usb: core: Add "quirks" parameter for usbcore

Trying quirks in usbcore needs to rebuild the driver or the entire
kernel if it's builtin. It can save a lot of time if usbcore has similar
ability like "usbhid.quirks=" and "usb-storage.quirks=".

Rename the original quirk detection function to "static" as we introduce
this new "dynamic" function.

Now users can use "usbcore.quirks=" as short term workaround before the
next kernel release. Also, the quirk parameter can XOR the builtin
quirks for debugging purpose.

This is inspired by usbhid and usb-storage.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/usb/core/quirks.c

@@ -6,11 +6,149 @@
  * Copyright (c) 2007 Greg Kroah-Hartman <gregkh@suse.de>
  */
 
+#include <linux/moduleparam.h>
 #include <linux/usb.h>
 #include <linux/usb/quirks.h>
 #include <linux/usb/hcd.h>
 #include "usb.h"
 
+struct quirk_entry {
+	u16 vid;
+	u16 pid;
+	u32 flags;
+};
+
+static DEFINE_MUTEX(quirk_mutex);
+
+static struct quirk_entry *quirk_list;
+static unsigned int quirk_count;
+
+static char quirks_param[128];
+
+static int quirks_param_set(const char *val, const struct kernel_param *kp)
+{
+	char *p, *field;
+	u16 vid, pid;
+	u32 flags;
+	size_t i;
+
+	mutex_lock(&quirk_mutex);
+
+	if (!val || !*val) {
+		quirk_count = 0;
+		kfree(quirk_list);
+		quirk_list = NULL;
+		goto unlock;
+	}
+
+	for (quirk_count = 1, i = 0; val[i]; i++)
+		if (val[i] == ',')
+			quirk_count++;
+
+	if (quirk_list) {
+		kfree(quirk_list);
+		quirk_list = NULL;
+	}
+
+	quirk_list = kcalloc(quirk_count, sizeof(struct quirk_entry),
+			     GFP_KERNEL);
+	if (!quirk_list) {
+		mutex_unlock(&quirk_mutex);
+		return -ENOMEM;
+	}
+
+	for (i = 0, p = (char *)val; p && *p;) {
+		/* Each entry consists of VID:PID:flags */
+		field = strsep(&p, ":");
+		if (!field)
+			break;
+
+		if (kstrtou16(field, 16, &vid))
+			break;
+
+		field = strsep(&p, ":");
+		if (!field)
+			break;
+
+		if (kstrtou16(field, 16, &pid))
+			break;
+
+		field = strsep(&p, ",");
+		if (!field || !*field)
+			break;
+
+		/* Collect the flags */
+		for (flags = 0; *field; field++) {
+			switch (*field) {
+			case 'a':
+				flags |= USB_QUIRK_STRING_FETCH_255;
+				break;
+			case 'b':
+				flags |= USB_QUIRK_RESET_RESUME;
+				break;
+			case 'c':
+				flags |= USB_QUIRK_NO_SET_INTF;
+				break;
+			case 'd':
+				flags |= USB_QUIRK_CONFIG_INTF_STRINGS;
+				break;
+			case 'e':
+				flags |= USB_QUIRK_RESET;
+				break;
+			case 'f':
+				flags |= USB_QUIRK_HONOR_BNUMINTERFACES;
+				break;
+			case 'g':
+				flags |= USB_QUIRK_DELAY_INIT;
+				break;
+			case 'h':
+				flags |= USB_QUIRK_LINEAR_UFRAME_INTR_BINTERVAL;
+				break;
+			case 'i':
+				flags |= USB_QUIRK_DEVICE_QUALIFIER;
+				break;
+			case 'j':
+				flags |= USB_QUIRK_IGNORE_REMOTE_WAKEUP;
+				break;
+			case 'k':
+				flags |= USB_QUIRK_NO_LPM;
+				break;
+			case 'l':
+				flags |= USB_QUIRK_LINEAR_FRAME_INTR_BINTERVAL;
+				break;
+			case 'm':
+				flags |= USB_QUIRK_DISCONNECT_SUSPEND;
+				break;
+			/* Ignore unrecognized flag characters */
+			}
+		}
+
+		quirk_list[i++] = (struct quirk_entry)
+			{ .vid = vid, .pid = pid, .flags = flags };
+	}
+
+	if (i < quirk_count)
+		quirk_count = i;
+
+unlock:
+	mutex_unlock(&quirk_mutex);
+
+	return param_set_copystring(val, kp);
+}
+
+static const struct kernel_param_ops quirks_param_ops = {
+	.set = quirks_param_set,
+	.get = param_get_string,
+};
+
+static struct kparam_string quirks_param_string = {
+	.maxlen = sizeof(quirks_param),
+	.string = quirks_param,
+};
+
+module_param_cb(quirks, &quirks_param_ops, &quirks_param_string, 0644);
+MODULE_PARM_DESC(quirks, "Add/modify USB quirks by specifying quirks=vendorID:productID:quirks");
+
 /* Lists of quirky USB devices, split in device quirks and interface quirks.
  * Device quirks are applied at the very beginning of the enumeration process,
  * right after reading the device descriptor. They can thus only match on device
@@ -321,8 +459,8 @@ static int usb_amd_resume_quirk(struct usb_device *udev)
 	return 0;
 }
 
