mt76: mt7921: introduce PCIe ASPM support (L0s/L1/L1ss)

for better power consumption, default enable PCIe ASPM

Tested-by: Leon Yen <Leon.Yen@mediatek.com>
Signed-off-by: Deren Wu <deren.wu@mediatek.com>

drivers/net/wireless/mediatek/mt76/mt7921/pci.c

@@ -88,6 +88,72 @@ static void mt7921_irq_tasklet(unsigned long data)
 		napi_schedule(&dev->mt76.napi[MT_RXQ_MAIN]);
 }
 
+static void mt7921_pci_config_L1(struct pci_dev *pdev, u8 enable)
+{
+	u32 reg32;
+	int pos;
+
+	if (!pdev)
+		return;
+
+	/* capability check */
+	pos = pdev->pcie_cap;
+	pci_read_config_dword(pdev, pos + PCI_EXP_LNKCAP, &reg32);
+	if (!(reg32 & PCI_EXP_LNKCAP_ASPMS)) {
+		dev_info(&pdev->dev, "ASPM L1: Invalid cap 0x%X\n", reg32);
+		return;
+	}
+
+	/* set config */
+	pci_read_config_dword(pdev, pos + PCI_EXP_LNKCTL, &reg32);
+	if (enable)
+		reg32 |= (PCI_EXP_LNKCTL_ASPMC);
+	else
+		reg32 &= ~(PCI_EXP_LNKCTL_ASPMC);
+	dev_dbg(&pdev->dev, "%s ASPM L1\n", (enable) ? "enable" : "disable");
+
+	pci_write_config_dword(pdev, pos + PCI_EXP_LNKCTL, reg32);
+}
+
+static void mt7921_pci_config_L1ss(struct pci_dev *pdev, u8 enable)
+{
+#define  PCIE_L1SS_CAP_CHK \
+		(PCI_L1SS_CAP_ASPM_L1_1 | PCI_L1SS_CAP_ASPM_L1_2)
+#define  PCIE_L1SS_CTL_CHK \
+		(PCI_L1SS_CTL1_ASPM_L1_1 | PCI_L1SS_CTL1_ASPM_L1_2)
+
+	int pos;
+	u32 reg32;
+
+	if (!pdev)
+		return;
+
+	/* capability check */
+	pos = pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_L1SS);
+	pci_read_config_dword(pdev, pos + PCI_L1SS_CAP, &reg32);
+	if (!(reg32 & (PCIE_L1SS_CAP_CHK))) {
+		dev_info(&pdev->dev, "ASPM L1SS: Invalid cap 0x%X\n", reg32);
+		return;
+	}
+
+	/* set config */
+	pci_read_config_dword(pdev, pos + PCI_L1SS_CTL1, &reg32);
+	if (enable)
+		reg32 |= (PCIE_L1SS_CTL_CHK);
+	else
+		reg32 &= ~(PCIE_L1SS_CTL_CHK);
+
+	dev_dbg(&pdev->dev, "%s ASPM L1SS\n", (enable) ? "enable" : "disable");
+
+	pci_write_config_dword(pdev, pos + PCI_L1SS_CTL1, reg32);
+}
+
+void mt7921_pci_enable_aspm(struct pci_dev *pdev)
+{
+	mt7921_pci_config_L1ss(pdev, true);
+	mt7921_pci_config_L1(pdev, true);
+}
+
 static int mt7921_pci_probe(struct pci_dev *pdev,
 			    const struct pci_device_id *id)
 {
@@ -131,7 +197,7 @@ static int mt7921_pci_probe(struct pci_dev *pdev,
 	if (ret)
 		goto err_free_pci_vec;
 
-	mt76_pci_disable_aspm(pdev);
+	mt7921_pci_enable_aspm(pdev);
 
 	mdev = mt76_alloc_device(&pdev->dev, sizeof(*dev), &mt7921_ops,
 				 &drv_ops);