PCI: rockchip: Add remove() support

Currently, if we try to unbind the platform device, the remove will
succeed, but the removal won't undo most of the registration, leaving
partially-configured PCI devices in the system.

This allows, for example, a simple 'lspci' to crash the system, as it will
try to touch the freed (via devm_*) driver structures, e.g., on RK3399:

  # echo f8000000.pcie > /sys/bus/platform/drivers/rockchip-pcie/unbind
  # lspci

So let's implement device remove().

Signed-off-by: Brian Norris <briannorris@chromium.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Shawn Lin <shawn.lin@rock-chips.com>

drivers/pci/host/pcie-rockchip.c

@@ -223,9 +223,11 @@ struct rockchip_pcie {
 	int	link_gen;
 	struct	device *dev;
 	struct	irq_domain *irq_domain;
-	u32     io_size;
 	int     offset;
+	struct pci_bus *root_bus;
+	struct resource *io;
 	phys_addr_t io_bus_addr;
+	u32     io_size;
 	void    __iomem *msg_region;
 	u32     mem_size;
 	phys_addr_t msg_bus_addr;
@@ -1366,6 +1368,7 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 					 err, io);
 				continue;
 			}
+			rockchip->io = io;
 			break;
 		case IORESOURCE_MEM:
 			mem = win->res;
@@ -1397,6 +1400,7 @@ static int rockchip_pcie_probe(struct platform_device *pdev)
 		err = -ENOMEM;
 		goto err_free_res;
 	}
+	rockchip->root_bus = bus;
 
 	pci_bus_size_bridges(bus);
 	pci_bus_assign_resources(bus);
@@ -1427,6 +1431,34 @@ err_aclk_pcie:
 	return err;
 }
 
+static int rockchip_pcie_remove(struct platform_device *pdev)
+{
+	struct device *dev = &pdev->dev;
+	struct rockchip_pcie *rockchip = dev_get_drvdata(dev);
+
+	pci_stop_root_bus(rockchip->root_bus);
+	pci_remove_root_bus(rockchip->root_bus);
+	pci_unmap_iospace(rockchip->io);
+	irq_domain_remove(rockchip->irq_domain);
+
+	phy_power_off(rockchip->phy);
+	phy_exit(rockchip->phy);
+
+	clk_disable_unprepare(rockchip->clk_pcie_pm);
+	clk_disable_unprepare(rockchip->hclk_pcie);
+	clk_disable_unprepare(rockchip->aclk_perf_pcie);
+	clk_disable_unprepare(rockchip->aclk_pcie);
+
+	if (!IS_ERR(rockchip->vpcie3v3))
+		regulator_disable(rockchip->vpcie3v3);
+	if (!IS_ERR(rockchip->vpcie1v8))
+		regulator_disable(rockchip->vpcie1v8);
+	if (!IS_ERR(rockchip->vpcie0v9))
+		regulator_disable(rockchip->vpcie0v9);
+
+	return 0;
+}
+
 static const struct dev_pm_ops rockchip_pcie_pm_ops = {
 	SET_NOIRQ_SYSTEM_SLEEP_PM_OPS(rockchip_pcie_suspend_noirq,
 				      rockchip_pcie_resume_noirq)
@@ -1444,6 +1476,6 @@ static struct platform_driver rockchip_pcie_driver = {
 		.pm = &rockchip_pcie_pm_ops,
 	},
 	.probe = rockchip_pcie_probe,
-
+	.remove = rockchip_pcie_remove,
 };
 builtin_platform_driver(rockchip_pcie_driver);