Feature control mechanism allows addition of dynamic features to
gadgetfs.
It provides a user-mode driver the ability to control those
features, by querying the supported and enabled features and
enable/disable features in runtime via ioctl on ep0 fd.
All user operations are done on the entire set of features.
e.g. in order to check a specific feature, a user needs to read
the supported and enabled features, set the desired bitmap on
the read bitmap and call the "set enabled features" ioctl with
the modified bitmap.
Signed-off-by: Binyamin Sharet <bsharet@xxxxxxxxx>
---
drivers/usb/gadget/legacy/inode.c | 120
+++++++++++++++++++++++++++++++++++++-
include/uapi/linux/usb/gadgetfs.h | 42 +++++++++++++
2 files changed, 160 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/gadget/legacy/inode.c
b/drivers/usb/gadget/legacy/inode.c
index 16104b5e..ba2f6f4 100644
--- a/drivers/usb/gadget/legacy/inode.c
+++ b/drivers/usb/gadget/legacy/inode.c
@@ -77,6 +77,8 @@ MODULE_LICENSE ("GPL");
static int ep_open(struct inode *, struct file *);
+static bool feature_set(struct usb_gadgetfs_features *,
+ enum usb_gadgetfs_feature_bits feature);
/*----------------------------------------------------------------------*/
@@ -144,6 +146,8 @@ struct dev_data {
wait_queue_head_t wait;
struct super_block *sb;
struct dentry *dentry;
+ struct usb_gadgetfs_features enabled_features;
+ struct usb_gadgetfs_features supported_features;
/* except this scratch i/o buffer for ep0 */
u8 rbuf [256];
@@ -175,6 +179,9 @@ static struct dev_data *dev_new (void)
spin_lock_init (&dev->lock);
INIT_LIST_HEAD (&dev->epfiles);
init_waitqueue_head (&dev->wait);
+ feature_set(&dev->supported_features,
+ GADGETFS_FEATURE_FEATURES0_SUPPORTED);
+
return dev;
}
@@ -1235,14 +1242,120 @@ out:
return mask;
}
+/* feature control */
+
+/* get a features unit, e.g. one u64 bitmap */
+static u64 *
+features_get_unit(struct usb_gadgetfs_features *features,
+ enum usb_gadgetfs_feature_bits feature_bit)
+{
+ if (feature_bit < GADGETFS_FEATURE_RESERVED)
+ if ((feature_bit / 64) == 0)
+ return &features->features0;
+ return NULL;
+}
+
+#ifdef CONFIG_USB_GADGETFS_ALLOW_DELEGATE_DESCRIPTORS
+/* check if a feature is set in a feature bitmap */
+static bool
+feature_is_set(struct usb_gadgetfs_features *features,
+ enum usb_gadgetfs_feature_bits feature_bit)
+{
+ u64 *p_unit;
+ u64 feature_mask;
+
+ p_unit = features_get_unit(features, feature_bit);
+ if (p_unit == NULL)
+ return false;
+ feature_mask = 1 << (feature_bit % 64);
+ return (*p_unit & feature_mask) != 0;
+}
+#endif
+
+#ifdef CONFIG_USB_GADGETFS_ALLOW_DELEGATE_DESCRIPTORS
+/* clear a feature in a feature bitmap */
+static bool
+feature_clear(struct usb_gadgetfs_features *features,
+ enum usb_gadgetfs_feature_bits feature_bit)
+{
+ u64 *p_unit;
+ u64 feature_mask;
+
+ p_unit = features_get_unit(features, feature_bit);
+ if (p_unit == NULL)
+ return false;
+ if (feature_bit == GADGETFS_FEATURE_FEATURES0_SUPPORTED)
+ return false;
+ feature_mask = 1 << (feature_bit % 64);
+ *p_unit &= ~feature_mask;
+ return true;
+}
+#endif
+
+/* set a feature in a feature bitmap */
+static bool
+feature_set(struct usb_gadgetfs_features *features,
+ enum usb_gadgetfs_feature_bits feature_bit)
+{
+ u64 *p_unit;
+ u64 feature_mask;
+
