xref: /linux/sound/hda/hdac_controller.c (revision f055268e3946555deb9bb80b2c8c9798c64dbc47)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * HD-audio controller helpers
4  */
5 
6 #include <linux/kernel.h>
7 #include <linux/delay.h>
8 #include <linux/export.h>
9 #include <sound/core.h>
10 #include <sound/hdaudio.h>
11 #include <sound/hda_register.h>
12 #include "local.h"
13 
14 /* clear CORB read pointer properly */
15 static void azx_clear_corbrp(struct hdac_bus *bus)
16 {
17 	int timeout;
18 
19 	for (timeout = 1000; timeout > 0; timeout--) {
20 		if (snd_hdac_chip_readw(bus, CORBRP) & AZX_CORBRP_RST)
21 			break;
22 		udelay(1);
23 	}
24 	if (timeout <= 0)
25 		dev_err(bus->dev, "CORB reset timeout#1, CORBRP = %d\n",
26 			snd_hdac_chip_readw(bus, CORBRP));
27 
28 	snd_hdac_chip_writew(bus, CORBRP, 0);
29 	for (timeout = 1000; timeout > 0; timeout--) {
30 		if (snd_hdac_chip_readw(bus, CORBRP) == 0)
31 			break;
32 		udelay(1);
33 	}
34 	if (timeout <= 0)
35 		dev_err(bus->dev, "CORB reset timeout#2, CORBRP = %d\n",
36 			snd_hdac_chip_readw(bus, CORBRP));
37 }
38 
39 /**
40  * snd_hdac_bus_init_cmd_io - set up CORB/RIRB buffers
41  * @bus: HD-audio core bus
42  */
43 void snd_hdac_bus_init_cmd_io(struct hdac_bus *bus)
44 {
45 	WARN_ON_ONCE(!bus->rb.area);
46 
47 	spin_lock_irq(&bus->reg_lock);
48 	/* CORB set up */
49 	bus->corb.addr = bus->rb.addr;
50 	bus->corb.buf = (__le32 *)bus->rb.area;
51 	snd_hdac_chip_writel(bus, CORBLBASE, (u32)bus->corb.addr);
52 	snd_hdac_chip_writel(bus, CORBUBASE, upper_32_bits(bus->corb.addr));
53 
54 	/* set the corb size to 256 entries (ULI requires explicitly) */
55 	snd_hdac_chip_writeb(bus, CORBSIZE, 0x02);
56 	/* set the corb write pointer to 0 */
57 	snd_hdac_chip_writew(bus, CORBWP, 0);
58 
59 	/* reset the corb hw read pointer */
60 	snd_hdac_chip_writew(bus, CORBRP, AZX_CORBRP_RST);
61 	if (!bus->corbrp_self_clear)
62 		azx_clear_corbrp(bus);
63 
64 	/* enable corb dma */
65 	snd_hdac_chip_writeb(bus, CORBCTL, AZX_CORBCTL_RUN);
66 
67 	/* RIRB set up */
68 	bus->rirb.addr = bus->rb.addr + 2048;
69 	bus->rirb.buf = (__le32 *)(bus->rb.area + 2048);
70 	bus->rirb.wp = bus->rirb.rp = 0;
71 	memset(bus->rirb.cmds, 0, sizeof(bus->rirb.cmds));
72 	snd_hdac_chip_writel(bus, RIRBLBASE, (u32)bus->rirb.addr);
73 	snd_hdac_chip_writel(bus, RIRBUBASE, upper_32_bits(bus->rirb.addr));
74 
75 	/* set the rirb size to 256 entries (ULI requires explicitly) */
76 	snd_hdac_chip_writeb(bus, RIRBSIZE, 0x02);
77 	/* reset the rirb hw write pointer */
78 	snd_hdac_chip_writew(bus, RIRBWP, AZX_RIRBWP_RST);
79 	/* set N=1, get RIRB response interrupt for new entry */
80 	snd_hdac_chip_writew(bus, RINTCNT, 1);
81 	/* enable rirb dma and response irq */
82 	snd_hdac_chip_writeb(bus, RIRBCTL, AZX_RBCTL_DMA_EN | AZX_RBCTL_IRQ_EN);
83 	/* Accept unsolicited responses */
