1 /* Copyright (c) 2013 The Chromium OS Authors. All rights reserved.
2 * Use of this source code is governed by a BSD-style license that can be
3 * found in the LICENSE file.
4 *
5 * Delay/beep functions used in dev-mode kernel selection.
6 */
7
8 #include "sysincludes.h"
9
10 #include "crc32.h"
11 #include "gbb_header.h"
12 #include "utility.h"
13 #include "vboot_api.h"
14 #include "vboot_audio.h"
15 #include "vboot_audio_private.h"
16 #include "vboot_common.h"
17
18 /* BIOS doesn't have /usr/include */
19 #ifndef UINT_MAX
20 #define UINT_MAX 4294967295U /* 0xffffffff */
21 #endif
22
23 /*
24 * Need one second of noise in the first 22 seconds.
25 * Total delay >= 30 seconds, <= 60 seconds.
26 */
27 #define REQUIRED_NOISE_TIME 1000
28 #define REQUIRED_NOISE_WITHIN 22000
29 #define REQUIRED_TOTAL_DELAY 30000
30 #define MAX_CUSTOM_DELAY 60000
31
32 /* These are visible externally only to make testing easier */
33 VbDevMusicNote default_notes_[] = { {20000, 0}, /* 20 seconds */
34 {250, 400}, /* two beeps */
35 {250, 0},
36 {250, 400},
37 {9250, 0} }; /* total 30 seconds */
38 uint32_t default_count_ = sizeof(default_notes_) / sizeof(VbDevMusicNote);
39
40 VbDevMusicNote short_notes_[] = { {2000, 0} }; /* two seconds */
41 uint32_t short_count_ = sizeof(short_notes_) / sizeof(VbDevMusicNote);
42
43 /* No need to dynamically allocate this, is there? */
44 static VbAudioContext au;
45
46 /* Convert from msecs to VbExGetTimer() units. */
47 static uint64_t ticks_per_msec = 0; /* Initialized by VbAudioOpen() */
VbMsecToTicks(uint16_t msec)48 static uint64_t VbMsecToTicks(uint16_t msec) {
49 return ticks_per_msec * msec;
50 }
51
52 /**
53 * Find and return a valid set of note events.
54 *
55 * We'll use the user's struct if possible, but we will still enforce the
56 * 30-second timeout and require at least a second of audible noise within that
57 * period. We allocate storage for two reasons: the user's struct will be in
58 * flash, which is slow to read, and we may need one extra note at the end to
59 * pad out the user's notes to a full 30 seconds. The caller should free it
60 * when finished.
61 */
VbGetDevMusicNotes(VbAudioContext * audio,int use_short)62 static void VbGetDevMusicNotes(VbAudioContext *audio, int use_short)
63 {
64 VbDevMusicNote *notebuf = 0;
65 VbDevMusicNote *builtin = 0;
66 VbDevMusic *hdr = CUSTOM_MUSIC_NOTES;
67 uint32_t maxsize = CUSTOM_MUSIC_MAXSIZE; /* always <= flash size (8M) */
68 uint32_t maxnotes, mysum, mylen, i;
69 uint32_t this_msecs, on_msecs, total_msecs;
70 uint32_t count;
71
72 VBDEBUG(("VbGetDevMusicNotes: use_short is %d, hdr is %p, "
73 "maxsize is %d\n", use_short, hdr, maxsize));
74
75 if (use_short) {
76 builtin = short_notes_;
77 count = short_count_;
78 goto nope;
79 }
80
81 builtin = default_notes_;
82 count = default_count_;
83
84 /* If we can't beep in the background, don't allow customization. */
85 if (!audio->background_beep)
86 goto nope;
87
88 if (!hdr || maxsize < sizeof(VbDevMusic))
89 goto nope;
90
91 if (0 != Memcmp(hdr->sig, "$SND", sizeof(hdr->sig))) {
92 VBDEBUG(("VbGetDevMusicNotes: bad sig\n"));
93 goto nope;
94 }
95
96 /*
97 * How many notes will fit in the flash region? One more than you'd
98 * think, because there's one note in the header itself.
