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(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
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1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192// SPDX-License-Identifier: LGPL-2.1+/* * Copyright (C) 2003 David Brownell */
#include <linux/errno.h>#include <linux/kernel.h>#include <linux/module.h>#include <linux/list.h>#include <linux/string.h>#include <linux/device.h>#include <linux/nls.h>
#include <linux/usb/ch9.h>#include <linux/usb/gadget.h>
/** * usb_gadget_get_string - fill out a string descriptor * @table: of c strings encoded using UTF-8 * @id: string id, from low byte of wValue in get string descriptor * @buf: at least 256 bytes, must be 16-bit aligned * * Finds the UTF-8 string matching the ID, and converts it into a * string descriptor in utf16-le. * Returns length of descriptor (always even) or negative errno * * If your driver needs stings in multiple languages, you'll probably * "switch (wIndex) { ... }" in your ep0 string descriptor logic, * using this routine after choosing which set of UTF-8 strings to use. * Note that US-ASCII is a strict subset of UTF-8; any string bytes with * the eighth bit set will be multibyte UTF-8 characters, not ISO-8859/1 * characters (which are also widely used in C strings). */intusb_gadget_get_string (const struct usb_gadget_strings *table, int id, u8 *buf){ struct usb_string *s; int len;
/* descriptor 0 has the language id */ if (id == 0) { buf [0] = 4; buf [1] = USB_DT_STRING; buf [2] = (u8) table->language; buf [3] = (u8) (table->language >> 8); return 4; } for (s = table->strings; s && s->s; s++) if (s->id == id) break;
/* unrecognized: stall. */ if (!s || !s->s) return -EINVAL;
/* string descriptors have length, tag, then UTF16-LE text */ len = min_t(size_t, USB_MAX_STRING_LEN, strlen(s->s)); len = utf8s_to_utf16s(s->s, len, UTF16_LITTLE_ENDIAN, (wchar_t *) &buf[2], USB_MAX_STRING_LEN); if (len < 0) return -EINVAL; buf [0] = (len + 1) * 2; buf [1] = USB_DT_STRING; return buf [0];}EXPORT_SYMBOL_GPL(usb_gadget_get_string);
/** * usb_validate_langid - validate usb language identifiers * @langid: usb language identifier * * Returns true for valid language identifier, otherwise false. */bool usb_validate_langid(u16 langid){ u16 primary_lang = langid & 0x3ff; /* bit [9:0] */ u16 sub_lang = langid >> 10; /* bit [15:10] */
switch (primary_lang) { case 0: case 0x62 ... 0xfe: case 0x100 ... 0x3ff: return false; } if (!sub_lang) return false;
return true;}EXPORT_SYMBOL_GPL(usb_validate_langid);