PCI: mvebu: Obey bridge PCI_COMMAND_MEM and PCI_COMMAND_IO bits

When PCI_COMMAND_MEMORY/PCI_COMMAND_IO are cleared, the bridge should not
allocate windows or even look at the window limit/base registers.

Otherwise we may set up bogus windows while the PCI core code performs
discovery.  The core will leave PCI_COMMAND_IO cleared if it doesn't need
an IO window.

Have mvebu_pcie_handle_*_change respect the bits, and call the change
function whenever the bits changes.

Tested-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Jason Cooper <jason@lakedaemon.net>

drivers/pci/host/pci-mvebu.c

@@ -300,7 +300,8 @@ static void mvebu_pcie_handle_iobase_change(struct mvebu_pcie_port *port)
 
 	/* Are the new iobase/iolimit values invalid? */
 	if (port->bridge.iolimit < port->bridge.iobase ||
-	    port->bridge.iolimitupper < port->bridge.iobaseupper) {
+	    port->bridge.iolimitupper < port->bridge.iobaseupper ||
+	    !(port->bridge.command & PCI_COMMAND_IO)) {
 
 		/* If a window was configured, remove it */
 		if (port->iowin_base) {
@@ -337,7 +338,8 @@ static void mvebu_pcie_handle_iobase_change(struct mvebu_pcie_port *port)
 static void mvebu_pcie_handle_membase_change(struct mvebu_pcie_port *port)
 {
 	/* Are the new membase/memlimit values invalid? */
-	if (port->bridge.memlimit < port->bridge.membase) {
+	if (port->bridge.memlimit < port->bridge.membase ||
+	    !(port->bridge.command & PCI_COMMAND_MEMORY)) {
 
 		/* If a window was configured, remove it */
 		if (port->memwin_base) {
@@ -485,8 +487,16 @@ static int mvebu_sw_pci_bridge_write(struct mvebu_pcie_port *port,
 
 	switch (where & ~3) {
 	case PCI_COMMAND:
+	{
+		u32 old = bridge->command;
+
 		bridge->command = value & 0xffff;
+		if ((old ^ bridge->command) & PCI_COMMAND_IO)
+			mvebu_pcie_handle_iobase_change(port);
+		if ((old ^ bridge->command) & PCI_COMMAND_MEMORY)
+			mvebu_pcie_handle_membase_change(port);
 		break;
+	}
 
 	case PCI_BASE_ADDRESS_0 ... PCI_BASE_ADDRESS_1:
 		bridge->bar[((where & ~3) - PCI_BASE_ADDRESS_0) / 4] = value;