developer | b11a539 | 2022-03-31 00:34:47 +0800 | [diff] [blame] | 1 | // SPDX-License-Identifier: ISC |
| 2 | /* |
| 3 | * Copyright (C) 2019 Lorenzo Bianconi <lorenzo@kernel.org> |
| 4 | */ |
| 5 | |
| 6 | #include "mt76.h" |
| 7 | #include <linux/pci.h> |
| 8 | |
| 9 | void 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 | } |
| 47 | EXPORT_SYMBOL_GPL(mt76_pci_disable_aspm); |