1 files changed, 62 insertions, 0 deletions

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index f3e606b038c3..10b00fa2c6d1 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -244,6 +244,7 @@ struct qcom_pcie {
 	struct icc_path *icc_mem;
 	const struct qcom_pcie_cfg *cfg;
 	struct dentry *debugfs;
+	bool suspended;
 };
 
 #define to_qcom_pcie(x)		dev_get_drvdata((x)->dev)
@@ -1538,6 +1539,62 @@ err_pm_runtime_put:
 	return ret;
 }
 
+static int qcom_pcie_suspend_noirq(struct device *dev)
+{
+	struct qcom_pcie *pcie = dev_get_drvdata(dev);
+	int ret;
+
+	/*
+	 * Set minimum bandwidth required to keep data path functional during
+	 * suspend.
+	 */
+	ret = icc_set_bw(pcie->icc_mem, 0, kBps_to_icc(1));
+	if (ret) {
+		dev_err(dev, "Failed to set interconnect bandwidth: %d\n", ret);
+		return ret;
+	}
+
+	/*
+	 * Turn OFF the resources only for controllers without active PCIe
+	 * devices. For controllers with active devices, the resources are kept
+	 * ON and the link is expected to be in L0/L1 (sub)states.
+	 *
+	 * Turning OFF the resources for controllers with active PCIe devices
+	 * will trigger access violation during the end of the suspend cycle,
+	 * as kernel tries to access the PCIe devices config space for masking
+	 * MSIs.
+	 *
+	 * Also, it is not desirable to put the link into L2/L3 state as that
+	 * implies VDD supply will be removed and the devices may go into
+	 * powerdown state. This will affect the lifetime of the storage devices
+	 * like NVMe.
+	 */
+	if (!dw_pcie_link_up(pcie->pci)) {
+		qcom_pcie_host_deinit(&pcie->pci->pp);
+		pcie->suspended = true;
+	}
+
+	return 0;
+}
+
+static int qcom_pcie_resume_noirq(struct device *dev)
+{
+	struct qcom_pcie *pcie = dev_get_drvdata(dev);
+	int ret;
+
+	if (pcie->suspended) {
+		ret = qcom_pcie_host_init(&pcie->pci->pp);
+		if (ret)
+			return ret;
+
+		pcie->suspended = false;
+	}
+
+	qcom_pcie_icc_update(pcie);
+
+	return 0;
+}
+
 static const struct of_device_id qcom_pcie_match[] = {
 	{ .compatible = "qcom,pcie-apq8064", .data = &cfg_2_1_0 },
 	{ .compatible = "qcom,pcie-apq8084", .data = &cfg_1_0_0 },
@@ -1574,12 +1631,17 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_QCOM, 0x0302, qcom_fixup_class);
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_QCOM, 0x1000, qcom_fixup_class);
 DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_QCOM, 0x1001, qcom_fixup_class);
 
+static const struct dev_pm_ops qcom_pcie_pm_ops = {
+	NOIRQ_SYSTEM_SLEEP_PM_OPS(qcom_pcie_suspend_noirq, qcom_pcie_resume_noirq)
+};
+
 static struct platform_driver qcom_pcie_driver = {
 	.probe = qcom_pcie_probe,
 	.driver = {
 		.name = "qcom-pcie",
 		.suppress_bind_attrs = true,
 		.of_match_table = qcom_pcie_match,
+		.pm = &qcom_pcie_pm_ops,
 	},
 };
 builtin_platform_driver(qcom_pcie_driver);