84 	snd_hdac_chip_updatel(bus, GCTL, AZX_GCTL_UNSOL, AZX_GCTL_UNSOL);
85 	spin_unlock_irq(&bus->reg_lock);
86 }
87 EXPORT_SYMBOL_GPL(snd_hdac_bus_init_cmd_io);
88 
89 /* wait for cmd dmas till they are stopped */
90 static void hdac_wait_for_cmd_dmas(struct hdac_bus *bus)
91 {
92 	unsigned long timeout;
93 
94 	timeout = jiffies + msecs_to_jiffies(100);
95 	while ((snd_hdac_chip_readb(bus, RIRBCTL) & AZX_RBCTL_DMA_EN)
96 		&& time_before(jiffies, timeout))
97 		udelay(10);
98 
99 	timeout = jiffies + msecs_to_jiffies(100);
100 	while ((snd_hdac_chip_readb(bus, CORBCTL) & AZX_CORBCTL_RUN)
101 		&& time_before(jiffies, timeout))
102 		udelay(10);
103 }
104 
105 /**
106  * snd_hdac_bus_stop_cmd_io - clean up CORB/RIRB buffers
107  * @bus: HD-audio core bus
108  */
109 void snd_hdac_bus_stop_cmd_io(struct hdac_bus *bus)
110 {
111 	spin_lock_irq(&bus->reg_lock);
112 	/* disable ringbuffer DMAs */
113 	snd_hdac_chip_writeb(bus, RIRBCTL, 0);
114 	snd_hdac_chip_writeb(bus, CORBCTL, 0);
115 	spin_unlock_irq(&bus->reg_lock);
116 
117 	hdac_wait_for_cmd_dmas(bus);
118 
119 	spin_lock_irq(&bus->reg_lock);
120 	/* disable unsolicited responses */
121 	snd_hdac_chip_updatel(bus, GCTL, AZX_GCTL_UNSOL, 0);
122 	spin_unlock_irq(&bus->reg_lock);
123 }
124 EXPORT_SYMBOL_GPL(snd_hdac_bus_stop_cmd_io);
125 
126 static unsigned int azx_command_addr(u32 cmd)
127 {
128 	unsigned int addr = cmd >> 28;
129 
130 	if (snd_BUG_ON(addr >= HDA_MAX_CODECS))
131 		addr = 0;
132 	return addr;
133 }
134 
135 /**
136  * snd_hdac_bus_send_cmd - send a command verb via CORB
137  * @bus: HD-audio core bus
138  * @val: encoded verb value to send
139  *
140  * Returns zero for success or a negative error code.
141  */
142 int snd_hdac_bus_send_cmd(struct hdac_bus *bus, unsigned int val)
143 {
144 	unsigned int addr = azx_command_addr(val);
145 	unsigned int wp, rp;
146 
147 	spin_lock_irq(&bus->reg_lock);
148 
149 	bus->last_cmd[azx_command_addr(val)] = val;
150 
151 	/* add command to corb */
152 	wp = snd_hdac_chip_readw(bus, CORBWP);
153 	if (wp == 0xffff) {
154 		/* something wrong, controller likely turned to D3 */
155 		spin_unlock_irq(&bus->reg_lock);
156 		return -EIO;
157 	}
158 	wp++;
159 	wp %= AZX_MAX_CORB_ENTRIES;
160 
161 	rp = snd_hdac_chip_readw(bus, CORBRP);
162 	if (wp == rp) {
163 		/* oops, it's full */
164 		spin_unlock_irq(&bus->reg_lock);
165 		return -EAGAIN;
166 	}
167 
168 	bus->rirb.cmds[addr]++;
169 	bus->corb.buf[wp] = cpu_to_le32(val);
170 	snd_hdac_chip_writew(bus, CORBWP, wp);
171 
172 	spin_unlock_irq(&bus->reg_lock);
173 
174 	return 0;
175 }
176 EXPORT_SYMBOL_GPL(snd_hdac_bus_send_cmd);
177 
178 #define AZX_RIRB_EX_UNSOL_EV	(1<<4)
179 
180 /**
181  * snd_hdac_bus_update_rirb - retrieve RIRB entries
182  * @bus: HD-audio core bus
183  *
184  * Usually called from interrupt handler.
