3 files changed, 112 insertions, 1 deletions

diff --git a/src/device/Kconfig b/src/device/Kconfig
index 0bd9fe1d8b..a25bb911c9 100644
--- a/src/device/Kconfig
+++ b/src/device/Kconfig
@@ -555,6 +555,50 @@ config PCIEXP_L1_SUB_STATE
 	help
 	  Detect and enable ASPM on PCIe links.
 
+config PCIEXP_HOTPLUG
+	prompt "Enable PCIe Hotplug Support"
+	bool
+	default n
+	help
+	  Allocate resources for PCIe hotplug bridges
+
+if PCIEXP_HOTPLUG
+
+config PCIEXP_HOTPLUG_BUSES
+	int "PCI Express Hotplug Buses"
+	default 32
+	help
+	  This is the number of buses allocated for hotplug PCI express
+	  bridges, for use by hotplugged child devices. The default is 32
+	  buses.
+
+config PCIEXP_HOTPLUG_MEM
+	hex "PCI Express Hotplug Memory"
+	default 0x800000
+	help
+	  This is the amount of memory space, in bytes, to allocate to
+	  hotplug PCI express bridges, for use by hotplugged child devices.
+	  This size should be page-aligned. The default is 8 MiB.
+
+config PCIEXP_HOTPLUG_PREFETCH_MEM
+	hex "PCI Express Hotplug Prefetch Memory"
+	default 0x10000000
+	help
+	  This is the amount of pre-fetchable memory space, in bytes, to
+	  allocate to hot-plug PCI express bridges, for use by hotplugged
+	  child devices. This size should be page-aligned. The default is
+	  256 MiB.
+
+config PCIEXP_HOTPLUG_IO
+	hex "PCI Express Hotplug I/O Space"
+	default 0x2000
+	help
+	  This is the amount of I/O space to allocate to hot-plug PCI
+	  express bridges, for use by hotplugged child devices. The default
+	  is 8 KiB.
+
+endif # PCIEXP_HOTPLUG
+
 endif # PCIEXP_PLUGIN_SUPPORT
 
 config EARLY_PCI_BRIDGE
diff --git a/src/device/pci_device.c b/src/device/pci_device.c
index 36b7c82d2a..47c0e9f2d2 100644
--- a/src/device/pci_device.c
+++ b/src/device/pci_device.c
@@ -878,6 +878,14 @@ static struct device_operations *get_pci_bridge_ops(struct device *dev)
 		case PCI_EXP_TYPE_DOWNSTREAM:
 			printk(BIOS_DEBUG, "%s subordinate bus PCI Express\n",
 			       dev_path(dev));
+#if CONFIG(PCIEXP_HOTPLUG)
+			u16 sltcap;
+			sltcap = pci_read_config16(dev, pciexpos + PCI_EXP_SLTCAP);
+			if (sltcap & PCI_EXP_SLTCAP_HPC) {
+				printk(BIOS_DEBUG, "%s hot-plug capable\n", dev_path(dev));
+				return &default_pciexp_hotplug_ops_bus;
+			}
+#endif /* CONFIG(PCIEXP_HOTPLUG) */
 			return &default_pciexp_ops_bus;
 		case PCI_EXP_TYPE_PCI_BRIDGE:
 			printk(BIOS_DEBUG, "%s subordinate PCI\n",
@@ -1259,7 +1267,7 @@ static void pci_bridge_route(struct bus *link, scan_state state)
 
 	if (state == PCI_ROUTE_SCAN) {
 		link->secondary = parent->subordinate + 1;
-		link->subordinate = link->secondary;
+		link->subordinate = link->secondary + dev->hotplug_buses;
 	}
 
 	if (state == PCI_ROUTE_CLOSE) {
diff --git a/src/device/pciexp_device.c b/src/device/pciexp_device.c
index 479891c5d6..b0ad1450e0 100644
--- a/src/device/pciexp_device.c
+++ b/src/device/pciexp_device.c
@@ -518,3 +518,62 @@ struct device_operations default_pciexp_ops_bus = {
 	.reset_bus        = pci_bus_reset,
 	.ops_pci          = &pciexp_bus_ops_pci,
 };
+
+#if CONFIG(PCIEXP_HOTPLUG)
+
+static void pciexp_hotplug_dummy_read_resources(struct device *dev)
+{
+	struct resource *resource;
+
+	// Add extra memory space
+	resource = new_resource(dev, 0x10);
+	resource->size = CONFIG_PCIEXP_HOTPLUG_MEM;
+	resource->align = 12;
+	resource->gran = 12;
+	resource->limit = 0xffffffff;
+	resource->flags |= IORESOURCE_MEM;
+
+	// Add extra prefetchable memory space
+	resource = new_resource(dev, 0x14);
+	resource->size = CONFIG_PCIEXP_HOTPLUG_PREFETCH_MEM;
+	resource->align = 12;
+	resource->gran = 12;
+	resource->limit = 0xffffffffffffffff;
+	resource->flags |= IORESOURCE_MEM | IORESOURCE_PREFETCH;
+
+	// Add extra I/O space
+	resource = new_resource(dev, 0x18);
+	resource->size = CONFIG_PCIEXP_HOTPLUG_IO;
+	resource->align = 12;
+	resource->gran = 12;
+	resource->limit = 0xffff;
+	resource->flags |= IORESOURCE_IO;
+}
+
+static struct device_operations pciexp_hotplug_dummy_ops = {
+	.read_resources   = pciexp_hotplug_dummy_read_resources,
+};
+
+void pciexp_hotplug_scan_bridge(struct device *dev)
+{
+	dev->hotplug_buses = CONFIG_PCIEXP_HOTPLUG_BUSES;
+
+	/* Normal PCIe Scan */
+	pciexp_scan_bridge(dev);
+
+	/* Add dummy slot to preserve resources, must happen after bus scan */
+	struct device *dummy;
+	struct device_path dummy_path = { .type = DEVICE_PATH_NONE };
+	dummy = alloc_dev(dev->link_list, &dummy_path);
+	dummy->ops = &pciexp_hotplug_dummy_ops;
+}
+
+struct device_operations default_pciexp_hotplug_ops_bus = {
+	.read_resources   = pci_bus_read_resources,
+	.set_resources    = pci_dev_set_resources,
+	.enable_resources = pci_bus_enable_resources,
+	.scan_bus         = pciexp_hotplug_scan_bridge,
+	.reset_bus        = pci_bus_reset,
+	.ops_pci          = &pciexp_bus_ops_pci,
+};
+#endif /* CONFIG(PCIEXP_HOTPLUG) */