text: /*
   * Copyright (C) 2010 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  #ifndef __USB_HOST_H
  #define __USB_HOST_H
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  #include <stddef.h>
  #include <stdint.h>
  
  #include <linux/version.h>
  #if LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 20)
  #include <linux/usb/ch9.h>
  #else
  #include <linux/usb_ch9.h>
  #endif
  
  struct usb_host_context;
  struct usb_endpoint_descriptor;
  
  struct usb_descriptor_iter {
      unsigned char*  config;
      unsigned char*  config_end;
      unsigned char*  curr_desc;
  };
  
  struct usb_request
  {
      struct usb_device *dev;
      void* buffer;
      int buffer_length;
      int actual_length;
      int max_packet_size;
      void *private_data; /* struct usbdevfs_urb* */
      int endpoint;
      void *client_data;  /* free for use by client */
  };
  
  /* Callback for notification when new USB devices are attached.
   * Return true to exit from usb_host_run.
   */
  typedef int (* usb_device_added_cb)(const char *dev_name, void *client_data);
  
  /* Callback for notification when USB devices are removed.
   * Return true to exit from usb_host_run.
   */
  typedef int (* usb_device_removed_cb)(const char *dev_name, void *client_data);
  
  /* Callback indicating that initial device discovery is done.
   * Return true to exit from usb_host_run.
   */
  typedef int (* usb_discovery_done_cb)(void *client_data);
  
  /* Call this to initialize the USB host library. */
  struct usb_host_context *usb_host_init(void);
  
  /* Call this to cleanup the USB host library. */
  void usb_host_cleanup(struct usb_host_context *context);
  
  /* Call this to get the inotify file descriptor. */
  int usb_host_get_fd(struct usb_host_context *context);
  
  /* Call this to initialize the usb host context. */
  int usb_host_load(struct usb_host_context *context,
                    usb_device_added_cb added_cb,
                    usb_device_removed_cb removed_cb,
                    usb_discovery_done_cb discovery_done_cb,
                    void *client_data);
  
  /* Call this to read and handle occuring usb event. */
  int usb_host_read_event(struct usb_host_context *context);
  
  /* Call this to monitor the USB bus for new and removed devices.
   * This is intended to be called from a dedicated thread,
   * as it will not return until one of the callbacks returns true.
   * added_cb will be called immediately for each existing USB device,
   * and subsequently each time a new device is added.
   * removed_cb is called when USB devices are removed from the bus.
   * discovery_done_cb is called after the initial discovery of already
   * connected devices is complete.
   */
  void usb_host_run(struct usb_host_context *context,
                    usb_device_added_cb added_cb,
                    usb_device_removed_cb removed_cb,
                    usb_discovery_done_cb discovery_done_cb,
                    void *client_data);
  
  /* Creates a usb_device object for a USB device */
  struct usb_device *usb_device_open(const char *dev_name);
  
  /* Releases all resources associated with the USB device */
  void usb_device_close(struct usb_device *device);
  
  /* Creates a usb_device object for already open USB device */
  struct usb_device *usb_device_new(const char *dev_name, int fd);
  
  /* Returns the file descriptor for the usb_device */
  int usb_device_get_fd(struct usb_device *device);
  
  /* Returns the name for the USB device, which is the same as
   * the dev_name passed to usb_device_open()
   */
  const char* usb_device_get_name(struct usb_device *device);
  
  /* Returns a unique ID for the device.
   *Currently this is generated from the dev_name path.
   */
  int usb_device_get_unique_id(struct usb_device *device);
  
  /* Returns a unique ID for the device name.
   * Currently this is generated from the device path.
   */
  int usb_device_get_unique_id_from_name(const char* name);
  
  /* Returns the device name for the unique ID.
   * Call free() to deallocate the returned string */
  char* usb_device_get_name_from_unique_id(int id);
  
  /* Returns the USB vendor ID from the device descriptor for the USB device */
  uint16_t usb_device_get_vendor_id(struct usb_device *device);
  
  /* Returns the USB product ID from the device descriptor for the USB device */
  uint16_t usb_device_get_product_id(struct usb_device *device);
  
  /* Returns a pointer to device descriptor */
  const struct usb_device_descriptor* usb_device_get_device_descriptor(struct usb_device *device);
  
  /* Returns a USB descriptor string for the given string ID.
   * Return value: < 0 on error.  0 on success.
   * The string is returned in ucs2_out in USB-native UCS-2 encoding.
   *
   * parameters:
   *  id - the string descriptor index.
   *  timeout - in milliseconds (see Documentation/driver-api/usb/usb.rst)
   *  ucs2_out - Must point to null on call.
   *             Will be filled in with a buffer on success.
   *             If this is non-null on return, it must be free()d.
   *  response_size - size, in bytes, of ucs-2 string in ucs2_out.
   *                  The size isn't guaranteed to include null termination.
   * Call free() to free the result when you are done with it.
   */
  int usb_device_get_string_ucs2(struct usb_device* device, int id, int timeout, void** ucs2_out,
                                 size_t* response_size);
  
