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>

1 files changed, 12 insertions, 2 deletions

diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c
index 6f5a20f3cdf6..94294123e7bd 100644
--- a/drivers/pci/host/pci-mvebu.c
+++ b/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;