[PATCH v9 15/16] PCI/acpiphp: introduce a kernel option to disable the acpiphp driver

[Jiang Liu <liuj97@gmail.com>]

Now the acpiphp driver has been converted as builtin, so introduce
a kernel boot option "acpiphp.disable" to disable the acpiphp driver
on boot.

Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
---
 Documentation/kernel-parameters.txt |    3 +++
 drivers/pci/hotplug/acpiphp.h       |    1 +
 drivers/pci/hotplug/acpiphp_core.c  |    6 +++++-
 drivers/pci/hotplug/acpiphp_glue.c  |    6 ++++++
 4 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 4609e81..38baa0d 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -290,6 +290,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			no: ACPI OperationRegions are not marked as reserved,
 			no further checks are performed.
 
+	acpiphp.disable
+			Disable the PCI acpiphp hotplug driver.
+
 	add_efi_memmap	[EFI; X86] Include EFI memory map in
 			kernel's map of available physical RAM.
 
diff --git a/drivers/pci/hotplug/acpiphp.h b/drivers/pci/hotplug/acpiphp.h
index 7577bb3..6a319f4 100644
--- a/drivers/pci/hotplug/acpiphp.h
+++ b/drivers/pci/hotplug/acpiphp.h
@@ -188,5 +188,6 @@ extern u8 acpiphp_get_adapter_status (struct acpiphp_slot *slot);
 
 /* variables */
 extern bool acpiphp_debug;
+extern bool acpiphp_disabled;
 
 #endif /* _ACPIPHP_H */
diff --git a/drivers/pci/hotplug/acpiphp_core.c b/drivers/pci/hotplug/acpiphp_core.c
index 80d777c..cdbd983 100644
--- a/drivers/pci/hotplug/acpiphp_core.c
+++ b/drivers/pci/hotplug/acpiphp_core.c
@@ -49,6 +49,7 @@
 #define SLOT_NAME_SIZE  21              /* {_SUN} */
 
 bool acpiphp_debug;
+bool acpiphp_disabled;
 
 /* local variables */
 static struct acpiphp_attention_info *attention_info;
@@ -61,7 +62,9 @@ MODULE_AUTHOR(DRIVER_AUTHOR);
 MODULE_DESCRIPTION(DRIVER_DESC);
 MODULE_LICENSE("GPL");
 MODULE_PARM_DESC(debug, "Debugging mode enabled or not");
+MODULE_PARM_DESC(disable, "disable acpiphp driver");
 module_param_named(debug, acpiphp_debug, bool, 0644);
+module_param_named(disable, acpiphp_disabled, bool, 0444);
 
 /* export the attention callback registration methods */
 EXPORT_SYMBOL_GPL(acpiphp_register_attention);
@@ -354,5 +357,6 @@ void acpiphp_unregister_hotplug_slot(struct acpiphp_slot *acpiphp_slot)
 
 void __init acpiphp_init(void)
 {
-	info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
+	info(DRIVER_DESC " version: " DRIVER_VERSION "%s\n",
+	     acpiphp_disabled ? ", disabled by user" : "");
 }
diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c
index 896d680..96fed19 100644
--- a/drivers/pci/hotplug/acpiphp_glue.c
+++ b/drivers/pci/hotplug/acpiphp_glue.c
@@ -1139,6 +1139,9 @@ void acpiphp_enumerate_slots(struct pci_bus *bus, acpi_handle handle)
 	acpi_handle dummy_handle;
 	struct acpiphp_bridge *bridge;
 
+	if (acpiphp_disabled)
+		return;
+
 	if (detect_ejectable_slots(handle) <= 0)
 		return;
 
@@ -1177,6 +1180,9 @@ void acpiphp_remove_slots(struct pci_bus *bus)
 {
 	struct acpiphp_bridge *bridge, *tmp;
 
+	if (acpiphp_disabled)
+		return;
+
 	list_for_each_entry_safe(bridge, tmp, &bridge_list, list)
 		if (bridge->pci_bus == bus) {
 			cleanup_bridge(bridge);
-- 
1.7.9.5