  /* Returns the length in bytes read into the raw descriptors array */
  size_t usb_device_get_descriptors_length(const struct usb_device* device);
  
  /* Returns a pointer to the raw descriptors array */
  const unsigned char* usb_device_get_raw_descriptors(const struct usb_device* device);
  
  /* Returns a USB descriptor string for the given string ID.
   * Used to implement usb_device_get_manufacturer_name,
   * usb_device_get_product_name and usb_device_get_serial.
   * Returns ascii - non ascii characters will be replaced with '?'.
   * Call free() to free the result when you are done with it.
   */
  char* usb_device_get_string(struct usb_device *device, int id, int timeout);
  
  /* Returns the manufacturer name for the USB device.
   * Call free() to free the result when you are done with it.
   */
  char* usb_device_get_manufacturer_name(struct usb_device *device, int timeout);
  
  /* Returns the product name for the USB device.
   * Call free() to free the result when you are done with it.
   */
  char* usb_device_get_product_name(struct usb_device *device, int timeout);
  
  /* Returns the version number for the USB device.
   */
  int usb_device_get_version(struct usb_device *device);
  
  /* Returns the USB serial number for the USB device.
   * Call free() to free the result when you are done with it.
   */
  char* usb_device_get_serial(struct usb_device *device, int timeout);
  
  /* Returns true if we have write access to the USB device,
   * and false if we only have access to the USB device configuration.
   */
  int usb_device_is_writeable(struct usb_device *device);
  
  /* Initializes a usb_descriptor_iter, which can be used to iterate through all
   * the USB descriptors for a USB device.
   */
  void usb_descriptor_iter_init(struct usb_device *device, struct usb_descriptor_iter *iter);
  
  /* Returns the next USB descriptor for a device, or NULL if we have reached the
   * end of the list.
   */
  struct usb_descriptor_header *usb_descriptor_iter_next(struct usb_descriptor_iter *iter);
  
  /* Claims the specified interface of a USB device */
  int usb_device_claim_interface(struct usb_device *device, unsigned int interface);
  
  /* Releases the specified interface of a USB device */
  int usb_device_release_interface(struct usb_device *device, unsigned int interface);
  
  /* Requests the kernel to connect or disconnect its driver for the specified interface.
   * This can be used to ask the kernel to disconnect its driver for a device
   * so usb_device_claim_interface can claim it instead.
   */
  int usb_device_connect_kernel_driver(struct usb_device *device,
                                       unsigned int interface, int connect);
  
  /* Sets the current configuration for the device to the specified configuration */
  int usb_device_set_configuration(struct usb_device *device, int configuration);
  
  /* Sets the specified interface of a USB device */
  int usb_device_set_interface(struct usb_device *device, unsigned int interface,
                               unsigned int alt_setting);
  
  /* Sends a control message to the specified device on endpoint zero */
  int usb_device_control_transfer(struct usb_device *device,
                                  int requestType,
                                  int request,
                                  int value,
                                  int index,
                                  void* buffer,
                                  int length,
                                  unsigned int timeout);
  
  /* Reads or writes on a bulk endpoint.
   * Returns number of bytes transferred, or negative value for error.
   */
  int usb_device_bulk_transfer(struct usb_device *device,
                               int endpoint,
                               void* buffer,
                               unsigned int length,
                               unsigned int timeout);
  
  /** Reset USB bus for the device */
  int usb_device_reset(struct usb_device *device);
  
  /* Creates a new usb_request. */
  struct usb_request *usb_request_new(struct usb_device *dev,
                                      const struct usb_endpoint_descriptor *ep_desc);
  
  /* Releases all resources associated with the request */
  void usb_request_free(struct usb_request *req);
  
  /* Submits a read or write request on the specified device */
  int usb_request_queue(struct usb_request *req);
  
  /* Waits for the results of a previous usb_request_queue operation. timeoutMillis == -1 requests
   * to wait forever.
   * Returns a usb_request, or NULL for error.
   */
  struct usb_request *usb_request_wait(struct usb_device *dev, int timeoutMillis);
  
  /* Cancels a pending usb_request_queue() operation. */
  int usb_request_cancel(struct usb_request *req);
  
  #ifdef __cplusplus
  }
  #endif
  #endif /* __USB_HOST_H */
  