1/*
2 *	Mac bong noise generator. Note - we ought to put a boingy noise
3 *	here 8)
4 *
5 *	----------------------------------------------------------------------
6 *	16.11.98:
7 *	rewrote some functions, added support for Enhanced ASC (Quadras)
8 *	after the NetBSD asc.c console bell patch by Colin Wood/Frederick Bruck
9 *	Juergen Mellinger (juergen.mellinger@t-online.de)
10 */
11
12#include <linux/sched.h>
13#include <linux/timer.h>
14
15#include <asm/macintosh.h>
16#include <asm/mac_asc.h>
17
18static int mac_asc_inited;
19/*
20 * dumb triangular wave table
21 */
22static __u8 mac_asc_wave_tab[ 0x800 ];
23
24/*
25 * Alan's original sine table; needs interpolating to 0x800
26 * (hint: interpolate or hardwire [0 -> Pi/2[, it's symmetric)
27 */
28static const signed char sine_data[] = {
29	0,  39,  75,  103,  121,  127,  121,  103,  75,  39,
30	0, -39, -75, -103, -121, -127, -121, -103, -75, -39
31};
32
33/*
34 * where the ASC hides ...
35 */
36static volatile __u8* mac_asc_regs = ( void* )0x50F14000;
37
38/*
39 * sample rate; is this a good default value?
40 */
41static unsigned long mac_asc_samplespersec = 11050;
42static int mac_bell_duration;
43static unsigned long mac_bell_phase; /* 0..2*Pi -> 0..0x800 (wavetable size) */
44static unsigned long mac_bell_phasepersample;
45
46/*
47 * some function protos
48 */
49static void mac_init_asc( void );
50static void mac_nosound( unsigned long );
51static void mac_quadra_start_bell( unsigned int, unsigned int, unsigned int );
52static void mac_quadra_ring_bell( unsigned long );
53static void mac_av_start_bell( unsigned int, unsigned int, unsigned int );
54static void ( *mac_special_bell )( unsigned int, unsigned int, unsigned int );
55
56/*
57 * our timer to start/continue/stop the bell
58 */
59static DEFINE_TIMER(mac_sound_timer, mac_nosound, 0, 0);
60
61/*
62 * Sort of initialize the sound chip (called from mac_mksound on the first
63 * beep).
64 */
65static void mac_init_asc( void )
66{
67	int i;
68
69	/*
70	 * do some machine specific initialization
71	 * BTW:
72	 * the NetBSD Quadra patch identifies the Enhanced Apple Sound Chip via
73	 *	mac_asc_regs[ 0x800 ] & 0xF0 != 0
74	 * this makes no sense here, because we have to set the default sample
75	 * rate anyway if we want correct frequencies
76	 */
77	switch ( macintosh_config->ident )
78	{
79		case MAC_MODEL_IIFX:
80			/*
81			 * The IIfx is always special ...
82			 */
83			mac_asc_regs = ( void* )0x50010000;
84			break;
85			/*
86			 * not sure about how correct this list is
87			 * machines with the EASC enhanced apple sound chip
88			 */
89		case MAC_MODEL_Q630:
90		case MAC_MODEL_P475:
91			mac_special_bell = mac_quadra_start_bell;
92			mac_asc_samplespersec = 22150;
93			break;
94		case MAC_MODEL_C660:
95		case MAC_MODEL_Q840:
96			/*
97			 * The Quadra 660AV and 840AV use the "Singer" custom ASIC for sound I/O.
98			 * It appears to be similar to the "AWACS" custom ASIC in the Power Mac
99			 * [678]100.  Because Singer and AWACS may have a similar hardware
100			 * interface, this would imply that the code in drivers/sound/dmasound.c
101			 * for AWACS could be used as a basis for Singer support.  All we have to
102			 * do is figure out how to do DMA on the 660AV/840AV through the PSC and
103			 * figure out where the Singer hardware sits in memory. (I'd look in the
104			 * vicinity of the AWACS location in a Power Mac [678]100 first, or the
105			 * current location of the Apple Sound Chip--ASC--in other Macs.)  The
106			 * Power Mac [678]100 info can be found in MkLinux Mach kernel sources.
107			 *
108			 * Quoted from Apple's Tech Info Library, article number 16405:
109			 *   "Among desktop Macintosh computers, only the 660AV, 840AV, and Power
110			 *   Macintosh models have 16-bit audio input and output capability
111			 *   because of the AT&T DSP3210 hardware circuitry and the 16-bit Singer
112			 *   codec circuitry in the AVs.  The Audio Waveform Amplifier and
113			 *   Converter (AWAC) chip in the Power Macintosh performs the same
114			 *   16-bit I/O functionality.  The PowerBook 500 series computers
115			 *   support 16-bit stereo output, but only mono input."
116			 *
117			 *   Technical Information Library (TIL) article number 16405.
118			 *   http://support.apple.com/kb/TA32601
119			 *
120			 * --David Kilzer
121			 */
122			mac_special_bell = mac_av_start_bell;
123			break;
124		case MAC_MODEL_Q650:
125		case MAC_MODEL_Q700:
126		case MAC_MODEL_Q800:
127		case MAC_MODEL_Q900:
128		case MAC_MODEL_Q950:
129			/*
130			 * Currently not implemented!
131			 */
132			mac_special_bell = NULL;
133			break;
134		default:
135			/*
136			 * Every switch needs a default
137			 */
138			mac_special_bell = NULL;
139			break;
140	}
141
142	/*
143	 * init the wave table with a simple triangular wave
144	 * A sine wave would sure be nicer here ...
