PCI: dwc: Remove root_bus pointer

The pci_host_bridge struct already has a pointer to its pci_bus, so
let's convert the one user to use the bridge struct and remove the
private 'root_bus' pointer.

Link: https://lore.kernel.org/r/20200821035420.380495-18-robh@kernel.org
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Jingoo Han <jingoohan1@gmail.com>
Cc: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Jonathan Hunter <jonathanh@nvidia.com>
Cc: linux-tegra@vger.kernel.org

Author: robherring

drivers/pci/controller/dwc/pcie-designware-host.c

@@ -448,8 +448,8 @@ EXPORT_SYMBOL_GPL(dw_pcie_host_init);
 
 void dw_pcie_host_deinit(struct pcie_port *pp)
 {
-	pci_stop_root_bus(pp->root_bus);
-	pci_remove_root_bus(pp->root_bus);
+	pci_stop_root_bus(pp->bridge->bus);
+	pci_remove_root_bus(pp->bridge->bus);
 	if (pci_msi_enabled() && !pp->ops->msi_host_init)
 		dw_pcie_free_msi(pp);
 }

drivers/pci/controller/dwc/pcie-designware.h

@@ -192,7 +192,6 @@ struct pcie_port {
 	struct irq_chip		*msi_irq_chip;
 	u32			num_vectors;
 	u32			irq_mask[MAX_MSI_CTRLS];
-	struct pci_bus		*root_bus;
 	struct pci_host_bridge  *bridge;
 	raw_spinlock_t		lock;
 	DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS);

drivers/pci/controller/dwc/pcie-tegra194.c

@@ -1264,9 +1264,9 @@ static void tegra_pcie_downstream_dev_to_D0(struct tegra_pcie_dw *pcie)
 	 * 5.2 Link State Power Management (Page #428).
 	 */
 
-	list_for_each_entry(child, &pp->root_bus->children, node) {
+	list_for_each_entry(child, &pp->bridge->bus->children, node) {
 		/* Bring downstream devices to D0 if they are not already in */
-		if (child->parent == pp->root_bus) {
+		if (child->parent == pp->bridge->bus) {
 			root_bus = child;
 			break;
 		}