185  * The caller needs bus->reg_lock spinlock before calling this.
186  */
187 void snd_hdac_bus_update_rirb(struct hdac_bus *bus)
188 {
189 	unsigned int rp, wp;
190 	unsigned int addr;
191 	u32 res, res_ex;
192 
193 	wp = snd_hdac_chip_readw(bus, RIRBWP);
194 	if (wp == 0xffff) {
195 		/* something wrong, controller likely turned to D3 */
196 		return;
197 	}
198 
199 	if (wp == bus->rirb.wp)
200 		return;
201 	bus->rirb.wp = wp;
202 
203 	while (bus->rirb.rp != wp) {
204 		bus->rirb.rp++;
205 		bus->rirb.rp %= AZX_MAX_RIRB_ENTRIES;
206 
207 		rp = bus->rirb.rp << 1; /* an RIRB entry is 8-bytes */
208 		res_ex = le32_to_cpu(bus->rirb.buf[rp + 1]);
209 		res = le32_to_cpu(bus->rirb.buf[rp]);
210 		addr = res_ex & 0xf;
211 		if (addr >= HDA_MAX_CODECS) {
212 			dev_err(bus->dev,
213 				"spurious response %#x:%#x, rp = %d, wp = %d",
214 				res, res_ex, bus->rirb.rp, wp);
215 			snd_BUG();
216 		} else if (res_ex & AZX_RIRB_EX_UNSOL_EV)
217 			snd_hdac_bus_queue_event(bus, res, res_ex);
218 		else if (bus->rirb.cmds[addr]) {
219 			bus->rirb.res[addr] = res;
220 			bus->rirb.cmds[addr]--;
221 			if (!bus->rirb.cmds[addr] &&
222 			    waitqueue_active(&bus->rirb_wq))
223 				wake_up(&bus->rirb_wq);
224 		} else {
225 			dev_err_ratelimited(bus->dev,
226 				"spurious response %#x:%#x, last cmd=%#08x\n",
227 				res, res_ex, bus->last_cmd[addr]);
228 		}
229 	}
230 }
231 EXPORT_SYMBOL_GPL(snd_hdac_bus_update_rirb);
232 
233 /**
234  * snd_hdac_bus_get_response - receive a response via RIRB
235  * @bus: HD-audio core bus
236  * @addr: codec address
237  * @res: pointer to store the value, NULL when not needed
238  *
239  * Returns zero if a value is read, or a negative error code.
240  */
241 int snd_hdac_bus_get_response(struct hdac_bus *bus, unsigned int addr,
242 			      unsigned int *res)
243 {
244 	unsigned long timeout;
245 	unsigned long loopcounter;
246 	wait_queue_entry_t wait;
247 	bool warned = false;
248 
249 	init_wait_entry(&wait, 0);
250 	timeout = jiffies + msecs_to_jiffies(1000);
251 
252 	for (loopcounter = 0;; loopcounter++) {
253 		spin_lock_irq(&bus->reg_lock);
254 		if (!bus->polling_mode)
255 			prepare_to_wait(&bus->rirb_wq, &wait,
256 					TASK_UNINTERRUPTIBLE);
257 		if (bus->polling_mode)
258 			snd_hdac_bus_update_rirb(bus);
259 		if (!bus->rirb.cmds[addr]) {
260 			if (res)
261 				*res = bus->rirb.res[addr]; /* the last value */
262 			if (!bus->polling_mode)
263 				finish_wait(&bus->rirb_wq, &wait);
264 			spin_unlock_irq(&bus->reg_lock);
265 			return 0;
266 		}
267 		spin_unlock_irq(&bus->reg_lock);
268 		if (time_after(jiffies, timeout))
269 			break;
270 #define LOOP_COUNT_MAX	3000
271 		if (!bus->polling_mode) {
272 			schedule_timeout(msecs_to_jiffies(2));
273 		} else if (bus->needs_damn_long_delay ||
274 			   loopcounter > LOOP_COUNT_MAX) {
275 			if (loopcounter > LOOP_COUNT_MAX && !warned) {
276 				dev_dbg_ratelimited(bus->dev,
277 						    "too slow response, last cmd=%#08x\n",
278 						    bus->last_cmd[addr]);
279 				warned = true;
280 			}
281 			msleep(2); /* temporary workaround */
282 		} else {
283 			udelay(10);
284 			cond_resched();
285 		}
286 	}
287 
288 	if (!bus->polling_mode)
289 		finish_wait(&bus->rirb_wq, &wait);
290 
291 	return -EIO;
292 }
293 EXPORT_SYMBOL_GPL(snd_hdac_bus_get_response);
294 
295 #define HDAC_MAX_CAPS 10
296 /**
297  * snd_hdac_bus_parse_capabilities - parse capability structure
298  * @bus: the pointer to bus object
299  *
300  * Returns 0 if successful, or a negative error code.
