linux/drivers/net/wireless/mediatek/mt76/pci.c
Lorenzo Bianconi f37f055035 mt76: mt76x2e: disable pcie_aspm by default
On same device (e.g. U7612E-H1) PCIE_ASPM causes continuous mcu hangs and
instability. Since mt76x2 series does not manage PCIE PS states, first we
try to disable ASPM using pci_disable_link_state. If it fails, we will
disable PCIE PS configuring PCI registers.
This patch has been successfully tested on U7612E-H1 mini-pice card

Tested-by: Oleksandr Natalenko <oleksandr@natalenko.name>
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
2019-10-30 16:59:46 +02:00

47 lines
1.2 KiB
C

// 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);