// SPDX-License-Identifier: ISC
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/*
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* Copyright (C) 2019 Lorenzo Bianconi <lorenzo@kernel.org>
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*/
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#include "mt76.h"
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#include <linux/pci.h>
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void mt76_pci_disable_aspm(struct pci_dev *pdev)
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{
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struct pci_dev *parent = pdev->bus->self;
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u16 aspm_conf, parent_aspm_conf = 0;
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pcie_capability_read_word(pdev, PCI_EXP_LNKCTL, &aspm_conf);
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aspm_conf &= PCI_EXP_LNKCTL_ASPMC;
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if (parent) {
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pcie_capability_read_word(parent, PCI_EXP_LNKCTL,
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&parent_aspm_conf);
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parent_aspm_conf &= PCI_EXP_LNKCTL_ASPMC;
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}
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if (!aspm_conf && (!parent || !parent_aspm_conf)) {
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/* aspm already disabled */
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return;
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}
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dev_info(&pdev->dev, "disabling ASPM %s %s\n",
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(aspm_conf & PCI_EXP_LNKCTL_ASPM_L0S) ? "L0s" : "",
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(aspm_conf & PCI_EXP_LNKCTL_ASPM_L1) ? "L1" : "");
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if (IS_ENABLED(CONFIG_PCIEASPM)) {
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int err;
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err = pci_disable_link_state(pdev, aspm_conf);
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if (!err)
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return;
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}
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/* both device and parent should have the same ASPM setting.
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* disable ASPM in downstream component first and then upstream.
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*/
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pcie_capability_clear_word(pdev, PCI_EXP_LNKCTL, aspm_conf);
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if (parent)
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pcie_capability_clear_word(parent, PCI_EXP_LNKCTL,
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aspm_conf);
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}
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EXPORT_SYMBOL_GPL(mt76_pci_disable_aspm);
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