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23cd1385 RB |
1 | /* |
2 | * Copyright (C) 2003 David Brownell | |
3 | * | |
eee479cf | 4 | * SPDX-License-Identifier: LGPL-2.1+ |
23cd1385 RB |
5 | * |
6 | * Ported to U-boot by: Thomas Smits <ts.smits@gmail.com> and | |
7 | * Remy Bohmer <linux@bohmer.net> | |
8 | */ | |
9 | ||
10 | #include <common.h> | |
11 | #include <asm/errno.h> | |
12 | #include <linux/usb/ch9.h> | |
13 | #include <linux/usb/gadget.h> | |
14 | ||
15 | #include <asm/unaligned.h> | |
16 | ||
17 | ||
18 | static int utf8_to_utf16le(const char *s, __le16 *cp, unsigned len) | |
19 | { | |
20 | int count = 0; | |
21 | u8 c; | |
22 | u16 uchar; | |
23 | ||
6142e0ae VK |
24 | /* |
25 | * this insists on correct encodings, though not minimal ones. | |
23cd1385 RB |
26 | * BUT it currently rejects legit 4-byte UTF-8 code points, |
27 | * which need surrogate pairs. (Unicode 3.1 can use them.) | |
28 | */ | |
29 | while (len != 0 && (c = (u8) *s++) != 0) { | |
30 | if ((c & 0x80)) { | |
6142e0ae VK |
31 | /* |
32 | * 2-byte sequence: | |
33 | * 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx | |
34 | */ | |
23cd1385 RB |
35 | if ((c & 0xe0) == 0xc0) { |
36 | uchar = (c & 0x1f) << 6; | |
37 | ||
38 | c = (u8) *s++; | |
39 | if ((c & 0xc0) != 0x80) | |
40 | goto fail; | |
41 | c &= 0x3f; | |
42 | uchar |= c; | |
43 | ||
6142e0ae VK |
44 | /* |
45 | * 3-byte sequence (most CJKV characters): | |
46 | * zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx | |
47 | */ | |
23cd1385 RB |
48 | } else if ((c & 0xf0) == 0xe0) { |
49 | uchar = (c & 0x0f) << 12; | |
50 | ||
51 | c = (u8) *s++; | |
52 | if ((c & 0xc0) != 0x80) | |
53 | goto fail; | |
54 | c &= 0x3f; | |
55 | uchar |= c << 6; | |
56 | ||
57 | c = (u8) *s++; | |
58 | if ((c & 0xc0) != 0x80) | |
59 | goto fail; | |
60 | c &= 0x3f; | |
61 | uchar |= c; | |
62 | ||
63 | /* no bogus surrogates */ | |
64 | if (0xd800 <= uchar && uchar <= 0xdfff) | |
65 | goto fail; | |
66 | ||
6142e0ae VK |
67 | /* |
68 | * 4-byte sequence (surrogate pairs, currently rare): | |
69 | * 11101110wwwwzzzzyy + 110111yyyyxxxxxx | |
70 | * = 11110uuu 10uuzzzz 10yyyyyy 10xxxxxx | |
71 | * (uuuuu = wwww + 1) | |
72 | * FIXME accept the surrogate code points (only) | |
73 | */ | |
23cd1385 RB |
74 | } else |
75 | goto fail; | |
76 | } else | |
77 | uchar = c; | |
78 | put_unaligned_le16(uchar, cp++); | |
79 | count++; | |
80 | len--; | |
81 | } | |
82 | return count; | |
83 | fail: | |
84 | return -1; | |
85 | } | |
86 | ||
87 | ||
88 | /** | |
89 | * usb_gadget_get_string - fill out a string descriptor | |
90 | * @table: of c strings encoded using UTF-8 | |
91 | * @id: string id, from low byte of wValue in get string descriptor | |
92 | * @buf: at least 256 bytes | |
93 | * | |
94 | * Finds the UTF-8 string matching the ID, and converts it into a | |
95 | * string descriptor in utf16-le. | |
96 | * Returns length of descriptor (always even) or negative errno | |
97 | * | |
98 | * If your driver needs stings in multiple languages, you'll probably | |
99 | * "switch (wIndex) { ... }" in your ep0 string descriptor logic, | |
100 | * using this routine after choosing which set of UTF-8 strings to use. | |
101 | * Note that US-ASCII is a strict subset of UTF-8; any string bytes with | |
102 | * the eighth bit set will be multibyte UTF-8 characters, not ISO-8859/1 | |
103 | * characters (which are also widely used in C strings). | |
104 | */ | |
105 | int | |
6142e0ae | 106 | usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf) |
23cd1385 RB |
107 | { |
108 | struct usb_string *s; | |
109 | int len; | |
110 | ||
52d45012 RH |
111 | if (!table) |
112 | return -EINVAL; | |
113 | ||
23cd1385 RB |
114 | /* descriptor 0 has the language id */ |
115 | if (id == 0) { | |
6142e0ae VK |
116 | buf[0] = 4; |
117 | buf[1] = USB_DT_STRING; | |
118 | buf[2] = (u8) table->language; | |
119 | buf[3] = (u8) (table->language >> 8); | |
23cd1385 RB |
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 */ | |
6142e0ae VK |
131 | len = min((size_t) 126, strlen(s->s)); |
132 | memset(buf + 2, 0, 2 * len); /* zero all the bytes */ | |
23cd1385 RB |
133 | len = utf8_to_utf16le(s->s, (__le16 *)&buf[2], len); |
134 | if (len < 0) | |
135 | return -EINVAL; | |
6142e0ae VK |
136 | buf[0] = (len + 1) * 2; |
137 | buf[1] = USB_DT_STRING; | |
138 | return buf[0]; | |
23cd1385 | 139 | } |