1*6c92544dSBjoern A. Zeeb // SPDX-License-Identifier: ISC 2*6c92544dSBjoern A. Zeeb /* 3*6c92544dSBjoern A. Zeeb * Copyright (C) 2019 Lorenzo Bianconi <lorenzo@kernel.org> 4*6c92544dSBjoern A. Zeeb */ 5*6c92544dSBjoern A. Zeeb 6*6c92544dSBjoern A. Zeeb #include "mt76.h" 7*6c92544dSBjoern A. Zeeb #include <linux/pci.h> 8*6c92544dSBjoern A. Zeeb 9*6c92544dSBjoern A. Zeeb void mt76_pci_disable_aspm(struct pci_dev *pdev) 10*6c92544dSBjoern A. Zeeb { 11*6c92544dSBjoern A. Zeeb struct pci_dev *parent = pdev->bus->self; 12*6c92544dSBjoern A. Zeeb u16 aspm_conf, parent_aspm_conf = 0; 13*6c92544dSBjoern A. Zeeb 14*6c92544dSBjoern A. Zeeb pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &aspm_conf); 15*6c92544dSBjoern A. Zeeb aspm_conf &= PCI_EXP_LNKCTL_ASPMC; 16*6c92544dSBjoern A. Zeeb if (parent) { 17*6c92544dSBjoern A. Zeeb pcie_capability_read_word(parent, PCI_EXP_LNKCTL, 18*6c92544dSBjoern A. Zeeb &parent_aspm_conf); 19*6c92544dSBjoern A. Zeeb parent_aspm_conf &= PCI_EXP_LNKCTL_ASPMC; 20*6c92544dSBjoern A. Zeeb } 21*6c92544dSBjoern A. Zeeb 22*6c92544dSBjoern A. Zeeb if (!aspm_conf && (!parent || !parent_aspm_conf)) { 23*6c92544dSBjoern A. Zeeb /* aspm already disabled */ 24*6c92544dSBjoern A. Zeeb return; 25*6c92544dSBjoern A. Zeeb } 26*6c92544dSBjoern A. Zeeb 27*6c92544dSBjoern A. Zeeb dev_info(&pdev->dev, "disabling ASPM %s %s\n", 28*6c92544dSBjoern A. Zeeb (aspm_conf & PCI_EXP_LNKCTL_ASPM_L0S) ? "L0s" : "", 29*6c92544dSBjoern A. Zeeb (aspm_conf & PCI_EXP_LNKCTL_ASPM_L1) ? "L1" : ""); 30*6c92544dSBjoern A. Zeeb 31*6c92544dSBjoern A. Zeeb if (IS_ENABLED(CONFIG_PCIEASPM)) { 32*6c92544dSBjoern A. Zeeb int err; 33*6c92544dSBjoern A. Zeeb 34*6c92544dSBjoern A. Zeeb err = pci_disable_link_state(pdev, aspm_conf); 35*6c92544dSBjoern A. Zeeb if (!err) 36*6c92544dSBjoern A. Zeeb return; 37*6c92544dSBjoern A. Zeeb } 38*6c92544dSBjoern A. Zeeb 39*6c92544dSBjoern A. Zeeb /* both device and parent should have the same ASPM setting. 40*6c92544dSBjoern A. Zeeb * disable ASPM in downstream component first and then upstream. 41*6c92544dSBjoern A. Zeeb */ 42*6c92544dSBjoern A. Zeeb pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, aspm_conf); 43*6c92544dSBjoern A. Zeeb if (parent) 44*6c92544dSBjoern A. Zeeb pcie_capability_clear_word(parent, PCI_EXP_LNKCTL, 45*6c92544dSBjoern A. Zeeb aspm_conf); 46*6c92544dSBjoern A. Zeeb } 47*6c92544dSBjoern A. Zeeb EXPORT_SYMBOL_GPL(mt76_pci_disable_aspm); 48