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authorAlan Stern <stern@rowland.harvard.edu>2007-05-30 23:39:33 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2007-07-13 03:34:30 +0400
commitb41a60eca833d76593d4dac8a59f5c38714194ee (patch)
treea7c5cf721d9978503c3c8c88183747cf954b8733 /drivers/usb/core/sysfs.c
parent54515fe528d8c6f9bfaf7d0b9fffb908deecad78 (diff)
downloadlinux-b41a60eca833d76593d4dac8a59f5c38714194ee.tar.xz
USB: add power/persist device attribute
This patch (as920) adds an extra level of protection to the USB-Persist facility. Now it will apply by default only to hubs; for all other devices the user must enable it explicitly by setting the power/persist device attribute. The disconnect_all_children() routine in hub.c has been removed and its code placed inline. This is the way it was originally as part of hub_pre_reset(); the revised usage in hub_reset_resume() is sufficiently different that the code can no longer be shared. Likewise, mark_children_for_reset() is now inline as part of hub_reset_resume(). The end result looks much cleaner than before. The sysfs interface is updated to add the new attribute file, and there are corresponding documentation updates. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/core/sysfs.c')
-rw-r--r--drivers/usb/core/sysfs.c75
1 files changed, 73 insertions, 2 deletions
diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
index be37c863fdfb..5dfe31bc32ba 100644
--- a/drivers/usb/core/sysfs.c
+++ b/drivers/usb/core/sysfs.c
@@ -169,6 +169,73 @@ show_quirks(struct device *dev, struct device_attribute *attr, char *buf)
}
static DEVICE_ATTR(quirks, S_IRUGO, show_quirks, NULL);
+
+#if defined(CONFIG_USB_PERSIST) || defined(CONFIG_USB_SUSPEND)
+static const char power_group[] = "power";
+#endif
+
+#ifdef CONFIG_USB_PERSIST
+
+static ssize_t
+show_persist(struct device *dev, struct device_attribute *attr, char *buf)
+{
+ struct usb_device *udev = to_usb_device(dev);
+
+ return sprintf(buf, "%d\n", udev->persist_enabled);
+}
+
+static ssize_t
+set_persist(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct usb_device *udev = to_usb_device(dev);
+ int value;
+
+ /* Hubs are always enabled for USB_PERSIST */
+ if (udev->descriptor.bDeviceClass == USB_CLASS_HUB)
+ return -EPERM;
+
+ if (sscanf(buf, "%d", &value) != 1)
+ return -EINVAL;
+ usb_pm_lock(udev);
+ udev->persist_enabled = !!value;
+ usb_pm_unlock(udev);
+ return count;
+}
+
+static DEVICE_ATTR(persist, S_IRUGO | S_IWUSR, show_persist, set_persist);
+
+static int add_persist_attributes(struct device *dev)
+{
+ int rc = 0;
+
+ if (is_usb_device(dev)) {
+ struct usb_device *udev = to_usb_device(dev);
+
+ /* Hubs are automatically enabled for USB_PERSIST */
+ if (udev->descriptor.bDeviceClass == USB_CLASS_HUB)
+ udev->persist_enabled = 1;
+ rc = sysfs_add_file_to_group(&dev->kobj,
+ &dev_attr_persist.attr,
+ power_group);
+ }
+ return rc;
+}
+
+static void remove_persist_attributes(struct device *dev)
+{
+ sysfs_remove_file_from_group(&dev->kobj,
+ &dev_attr_persist.attr,
+ power_group);
+}
+
+#else
+
+#define add_persist_attributes(dev) 0
+#define remove_persist_attributes(dev) do {} while (0)
+
+#endif /* CONFIG_USB_PERSIST */
+
#ifdef CONFIG_USB_SUSPEND
static ssize_t
@@ -276,8 +343,6 @@ set_level(struct device *dev, struct device_attribute *attr,
static DEVICE_ATTR(level, S_IRUGO | S_IWUSR, show_level, set_level);
-static char power_group[] = "power";
-
static int add_power_attributes(struct device *dev)
{
int rc = 0;
@@ -311,6 +376,7 @@ static void remove_power_attributes(struct device *dev)
#endif /* CONFIG_USB_SUSPEND */
+
/* Descriptor fields */
#define usb_descriptor_attr_le16(field, format_string) \
static ssize_t \
@@ -384,6 +450,10 @@ int usb_create_sysfs_dev_files(struct usb_device *udev)
if (retval)
return retval;
+ retval = add_persist_attributes(dev);
+ if (retval)
+ goto error;
+
retval = add_power_attributes(dev);
if (retval)
goto error;
@@ -421,6 +491,7 @@ void usb_remove_sysfs_dev_files(struct usb_device *udev)
device_remove_file(dev, &dev_attr_product);
device_remove_file(dev, &dev_attr_serial);
remove_power_attributes(dev);
+ remove_persist_attributes(dev);
sysfs_remove_group(&dev->kobj, &dev_attr_grp);
}