71 lines · c
1// SPDX-License-Identifier: ISC2/*3 * Copyright (C) 2019 Lorenzo Bianconi <lorenzo@kernel.org>4 */5 6#include "mt76.h"7#include <linux/pci.h>8 9void mt76_pci_disable_aspm(struct pci_dev *pdev)10{11 struct pci_dev *parent = pdev->bus->self;12 u16 aspm_conf, parent_aspm_conf = 0;13 14 pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &aspm_conf);15 aspm_conf &= PCI_EXP_LNKCTL_ASPMC;16 if (parent) {17 pcie_capability_read_word(parent, PCI_EXP_LNKCTL,18 &parent_aspm_conf);19 parent_aspm_conf &= PCI_EXP_LNKCTL_ASPMC;20 }21 22 if (!aspm_conf && (!parent || !parent_aspm_conf)) {23 /* aspm already disabled */24 return;25 }26 27 dev_info(&pdev->dev, "disabling ASPM %s %s\n",28 (aspm_conf & PCI_EXP_LNKCTL_ASPM_L0S) ? "L0s" : "",29 (aspm_conf & PCI_EXP_LNKCTL_ASPM_L1) ? "L1" : "");30 31 if (IS_ENABLED(CONFIG_PCIEASPM)) {32 int err;33 34 err = pci_disable_link_state(pdev, aspm_conf);35 if (!err)36 return;37 }38 39 /* both device and parent should have the same ASPM setting.40 * disable ASPM in downstream component first and then upstream.41 */42 pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, aspm_conf);43 if (parent)44 pcie_capability_clear_word(parent, PCI_EXP_LNKCTL,45 aspm_conf);46}47EXPORT_SYMBOL_GPL(mt76_pci_disable_aspm);48 49bool mt76_pci_aspm_supported(struct pci_dev *pdev)50{51 struct pci_dev *parent = pdev->bus->self;52 u16 aspm_conf, parent_aspm_conf = 0;53 bool result = true;54 55 pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &aspm_conf);56 aspm_conf &= PCI_EXP_LNKCTL_ASPMC;57 if (parent) {58 pcie_capability_read_word(parent, PCI_EXP_LNKCTL,59 &parent_aspm_conf);60 parent_aspm_conf &= PCI_EXP_LNKCTL_ASPMC;61 }62 63 if (!aspm_conf && (!parent || !parent_aspm_conf)) {64 /* aspm already disabled */65 result = false;66 }67 68 return result;69}70EXPORT_SYMBOL_GPL(mt76_pci_aspm_supported);71