PCI: acpiphp: Convert acpiphp to be builtin only, not modular

Convert acpiphp to be builtin only, with no module option.

Previously, when HOTPLUG_PCI_ACPI=m, users could disable acpiphp by
removing the module or preventing it from loading.  That can't be done
if acpiphp is builtin statically, so this adds an "acpiphp.disable"
kernel parameter.  If a user needs to use this parameter, it is a bug,
and we want to hear about it.

[bhelgaas: fold in acpiphp.disable here, remove documentation]
Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/hotplug/Kconfig

@@ -52,15 +52,12 @@ config HOTPLUG_PCI_IBM
 	  When in doubt, say N.
 
 config HOTPLUG_PCI_ACPI
-	tristate "ACPI PCI Hotplug driver"
-	depends on (!ACPI_DOCK && ACPI) || (ACPI_DOCK)
+	bool "ACPI PCI Hotplug driver"
+	depends on HOTPLUG_PCI=y && ((!ACPI_DOCK && ACPI) || (ACPI_DOCK))
 	help
 	  Say Y here if you have a system that supports PCI Hotplug using
 	  ACPI.
 
-	  To compile this driver as a module, choose M here: the
-	  module will be called acpiphp.
-
 	  When in doubt, say N.
 
 config HOTPLUG_PCI_ACPI_IBM

drivers/pci/hotplug/acpiphp.h

@@ -190,5 +190,6 @@ extern u8 acpiphp_get_adapter_status (struct acpiphp_slot *slot);
 
 /* variables */
 extern bool acpiphp_debug;
+extern bool acpiphp_disabled;
 
 #endif /* _ACPIPHP_H */

drivers/pci/hotplug/acpiphp_core.c

@@ -48,6 +48,7 @@
 #define SLOT_NAME_SIZE  21              /* {_SUN} */
 
 bool acpiphp_debug;
+bool acpiphp_disabled;
 
 /* local variables */
 static struct acpiphp_attention_info *attention_info;
@@ -60,7 +61,9 @@ 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);
@@ -353,9 +356,11 @@ void acpiphp_unregister_hotplug_slot(struct acpiphp_slot *acpiphp_slot)
 
 static int __init acpiphp_init(void)
 {
-	info(DRIVER_DESC " version: " DRIVER_VERSION "\n");
+	info(DRIVER_DESC " version: " DRIVER_VERSION "%s\n",
+		acpiphp_disabled ? ", disabled by user; please report a bug"
+				 : "");
 
-	if (acpi_pci_disabled)
+	if (acpi_pci_disabled || acpiphp_disabled)
 		return 0;
 
 	/* read all the ACPI info from the system */
@@ -364,14 +369,4 @@ static int __init acpiphp_init(void)
 }
 
 
-static void __exit acpiphp_exit(void)
-{
-	if (acpi_pci_disabled)
-		return;
-
-	/* deallocate internal data structures etc. */
-	acpiphp_glue_exit();
-}
-
 module_init(acpiphp_init);
-module_exit(acpiphp_exit);