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| 2 | |
| 3 | * Copyright (C) 2003 David Brownell
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| 4 |
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| 5 |
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| 6 | #include <linux/errno.h>
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| 7 | #include <linux/kernel.h>
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| 8 | #include <linux/module.h>
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| 9 | #include <linux/list.h>
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| 10 | #include <linux/string.h>
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| 11 | #include <linux/device.h>
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| 12 | #include <linux/nls.h>
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| 13 |
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| 14 | #include <linux/usb/ch9.h>
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| 15 | #include <linux/usb/gadget.h>
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| 16 |
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| 17 |
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| 18 | |
| 19 | * usb_gadget_get_string - fill out a string descriptor
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| 20 | * @table: of c strings encoded using UTF-8
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| 21 | * @id: string id, from low byte of wValue in get string descriptor
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| 22 | * @buf: at least 256 bytes, must be 16-bit aligned
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| 23 | *
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| 24 | * Finds the UTF-8 string matching the ID, and converts it into a
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| 25 | * string descriptor in utf16-le.
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| 26 | * Returns length of descriptor (always even) or negative errno
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| 27 | *
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| 28 | * If your driver needs stings in multiple languages, you'll probably
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| 29 | * "switch (wIndex) { ... }" in your ep0 string descriptor logic,
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| 30 | * using this routine after choosing which set of UTF-8 strings to use.
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| 31 | * Note that US-ASCII is a strict subset of UTF-8; any string bytes with
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| 32 | * the eighth bit set will be multibyte UTF-8 characters, not ISO-8859/1
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| 33 | * characters (which are also widely used in C strings).
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| 34 |
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| 35 | int
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| 36 | usb_gadget_get_string (const struct usb_gadget_strings *table, int id, u8 *buf)
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| 37 | {
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| 38 | struct usb_string *s;
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| 39 | int len;
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| 40 |
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| 41 |
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| 42 | if (id == 0) {
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| 43 | buf [0] = 4;
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| 44 | buf [1] = USB_DT_STRING;
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| 45 | buf [2] = (u8) table->language;
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| 46 | buf [3] = (u8) (table->language >> 8);
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| 47 | return 4;
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| 48 | }
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| 49 | for (s = table->strings; s && s->s; s++)
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| 50 | if (s->id == id)
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| 51 | break;
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| 52 |
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| 53 |
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| 54 | if (!s || !s->s)
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| 55 | return -EINVAL;
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| 56 |
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| 57 |
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| 58 | len = min_t(size_t, USB_MAX_STRING_LEN, strlen(s->s));
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| 59 | len = utf8s_to_utf16s(s->s, len, UTF16_LITTLE_ENDIAN,
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| 60 | (wchar_t *) &buf[2], USB_MAX_STRING_LEN);
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| 61 | if (len < 0)
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| 62 | return -EINVAL;
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| 63 | buf [0] = (len + 1) * 2;
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| 64 | buf [1] = USB_DT_STRING;
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| 65 | return buf [0];
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| 66 | }
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| 67 | EXPORT_SYMBOL_GPL(usb_gadget_get_string);
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| 68 |
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| 69 | |
| 70 | * usb_validate_langid - validate usb language identifiers
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| 71 | * @langid: usb language identifier
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| 72 | *
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| 73 | * Returns true for valid language identifier, otherwise false.
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| 74 |
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| 75 | bool usb_validate_langid(u16 langid)
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| 76 | {
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| 77 | u16 primary_lang = langid & 0x3ff;
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| 78 | u16 sub_lang = langid >> 10;
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| 79 |
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| 80 | switch (primary_lang) {
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| 81 | case 0:
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| 82 | case 0x62 ... 0xfe:
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| 83 | case 0x100 ... 0x3ff:
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| 84 | return false;
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| 85 | }
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| 86 | if (!sub_lang)
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| 87 | return false;
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| 88 |
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| 89 | return true;
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| 90 | }
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| 91 | EXPORT_SYMBOL_GPL(usb_validate_langid);
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