PCI: rcar: Use pci_is_root_bus() to check if bus is root bus

Use pci_is_root_bus() rather than tracking the root bus number to
determine if the bus is the root bus or not. This removes storing
duplicated data as well as the need for the host bridge driver to have
to care about the bus numbers in most cases.

Link: https://lore.kernel.org/r/20200722022514.1283916-11-robh@kernel.orgSigned-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Cc: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: linux-renesas-soc@vger.kernel.org

drivers/pci/controller/pcie-rcar-host.c

@@ -54,7 +54,6 @@ struct rcar_pcie_host {
 	struct phy		*phy;
 	void __iomem		*base;
 	struct list_head	resources;
-	int			root_bus_nr;
 	struct clk		*bus_clk;
 	struct			rcar_msi msi;
 	int			(*phy_init_fn)(struct rcar_pcie_host *host);
@@ -100,22 +99,14 @@ static int rcar_pcie_config_access(struct rcar_pcie_host *host,
 		if (dev != 0)
 			return PCIBIOS_DEVICE_NOT_FOUND;
 
-		if (access_type == RCAR_PCI_ACCESS_READ) {
+		if (access_type == RCAR_PCI_ACCESS_READ)
 			*data = rcar_pci_read_reg(pcie, PCICONF(index));
-		} else {
-			/* Keep an eye out for changes to the root bus number */
-			if (pci_is_root_bus(bus) && (reg == PCI_PRIMARY_BUS))
-				host->root_bus_nr = *data & 0xff;
-
+		else
 			rcar_pci_write_reg(pcie, *data, PCICONF(index));
-		}
 
 		return PCIBIOS_SUCCESSFUL;
 	}
 
-	if (host->root_bus_nr < 0)
-		return PCIBIOS_DEVICE_NOT_FOUND;
-
 	/* Clear errors */
 	rcar_pci_write_reg(pcie, rcar_pci_read_reg(pcie, PCIEERRFR), PCIEERRFR);
 
@@ -124,7 +115,7 @@ static int rcar_pcie_config_access(struct rcar_pcie_host *host,
 		PCIE_CONF_DEV(dev) | PCIE_CONF_FUNC(func) | reg, PCIECAR);
 
 	/* Enable the configuration access */
-	if (bus->parent->number == host->root_bus_nr)
+	if (pci_is_root_bus(bus->parent))
 		rcar_pci_write_reg(pcie, CONFIG_SEND_ENABLE | TYPE0, PCIECCTLR);
 	else
 		rcar_pci_write_reg(pcie, CONFIG_SEND_ENABLE | TYPE1, PCIECCTLR);
@@ -215,6 +206,7 @@ static struct pci_ops rcar_pcie_ops = {
 static int rcar_pcie_setup(struct list_head *resource,
 			   struct rcar_pcie_host *host)
 {
+	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(host);
 	struct resource_entry *win;
 	int i = 0;
 
@@ -232,7 +224,7 @@ static int rcar_pcie_setup(struct list_head *resource,
 			i++;
 			break;
 		case IORESOURCE_BUS:
-			host->root_bus_nr = res->start;
+			bridge->busnr = res->start;
 			break;
 		default:
 			continue;
@@ -338,7 +330,6 @@ static int rcar_pcie_enable(struct rcar_pcie_host *host)
 	pci_add_flags(PCI_REASSIGN_ALL_BUS);
 
 	bridge->sysdata = host;
-	bridge->busnr = host->root_bus_nr;
 	bridge->ops = &rcar_pcie_ops;
 	bridge->map_irq = of_irq_parse_and_map_pci;
 	bridge->swizzle_irq = pci_common_swizzle;