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
18static bool nforce_wa;
19module_param(nforce_wa, bool, 0444);
20MODULE_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 work
27 * This avoids spinlock messes and long-running irq contexts
28 */
29static void pcsp_call_pcm_elapsed(struct work_struct *work)
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
39static DECLARE_WORK(pcsp_pcm_work, pcsp_call_pcm_elapsed);
40
41/* write the port and returns the next expire time in ns;
42 * called at the trigger-start and in hrtimer callback
43 */
44static 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
88static 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		queue_work(system_highpri_wq, &pcsp_pcm_work);
123	}
124	spin_unlock_irqrestore(&chip->substream_lock, flags);
125}
126
127enum hrtimer_restart pcsp_do_timer(struct hrtimer *handle)
128{
129	struct snd_pcsp *chip = container_of(handle, struct snd_pcsp, timer);
130	int pointer_update;
131	u64 ns;
132
133	if (!atomic_read(&chip->timer_active) || !chip->playback_substream)
134		return HRTIMER_NORESTART;
135
136	pointer_update = !chip->thalf;
137	ns = pcsp_timer_update(chip);
138	if (!ns) {
139		printk(KERN_WARNING "PCSP: unexpected stop\n");
140		return HRTIMER_NORESTART;
141	}
142
143	if (pointer_update)
144		pcsp_pointer_update(chip);
145
146	hrtimer_forward_now(handle, ns_to_ktime(ns));
147
148	return HRTIMER_RESTART;
149}
150
151static int pcsp_start_playing(struct snd_pcsp *chip)
152{
153#if PCSP_DEBUG
154	printk(KERN_INFO "PCSP: start_playing called\n");
155#endif
156	if (atomic_read(&chip->timer_active)) {
157		printk(KERN_ERR "PCSP: Timer already active\n");
158		return -EIO;
159	}
160
161	raw_spin_lock(&i8253_lock);
162	chip->val61 = inb(0x61) | 0x03;
163	outb_p(0x92, 0x43);	/* binary, mode 1, LSB only, ch 2 */
164	raw_spin_unlock(&i8253_lock);
165	atomic_set(&chip->timer_active, 1);
166	chip->thalf = 0;
167
168	hrtimer_start(&pcsp_chip.timer, 0, HRTIMER_MODE_REL);
169	return 0;
170}
171
172static void pcsp_stop_playing(struct snd_pcsp *chip)
173{
174#if PCSP_DEBUG
175	printk(KERN_INFO "PCSP: stop_playing called\n");
176#endif
177	if (!atomic_read(&chip->timer_active))
178		return;
179
180	atomic_set(&chip->timer_active, 0);
181	raw_spin_lock(&i8253_lock);
182	/* restore the timer */
183	outb_p(0xb6, 0x43);	/* binary, mode 3, LSB/MSB, ch 2 */
184	outb(chip->val61 & 0xFC, 0x61);
185	raw_spin_unlock(&i8253_lock);
186}
187
188/*
189 * Force to stop and sync the stream
190 */
191void pcsp_sync_stop(struct snd_pcsp *chip)
192{
193	local_irq_disable();
194	pcsp_stop_playing(chip);
195	local_irq_enable();
196	hrtimer_cancel(&chip->timer);
197	cancel_work_sync(&pcsp_pcm_work);
198}
199
200static int snd_pcsp_playback_close(struct snd_pcm_substream *substream)
201{
202	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
203#if PCSP_DEBUG
204	printk(KERN_INFO "PCSP: close called\n");
205#endif
206	pcsp_sync_stop(chip);
207	chip->playback_substream = NULL;
208	return 0;
209}
210
211static int snd_pcsp_playback_hw_params(struct snd_pcm_substream *substream,
212				       struct snd_pcm_hw_params *hw_params)
213{
214	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
215	pcsp_sync_stop(chip);
216	return 0;
217}
218
219static int snd_pcsp_playback_hw_free(struct snd_pcm_substream *substream)
220{
221	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
222#if PCSP_DEBUG
223	printk(KERN_INFO "PCSP: hw_free called\n");
224#endif
225	pcsp_sync_stop(chip);
226	return 0;
227}
228
229static int snd_pcsp_playback_prepare(struct snd_pcm_substream *substream)
230{
231	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
