[PATCH] "nousb" for in-kernel USB

Here's the updated "nousb" patch for vanilla 2.5.41.
It applies with 2 small offsets to 2.5.41-bk3.

drivers/usb/core/hcd-pci.c

@@ -62,6 +62,9 @@ int usb_hcd_pci_probe (struct pci_dev *dev, const struct pci_device_id *id)
 	int			retval, region;
 	char			buf [8], *bufp = buf;
 
+	if (usb_disabled())
+		return -ENODEV;
+
 	if (!id || !(driver = (struct hc_driver *) id->driver_data))
 		return -EINVAL;
 

drivers/usb/core/usb.c

@@ -50,6 +50,9 @@ extern int usb_major_init(void);
 extern void usb_major_cleanup(void);
 
 
+int nousb;		/* Disable USB when built into kernel image */
+			/* Not honored on modular build */
+
 
 static int generic_probe (struct device *dev)
 {
@@ -167,6 +170,9 @@ int usb_register(struct usb_driver *new_driver)
 {
 	int retval = 0;
 
+	if (nousb)
+		return -ENODEV;
+
 	new_driver->driver.name = (char *)new_driver->name;
 	new_driver->driver.bus = &usb_bus_type;
 	new_driver->driver.probe = usb_device_probe;
@@ -1338,11 +1344,37 @@ struct bus_type usb_bus_type = {
 	.hotplug =	usb_hotplug,
 };
 
+#ifndef MODULE
+
+static int __init usb_setup_disable(char *str)
+{
+	nousb = 1;
+	return 1;
+}
+
+/* format to disable USB on kernel command line is: nousb */
+__setup("nousb", usb_setup_disable);
+
+#endif
+
+/*
+ * for external read access to <nousb>
+ */
+int usb_disabled(void)
+{
+	return nousb;
+}
+
 /*
  * Init
  */
 static int __init usb_init(void)
 {
+	if (nousb) {
+		info("USB support disabled\n");
+		return 0;
+	}
+
 	bus_register(&usb_bus_type);
 	usb_major_init();
 	usbfs_init();
@@ -1358,6 +1390,10 @@ static int __init usb_init(void)
  */
 static void __exit usb_exit(void)
 {
+	/* This will matter if shutdown/reboot does exitcalls. */
+	if (nousb)
+		return;
+
 	remove_driver(&usb_generic_driver);
 	usb_major_cleanup();
 	usbfs_cleanup();
@@ -1377,6 +1413,7 @@ EXPORT_SYMBOL(usb_epnum_to_ep_desc);
 
 EXPORT_SYMBOL(usb_register);
 EXPORT_SYMBOL(usb_deregister);
+EXPORT_SYMBOL(usb_disabled);
 
 EXPORT_SYMBOL(usb_device_probe);
 EXPORT_SYMBOL(usb_device_remove);

drivers/usb/host/ehci-hcd.c

@@ -985,6 +985,9 @@ MODULE_LICENSE ("GPL");
 static int __init init (void) 
 {
 	dbg (DRIVER_INFO);
+	if (usb_disabled())
+		return -ENODEV;
+
 	dbg ("block sizes: qh %Zd qtd %Zd itd %Zd sitd %Zd",
 		sizeof (struct ehci_qh), sizeof (struct ehci_qtd),
 		sizeof (struct ehci_itd), sizeof (struct ehci_sitd));

drivers/usb/host/hc_sl811.c

@@ -1321,6 +1321,9 @@ static int __init hci_hcd_init (void)
 	int ret;
 
 	DBGFUNC ("Enter hci_hcd_init\n");
+	if (usb_disabled())
+		return -ENODEV;
+
 	ret = hc_found_hci (base_addr, data_reg_addr, irq);
 
 	return ret;

drivers/usb/host/ohci-pci.c

@@ -365,6 +365,9 @@ static struct pci_driver ohci_pci_driver = {
 static int __init ohci_hcd_pci_init (void) 
 {
 	dbg (DRIVER_INFO " (PCI)");
+	if (usb_disabled())
+		return -ENODEV;
+
 	dbg ("block sizes: ed %d td %d",
 		sizeof (struct ed), sizeof (struct td));
 	return pci_module_init (&ohci_pci_driver);

drivers/usb/host/ohci-sa1111.c

@@ -23,6 +23,8 @@
 #error "This file is SA-1111 bus glue.  CONFIG_SA1111 must be defined."
 #endif
 
+extern int usb_disabled(void);
+
 /*-------------------------------------------------------------------------*/
 
 static void sa1111_start_hc(struct sa1111_dev *dev)
@@ -355,6 +357,9 @@ static int ohci_hcd_sa1111_drv_probe(struct device *_dev)
 	struct usb_hcd *hcd = NULL;
 	int ret;
 
+	if (usb_disabled())
+		return -ENODEV;
+
 	ret = usb_hcd_sa1111_probe(&ohci_sa1111_hc_driver, &hcd, dev);
 
 	if (ret == 0)

drivers/usb/host/uhci-hcd.c

@@ -2484,6 +2484,9 @@ static int __init uhci_hcd_init(void)
 
 	info(DRIVER_DESC " " DRIVER_VERSION);
 
+	if (usb_disabled())
+		return -ENODEV;
+
 	if (debug) {
 		errbuf = kmalloc(ERRBUF_LEN, GFP_KERNEL);
 		if (!errbuf)

include/linux/usb.h

@@ -670,6 +670,7 @@ extern void usb_deregister_dev(int num_minors, int start_minor);
 
 extern int usb_device_probe(struct device *dev);
 extern int usb_device_remove(struct device *dev);
+extern int usb_disabled(void);
 
 /* -------------------------------------------------------------------------- */