From ad9b9b6e36c920234af6e86982dd48be560385b1 Mon Sep 17 00:00:00 2001 From: Manivannan Sadhasivam Date: Mon, 3 Apr 2023 21:19:22 +0530 Subject: [PATCH] PCI: qcom: Add support for system suspend and resume During the system suspend, vote for minimal interconnect bandwidth (1KiB) to keep the interconnect path active for config access and also turn OFF the resources like clock and PHY if there are no active devices connected to the controller. For the controllers with active devices, the resources are kept ON as removing the resources will trigger access violation during the late end of suspend cycle as kernel tries to access the config space of PCIe devices to mask the 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 storage devices like NVMe. And finally, during resume, turn ON the resources if the controller was truly suspended (resources OFF) and update the interconnect bandwidth based on PCIe Gen speed. Suggested-by: Krishna chaitanya chundru Link: https://lore.kernel.org/r/20230403154922.20704-2-manivannan.sadhasivam@linaro.org Tested-by: Johan Hovold Signed-off-by: Manivannan Sadhasivam Signed-off-by: Lorenzo Pieralisi Reviewed-by: Johan Hovold Acked-by: Dhruva Gole --- drivers/pci/controller/dwc/pcie-qcom.c | 62 ++++++++++++++++++++++++++ 1 file changed, 62 insertions(+) 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);