99 */
100 maxnotes = 1 + (maxsize - sizeof(VbDevMusic)) / sizeof(VbDevMusicNote);
101 if (hdr->count == 0 || hdr->count > maxnotes) {
102 VBDEBUG(("VbGetDevMusicNotes: count=%d maxnotes=%d\n",
103 hdr->count, maxnotes));
104 goto nope;
105 }
106
107 /*
108 * CUSTOM_MUSIC_MAXSIZE can't be larger than the size of the flash
109 * (around 8M or so) so this isn't really necessary, but let's be safe
110 * anyway.
111 */
112 if ((sizeof(VbDevMusicNote) > UINT_MAX / hdr->count) ||
113 (sizeof(hdr->count) >
114 UINT_MAX - hdr->count * sizeof(VbDevMusicNote))) {
115 VBDEBUG(("VbGetDevMusicNotes: count=%d, just isn't right\n",
116 hdr->count));
117 goto nope;
118 }
119
120 /* Now we know this won't overflow */
121 mylen = (uint32_t)(sizeof(hdr->count) +
122 hdr->count * sizeof(VbDevMusicNote));
123 mysum = Crc32(&(hdr->count), mylen);
124
125 if (mysum != hdr->checksum) {
126 VBDEBUG(("VbGetDevMusicNotes: mysum=%08x, want=%08x\n",
127 mysum, hdr->checksum));
128 goto nope;
129 }
130
131 VBDEBUG(("VbGetDevMusicNotes: custom notes struct at %p\n", hdr));
132
133 /*
134 * Measure the audible sound up to the first 22 seconds, being careful
135 * to avoid rollover. The note time is 16 bits, and the note count is
136 * 32 bits. The product should fit in 64 bits.
137 */
138 total_msecs = 0;
139 on_msecs = 0;
140 for (i=0; i < hdr->count; i++) {
141 this_msecs = hdr->notes[i].msec ;
142 if (this_msecs) {
143 total_msecs += this_msecs;
144 if (total_msecs <= REQUIRED_NOISE_WITHIN &&
145 hdr->notes[i].frequency >= 100 &&
146 hdr->notes[i].frequency <= 2000)
147 on_msecs += this_msecs;
148 }
149 }
150
151 /* We require at least one second of noise in the first 22 seconds */
152 VBDEBUG(("VbGetDevMusicNotes: with %d msecs of sound to begin\n",
153 on_msecs));
154 if (on_msecs < REQUIRED_NOISE_TIME)
155 goto nope;
156
157 /*
158 * We'll also require that the total time be less than a minute. No
159 * real reason, it just gives us less to worry about.
160 */
161 VBDEBUG(("VbGetDevMusicNotes: lasting %d msecs\n", total_msecs));
162 if (total_msecs > MAX_CUSTOM_DELAY) {
163 goto nope;
164 }
165
166 /* One more check, just to be paranoid. */
167 if (hdr->count > (UINT_MAX / sizeof(VbDevMusicNote) - 1)) {
168 VBDEBUG(("VbGetDevMusicNotes: they're all out to get me!\n"));
169 goto nope;
170 }
171
172 /* Looks good. Allocate the space (plus one) and copy it over. */
173 notebuf = VbExMalloc((hdr->count + 1) * sizeof(VbDevMusicNote));
174 Memcpy(notebuf, hdr->notes, hdr->count * sizeof(VbDevMusicNote));
175 count = hdr->count;
176
177 /* We also require at least 30 seconds of delay. */
178 if (total_msecs < REQUIRED_TOTAL_DELAY) {
179 /*
180 * If the total time is less than 30 seconds, the needed
181 * difference will fit in 16 bits.
