xref: /openbmc/linux/arch/m68k/mac/macboing.c (revision 7effbd18)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *	Mac bong noise generator. Note - we ought to put a boingy noise
4  *	here 8)
5  *
6  *	----------------------------------------------------------------------
7  *	16.11.98:
8  *	rewrote some functions, added support for Enhanced ASC (Quadras)
9  *	after the NetBSD asc.c console bell patch by Colin Wood/Frederick Bruck
10  *	Juergen Mellinger (juergen.mellinger@t-online.de)
11  */
12 
13 #include <linux/sched.h>
14 #include <linux/timer.h>
15 
16 #include <asm/macintosh.h>
17 #include <asm/mac_asc.h>
18 
19 static int mac_asc_inited;
20 /*
21  * dumb triangular wave table
22  */
23 static __u8 mac_asc_wave_tab[ 0x800 ];
24 
25 /*
26  * Alan's original sine table; needs interpolating to 0x800
27  * (hint: interpolate or hardwire [0 -> Pi/2[, it's symmetric)
28  */
29 static const signed char sine_data[] = {
30 	0,  39,  75,  103,  121,  127,  121,  103,  75,  39,
31 	0, -39, -75, -103, -121, -127, -121, -103, -75, -39
32 };
33 
34 /*
35  * where the ASC hides ...
36  */
37 static volatile __u8* mac_asc_regs = ( void* )0x50F14000;
38 
39 /*
40  * sample rate; is this a good default value?
41  */
42 static unsigned long mac_asc_samplespersec = 11050;
43 static int mac_bell_duration;
44 static unsigned long mac_bell_phase; /* 0..2*Pi -> 0..0x800 (wavetable size) */
45 static unsigned long mac_bell_phasepersample;
46 
47 /*
48  * some function protos
49  */
50 static void mac_init_asc( void );
51 static void mac_nosound(struct timer_list *);
52 static void mac_quadra_start_bell( unsigned int, unsigned int, unsigned int );
53 static void mac_quadra_ring_bell(struct timer_list *);
54 static void mac_av_start_bell( unsigned int, unsigned int, unsigned int );
55 static void ( *mac_special_bell )( unsigned int, unsigned int, unsigned int );
56 
57 /*
58  * our timer to start/continue/stop the bell
59  */
60 static DEFINE_TIMER(mac_sound_timer, mac_nosound);
61 
62 /*
63  * Sort of initialize the sound chip (called from mac_mksound on the first
64  * beep).
65  */
66 static void mac_init_asc( void )
67 {
68 	int i;
69 
70 	/*
71 	 * do some machine specific initialization
72 	 * BTW:
73 	 * the NetBSD Quadra patch identifies the Enhanced Apple Sound Chip via
74 	 *	mac_asc_regs[ 0x800 ] & 0xF0 != 0
75 	 * this makes no sense here, because we have to set the default sample
76 	 * rate anyway if we want correct frequencies
77 	 */
78 	switch ( macintosh_config->ident )
79 	{
80 		case MAC_MODEL_IIFX:
81 			/*
82 			 * The IIfx is always special ...
83 			 */
84 			mac_asc_regs = ( void* )0x50010000;
85 			break;
86 			/*
87 			 * not sure about how correct this list is
88 			 * machines with the EASC enhanced apple sound chip
89 			 */
90 		case MAC_MODEL_Q630:
91 		case MAC_MODEL_P475:
92 			mac_special_bell = mac_quadra_start_bell;
93 			mac_asc_samplespersec = 22150;
94 			break;
95 		case MAC_MODEL_C660:
96 		case MAC_MODEL_Q840:
97 			/*
98 			 * The Quadra 660AV and 840AV use the "Singer" custom ASIC for sound I/O.
