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path: root/drivers/net/wireless/mediatek/mt76/pci.c
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Diffstat (limited to 'drivers/net/wireless/mediatek/mt76/pci.c')
-rw-r--r--drivers/net/wireless/mediatek/mt76/pci.c46
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 000000000000..04c5a692bc85
--- /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);