232	pcsp_sync_stop(chip);
233	chip->playback_ptr = 0;
234	chip->period_ptr = 0;
235	chip->fmt_size =
236		snd_pcm_format_physical_width(substream->runtime->format) >> 3;
237	chip->is_signed = snd_pcm_format_signed(substream->runtime->format);
238#if PCSP_DEBUG
239	printk(KERN_INFO "PCSP: prepare called, "
240			"size=%zi psize=%zi f=%zi f1=%i fsize=%i\n",
241			snd_pcm_lib_buffer_bytes(substream),
242			snd_pcm_lib_period_bytes(substream),
243			snd_pcm_lib_buffer_bytes(substream) /
244			snd_pcm_lib_period_bytes(substream),
245			substream->runtime->periods,
246			chip->fmt_size);
247#endif
248	return 0;
249}
250
251static int snd_pcsp_trigger(struct snd_pcm_substream *substream, int cmd)
252{
253	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
254#if PCSP_DEBUG
255	printk(KERN_INFO "PCSP: trigger called\n");
256#endif
257	switch (cmd) {
258	case SNDRV_PCM_TRIGGER_START:
259	case SNDRV_PCM_TRIGGER_RESUME:
260		return pcsp_start_playing(chip);
261	case SNDRV_PCM_TRIGGER_STOP:
262	case SNDRV_PCM_TRIGGER_SUSPEND:
263		pcsp_stop_playing(chip);
264		break;
265	default:
266		return -EINVAL;
267	}
268	return 0;
269}
270
271static snd_pcm_uframes_t snd_pcsp_playback_pointer(struct snd_pcm_substream
272						   *substream)
273{
274	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
275	unsigned int pos;
276	spin_lock(&chip->substream_lock);
277	pos = chip->playback_ptr;
278	spin_unlock(&chip->substream_lock);
279	return bytes_to_frames(substream->runtime, pos);
280}
281
282static const struct snd_pcm_hardware snd_pcsp_playback = {
283	.info = (SNDRV_PCM_INFO_INTERLEAVED |
284		 SNDRV_PCM_INFO_HALF_DUPLEX |
285		 SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID),
286	.formats = (SNDRV_PCM_FMTBIT_U8
287#if DMIX_WANTS_S16
288		    | SNDRV_PCM_FMTBIT_S16_LE
289#endif
290	    ),
291	.rates = SNDRV_PCM_RATE_KNOT,
292	.rate_min = PCSP_DEFAULT_SRATE,
293	.rate_max = PCSP_DEFAULT_SRATE,
294	.channels_min = 1,
295	.channels_max = 1,
296	.buffer_bytes_max = PCSP_BUFFER_SIZE,
297	.period_bytes_min = 64,
298	.period_bytes_max = PCSP_MAX_PERIOD_SIZE,
299	.periods_min = 2,
300	.periods_max = PCSP_MAX_PERIODS,
301	.fifo_size = 0,
302};
303
304static int snd_pcsp_playback_open(struct snd_pcm_substream *substream)
305{
306	struct snd_pcsp *chip = snd_pcm_substream_chip(substream);
307	struct snd_pcm_runtime *runtime = substream->runtime;
308#if PCSP_DEBUG
309	printk(KERN_INFO "PCSP: open called\n");
310#endif
311	if (atomic_read(&chip->timer_active)) {
312		printk(KERN_ERR "PCSP: still active!!\n");
313		return -EBUSY;
314	}
315	runtime->hw = snd_pcsp_playback;
316	chip->playback_substream = substream;
317	return 0;
318}
319
320static const struct snd_pcm_ops snd_pcsp_playback_ops = {
321	.open = snd_pcsp_playback_open,
322	.close = snd_pcsp_playback_close,
323	.hw_params = snd_pcsp_playback_hw_params,
324	.hw_free = snd_pcsp_playback_hw_free,
325	.prepare = snd_pcsp_playback_prepare,
326	.trigger = snd_pcsp_trigger,
327	.pointer = snd_pcsp_playback_pointer,
328};
329
330int snd_pcsp_new_pcm(struct snd_pcsp *chip)
331{
332	int err;
333
334	err = snd_pcm_new(chip->card, "pcspeaker", 0, 1, 0, &chip->pcm);
335	if (err < 0)
336		return err;
337
338	snd_pcm_set_ops(chip->pcm, SNDRV_PCM_STREAM_PLAYBACK,
339			&snd_pcsp_playback_ops);
340
341	chip->pcm->private_data = chip;
342	chip->pcm->info_flags = SNDRV_PCM_INFO_HALF_DUPLEX;
343	strcpy(chip->pcm->name, "pcsp");
344
345	snd_pcm_set_managed_buffer_all(chip->pcm,
346				       SNDRV_DMA_TYPE_CONTINUOUS,
347				       NULL,
348				       PCSP_BUFFER_SIZE,
349				       PCSP_BUFFER_SIZE);
350
351	return 0;
352}
353