99 			 * It appears to be similar to the "AWACS" custom ASIC in the Power Mac
100 			 * [678]100.  Because Singer and AWACS may have a similar hardware
101 			 * interface, this would imply that the code in drivers/sound/dmasound.c
102 			 * for AWACS could be used as a basis for Singer support.  All we have to
103 			 * do is figure out how to do DMA on the 660AV/840AV through the PSC and
104 			 * figure out where the Singer hardware sits in memory. (I'd look in the
105 			 * vicinity of the AWACS location in a Power Mac [678]100 first, or the
106 			 * current location of the Apple Sound Chip--ASC--in other Macs.)  The
107 			 * Power Mac [678]100 info can be found in MkLinux Mach kernel sources.
108 			 *
109 			 * Quoted from Apple's Tech Info Library, article number 16405:
110 			 *   "Among desktop Macintosh computers, only the 660AV, 840AV, and Power
111 			 *   Macintosh models have 16-bit audio input and output capability
112 			 *   because of the AT&T DSP3210 hardware circuitry and the 16-bit Singer
113 			 *   codec circuitry in the AVs.  The Audio Waveform Amplifier and
114 			 *   Converter (AWAC) chip in the Power Macintosh performs the same
115 			 *   16-bit I/O functionality.  The PowerBook 500 series computers
116 			 *   support 16-bit stereo output, but only mono input."
117 			 *
118 			 *   Technical Information Library (TIL) article number 16405.
119 			 *   https://support.apple.com/kb/TA32601
120 			 *
121 			 * --David Kilzer
122 			 */
123 			mac_special_bell = mac_av_start_bell;
124 			break;
125 		case MAC_MODEL_Q650:
126 		case MAC_MODEL_Q700:
127 		case MAC_MODEL_Q800:
128 		case MAC_MODEL_Q900:
129 		case MAC_MODEL_Q950:
130 			/*
131 			 * Currently not implemented!
132 			 */
133 			mac_special_bell = NULL;
134 			break;
135 		default:
136 			/*
137 			 * Every switch needs a default
138 			 */
139 			mac_special_bell = NULL;
140 			break;
141 	}
142 
143 	/*
144 	 * init the wave table with a simple triangular wave
145 	 * A sine wave would sure be nicer here ...
146 	 */
147 	for ( i = 0; i < 0x400; i++ )
148 	{
149 		mac_asc_wave_tab[ i ] = i / 4;
150 		mac_asc_wave_tab[ i + 0x400 ] = 0xFF - i / 4;
151 	}
152 	mac_asc_inited = 1;
153 }
154 
155 /*
156  * Called to make noise; current single entry to the boing driver.
157  * Does the job for simple ASC, calls other routines else.
158  * XXX Fixme:
159  * Should be split into asc_mksound, easc_mksound, av_mksound and
160  * function pointer set in mac_init_asc which would be called at
161  * init time.
162  * _This_ is rather ugly ...
163  */
164 void mac_mksound( unsigned int freq, unsigned int length )
165 {
166 	__u32 cfreq = ( freq << 5 ) / 468;
167 	unsigned long flags;
168 	int i;
169 
170 	if ( mac_special_bell == NULL )
171 	{
172 		/* Do nothing */
173 		return;
174 	}
175 
176 	if ( !mac_asc_inited )
177 		mac_init_asc();
178 
179 	if ( mac_special_bell )
180 	{
181 		mac_special_bell( freq, length, 128 );
182 		return;
183 	}
184 
185 	if ( freq < 20 || freq > 20000 || length == 0 )
186 	{
187 		mac_nosound( 0 );
188 		return;
189 	}
190 
191 	local_irq_save(flags);
192 
193 	del_timer( &mac_sound_timer );
194 
195 	for ( i = 0; i < 0x800; i++ )
196 		mac_asc_regs[ i ] = 0;
197 	for ( i = 0; i < 0x800; i++ )
198 		mac_asc_regs[ i ] = mac_asc_wave_tab[ i ];
199 
200 	for ( i = 0; i < 8; i++ )
201 		*( __u32* )( ( __u32 )mac_asc_regs + ASC_CONTROL + 0x814 + 8 * i ) = cfreq;
202 
203 	mac_asc_regs[ 0x807 ] = 0;
204 	mac_asc_regs[ ASC_VOLUME ] = 128;
205 	mac_asc_regs[ 0x805 ] = 0;
206 	mac_asc_regs[ 0x80F ] = 0;
207 	mac_asc_regs[ ASC_MODE ] = ASC_MODE_SAMPLE;
208 	mac_asc_regs[ ASC_ENABLE ] = ASC_ENABLE_SAMPLE;
209 
210 	mac_sound_timer.expires = jiffies + length;
211 	add_timer( &mac_sound_timer );
212 
213 	local_irq_restore(flags);
214 }
215 
216 /*
217  * regular ASC: stop whining ..