301  */
302 int snd_hdac_bus_parse_capabilities(struct hdac_bus *bus)
303 {
304 	unsigned int cur_cap;
305 	unsigned int offset;
306 	unsigned int counter = 0;
307 
308 	offset = snd_hdac_chip_readw(bus, LLCH);
309 
310 	/* Lets walk the linked capabilities list */
311 	do {
312 		cur_cap = _snd_hdac_chip_readl(bus, offset);
313 
314 		dev_dbg(bus->dev, "Capability version: 0x%x\n",
315 			(cur_cap & AZX_CAP_HDR_VER_MASK) >> AZX_CAP_HDR_VER_OFF);
316 
317 		dev_dbg(bus->dev, "HDA capability ID: 0x%x\n",
318 			(cur_cap & AZX_CAP_HDR_ID_MASK) >> AZX_CAP_HDR_ID_OFF);
319 
320 		if (cur_cap == -1) {
321 			dev_dbg(bus->dev, "Invalid capability reg read\n");
322 			break;
323 		}
324 
325 		switch ((cur_cap & AZX_CAP_HDR_ID_MASK) >> AZX_CAP_HDR_ID_OFF) {
326 		case AZX_ML_CAP_ID:
327 			dev_dbg(bus->dev, "Found ML capability\n");
328 			bus->mlcap = bus->remap_addr + offset;
329 			break;
330 
331 		case AZX_GTS_CAP_ID:
332 			dev_dbg(bus->dev, "Found GTS capability offset=%x\n", offset);
333 			bus->gtscap = bus->remap_addr + offset;
334 			break;
335 
336 		case AZX_PP_CAP_ID:
337 			/* PP capability found, the Audio DSP is present */
338 			dev_dbg(bus->dev, "Found PP capability offset=%x\n", offset);
339 			bus->ppcap = bus->remap_addr + offset;
340 			break;
341 
342 		case AZX_SPB_CAP_ID:
343 			/* SPIB capability found, handler function */
344 			dev_dbg(bus->dev, "Found SPB capability\n");
345 			bus->spbcap = bus->remap_addr + offset;
346 			break;
347 
348 		case AZX_DRSM_CAP_ID:
349 			/* DMA resume  capability found, handler function */
350 			dev_dbg(bus->dev, "Found DRSM capability\n");
351 			bus->drsmcap = bus->remap_addr + offset;
352 			break;
353 
354 		default:
355 			dev_err(bus->dev, "Unknown capability %d\n", cur_cap);
356 			cur_cap = 0;
357 			break;
358 		}
359 
360 		counter++;
361 
362 		if (counter > HDAC_MAX_CAPS) {
363 			dev_err(bus->dev, "We exceeded HDAC capabilities!!!\n");
364 			break;
365 		}
366 
367 		/* read the offset of next capability */
368 		offset = cur_cap & AZX_CAP_HDR_NXT_PTR_MASK;
369 
370 	} while (offset);
371 
372 	return 0;
373 }
374 EXPORT_SYMBOL_GPL(snd_hdac_bus_parse_capabilities);
375 
376 /*
377  * Lowlevel interface
378  */
379 
380 /**
381  * snd_hdac_bus_enter_link_reset - enter link reset
382  * @bus: HD-audio core bus
383  *
384  * Enter to the link reset state.
