_power_off(pcie->phy);
+	qcom_pcie_phy_power_off(pcie);
 	pcie->cfg->ops->deinit(pcie);
 }
 
@@ -1631,11 +1699,41 @@ static const struct pci_ecam_ops pci_qcom_ecam_ops = {
 	}
 };
 
+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 gpio_desc *reset;
+	struct phy *phy;
+
+	reset = devm_fwnode_gpiod_get(dev, of_fwnode_handle(node),
+				      "reset", GPIOD_OUT_HIGH, "PERST#");
+	if (IS_ERR(reset))
+		return PTR_ERR(reset);
+
+	phy = devm_of_phy_get(dev, node, NULL);
+	if (IS_ERR(phy))
+		return PTR_ERR(phy);
+
+	port = devm_kzalloc(dev, sizeof(*port), GFP_KERNEL);
+	if (!port)
+		return -ENOMEM;
+
+	port->reset = reset;
+	port->phy = phy;
+	INIT_LIST_HEAD(&port->list);
+	list_add_tail(&port->list, &pcie->ports);
+
+	return 0;
+}
+
 static int qcom_pcie_probe(struct platform_device *pdev)
 {
 	const struct qcom_pcie_cfg *pcie_cfg;
 	unsigned long max_freq = ULONG_MAX;
+	struct qcom_pcie_port *port, *tmp;
 	struct device *dev = &pdev->dev;
+	struct device_node *of_port;
 	struct dev_pm_opp *opp;
 	struct qcom_pcie *pcie;
 	struct dw_pcie_rp *pp;
@@ -1701,6 +1799,8 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 		goto err_pm_runtime_put;
 	}
 
+	INIT_LIST_HEAD(&pcie->ports);
+
 	pci->dev = dev;
 	pci->ops = &dw_pcie_ops;
 	pp = &pci->pp;
@@ -1709,12 +1809,6 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 
 	pcie->cfg = pcie_cfg;
 
-	pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH);
-	if (IS_ERR(pcie->reset)) {
-		ret = PTR_ERR(pcie->reset);
-		goto err_pm_runtime_put;
-	}
-
 	pcie->parf = devm_platform_ioremap_resource_byname(pdev, "parf");
 	if (IS_ERR(pcie->parf)) {
 		ret = PTR_ERR(pcie->parf);
@@ -1737,12 +1831,6 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 		}
 	}
 
-	pcie->phy = devm_phy_optional_get(dev, "pciephy");
-	if (IS_ERR(pcie->phy)) {
-		ret = PTR_ERR(pcie->phy);
-		goto err_pm_runtime_put;
-	}
-
 	/* OPP table is optional */
 	ret = devm_pm_opp_of_add_table(dev);
 	if (ret && ret != -ENODEV) {
@@ -1789,9 +1877,42 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 
 	pp->ops = &qcom_pcie_dw_ops;
 
-	ret = phy_init(pcie->phy);
-	if (ret)
-		goto err_pm_runtime_put;
+	for_each_available_child_of_node(dev->of_node, of_port) {
+		ret = qcom_pcie_parse_port(pcie, of_port);
+		of_node_put(of_port);
+		if (ret) {
+			if (ret != -ENOENT) {
+				dev_err_probe(pci->dev, ret,
+					      "Failed to parse port nodes %d\n",
+					      ret);
+				goto err_port_del;
+			}
+			break;
+		}
+	}
+
+	/*
+	 * In the case of properties not populated in root port, fallback to the
+	 * legacy method of parsing the host bridge node. This is to maintain DT
+	 * backwards compatibility.
+	 */
+	if (ret) {
+		pcie->phy = devm_phy_optional_get(dev, "pciephy");
+		if (IS_ERR(pcie->phy)) {
+			ret = PTR_ERR(pcie->phy);
+			goto err_pm_runtime_put;
+		}
+
+		pcie->reset = devm_gpiod_get_optional(dev, "perst", GPIOD_OUT_HIGH);
+		if (IS_ERR(pcie->reset)) {
+			ret = PTR_ERR(pcie->reset);
+			goto err_pm_runtime_put;
+		}
+
+		ret = phy_init(pcie->phy);
+		if (ret)
+			goto err_pm_runtime_put;
+	}
 
 	platform_set_drvdata(pdev, pcie);
 
@@ -1836,7 +1957,10 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 err_host_deinit:
 	dw_pcie_host_deinit(pp);
 err_phy_exit:
-	phy_exit(pcie->phy);
+	qcom_pcie_phy_exit(pcie);
+err_port_del:
+	list_for_each_entry_safe(port, tmp, &pcie->ports, list)
+		list_del(&port->list);
 err_pm_runtime_put:
 	pm_runtime_put(dev);
 	pm_runtime_disable(dev);

-- 
2.34.1

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