xref: /openbmc/linux/sound/drivers/pcsp/pcsp_lib.c (revision 7b73a9c8)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * PC-Speaker driver for Linux
4  *
5  * Copyright (C) 1993-1997  Michael Beck
6  * Copyright (C) 1997-2001  David Woodhouse
7  * Copyright (C) 2001-2008  Stas Sergeev
8  */
9 
10 #include <linux/module.h>
11 #include <linux/gfp.h>
12 #include <linux/moduleparam.h>
13 #include <linux/interrupt.h>
14 #include <linux/io.h>
15 #include <sound/pcm.h>
16 #include "pcsp.h"
17 
18 static bool nforce_wa;
19 module_param(nforce_wa, bool, 0444);
20 MODULE_PARM_DESC(nforce_wa, "Apply NForce chipset workaround "
21 		"(expect bad sound)");
22 
23 #define DMIX_WANTS_S16	1
24 
25 /*
26  * Call snd_pcm_period_elapsed in a tasklet
27  * This avoids spinlock messes and long-running irq contexts
28  */
29 static void pcsp_call_pcm_elapsed(unsigned long priv)
30 {
31 	if (atomic_read(&pcsp_chip.timer_active)) {
32 		struct snd_pcm_substream *substream;
33 		substream = pcsp_chip.playback_substream;
34 		if (substream)
35 			snd_pcm_period_elapsed(substream);
36 	}
37 }
38 
39 static DECLARE_TASKLET(pcsp_pcm_tasklet, pcsp_call_pcm_elapsed, 0);
40 
41 /* write the port and returns the next expire time in ns;
42  * called at the trigger-start and in hrtimer callback
43  */
44 static u64 pcsp_timer_update(struct snd_pcsp *chip)
45 {
46 	unsigned char timer_cnt, val;
47 	u64 ns;
48 	struct snd_pcm_substream *substream;
49 	struct snd_pcm_runtime *runtime;
50 	unsigned long flags;
51 
52 	if (chip->thalf) {
53 		outb(chip->val61, 0x61);
54 		chip->thalf = 0;
55 		return chip->ns_rem;
56 	}
57 
58 	substream = chip->playback_substream;
59 	if (!substream)
60 		return 0;
61 
62 	runtime = substream->runtime;
63 	/* assume it is mono! */
64 	val = runtime->dma_area[chip->playback_ptr + chip->fmt_size - 1];
65 	if (chip->is_signed)
66 		val ^= 0x80;
67 	timer_cnt = val * CUR_DIV() / 256;
68 
69 	if (timer_cnt && chip->enable) {
70 		raw_spin_lock_irqsave(&i8253_lock, flags);
71 		if (!nforce_wa) {
72 			outb_p(chip->val61, 0x61);
73 			outb_p(timer_cnt, 0x42);
74 			outb(chip->val61 ^ 1, 0x61);
75 		} else {
76 			outb(chip->val61 ^ 2, 0x61);
77 			chip->thalf = 1;
78 		}
79 		raw_spin_unlock_irqrestore(&i8253_lock, flags);
80 	}
81 
82 	chip->ns_rem = PCSP_PERIOD_NS();
83 	ns = (chip->thalf ? PCSP_CALC_NS(timer_cnt) : chip->ns_rem);
84 	chip->ns_rem -= ns;
85 	return ns;
86 }
87 
88 static void pcsp_pointer_update(struct snd_pcsp *chip)
89 {
90 	struct snd_pcm_substream *substream;
91 	size_t period_bytes, buffer_bytes;
92 	int periods_elapsed;
93 	unsigned long flags;
94 
95 	/* update the playback position */
96 	substream = chip->playback_substream;
97 	if (!substream)
98 		return;
99 
100 	period_bytes = snd_pcm_lib_period_bytes(substream);
101 	buffer_bytes = snd_pcm_lib_buffer_bytes(substream);
102 
103 	spin_lock_irqsave(&chip->substream_lock, flags);
104 	chip->playback_ptr += PCSP_INDEX_INC() * chip->fmt_size;
105 	periods_elapsed = chip->playback_ptr - chip->period_ptr;
106 	if (periods_elapsed < 0) {
107 #if PCSP_DEBUG
108 		printk(KERN_INFO "PCSP: buffer_bytes mod period_bytes != 0 ? "
109 			"(%zi %zi %zi)\n",
110 			chip->playback_ptr, period_bytes, buffer_bytes);
111 #endif
112 		periods_elapsed += buffer_bytes;
113 	}
114 	periods_elapsed /= period_bytes;
115 	/* wrap the pointer _before_ calling snd_pcm_period_elapsed(),
116 	 * or ALSA will BUG on us. */
117 	chip->playback_ptr %= buffer_bytes;
118 
119 	if (periods_elapsed) {
120 		chip->period_ptr += periods_elapsed * period_bytes;
