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Diffstat (limited to 'include/usb_device.h')
| -rw-r--r-- | include/usb_device.h | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/include/usb_device.h b/include/usb_device.h new file mode 100644 index 000000000..ed8187bb3 --- /dev/null +++ b/include/usb_device.h @@ -0,0 +1,181 @@ +/* + * This file is part of the flashrom project. + * + * Copyright (C) 2020, Google Inc. All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#ifndef USB_DEVICE_H +#define USB_DEVICE_H + +/* + * USB device matching framework + * + * This can be used to match a USB device by a number of different parameters. + * The parameters can be passed on the command line and defaults can be set + * by the programmer. + */ + +#include <libusb.h> +#include <stdint.h> +#include <stdbool.h> + +/* + * The LIBUSB_ERROR macro converts a libusb failure code into an error code that + * flashrom recognizes. It does so without displaying an error code allowing us + * to compare error codes against the library enumeration values. + */ +#define LIBUSB_ERROR(error_code) (0x20000 | -(error_code)) + +/* + * The LIBUSB macro converts a libusb failure code into an error code that + * flashrom recognizes. It also displays additional libusb specific + * information about the failure. + */ +#define LIBUSB(expression) \ + ({ \ + int libusb_error__ = (expression); \ + \ + if (libusb_error__ < 0) { \ + msg_perr("libusb error: %s:%d %s\n", \ + __FILE__, \ + __LINE__, \ + libusb_error_name(libusb_error__)); \ + libusb_error__ = LIBUSB_ERROR(libusb_error__); \ + } else { \ + libusb_error__ = 0; \ + } \ + \ + libusb_error__; \ + }) + +/* + * Returns true if the error code falls within the range of valid libusb + * error codes. + */ +static inline bool usb_device_is_libusb_error(int error_code) +{ + return (0x20000 <= error_code && error_code < 0x20064); +} + +/* + * A USB match and associated value struct are used to encode the information + * about a device against which we wish to match. If the value of a + * usb_match_value has been set then a device must match that value. The name + * of the usb_match_value is used to fetch the programmer parameter from the + * flashrom command line and is the same as the name of the corresponding + * field in usb_match. + */ +struct usb_match_value { + char const *name; + int value; + int set; +}; + +struct usb_match { + struct usb_match_value bus; + struct usb_match_value address; + struct usb_match_value vid; + struct usb_match_value pid; + struct usb_match_value serial; + struct usb_match_value config; + struct usb_match_value interface; + struct usb_match_value altsetting; + struct usb_match_value class; + struct usb_match_value subclass; + struct usb_match_value protocol; +}; + +/* + * Initialize a usb_match structure so that each value's name matches the + * values name in the usb_match structure (so bus.name == "bus"...), and + * look for each value in the flashrom command line via + * extract_programmer_param_str. If the value is found convert it to an integer + * using strtol, accepting hex, decimal and octal encoding. + */ +void usb_match_init(const struct programmer_cfg *cfg, struct usb_match *match); + +/* + * Add a default value to a usb_match_value. This must be done after calling + * usb_match_init. If usb_match_init already set the value of a usb_match_value + * we do nothing, otherwise set the value to default_value. This ensures that + * parameters passed on the command line override defaults. + */ +void usb_match_value_default(struct usb_match_value *match, + long int default_value); + +/* + * The usb_device structure is an entry in a linked list of devices that were + * matched by usb_device_find. + */ +struct usb_device { + struct libusb_device *device; + struct libusb_config_descriptor *config_descriptor; + struct libusb_interface_descriptor const *interface_descriptor; + + /* + * Initially NULL, the libusb_device_handle is only valid once the + * usb_device has been successfully passed to usb_device_show or + * usb_device_claim. + */ + struct libusb_device_handle *handle; + + /* + * Link to next device, or NULL + */ + struct usb_device *next; +}; + +/* + * Find and return a list of all compatible devices. Each device is added to + * the list with its first valid configuration and interface. If an alternate + * configuration (config, interface, altsetting...) is desired the specifics + * can be supplied as programmer parameters. + * + * Return: + * 0: At least one matching device was found. + * 1: No matching devices were found. + */ +int usb_device_find(struct usb_match const *match, struct usb_device **devices); + +/* + * Display the devices bus and address as well as its product string. The + * underlying libusb device is opened if it is not already open. + * + * Return: + * 0: The device information was displayed. + * non-zero: There was a failure while displaying the device information. + */ +int usb_device_show(char const *prefix, struct usb_device *device); + +/* + * Open the underlying libusb device, set its config, claim the interface and + * select the correct alternate interface. + * + * Return: + * 0: The device was successfully claimed. + * non-zero: There was a failure while trying to claim the device. + */ +int usb_device_claim(struct usb_device *device); + +/* + * Free a usb_device structure. + * + * This ensures that the libusb device is closed and that all allocated + * handles and descriptors are freed. + * + * Return: + * The next device in the device list. + */ +struct usb_device *usb_device_free(struct usb_device *device); + +#endif /* USB_DEVICE_H */ |