-static u32 __usb_detect_quirks(struct usb_device *udev,
-			       const struct usb_device_id *id)
+static u32 usb_detect_static_quirks(struct usb_device *udev,
+				    const struct usb_device_id *id)
 {
 	u32 quirks = 0;
 
@@ -340,21 +478,43 @@ static u32 __usb_detect_quirks(struct usb_device *udev,
 	return quirks;
 }
 
+static u32 usb_detect_dynamic_quirks(struct usb_device *udev)
+{
+	u16 vid = le16_to_cpu(udev->descriptor.idVendor);
+	u16 pid = le16_to_cpu(udev->descriptor.idProduct);
+	int i, flags = 0;
+
+	mutex_lock(&quirk_mutex);
+
+	for (i = 0; i < quirk_count; i++) {
+		if (vid == quirk_list[i].vid && pid == quirk_list[i].pid) {
+			flags = quirk_list[i].flags;
+			break;
+		}
+	}
+
+	mutex_unlock(&quirk_mutex);
+
+	return flags;
+}
+
 /*
  * Detect any quirks the device has, and do any housekeeping for it if needed.
  */
 void usb_detect_quirks(struct usb_device *udev)
 {
-	udev->quirks = __usb_detect_quirks(udev, usb_quirk_list);
+	udev->quirks = usb_detect_static_quirks(udev, usb_quirk_list);
 
 	/*
 	 * Pixart-based mice would trigger remote wakeup issue on AMD
 	 * Yangtze chipset, so set them as RESET_RESUME flag.
 	 */
 	if (usb_amd_resume_quirk(udev))
-		udev->quirks |= __usb_detect_quirks(udev,
+		udev->quirks |= usb_detect_static_quirks(udev,
 				usb_amd_resume_quirk_list);
 
+	udev->quirks ^= usb_detect_dynamic_quirks(udev);
+
 	if (udev->quirks)
 		dev_dbg(&udev->dev, "USB quirks for this device: %x\n",
 			udev->quirks);
@@ -373,7 +533,7 @@ void usb_detect_interface_quirks(struct usb_device *udev)
 {
 	u32 quirks;
 
-	quirks = __usb_detect_quirks(udev, usb_interface_quirk_list);
+	quirks = usb_detect_static_quirks(udev, usb_interface_quirk_list);
 	if (quirks == 0)
 		return;
 
@@ -381,3 +541,11 @@ void usb_detect_interface_quirks(struct usb_device *udev)
 		quirks);
 	udev->quirks |= quirks;
 }
+
+void usb_release_quirk_list(void)
+{
+	mutex_lock(&quirk_mutex);
+	kfree(quirk_list);
+	quirk_list = NULL;
+	mutex_unlock(&quirk_mutex);
+}

drivers/usb/core/usb.c

@@ -1259,6 +1259,7 @@ static void __exit usb_exit(void)
 	if (usb_disabled())
 		return;
 
+	usb_release_quirk_list();
 	usb_deregister_device_driver(&usb_generic_driver);
 	usb_major_cleanup();
 	usb_deregister(&usbfs_driver);

drivers/usb/core/usb.h

@@ -36,6 +36,7 @@ extern void usb_deauthorize_interface(struct usb_interface *);
 extern void usb_authorize_interface(struct usb_interface *);
 extern void usb_detect_quirks(struct usb_device *udev);
 extern void usb_detect_interface_quirks(struct usb_device *udev);
+extern void usb_release_quirk_list(void);
 extern int usb_remove_device(struct usb_device *udev);
 
 extern int usb_get_device_descriptor(struct usb_device *dev,