path: root/drivers/usb/storage/usb.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * Driver for USB Mass Storage compliant devices
 *
 * Current development and maintenance by:
 *   (c) 1999-2003 Matthew Dharm (mdharm-usb@one-eyed-alien.net)
 *
 * Developed with the assistance of:
 *   (c) 2000 David L. Brown, Jr. (usb-storage@davidb.org)
 *   (c) 2003-2009 Alan Stern (stern@rowland.harvard.edu)
 *
 * Initial work by:
 *   (c) 1999 Michael Gee (michael@linuxspecific.com)
 *
 * usb_device_id support by Adam J. Richter (adam@yggdrasil.com):
 *   (c) 2000 Yggdrasil Computing, Inc.
 *
 * This driver is based on the 'USB Mass Storage Class' document. This
 * describes in detail the protocol used to communicate with such
 * devices.  Clearly, the designers had SCSI and ATAPI commands in
 * mind when they created this document.  The commands are all very
 * similar to commands in the SCSI-II and ATAPI specifications.
 *
 * It is important to note that in a number of cases this class
 * exhibits class-specific exemptions from the USB specification.
 * Notably the usage of NAK, STALL and ACK differs from the norm, in
 * that they are used to communicate wait, failed and OK on commands.
 *
 * Also, for certain devices, the interrupt endpoint is used to convey
 * status of a command.
 */

#ifdef CONFIG_USB_STORAGE_DEBUG
#define DEBUG
#endif

#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/utsname.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>

#include "usb.h"
#include <linux/usb/hcd.h>
#include "scsiglue.h"
#include "transport.h"
#include "protocol.h"
#include "debug.h"
#include "initializers.h"

#include "sierra_ms.h"
#include "option_ms.h"

#if IS_ENABLED(CONFIG_USB_UAS)
#include "uas-detect.h"
#endif

#define DRV_NAME "usb-storage"

/* Some informational data */
MODULE_AUTHOR("Matthew Dharm <mdharm-usb@one-eyed-alien.net>");
MODULE_DESCRIPTION("USB Mass Storage driver for Linux");
MODULE_LICENSE("GPL");

static unsigned int delay_use = 1 * MSEC_PER_SEC;

/**
 * parse_delay_str - parse an unsigned decimal integer delay
 * @str: String to parse.
 * @ndecimals: Number of decimal to scale up.
 * @suffix: Suffix string to parse.
 * @val: Where to store the parsed value.
 *
 * Parse an unsigned decimal value in @str, optionally end with @suffix.
 * Stores the parsed value in @val just as it is if @str ends with @suffix.
 * Otherwise store the value scale up by 10^(@ndecimal).
 *
 * Returns 0 on success, a negative error code otherwise.
 */
static int parse_delay_str(const char *str, int ndecimals, const char *suffix,
			unsigned int *val)
{
	int n, n2, l;
	char buf[16];

	l = strlen(suffix);
	n = strlen(str);
	if (n > 0 && str[n - 1] == '\n')
		--n;
	if (n >= l && !strncmp(&str[n - l], suffix, l)) {
		n -= l;
		n2 = 0;
	} else
		n2 = ndecimals;

	if (n + n2 > sizeof(buf) - 1)
		return -EINVAL;

	memcpy(buf, str, n);
	while (n2-- > 0)
		buf[n++] = '0';
	buf[n] = 0;

	return kstrtouint(buf, 10, val);
}

/**
 * format_delay_ms - format an integer value into a delay string
 * @val: The integer value to format, scaled by 10^(@ndecimals).
 * @ndecimals: Number of decimal to scale down.
 * @suffix: Suffix string to format.
 * @str: Where to store the formatted string.
 * @size: The size of buffer for @str.
 *
 * Format an integer value in @val scale down by 10^(@ndecimals) without @suffix
 * if @val is divisible by 10^(@ndecimals).
 * Otherwise format a value in @val just as it is with @suffix
 *
 * Returns the number of characters written into @str.
 */
static int format_delay_ms(unsigned int val, int ndecimals, const char *suffix,
			char *str, int size)
{
	u64 delay_ms = val;
	unsigned int rem = do_div(delay_ms, int_pow(10, ndecimals));
	int ret;

	if (rem)
		ret = scnprintf(str, size, "%u%s\n", val, suffix);
	else
		ret = scnprintf(str, size, "%u\n", (unsigned int)delay_ms);
	return ret;
}

static int delay_use_set(const char *s, const struct kernel_param *kp)
{
	unsigned int delay_ms;
	int ret;

	ret