blob: 8c3ff64fe35359566a673a08791228d4f95989cf [file] [log] [blame]
Remy Bohmer23cd1382009-07-29 18:18:43 +02001/*
2 * Copyright (C) 2003 David Brownell
3 *
Wolfgang Denkeee479c2013-07-08 11:48:07 +02004 * SPDX-License-Identifier: LGPL-2.1+
Remy Bohmer23cd1382009-07-29 18:18:43 +02005 *
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
18static int utf8_to_utf16le(const char *s, __le16 *cp, unsigned len)
19{
20 int count = 0;
21 u8 c;
22 u16 uchar;
23
Vitaly Kuzmichev6142e0a2010-09-13 18:37:11 +040024 /*
25 * this insists on correct encodings, though not minimal ones.
Remy Bohmer23cd1382009-07-29 18:18:43 +020026 * 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)) {
Vitaly Kuzmichev6142e0a2010-09-13 18:37:11 +040031 /*
32 * 2-byte sequence:
33 * 00000yyyyyxxxxxx = 110yyyyy 10xxxxxx
34 */
Remy Bohmer23cd1382009-07-29 18:18:43 +020035 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
Vitaly Kuzmichev6142e0a2010-09-13 18:37:11 +040044 /*
45 * 3-byte sequence (most CJKV characters):
46 * zzzzyyyyyyxxxxxx = 1110zzzz 10yyyyyy 10xxxxxx
47 */
Remy Bohmer23cd1382009-07-29 18:18:43 +020048 } 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
Vitaly Kuzmichev6142e0a2010-09-13 18:37:11 +040067 /*
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 */
Remy Bohmer23cd1382009-07-29 18:18:43 +020074 } else
75 goto fail;
76 } else
77 uchar = c;
78 put_unaligned_le16(uchar, cp++);
79 count++;
80 len--;
81 }
82 return count;
83fail:
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 */
105int
Vitaly Kuzmichev6142e0a2010-09-13 18:37:11 +0400106usb_gadget_get_string(struct usb_gadget_strings *table, int id, u8 *buf)
Remy Bohmer23cd1382009-07-29 18:18:43 +0200107{
108 struct usb_string *s;
109 int len;
110
Rob Herring52d45012014-04-18 08:54:28 -0500111 if (!table)
112 return -EINVAL;
113
Remy Bohmer23cd1382009-07-29 18:18:43 +0200114 /* descriptor 0 has the language id */
115 if (id == 0) {
Vitaly Kuzmichev6142e0a2010-09-13 18:37:11 +0400116 buf[0] = 4;
117 buf[1] = USB_DT_STRING;
118 buf[2] = (u8) table->language;
119 buf[3] = (u8) (table->language >> 8);
Remy Bohmer23cd1382009-07-29 18:18:43 +0200120 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 */
Vitaly Kuzmichev6142e0a2010-09-13 18:37:11 +0400131 len = min((size_t) 126, strlen(s->s));
132 memset(buf + 2, 0, 2 * len); /* zero all the bytes */
Remy Bohmer23cd1382009-07-29 18:18:43 +0200133 len = utf8_to_utf16le(s->s, (__le16 *)&buf[2], len);
134 if (len < 0)
135 return -EINVAL;
Vitaly Kuzmichev6142e0a2010-09-13 18:37:11 +0400136 buf[0] = (len + 1) * 2;
137 buf[1] = USB_DT_STRING;
138 return buf[0];
Remy Bohmer23cd1382009-07-29 18:18:43 +0200139}