1f37f0550SLorenzo Bianconi // SPDX-License-Identifier: ISC 2f37f0550SLorenzo Bianconi /* 3f37f0550SLorenzo Bianconi * Copyright (C) 2019 Lorenzo Bianconi <lorenzo@kernel.org> 4f37f0550SLorenzo Bianconi */ 5f37f0550SLorenzo Bianconi 6f37f0550SLorenzo Bianconi #include <linux/pci.h> 7f37f0550SLorenzo Bianconi 8f37f0550SLorenzo Bianconi void mt76_pci_disable_aspm(struct pci_dev *pdev) 9f37f0550SLorenzo Bianconi { 10f37f0550SLorenzo Bianconi struct pci_dev *parent = pdev->bus->self; 11f37f0550SLorenzo Bianconi u16 aspm_conf, parent_aspm_conf = 0; 12f37f0550SLorenzo Bianconi 13f37f0550SLorenzo Bianconi pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &aspm_conf); 14f37f0550SLorenzo Bianconi aspm_conf &= PCI_EXP_LNKCTL_ASPMC; 15f37f0550SLorenzo Bianconi if (parent) { 16f37f0550SLorenzo Bianconi pcie_capability_read_word(parent, PCI_EXP_LNKCTL, 17f37f0550SLorenzo Bianconi &parent_aspm_conf); 18f37f0550SLorenzo Bianconi parent_aspm_conf &= PCI_EXP_LNKCTL_ASPMC; 19f37f0550SLorenzo Bianconi } 20f37f0550SLorenzo Bianconi 21f37f0550SLorenzo Bianconi if (!aspm_conf && (!parent || !parent_aspm_conf)) { 22f37f0550SLorenzo Bianconi /* aspm already disabled */ 23f37f0550SLorenzo Bianconi return; 24f37f0550SLorenzo Bianconi } 25f37f0550SLorenzo Bianconi 26f37f0550SLorenzo Bianconi dev_info(&pdev->dev, "disabling ASPM %s %s\n", 27f37f0550SLorenzo Bianconi (aspm_conf & PCI_EXP_LNKCTL_ASPM_L0S) ? "L0s" : "", 28f37f0550SLorenzo Bianconi (aspm_conf & PCI_EXP_LNKCTL_ASPM_L1) ? "L1" : ""); 29f37f0550SLorenzo Bianconi 30f37f0550SLorenzo Bianconi if (IS_ENABLED(CONFIG_PCIEASPM)) { 31f37f0550SLorenzo Bianconi int err; 32f37f0550SLorenzo Bianconi 33f37f0550SLorenzo Bianconi err = pci_disable_link_state(pdev, aspm_conf); 34f37f0550SLorenzo Bianconi if (!err) 35f37f0550SLorenzo Bianconi return; 36f37f0550SLorenzo Bianconi } 37f37f0550SLorenzo Bianconi 38f37f0550SLorenzo Bianconi /* both device and parent should have the same ASPM setting. 39f37f0550SLorenzo Bianconi * disable ASPM in downstream component first and then upstream. 40f37f0550SLorenzo Bianconi */ 41f37f0550SLorenzo Bianconi pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, aspm_conf); 42f37f0550SLorenzo Bianconi if (parent) 43f37f0550SLorenzo Bianconi pcie_capability_clear_word(parent, PCI_EXP_LNKCTL, 44f37f0550SLorenzo Bianconi aspm_conf); 45f37f0550SLorenzo Bianconi } 46f37f0550SLorenzo Bianconi EXPORT_SYMBOL_GPL(mt76_pci_disable_aspm); 47