121 		chip->period_ptr %= buffer_bytes;
122 	}
123 	spin_unlock_irqrestore(&chip->substream_lock, flags);
124 
125 	if (periods_elapsed)
126 		tasklet_schedule(&pcsp_pcm_tasklet);
127 }
128 
129 enum hrtimer_restart pcsp_do_timer(struct hrtimer *handle)
130 {
131 	struct snd_pcsp *chip = container_of(handle, struct snd_pcsp, timer);
132 	int pointer_update;
133 	u64 ns;
134 
135 	if (!atomic_read(&chip->timer_active) || !chip->playback_substream)
136 		return HRTIMER_NORESTART;
137 
138 	pointer_update = !chip->thalf;
139 	ns = pcsp_timer_update(chip);
140 	if (!ns) {
141 		printk(KERN_WARNING "PCSP: unexpected stop\n");
142 		return HRTIMER_NORESTART;
143 	}
144 
145 	if (pointer_update)
146 		pcsp_pointer_update(chip);
147 
148 	hrtimer_forward(handle, hrtimer_get_expires(handle), ns_to_ktime(ns));
149 
150 	return HRTIMER_RESTART;
151 }
152 
153 static int pcsp_start_playing(struct snd_pcsp *chip)
154 {
155 #if PCSP_DEBUG
156 	printk(KERN_INFO "PCSP: start_playing called\n");
157 #endif
158 	if (atomic_read(&chip->timer_active)) {
159 		printk(KERN_ERR "PCSP: Timer already active\n");
160 		return -EIO;
161 	}
162 
163 	raw_spin_lock(&i8253_lock);
164 	chip->val61 = inb(0x61) | 0x03;
165 	outb_p(0x92, 0x43);	/* binary, mode 1, LSB only, ch 2 */
166 	raw_spin_unlock(&i8253_lock);
167 	atomic_set(&chip->timer_active, 1);
168 	chip->thalf = 0;
169 
170 	hrtimer_start(&pcsp_chip.timer, 0, HRTIMER_MODE_REL);
171 	return 0;
172 }
173 
174 static void pcsp_stop_playing(struct snd_pcsp *chip)
175 {
176 #if PCSP_DEBUG
177 	printk(KERN_INFO "PCSP: stop_playing called\n");
178 #endif
179 	if (!atomic_read(&chip->timer_active))
180 		return;
181 
182 	atomic_set(&chip->timer_active, 0);
183 	raw_spin_lock(&i8253_lock);
184 	/* restore the timer */
185 	outb_p(0xb6, 0x43);	/* binary, mode 3, LSB/MSB, ch 2 */
186 	outb(chip->val61 & 0xFC, 0x61);
187 	raw_spin_unlock(&i8253_lock);
188 }
189 
190 /*
191  * Force to stop and sync the stream
192  */
193 void pcsp_sync_stop(struct snd_pcsp *chip)
194 {
195 	local_irq_disable();
196 	pcsp_stop_playing(chip);
197 	local_irq_enable();
198 	hrtimer_cancel(&chip->timer);
199 	tasklet_kill(&pcsp_pcm_tasklet);
200 }
201 
202 static int snd_pcsp_playback_close(struct snd_pcm_substream *substream)
203 {
204 	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
205 #if PCSP_DEBUG
206 	printk(KERN_INFO "PCSP: close called\n");
207 #endif
208 	pcsp_sync_stop(chip);
209 	chip->playback_substream = NULL;
210 	return 0;
211 }
212 
213 static int snd_pcsp_playback_hw_params(struct snd_pcm_substream *substream,
214 				       struct snd_pcm_hw_params *hw_params)
215 {
216 	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
217 	int err;
218 	pcsp_sync_stop(chip);
219 	err = snd_pcm_lib_malloc_pages(substream,
220 				      params_buffer_bytes(hw_params));
221 	if (err < 0)
222 		return err;
223 	return 0;
224 }
225 
226 static int snd_pcsp_playback_hw_free(struct snd_pcm_substream *substream)
227 {
228 	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
229 #if PCSP_DEBUG
230 	printk(KERN_INFO "PCSP: hw_free called\n");
231 #endif
232 	pcsp_sync_stop(chip);
233 	return snd_pcm_lib_free_pages(substream);
234 }
235 
236 static int snd_pcsp_playback_prepare(struct snd_pcm_substream *substream)
237 {
238 	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
239 	pcsp_sync_stop(chip);
240 	chip->playback_ptr = 0;
241 	chip->period_ptr = 0;
242 	chip->fmt_size =
243 		snd_pcm_format_physical_width(substream->runtime->format) >> 3;
244 	chip->is_signed = snd_pcm_format_signed(substream->runtime->format);
