PCI: aardvark: Implement driver 'remove' function and allow to build it as module

Providing driver's 'remove' function allows kernel to bind and unbind devices
from aardvark driver. It also allows to build aardvark driver as a module.

Compiling aardvark as a module simplifies development and debugging of
this driver as it can be reloaded at runtime without the need to reboot
to new kernel.

Link: https://lore.kernel.org/r/20200907111038.5811-5-pali@kernel.orgSigned-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Marek Behún <marek.behun@nic.cz>

drivers/pci/controller/Kconfig

@@ -12,7 +12,7 @@ config PCI_MVEBU
 	select PCI_BRIDGE_EMUL
 
 config PCI_AARDVARK
-	bool "Aardvark PCIe controller"
+	tristate "Aardvark PCIe controller"
 	depends on (ARCH_MVEBU && ARM64) || COMPILE_TEST
 	depends on OF
 	depends on PCI_MSI_IRQ_DOMAIN

drivers/pci/controller/pci-aardvark.c

@@ -14,6 +14,7 @@
 #include <linux/irq.h>
 #include <linux/irqdomain.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/pci.h>
 #include <linux/init.h>
 #include <linux/phy/phy.h>
@@ -1121,6 +1122,7 @@ static int advk_pcie_probe(struct platform_device *pdev)
 
 	pcie = pci_host_bridge_priv(bridge);
 	pcie->pdev = pdev;
+	platform_set_drvdata(pdev, pcie);
 
 	pcie->base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(pcie->base))
@@ -1198,18 +1200,37 @@ static int advk_pcie_probe(struct platform_device *pdev)
 	return 0;
 }
 
+static int advk_pcie_remove(struct platform_device *pdev)
+{
+	struct advk_pcie *pcie = platform_get_drvdata(pdev);
+	struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
+
+	pci_lock_rescan_remove();
+	pci_stop_root_bus(bridge->bus);
+	pci_remove_root_bus(bridge->bus);
+	pci_unlock_rescan_remove();
+
+	advk_pcie_remove_msi_irq_domain(pcie);
+	advk_pcie_remove_irq_domain(pcie);
+
+	return 0;
+}
+
 static const struct of_device_id advk_pcie_of_match_table[] = {
 	{ .compatible = "marvell,armada-3700-pcie", },
 	{},
 };
+MODULE_DEVICE_TABLE(of, advk_pcie_of_match_table);
 
 static struct platform_driver advk_pcie_driver = {
 	.driver = {
 		.name = "advk-pcie",
 		.of_match_table = advk_pcie_of_match_table,
-		/* Driver unloading/unbinding currently not supported */
-		.suppress_bind_attrs = true,
 	},
 	.probe = advk_pcie_probe,
+	.remove = advk_pcie_remove,
 };
-builtin_platform_driver(advk_pcie_driver);
+module_platform_driver(advk_pcie_driver);
+
+MODULE_DESCRIPTION("Aardvark PCIe controller");
+MODULE_LICENSE("GPL v2");