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-rw-r--r--include/linux/usb/gadgetfs.h81
1 files changed, 81 insertions, 0 deletions
diff --git a/include/linux/usb/gadgetfs.h b/include/linux/usb/gadgetfs.h
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+++ b/include/linux/usb/gadgetfs.h
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+#ifndef __LINUX_USB_GADGETFS_H
+#define __LINUX_USB_GADGETFS_H
+
+#include <asm/types.h>
+#include <asm/ioctl.h>
+
+#include <linux/usb/ch9.h>
+
+/*
+ * Filesystem based user-mode API to USB Gadget controller hardware
+ *
+ * Other than ep0 operations, most things are done by read() and write()
+ * on endpoint files found in one directory. They are configured by
+ * writing descriptors, and then may be used for normal stream style
+ * i/o requests. When ep0 is configured, the device can enumerate;
+ * when it's closed, the device disconnects from usb. Operations on
+ * ep0 require ioctl() operations.
+ *
+ * Configuration and device descriptors get written to /dev/gadget/$CHIP,
+ * which may then be used to read usb_gadgetfs_event structs. The driver
+ * may activate endpoints as it handles SET_CONFIGURATION setup events,
+ * or earlier; writing endpoint descriptors to /dev/gadget/$ENDPOINT
+ * then performing data transfers by reading or writing.
+ */
+
+/*
+ * Events are delivered on the ep0 file descriptor, when the user mode driver
+ * reads from this file descriptor after writing the descriptors. Don't
+ * stop polling this descriptor.
+ */
+
+enum usb_gadgetfs_event_type {
+ GADGETFS_NOP = 0,
+
+ GADGETFS_CONNECT,
+ GADGETFS_DISCONNECT,
+ GADGETFS_SETUP,
+ GADGETFS_SUSPEND,
+ // and likely more !
+};
+
+/* NOTE: this structure must stay the same size and layout on
+ * both 32-bit and 64-bit kernels.
+ */
+struct usb_gadgetfs_event {
+ union {
+ // NOP, DISCONNECT, SUSPEND: nothing
+ // ... some hardware can't report disconnection
+
+ // CONNECT: just the speed
+ enum usb_device_speed speed;
+
+ // SETUP: packet; DATA phase i/o precedes next event
+ // (setup.bmRequestType & USB_DIR_IN) flags direction
+ // ... includes SET_CONFIGURATION, SET_INTERFACE
+ struct usb_ctrlrequest setup;
+ } u;
+ enum usb_gadgetfs_event_type type;
+};
+
+
+/* endpoint ioctls */
+
+/* IN transfers may be reported to the gadget driver as complete
+ * when the fifo is loaded, before the host reads the data;
+ * OUT transfers may be reported to the host's "client" driver as
+ * complete when they're sitting in the FIFO unread.
+ * THIS returns how many bytes are "unclaimed" in the endpoint fifo
+ * (needed for precise fault handling, when the hardware allows it)
+ */
+#define GADGETFS_FIFO_STATUS _IO('g',1)
+
+/* discards any unclaimed data in the fifo. */
+#define GADGETFS_FIFO_FLUSH _IO('g',2)
+
+/* resets endpoint halt+toggle; used to implement set_interface.
+ * some hardware (like pxa2xx) can't support this.
+ */
+#define GADGETFS_CLEAR_HALT _IO('g',3)
+
+#endif /* __LINUX_USB_GADGETFS_H */