245 #if PCSP_DEBUG
246 	printk(KERN_INFO "PCSP: prepare called, "
247 			"size=%zi psize=%zi f=%zi f1=%i fsize=%i\n",
248 			snd_pcm_lib_buffer_bytes(substream),
249 			snd_pcm_lib_period_bytes(substream),
250 			snd_pcm_lib_buffer_bytes(substream) /
251 			snd_pcm_lib_period_bytes(substream),
252 			substream->runtime->periods,
253 			chip->fmt_size);
254 #endif
255 	return 0;
256 }
257 
258 static int snd_pcsp_trigger(struct snd_pcm_substream *substream, int cmd)
259 {
260 	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
261 #if PCSP_DEBUG
262 	printk(KERN_INFO "PCSP: trigger called\n");
263 #endif
264 	switch (cmd) {
265 	case SNDRV_PCM_TRIGGER_START:
266 	case SNDRV_PCM_TRIGGER_RESUME:
267 		return pcsp_start_playing(chip);
268 	case SNDRV_PCM_TRIGGER_STOP:
269 	case SNDRV_PCM_TRIGGER_SUSPEND:
270 		pcsp_stop_playing(chip);
271 		break;
272 	default:
273 		return -EINVAL;
274 	}
275 	return 0;
276 }
277 
278 static snd_pcm_uframes_t snd_pcsp_playback_pointer(struct snd_pcm_substream
279 						   *substream)
280 {
281 	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
282 	unsigned int pos;
283 	spin_lock(&chip->substream_lock);
284 	pos = chip->playback_ptr;
285 	spin_unlock(&chip->substream_lock);
286 	return bytes_to_frames(substream->runtime, pos);
287 }
288 
289 static const struct snd_pcm_hardware snd_pcsp_playback = {
290 	.info = (SNDRV_PCM_INFO_INTERLEAVED |
291 		 SNDRV_PCM_INFO_HALF_DUPLEX |
292 		 SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID),
293 	.formats = (SNDRV_PCM_FMTBIT_U8
294 #if DMIX_WANTS_S16
295 		    | SNDRV_PCM_FMTBIT_S16_LE
296 #endif
297 	    ),
298 	.rates = SNDRV_PCM_RATE_KNOT,
299 	.rate_min = PCSP_DEFAULT_SRATE,
300 	.rate_max = PCSP_DEFAULT_SRATE,
301 	.channels_min = 1,
302 	.channels_max = 1,
303 	.buffer_bytes_max = PCSP_BUFFER_SIZE,
304 	.period_bytes_min = 64,
305 	.period_bytes_max = PCSP_MAX_PERIOD_SIZE,
306 	.periods_min = 2,
307 	.periods_max = PCSP_MAX_PERIODS,
308 	.fifo_size = 0,
309 };
310 
311 static int snd_pcsp_playback_open(struct snd_pcm_substream *substream)
312 {
313 	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
314 	struct snd_pcm_runtime *runtime = substream->runtime;
315 #if PCSP_DEBUG
316 	printk(KERN_INFO "PCSP: open called\n");
317 #endif
318 	if (atomic_read(&chip->timer_active)) {
319 		printk(KERN_ERR "PCSP: still active!!\n");
320 		return -EBUSY;
321 	}
322 	runtime->hw = snd_pcsp_playback;
323 	chip->playback_substream = substream;
324 	return 0;
325 }
326 
327 static const struct snd_pcm_ops snd_pcsp_playback_ops = {
328 	.open = snd_pcsp_playback_open,
329 	.close = snd_pcsp_playback_close,
330 	.ioctl = snd_pcm_lib_ioctl,
331 	.hw_params = snd_pcsp_playback_hw_params,
332 	.hw_free = snd_pcsp_playback_hw_free,
333 	.prepare = snd_pcsp_playback_prepare,
334 	.trigger = snd_pcsp_trigger,
335 	.pointer = snd_pcsp_playback_pointer,
336 };
337 
338 int snd_pcsp_new_pcm(struct snd_pcsp *chip)
339 {
340 	int err;
341 
342 	err = snd_pcm_new(chip->card, "pcspeaker", 0, 1, 0, &chip->pcm);
343 	if (err < 0)
344 		return err;
345 
346 	snd_pcm_set_ops(chip->pcm, SNDRV_PCM_STREAM_PLAYBACK,
347 			&snd_pcsp_playback_ops);
348 
349 	chip->pcm->private_data = chip;
350 	chip->pcm->info_flags = SNDRV_PCM_INFO_HALF_DUPLEX;
351 	strcpy(chip->pcm->name, "pcsp");
352 
353 	snd_pcm_lib_preallocate_pages_for_all(chip->pcm,
354 					      SNDRV_DMA_TYPE_CONTINUOUS,
355 					      NULL,
356 					      PCSP_BUFFER_SIZE,
357 					      PCSP_BUFFER_SIZE);
358 
359 	return 0;
360 }
361