145	 */
146	for ( i = 0; i < 0x400; i++ )
147	{
148		mac_asc_wave_tab[ i ] = i / 4;
149		mac_asc_wave_tab[ i + 0x400 ] = 0xFF - i / 4;
150	}
151	mac_asc_inited = 1;
152}
153
154/*
155 * Called to make noise; current single entry to the boing driver.
156 * Does the job for simple ASC, calls other routines else.
157 * XXX Fixme:
158 * Should be split into asc_mksound, easc_mksound, av_mksound and
159 * function pointer set in mac_init_asc which would be called at
160 * init time.
161 * _This_ is rather ugly ...
162 */
163void mac_mksound( unsigned int freq, unsigned int length )
164{
165	__u32 cfreq = ( freq << 5 ) / 468;
166	unsigned long flags;
167	int i;
168
169	if ( mac_special_bell == NULL )
170	{
171		/* Do nothing */
172		return;
173	}
174
175	if ( !mac_asc_inited )
176		mac_init_asc();
177
178	if ( mac_special_bell )
179	{
180		mac_special_bell( freq, length, 128 );
181		return;
182	}
183
184	if ( freq < 20 || freq > 20000 || length == 0 )
185	{
186		mac_nosound( 0 );
187		return;
188	}
189
190	local_irq_save(flags);
191
192	del_timer( &mac_sound_timer );
193
194	for ( i = 0; i < 0x800; i++ )
195		mac_asc_regs[ i ] = 0;
196	for ( i = 0; i < 0x800; i++ )
197		mac_asc_regs[ i ] = mac_asc_wave_tab[ i ];
198
199	for ( i = 0; i < 8; i++ )
200		*( __u32* )( ( __u32 )mac_asc_regs + ASC_CONTROL + 0x814 + 8 * i ) = cfreq;
201
202	mac_asc_regs[ 0x807 ] = 0;
203	mac_asc_regs[ ASC_VOLUME ] = 128;
204	mac_asc_regs[ 0x805 ] = 0;
205	mac_asc_regs[ 0x80F ] = 0;
206	mac_asc_regs[ ASC_MODE ] = ASC_MODE_SAMPLE;
207	mac_asc_regs[ ASC_ENABLE ] = ASC_ENABLE_SAMPLE;
208
209	mac_sound_timer.expires = jiffies + length;
210	add_timer( &mac_sound_timer );
211
212	local_irq_restore(flags);
213}
214
215/*
216 * regular ASC: stop whining ..
217 */
218static void mac_nosound( unsigned long ignored )
219{
220	mac_asc_regs[ ASC_ENABLE ] = 0;
221}
222
223/*
224 * EASC entry; init EASC, don't load wavetable, schedule 'start whining'.
225 */
226static void mac_quadra_start_bell( unsigned int freq, unsigned int length, unsigned int volume )
227{
228	unsigned long flags;
229
230	/* if the bell is already ringing, ring longer */
231	if ( mac_bell_duration > 0 )
232	{
233		mac_bell_duration += length;
234		return;
235	}
236
237	mac_bell_duration = length;
238	mac_bell_phase = 0;
239	mac_bell_phasepersample = ( freq * sizeof( mac_asc_wave_tab ) ) / mac_asc_samplespersec;
240	/* this is reasonably big for small frequencies */
241
242	local_irq_save(flags);
243
244	/* set the volume */
245	mac_asc_regs[ 0x806 ] = volume;
246
247	/* set up the ASC registers */
248	if ( mac_asc_regs[ 0x801 ] != 1 )
249	{
250		/* select mono mode */
251		mac_asc_regs[ 0x807 ] = 0;
252		/* select sampled sound mode */
253		mac_asc_regs[ 0x802 ] = 0;
254		/* ??? */
255		mac_asc_regs[ 0x801 ] = 1;
256		mac_asc_regs[ 0x803 ] |= 0x80;
257		mac_asc_regs[ 0x803 ] &= 0x7F;
258	}
259
260	mac_sound_timer.function = mac_quadra_ring_bell;
261	mac_sound_timer.expires = jiffies + 1;
262	add_timer( &mac_sound_timer );
263
264	local_irq_restore(flags);
265}
266
267/*
268 * EASC 'start/continue whining'; I'm not sure why the above function didn't
269 * already load the wave table, or at least call this one...
270 * This piece keeps reloading the wave table until done.
271 */
272static void mac_quadra_ring_bell( unsigned long ignored )
273{
274	int	i, count = mac_asc_samplespersec / HZ;
275	unsigned long flags;
276
277	/*
278	 * we neither want a sound buffer overflow nor underflow, so we need to match
279	 * the number of samples per timer interrupt as exactly as possible.
280	 * using the asc interrupt will give better results in the future
281	 * ...and the possibility to use a real sample (a boingy noise, maybe...)
282	 */
283
284	local_irq_save(flags);
285
286	del_timer( &mac_sound_timer );
287
288	if ( mac_bell_duration-- > 0 )
289	{
290		for ( i = 0; i < count; i++ )
291		{
292			mac_bell_phase += mac_bell_phasepersample;
293			mac_asc_regs[ 0 ] = mac_asc_wave_tab[ mac_bell_phase & ( sizeof( mac_asc_wave_tab ) - 1 ) ];
294		}
295		mac_sound_timer.expires = jiffies + 1;
296		add_timer( &mac_sound_timer );
297	}
298	else
299		mac_asc_regs[ 0x801 ] = 0;
300
301	local_irq_restore(flags);
302}
303
304/*
305 * AV code - please fill in.
306 */
307static void mac_av_start_bell( unsigned int freq, unsigned int length, unsigned int volume )
308{
309}
310