[PATCH 18/23] PCI, ACPI: add acpi_pci_root_rescan()

[Yinghai Lu <yinghai@kernel.org>]

it will rescan all acpi pci root if related pci root bus get removed before.

Signed-off-by: Yinghai <yinghai@kernel.org>
Cc: Len Brown <lenb@kernel.org>
Cc: linux-acpi@vger.kernel.org
---
 drivers/acpi/pci_root.c |   52 +++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 52 insertions(+), 0 deletions(-)

diff --git a/drivers/acpi/pci_root.c b/drivers/acpi/pci_root.c
index b38e347..e1814e0 100644
--- a/drivers/acpi/pci_root.c
+++ b/drivers/acpi/pci_root.c
@@ -679,3 +679,55 @@ static int __init acpi_pci_root_init(void)
 }
 
 subsys_initcall(acpi_pci_root_init);
+
+static acpi_status
+rescan_root_bridge(acpi_handle handle, u32 lvl, void *context, void **rv)
+{
+	struct acpi_device *device, *pdevice;
+	struct acpi_pci_root *root;
+	acpi_handle phandle;
+	int ret_val;
+
+	if (!acpi_is_root_bridge(handle))
+		return AE_OK;
+
+	acpi_get_parent(handle, &phandle);
+	if (acpi_bus_get_device(phandle, &pdevice)) {
+		printk(KERN_DEBUG "no parent device, assuming NULL\n");
+		pdevice = NULL;
+	}
+
+	if (!acpi_bus_get_device(handle, &device)) {
+		/* check if  pci root_bus is removed */
+		root = acpi_driver_data(device);
+		if (pci_find_bus(root->segment, root->secondary.start))
+			return AE_OK;
+
+		printk(KERN_DEBUG "bus exists... trim\n");
+		/* this shouldn't be in here, so remove
+		 * the bus then re-add it...
+		 */
+		ret_val = acpi_bus_trim(device, 1);
+		printk(KERN_DEBUG "acpi_bus_trim return %x\n", ret_val);
+	}
+
+	ret_val = acpi_bus_add(&device, pdevice, handle, ACPI_BUS_TYPE_DEVICE);
+	if (ret_val) {
+		printk(KERN_ERR "error adding bus, %x\n", -ret_val);
+		goto out;
+	}
+
+	root = acpi_driver_data(device);
+	pci_assign_unassigned_bus_resources(root->bus);
+
+	ret_val = acpi_bus_start(device);
+
+out:
+	return ret_val;
+}
+
+void acpi_pci_root_rescan(void)
+{
+	acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT,
+		ACPI_UINT32_MAX, rescan_root_bridge, NULL, NULL, NULL);
+}
-- 
1.7.7