PCI: aardvark: Disable bus mastering when unbinding driver

commit a46f2f6 upstream.

Ensure that after driver unbind PCIe cards are not able to forward
memory and I/O requests in the upstream direction.

Link: https://lore.kernel.org/r/20211130172913.9727-7-kabel@kernel.org
Signed-off-by: Pali Rohár <pali@kernel.org>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/pci/controller/pci-aardvark.c

@@ -1679,6 +1679,7 @@ 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);
+	u32 val;
 	int i;
 
 	/* Remove PCI bus with all devices */
@@ -1687,6 +1688,11 @@ static int advk_pcie_remove(struct platform_device *pdev)
 	pci_remove_root_bus(bridge->bus);
 	pci_unlock_rescan_remove();
 
+	/* Disable Root Bridge I/O space, memory space and bus mastering */
+	val = advk_readl(pcie, PCIE_CORE_CMD_STATUS_REG);
+	val &= ~(PCI_COMMAND_IO | PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);
+	advk_writel(pcie, val, PCIE_CORE_CMD_STATUS_REG);
+
 	/* Remove IRQ domains */
 	advk_pcie_remove_msi_irq_domain(pcie);
 	advk_pcie_remove_irq_domain(pcie);