385  */
386 void snd_hdac_bus_enter_link_reset(struct hdac_bus *bus)
387 {
388 	unsigned long timeout;
389 
390 	/* reset controller */
391 	snd_hdac_chip_updatel(bus, GCTL, AZX_GCTL_RESET, 0);
392 
393 	timeout = jiffies + msecs_to_jiffies(100);
394 	while ((snd_hdac_chip_readb(bus, GCTL) & AZX_GCTL_RESET) &&
395 	       time_before(jiffies, timeout))
396 		usleep_range(500, 1000);
397 }
398 EXPORT_SYMBOL_GPL(snd_hdac_bus_enter_link_reset);
399 
400 /**
401  * snd_hdac_bus_exit_link_reset - exit link reset
402  * @bus: HD-audio core bus
403  *
404  * Exit from the link reset state.
405  */
406 void snd_hdac_bus_exit_link_reset(struct hdac_bus *bus)
407 {
408 	unsigned long timeout;
409 
410 	snd_hdac_chip_updateb(bus, GCTL, AZX_GCTL_RESET, AZX_GCTL_RESET);
411 
412 	timeout = jiffies + msecs_to_jiffies(100);
413 	while (!snd_hdac_chip_readb(bus, GCTL) && time_before(jiffies, timeout))
414 		usleep_range(500, 1000);
415 }
416 EXPORT_SYMBOL_GPL(snd_hdac_bus_exit_link_reset);
417 
418 /* reset codec link */
419 int snd_hdac_bus_reset_link(struct hdac_bus *bus, bool full_reset)
420 {
421 	if (!full_reset)
422 		goto skip_reset;
423 
424 	/* clear STATESTS if not in reset */
425 	if (snd_hdac_chip_readb(bus, GCTL) & AZX_GCTL_RESET)
426 		snd_hdac_chip_writew(bus, STATESTS, STATESTS_INT_MASK);
427 
428 	/* reset controller */
429 	snd_hdac_bus_enter_link_reset(bus);
430 
431 	/* delay for >= 100us for codec PLL to settle per spec
432 	 * Rev 0.9 section 5.5.1
433 	 */
434 	usleep_range(500, 1000);
435 
436 	/* Bring controller out of reset */
437 	snd_hdac_bus_exit_link_reset(bus);
438 
439 	/* Brent Chartrand said to wait >= 540us for codecs to initialize */
440 	usleep_range(1000, 1200);
441 
442  skip_reset:
443 	/* check to see if controller is ready */
444 	if (!snd_hdac_chip_readb(bus, GCTL)) {
445 		dev_dbg(bus->dev, "controller not ready!\n");
446 		return -EBUSY;
447 	}
448 
449 	/* detect codecs */
450 	if (!bus->codec_mask) {
451 		bus->codec_mask = snd_hdac_chip_readw(bus, STATESTS);
452 		dev_dbg(bus->dev, "codec_mask = 0x%lx\n", bus->codec_mask);
453 	}
454 
455 	return 0;
456 }
457 EXPORT_SYMBOL_GPL(snd_hdac_bus_reset_link);
458 
459 /* enable interrupts */
460 static void azx_int_enable(struct hdac_bus *bus)
461 {
462 	/* enable controller CIE and GIE */
463 	snd_hdac_chip_updatel(bus, INTCTL,
464 			      AZX_INT_CTRL_EN | AZX_INT_GLOBAL_EN,
465 			      AZX_INT_CTRL_EN | AZX_INT_GLOBAL_EN);
466 }
467 
468 /* disable interrupts */
469 static void azx_int_disable(struct hdac_bus *bus)
470 {
471 	struct hdac_stream *azx_dev;
472 
473 	/* disable interrupts in stream descriptor */
474 	list_for_each_entry(azx_dev, &bus->stream_list, list)
475 		snd_hdac_stream_updateb(azx_dev, SD_CTL, SD_INT_MASK, 0);
476 
477 	/* disable SIE for all streams & disable controller CIE and GIE */
478 	snd_hdac_chip_writel(bus, INTCTL, 0);
479 }
480 
481 /* clear interrupts */
