PCI: pcie: Ensure hotplug ports have a minimum number of resources

In general a BIOS may goof or we may hotplug in a hotplug controller.
In either case the kernel needs to reserve resources for plugging
in more devices in the future instead of creating a minimal resource
assignment.

We already do this for cardbus bridges I am just adding a variant
for pcie bridges.

v2: Make testing for pcie hotplug bridges based on a flag.

    So far we only set the flag for pcie but a header_quirk
    could easily be added for the non-standard pci hotplug
    bridges.

Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

1 files changed, 17 insertions, 5 deletions

diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index 7c443b4583ab6..cb1a027eb5522 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -309,7 +309,7 @@ static struct resource *find_free_bus_resource(struct pci_bus *bus, unsigned lon
    since these windows have 4K granularity and the IO ranges
    of non-bridge PCI devices are limited to 256 bytes.
    We must be careful with the ISA aliasing though. */
-static void pbus_size_io(struct pci_bus *bus)
+static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size)
 {
 	struct pci_dev *dev;
 	struct resource *b_res = find_free_bus_resource(bus, IORESOURCE_IO);
@@ -336,6 +336,8 @@ static void pbus_size_io(struct pci_bus *bus)
 				size1 += r_size;
 		}
 	}
+	if (size < min_size)
+		size = min_size;
 /* To be fixed in 2.5: we should have sort of HAVE_ISA
    flag in the struct pci_bus. */
 #if defined(CONFIG_ISA) || defined(CONFIG_EISA)
@@ -354,7 +356,8 @@ static void pbus_size_io(struct pci_bus *bus)
 
 /* Calculate the size of the bus and minimal alignment which
    guarantees that all child resources fit in this size. */
-static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, unsigned long type)
+static int pbus_size_mem(struct pci_bus *bus, unsigned long mask,
+			 unsigned long type, resource_size_t min_size)
 {
 	struct pci_dev *dev;
 	resource_size_t min_align, align, size;
@@ -404,6 +407,8 @@ static int pbus_size_mem(struct pci_bus *bus, unsigned long mask, unsigned long
 			mem64_mask &= r->flags & IORESOURCE_MEM_64;
 		}
 	}
+	if (size < min_size)
+		size = min_size;
 
 	align = 0;
 	min_align = 0;
@@ -483,6 +488,7 @@ void __ref pci_bus_size_bridges(struct pci_bus *bus)
 {
 	struct pci_dev *dev;
 	unsigned long mask, prefmask;
+	resource_size_t min_mem_size = 0, min_io_size = 0;
 
 	list_for_each_entry(dev, &bus->devices, bus_list) {
 		struct pci_bus *b = dev->subordinate;
@@ -512,8 +518,12 @@ void __ref pci_bus_size_bridges(struct pci_bus *bus)
 
 	case PCI_CLASS_BRIDGE_PCI:
 		pci_bridge_check_ranges(bus);
+		if (bus->self->is_hotplug_bridge) {
+			min_io_size  = pci_hotplug_io_size;
+			min_mem_size = pci_hotplug_mem_size;
+		}
 	default:
-		pbus_size_io(bus);
+		pbus_size_io(bus, min_io_size);
 		/* If the bridge supports prefetchable range, size it
 		   separately. If it doesn't, or its prefetchable window
 		   has already been allocated by arch code, try
@@ -521,9 +531,11 @@ void __ref pci_bus_size_bridges(struct pci_bus *bus)
 		   resources. */
 		mask = IORESOURCE_MEM;
 		prefmask = IORESOURCE_MEM | IORESOURCE_PREFETCH;
-		if (pbus_size_mem(bus, prefmask, prefmask))
+		if (pbus_size_mem(bus, prefmask, prefmask, min_mem_size))
 			mask = prefmask; /* Success, size non-prefetch only. */
-		pbus_size_mem(bus, mask, IORESOURCE_MEM);
+		else
+			min_mem_size += min_mem_size;
+		pbus_size_mem(bus, mask, IORESOURCE_MEM, min_mem_size);
 		break;
 	}
 }