diff options
Diffstat (limited to 'drivers/net/wireless/mediatek/mt76/pci.c')
| -rw-r--r-- | drivers/net/wireless/mediatek/mt76/pci.c | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/drivers/net/wireless/mediatek/mt76/pci.c b/drivers/net/wireless/mediatek/mt76/pci.c new file mode 100644 index 0000000..04c5a69 --- /dev/null +++ b/drivers/net/wireless/mediatek/mt76/pci.c @@ -0,0 +1,46 @@ +// SPDX-License-Identifier: ISC +/* + * Copyright (C) 2019 Lorenzo Bianconi <lorenzo@kernel.org> + */ + +#include <linux/pci.h> + +void mt76_pci_disable_aspm(struct pci_dev *pdev) +{ + struct pci_dev *parent = pdev->bus->self; + u16 aspm_conf, parent_aspm_conf = 0; + + pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &aspm_conf); + aspm_conf &= PCI_EXP_LNKCTL_ASPMC; + if (parent) { + pcie_capability_read_word(parent, PCI_EXP_LNKCTL, + &parent_aspm_conf); + parent_aspm_conf &= PCI_EXP_LNKCTL_ASPMC; + } + + if (!aspm_conf && (!parent || !parent_aspm_conf)) { + /* aspm already disabled */ + return; + } + + dev_info(&pdev->dev, "disabling ASPM %s %s\n", + (aspm_conf & PCI_EXP_LNKCTL_ASPM_L0S) ? "L0s" : "", + (aspm_conf & PCI_EXP_LNKCTL_ASPM_L1) ? "L1" : ""); + + if (IS_ENABLED(CONFIG_PCIEASPM)) { + int err; + + err = pci_disable_link_state(pdev, aspm_conf); + if (!err) + return; + } + + /* both device and parent should have the same ASPM setting. + * disable ASPM in downstream component first and then upstream. + */ + pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, aspm_conf); + if (parent) + pcie_capability_clear_word(parent, PCI_EXP_LNKCTL, + aspm_conf); +} +EXPORT_SYMBOL_GPL(mt76_pci_disable_aspm); |