PCI/PME: Use PCI Express Capability accessors

Use PCI Express Capability access functions to simplify PCIe PME.
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Yijing Wang <wangyijing@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/pcie/pme.c

@@ -57,17 +57,12 @@ struct pcie_pme_service_data {
  */
 void pcie_pme_interrupt_enable(struct pci_dev *dev, bool enable)
 {
-	int rtctl_pos;
-	u16 rtctl;
-
-	rtctl_pos = pci_pcie_cap(dev) + PCI_EXP_RTCTL;
-
-	pci_read_config_word(dev, rtctl_pos, &rtctl);
 	if (enable)
-		rtctl |= PCI_EXP_RTCTL_PMEIE;
+		pcie_capability_set_word(dev, PCI_EXP_RTCTL,
+					 PCI_EXP_RTCTL_PMEIE);
 	else
-		rtctl &= ~PCI_EXP_RTCTL_PMEIE;
-	pci_write_config_word(dev, rtctl_pos, rtctl);
+		pcie_capability_clear_word(dev, PCI_EXP_RTCTL,
+					   PCI_EXP_RTCTL_PMEIE);
 }
 
 /**
@@ -226,18 +221,15 @@ static void pcie_pme_work_fn(struct work_struct *work)
 	struct pcie_pme_service_data *data =
 			container_of(work, struct pcie_pme_service_data, work);
 	struct pci_dev *port = data->srv->port;
-	int rtsta_pos;
 	u32 rtsta;
 
-	rtsta_pos = pci_pcie_cap(port) + PCI_EXP_RTSTA;
-
 	spin_lock_irq(&data->lock);
 
 	for (;;) {
 		if (data->noirq)
 			break;
 
-		pci_read_config_dword(port, rtsta_pos, &rtsta);
+		pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
 		if (rtsta & PCI_EXP_RTSTA_PME) {
 			/*
 			 * Clear PME status of the port.  If there are other
@@ -276,17 +268,14 @@ static irqreturn_t pcie_pme_irq(int irq, void *context)
 {
 	struct pci_dev *port;
 	struct pcie_pme_service_data *data;
-	int rtsta_pos;
 	u32 rtsta;
 	unsigned long flags;
 
 	port = ((struct pcie_device *)context)->port;
 	data = get_service_data((struct pcie_device *)context);
 
-	rtsta_pos = pci_pcie_cap(port) + PCI_EXP_RTSTA;
-
 	spin_lock_irqsave(&data->lock, flags);
-	pci_read_config_dword(port, rtsta_pos, &rtsta);
+	pcie_capability_read_dword(port, PCI_EXP_RTSTA, &rtsta);
 
 	if (!(rtsta & PCI_EXP_RTSTA_PME)) {
 		spin_unlock_irqrestore(&data->lock, flags);