218  */
219 static void mac_nosound(struct timer_list *unused)
220 {
221 	mac_asc_regs[ ASC_ENABLE ] = 0;
222 }
223 
224 /*
225  * EASC entry; init EASC, don't load wavetable, schedule 'start whining'.
226  */
227 static void mac_quadra_start_bell( unsigned int freq, unsigned int length, unsigned int volume )
228 {
229 	unsigned long flags;
230 
231 	/* if the bell is already ringing, ring longer */
232 	if ( mac_bell_duration > 0 )
233 	{
234 		mac_bell_duration += length;
235 		return;
236 	}
237 
238 	mac_bell_duration = length;
239 	mac_bell_phase = 0;
240 	mac_bell_phasepersample = ( freq * sizeof( mac_asc_wave_tab ) ) / mac_asc_samplespersec;
241 	/* this is reasonably big for small frequencies */
242 
243 	local_irq_save(flags);
244 
245 	/* set the volume */
246 	mac_asc_regs[ 0x806 ] = volume;
247 
248 	/* set up the ASC registers */
249 	if ( mac_asc_regs[ 0x801 ] != 1 )
250 	{
251 		/* select mono mode */
252 		mac_asc_regs[ 0x807 ] = 0;
253 		/* select sampled sound mode */
254 		mac_asc_regs[ 0x802 ] = 0;
255 		/* ??? */
256 		mac_asc_regs[ 0x801 ] = 1;
257 		mac_asc_regs[ 0x803 ] |= 0x80;
258 		mac_asc_regs[ 0x803 ] &= 0x7F;
259 	}
260 
261 	mac_sound_timer.function = mac_quadra_ring_bell;
262 	mac_sound_timer.expires = jiffies + 1;
263 	add_timer( &mac_sound_timer );
264 
265 	local_irq_restore(flags);
266 }
267 
268 /*
269  * EASC 'start/continue whining'; I'm not sure why the above function didn't
270  * already load the wave table, or at least call this one...
271  * This piece keeps reloading the wave table until done.
272  */
273 static void mac_quadra_ring_bell(struct timer_list *unused)
274 {
275 	int	i, count = mac_asc_samplespersec / HZ;
276 	unsigned long flags;
277 
278 	/*
279 	 * we neither want a sound buffer overflow nor underflow, so we need to match
280 	 * the number of samples per timer interrupt as exactly as possible.
281 	 * using the asc interrupt will give better results in the future
282 	 * ...and the possibility to use a real sample (a boingy noise, maybe...)
283 	 */
284 
285 	local_irq_save(flags);
286 
287 	del_timer( &mac_sound_timer );
288 
289 	if ( mac_bell_duration-- > 0 )
290 	{
291 		for ( i = 0; i < count; i++ )
292 		{
293 			mac_bell_phase += mac_bell_phasepersample;
294 			mac_asc_regs[ 0 ] = mac_asc_wave_tab[ mac_bell_phase & ( sizeof( mac_asc_wave_tab ) - 1 ) ];
295 		}
296 		mac_sound_timer.expires = jiffies + 1;
297 		add_timer( &mac_sound_timer );
298 	}
299 	else
300 		mac_asc_regs[ 0x801 ] = 0;
301 
302 	local_irq_restore(flags);
303 }
304 
305 /*
306  * AV code - please fill in.
307  */
308 static void mac_av_start_bell( unsigned int freq, unsigned int length, unsigned int volume )
309 {
310 }
311