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// 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);
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