linux/drivers/usb/core/devices.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * devices.c
 * (C) Copyright 1999 Randy Dunlap.
 * (C) Copyright 1999,2000 Thomas Sailer <[email protected]>.
 *     (proc file per device)
 * (C) Copyright 1999 Deti Fliegl (new USB architecture)
 *
 *************************************************************
 *
 * <mountpoint>/devices contains USB topology, device, config, class,
 * interface, & endpoint data.
 *
 * I considered using /dev/bus/usb/device# for each device
 * as it is attached or detached, but I didn't like this for some
 * reason -- maybe it's just too deep of a directory structure.
 * I also don't like looking in multiple places to gather and view
 * the data.  Having only one file for ./devices also prevents race
 * conditions that could arise if a program was reading device info
 * for devices that are being removed (unplugged).  (That is, the
 * program may find a directory for devnum_12 then try to open it,
 * but it was just unplugged, so the directory is now deleted.
 * But programs would just have to be prepared for situations like
 * this in any plug-and-play environment.)
 *
 * 1999-12-16: Thomas Sailer <[email protected]>
 *   Converted the whole proc stuff to real
 *   read methods. Now not the whole device list needs to fit
 *   into one page, only the device list for one bus.
 *   Added a poll method to /sys/kernel/debug/usb/devices, to wake
 *   up an eventual usbd
 * 2000-01-04: Thomas Sailer <[email protected]>
 *   Turned into its own filesystem
 * 2000-07-05: Ashley Montanaro <[email protected]>
 *   Converted file reading routine to dump to buffer once
 *   per device, not per bus
 */

#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/gfp.h>
#include <linux/usb.h>
#include <linux/usbdevice_fs.h>
#include <linux/usb/hcd.h>
#include <linux/mutex.h>
#include <linux/uaccess.h>

#include "usb.h"

/* Define ALLOW_SERIAL_NUMBER if you want to see the serial number of devices */
#define ALLOW_SERIAL_NUMBER

static const char format_topo[] = …/* T:  Bus=dd Lev=dd Prnt=dd Port=dd Cnt=dd Dev#=ddd Spd=dddd MxCh=dd */
"\nT:  Bus=%2.2d Lev=%2.2d Prnt=%2.2d Port=%2.2d Cnt=%2.2d Dev#=%3d Spd=%-4s MxCh=%2d\n";

static const char format_string_manufacturer[] = …/* S:  Manufacturer=xxxx */
  "S:  Manufacturer=%.100s\n";

static const char format_string_product[] = …/* S:  Product=xxxx */
  "S:  Product=%.100s\n";

#ifdef ALLOW_SERIAL_NUMBER
static const char format_string_serialnumber[] = …/* S:  SerialNumber=xxxx */
  "S:  SerialNumber=%.100s\n";
#endif

static const char format_bandwidth[] = …/* B:  Alloc=ddd/ddd us (xx%), #Int=ddd, #Iso=ddd */
  "B:  Alloc=%3d/%3d us (%2d%%), #Int=%3d, #Iso=%3d\n";

static const char format_device1[] = …/* D:  Ver=xx.xx Cls=xx(sssss) Sub=xx Prot=xx MxPS=dd #Cfgs=dd */
  "D:  Ver=%2x.%02x Cls=%02x(%-5s) Sub=%02x Prot=%02x MxPS=%2d #Cfgs=%3d\n";

static const char format_device2[] = …/* P:  Vendor=xxxx ProdID=xxxx Rev=xx.xx */
  "P:  Vendor=%04x ProdID=%04x Rev=%2x.%02x\n";

static const char format_config[] = …/* C:  #Ifs=dd Cfg#=dd Atr=xx MPwr=dddmA */
  "C:%c #Ifs=%2d Cfg#=%2d Atr=%02x MxPwr=%3dmA\n";

static const char format_iad[] = …/* A:  FirstIf#=dd IfCount=dd Cls=xx(sssss) Sub=xx Prot=xx */
  "A:  FirstIf#=%2d IfCount=%2d Cls=%02x(%-5s) Sub=%02x Prot=%02x\n";

static const char format_iface[] = …/* I:  If#=dd Alt=dd #EPs=dd Cls=xx(sssss) Sub=xx Prot=xx Driver=xxxx*/
  "I:%c If#=%2d Alt=%2d #EPs=%2d Cls=%02x(%-5s) Sub=%02x Prot=%02x Driver=%s\n";

static const char format_endpt[] = …/* E:  Ad=xx(s) Atr=xx(ssss) MxPS=dddd Ivl=D?s */
  "E:  Ad=%02x(%c) Atr=%02x(%-4s) MxPS=%4d Ivl=%d%cs\n";

struct class_info { … };

static const struct class_info clas_info[] = …;

/*****************************************************************/

static const char *class_decode(const int class)
{ … }

static char *usb_dump_endpoint_descriptor(int speed, char *start, char *end,
				const struct usb_endpoint_descriptor *desc)
{ … }

static char *usb_dump_interface_descriptor(char *start, char *end,
					const struct usb_interface_cache *intfc,
					const struct usb_interface *iface,
					int setno)
{ … }

static char *usb_dump_interface(int speed, char *start, char *end,
				const struct usb_interface_cache *intfc,
				const struct usb_interface *iface, int setno)
{ … }

static char *usb_dump_iad_descriptor(char *start, char *end,
			const struct usb_interface_assoc_descriptor *iad)
{ … }

/* TBD:
 * 0. TBDs
 * 1. marking active interface altsettings (code lists all, but should mark
 *    which ones are active, if any)
 */
static char *usb_dump_config_descriptor(char *start, char *end,
				const struct usb_config_descriptor *desc,
				int active, int speed)
{ … }

static char *usb_dump_config(int speed, char *start, char *end,
			     const struct usb_host_config *config, int active)
{ … }

/*
 * Dump the different USB descriptors.
 */
static char *usb_dump_device_descriptor(char *start, char *end,
				const struct usb_device_descriptor *desc)
{ … }

/*
 * Dump the different strings that this device holds.
 */
static char *usb_dump_device_strings(char *start, char *end,
				     struct usb_device *dev)
{ … }

static char *usb_dump_desc(char *start, char *end, struct usb_device *dev)
{ … }

/*****************************************************************/

/* This is a recursive function. Parameters:
 * buffer - the user-space buffer to write data into
 * nbytes - the maximum number of bytes to write
 * skip_bytes - the number of bytes to skip before writing anything
 * file_offset - the offset into the devices file on completion
 * The caller must own the device lock.
 */
static ssize_t usb_device_dump(char __user **buffer, size_t *nbytes,
			       loff_t *skip_bytes, loff_t *file_offset,
			       struct usb_device *usbdev, struct usb_bus *bus,
			       int level, int index, int count)
{ … }

static ssize_t usb_device_read(struct file *file, char __user *buf,
			       size_t nbytes, loff_t *ppos)
{ … }

const struct file_operations usbfs_devices_fops = …;