182 */
183 this_msecs = (REQUIRED_TOTAL_DELAY - total_msecs) & 0xffff;
184 notebuf[hdr->count].msec = this_msecs;
185 notebuf[hdr->count].frequency = 0;
186 count++;
187 VBDEBUG(("VbGetDevMusicNotes: adding %d msecs of silence\n",
188 this_msecs));
189 }
190
191 /* Done */
192 audio->music_notes = notebuf;
193 audio->note_count = count;
194 audio->free_notes_when_done = 1;
195 return;
196
197 nope:
198 /* No custom notes, use the default. The count is already set. */
199 VBDEBUG(("VbGetDevMusicNotes: using %d default notes\n", count));
200 audio->music_notes = builtin;
201 audio->note_count = count;
202 audio->free_notes_when_done = 0;
203 }
204
205
206 /**
207 * Initialization function. Returns context for processing dev-mode delay.
208 */
VbAudioOpen(VbCommonParams * cparams)209 VbAudioContext *VbAudioOpen(VbCommonParams *cparams)
210 {
211 GoogleBinaryBlockHeader *gbb = cparams->gbb;
212 VbAudioContext *audio = &au;
213 int use_short = 0;
214 uint64_t a, b;
215
216 /* Note: may need to allocate things here in future */
217
218 /* Calibrate audio delay */
219 a = VbExGetTimer();
220 VbExSleepMs(10);
221 b = VbExGetTimer();
222 ticks_per_msec = (b - a) / 10ULL ;
223 VBDEBUG(("VbAudioOpen() - ticks_per_msec is %" PRIu64 "\n",
224 ticks_per_msec));
225
226 /* Initialize */
227 Memset(audio, 0, sizeof(*audio));
228 audio->background_beep = 1;
229 audio->play_until = b; /* "zero" starts now */
230
231 /* See if we have full background sound capability or not. */
232 if (VBERROR_SUCCESS != VbExBeep(0,0)) {
233 VBDEBUG(("VbAudioOpen() - VbExBeep() is limited\n"));
234 audio->background_beep = 0;
235 }
236
237 /*
238 * Prepare to generate audio/delay event. Use a short developer screen
239 * delay if indicated by GBB flags.
240 */
241 if (gbb->major_version == GBB_MAJOR_VER && gbb->minor_version >= 1
242 && (gbb->flags & GBB_FLAG_DEV_SCREEN_SHORT_DELAY)) {
243 VBDEBUG(("VbAudioOpen() - using short dev screen delay\n"));
244 use_short = 1;
245 }
246
247 VbGetDevMusicNotes(audio, use_short);
248 VBDEBUG(("VbAudioOpen() - note count %d\n", audio->note_count));
249
250 return audio;
251 }
252
253 /**
254 * Caller should loop without extra delay until this returns false.
255 */
VbAudioLooping(VbAudioContext * audio)256 int VbAudioLooping(VbAudioContext *audio)
257 {
258 uint64_t now;
259 uint16_t freq = audio->current_frequency;
260 uint16_t msec = 0;
261 int looping = 1;
262
263 now = VbExGetTimer();
264 while (audio->next_note < audio->note_count &&
265 now >= audio->play_until) {
266 freq = audio->music_notes[audio->next_note].frequency;
267 msec = audio->music_notes[audio->next_note].msec;
268 audio->play_until += VbMsecToTicks(msec);
269 audio->next_note++;
270 }
271
272 if (now >= audio->play_until) {
273 looping = 0;
274 freq = 0;
275 }
276
277 /* Do action here. */
278 if (audio->background_beep) {
279 if (audio->current_frequency != freq) {
280 VbExBeep(0, freq);
281 audio->current_frequency = freq;
282 }
283 } else if (freq && msec) {
284 VbExBeep(msec, freq);
285 now = VbExGetTimer();
286 }
287
288 audio->last_time = now;
289 return looping;
290 }
291
292 /**
293 * Caller should call this prior to booting.
294 */
VbAudioClose(VbAudioContext * audio)295 void VbAudioClose(VbAudioContext *audio)
296 {
297 VbExBeep(0,0);
298 if (audio->free_notes_when_done)
299 VbExFree(audio->music_notes);
300 }
301