1 /* 2 * Copyright (C) 2003 David Brownell 3 * 4 * This program is free software; you can redistribute it and/or modify 5 * it under the terms of the GNU Lesser General Public License as published 6 * by the Free Software Foundation; either version 2.1 of the License, or 7 * (at your option) any later version. 8 * 9 * Ported to U-boot by: Thomas Smits <ts.smits@gmail.com> and 10 * Remy Bohmer <linux@bohmer.net> 11 */ 12 13 #include <common.h> 14 #include <asm/errno.h> 15 #include <linux/usb/ch9.h> 16 #include <linux/usb/gadget.h> 17 18 #include <asm/unaligned.h> 19 20 21 static int utf8_to_utf16le(const char *s, __le16 *cp, unsigned len) 22 { 23 int count = 0; 24 u8 c; 25 u16 uchar; 26 27 /* 28 * this insists on correct encodings, though not minimal ones. 29 * BUT it currently rejects legit 4-byte UTF-8 code points, 30 * which need surrogate pairs. (Unicode 3.1 can use them.) 31 */ 32 while (len != 0 && (c = (u8) *s++) != 0) { 33 if ((c & 0x80)) { 34 /* 35 * 2-byte sequence: 36 * 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx 37 */ 38 if ((c & 0xe0) == 0xc0) { 39 uchar = (c & 0x1f) << 6; 40 41 c = (u8) *s++; 42 if ((c & 0xc0) != 0x80) 43 goto fail; 44 c &= 0x3f; 45 uchar |= c; 46 47 /* 48 * 3-byte sequence (most CJKV characters): 49 * zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx 50 */ 51 } else if ((c & 0xf0) == 0xe0) { 52 uchar = (c & 0x0f) << 12; 53 54 c = (u8) *s++; 55 if ((c & 0xc0) != 0x80) 56 goto fail; 57 c &= 0x3f; 58 uchar |= c << 6; 59 60 c = (u8) *s++; 61 if ((c & 0xc0) != 0x80) 62 goto fail; 63 c &= 0x3f; 64 uchar |= c; 65 66 /* no bogus surrogates */ 67 if (0xd800 <= uchar && uchar <= 0xdfff) 68 goto fail; 69 70 /* 71 * 4-byte sequence (surrogate pairs, currently rare): 72 * 11101110wwwwzzzzyy + 110111yyyyxxxxxx 73 * = 11110uuu 10uuzzzz 10yyyyyy 10xxxxxx 74 * (uuuuu = wwww + 1) 75 * FIXME accept the surrogate code points (only) 76 */ 77 } else 78 goto fail; 79 } else 80 uchar = c; 81 put_unaligned_le16(uchar, cp++); 82 count++; 83 len--; 84 } 85 return count; 86 fail: 87 return -1; 88 } 89 90 91 /** 92 * usb_gadget_get_string - fill out a string descriptor 93 * @table: of c strings encoded using UTF-8 94 * @id: string id, from low byte of wValue in get string descriptor 95 * @buf: at least 256 bytes 96 * 97 * Finds the UTF-8 string matching the ID, and converts it into a 98 * string descriptor in utf16-le. 99 * Returns length of descriptor (always even) or negative errno 100 * 101 * If your driver needs stings in multiple languages, you'll probably 102 * "switch (wIndex) { ... }" in your ep0 string descriptor logic, 103 * using this routine after choosing which set of UTF-8 strings to use. 104 * Note that US-ASCII is a strict subset of UTF-8; any string bytes with 105 * the eighth bit set will be multibyte UTF-8 characters, not ISO-8859/1 106 * characters (which are also widely used in C strings). 107 */ 108 int 109 usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf) 110 { 111 struct usb_string *s; 112 int len; 113 114 /* descriptor 0 has the language id */ 115 if (id == 0) { 116 buf[0] = 4; 117 buf[1] = USB_DT_STRING; 118 buf[2] = (u8) table->language; 119 buf[3] = (u8) (table->language >> 8); 120 return 4; 121 } 122 for (s = table->strings; s && s->s; s++) 123 if (s->id == id) 124 break; 125 126 /* unrecognized: stall. */ 127 if (!s || !s->s) 128 return -EINVAL; 129 130 /* string descriptors have length, tag, then UTF16-LE text */ 131 len = min((size_t) 126, strlen(s->s)); 132 memset(buf + 2, 0, 2 * len); /* zero all the bytes */ 133 len = utf8_to_utf16le(s->s, (__le16 *)&buf[2], len); 134 if (len < 0) 135 return -EINVAL; 136 buf[0] = (len + 1) * 2; 137 buf[1] = USB_DT_STRING; 138 return buf[0]; 139 } 140