+ p_unit = features_get_unit(features, feature_bit);
+ if (p_unit == NULL)
+ return false;
+ feature_mask = 1 << (feature_bit % 64);
+ *p_unit |= feature_mask;
+ return true;
+}
+
+/* set features based on user input */
+static void
+set_user_features(struct dev_data *dev, struct usb_gadgetfs_features *src)
+{
+ /* only set supported features */
+ src->features0 &= dev->supported_features.features0;
+ /* always set FEATURES0 */
+ src->features0 |= (1 << GADGETFS_FEATURE_FEATURES0_SUPPORTED);
+ dev->enabled_features.features0 = src->features0;
+}
+
static long dev_ioctl (struct file *fd, unsigned code, unsigned long value)
{
struct dev_data *dev = fd->private_data;
struct usb_gadget *gadget = dev->gadget;
long ret = -ENOTTY;
- if (gadget->ops->ioctl)
- ret = gadget->ops->ioctl (gadget, code, value);
+ switch (code) {
+ case GADGETFS_GET_SUPPORTED_FEATURES:
+ ret = copy_to_user((void *)value, &dev->supported_features,
+ sizeof(dev->supported_features));
+ if (ret != 0)
+ ret = -EFAULT;
+ break;
+ case GADGETFS_GET_ENABLED_FEATURES:
+ ret = copy_to_user((void *)value, &dev->enabled_features,
+ sizeof(dev->enabled_features));
+ if (ret != 0)
+ ret = -EFAULT;
+ break;
+ case GADGETFS_SET_ENABLED_FEATURES:
+ {
+ struct usb_gadgetfs_features user_features;
+
+ ret = copy_from_user(&user_features, (void *)value,
+ sizeof(user_features));
+ if (ret != 0)
+ ret = -EFAULT;
+ else
+ set_user_features(dev, &user_features);
+ }
+ break;
+ default:
+ /* pass unknown ioctl codes to UDC */
+ if (gadget && gadget->ops && gadget->ops->ioctl)
+ ret = gadget->ops->ioctl(gadget, code, value);
+ break;
+ }
return ret;
}
@@ -1859,6 +1972,9 @@ dev_open (struct inode *inode, struct file *fd)
dev->ev_next = 0;
dev->state = STATE_DEV_OPENED;
fd->private_data = dev;
+ feature_set(&dev->enabled_features,
+ GADGETFS_FEATURE_FEATURES0_SUPPORTED);
+
get_dev (dev);
value = 0;
}
diff --git a/include/uapi/linux/usb/gadgetfs.h
b/include/uapi/linux/usb/gadgetfs.h
index 0bb12e0..3abe3d3 100644
--- a/include/uapi/linux/usb/gadgetfs.h
+++ b/include/uapi/linux/usb/gadgetfs.h
@@ -85,4 +85,46 @@ struct usb_gadgetfs_event {
*/
#define GADGETFS_CLEAR_HALT _IO('g', 3)
+/* GadgetFS features.
+ * each feature is the bit number in the feature bitmap
+ */
+enum usb_gadgetfs_feature_bits {
+ /* indicates that gadgetfs supports features
+ * This should always be on
+ */
+ GADGETFS_FEATURE_FEATURES0_SUPPORTED,
+ /* reserved features.
+ * any new feature should be added BEFORE this one.
+ */
+ GADGETFS_FEATURE_RESERVED
+};
+
+struct usb_gadgetfs_features {
+ uint64_t features0;
+ /* keep 24 bytes reserved for possible future usage */
+ uint8_t RESERVED[24];
+};
+
+/* device ioctls */
+
+/*
+ * Those IOCTLs are called on the control endpoint fd.
+ */
+
+/*
+ * Returns the supported features bitmap
+ */
+#define GADGETFS_GET_SUPPORTED_FEATURES _IOW('g', 0x10, \
+ struct usb_gadgetfs_features)
+
+/*
+ * Returns enabled features as a bitmap
+ */
+#define GADGETFS_GET_ENABLED_FEATURES _IOW('g', 0x11, \
+ struct usb_gadgetfs_features)
+
+/* sets the enabled features bitmap */
+#define GADGETFS_SET_ENABLED_FEATURES _IOR('g', 0x12, \
+ struct usb_gadgetfs_features)
+
#endif /* __LINUX_USB_GADGETFS_H */
--
2.5.0
--
Binyamin Sharet,
Cisco, STARE-C
--
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