482 static void azx_int_clear(struct hdac_bus *bus)
483 {
484 	struct hdac_stream *azx_dev;
485 
486 	/* clear stream status */
487 	list_for_each_entry(azx_dev, &bus->stream_list, list)
488 		snd_hdac_stream_writeb(azx_dev, SD_STS, SD_INT_MASK);
489 
490 	/* clear STATESTS */
491 	snd_hdac_chip_writew(bus, STATESTS, STATESTS_INT_MASK);
492 
493 	/* clear rirb status */
494 	snd_hdac_chip_writeb(bus, RIRBSTS, RIRB_INT_MASK);
495 
496 	/* clear int status */
497 	snd_hdac_chip_writel(bus, INTSTS, AZX_INT_CTRL_EN | AZX_INT_ALL_STREAM);
498 }
499 
500 /**
501  * snd_hdac_bus_init_chip - reset and start the controller registers
502  * @bus: HD-audio core bus
503  * @full_reset: Do full reset
504  */
505 bool snd_hdac_bus_init_chip(struct hdac_bus *bus, bool full_reset)
506 {
507 	if (bus->chip_init)
508 		return false;
509 
510 	/* reset controller */
511 	snd_hdac_bus_reset_link(bus, full_reset);
512 
513 	/* clear interrupts */
514 	azx_int_clear(bus);
515 
516 	/* initialize the codec command I/O */
517 	snd_hdac_bus_init_cmd_io(bus);
518 
519 	/* enable interrupts after CORB/RIRB buffers are initialized above */
520 	azx_int_enable(bus);
521 
522 	/* program the position buffer */
523 	if (bus->use_posbuf && bus->posbuf.addr) {
524 		snd_hdac_chip_writel(bus, DPLBASE, (u32)bus->posbuf.addr);
525 		snd_hdac_chip_writel(bus, DPUBASE, upper_32_bits(bus->posbuf.addr));
526 	}
527 
528 	bus->chip_init = true;
529 
530 	return true;
531 }
532 EXPORT_SYMBOL_GPL(snd_hdac_bus_init_chip);
533 
534 /**
535  * snd_hdac_bus_stop_chip - disable the whole IRQ and I/Os
536  * @bus: HD-audio core bus
537  */
538 void snd_hdac_bus_stop_chip(struct hdac_bus *bus)
539 {
540 	if (!bus->chip_init)
541 		return;
542 
543 	/* disable interrupts */
544 	azx_int_disable(bus);
545 	azx_int_clear(bus);
546 
547 	/* disable CORB/RIRB */
548 	snd_hdac_bus_stop_cmd_io(bus);
549 
550 	/* disable position buffer */
551 	if (bus->posbuf.addr) {
552 		snd_hdac_chip_writel(bus, DPLBASE, 0);
553 		snd_hdac_chip_writel(bus, DPUBASE, 0);
554 	}
555 
556 	bus->chip_init = false;
557 }
558 EXPORT_SYMBOL_GPL(snd_hdac_bus_stop_chip);
559 
560 /**
561  * snd_hdac_bus_handle_stream_irq - interrupt handler for streams
562  * @bus: HD-audio core bus
563  * @status: INTSTS register value
564  * @ack: callback to be called for woken streams
565  *
566  * Returns the bits of handled streams, or zero if no stream is handled.
567  */
568 int snd_hdac_bus_handle_stream_irq(struct hdac_bus *bus, unsigned int status,
569 				    void (*ack)(struct hdac_bus *,
570 						struct hdac_stream *))
571 {
572 	struct hdac_stream *azx_dev;
573 	u8 sd_status;
574 	int handled = 0;
575 
576 	list_for_each_entry(azx_dev, &bus->stream_list, list) {
577 		if (status & azx_dev->sd_int_sta_mask) {
578 			sd_status = snd_hdac_stream_readb(azx_dev, SD_STS);
579 			snd_hdac_stream_writeb(azx_dev, SD_STS, SD_INT_MASK);
580 			handled |= 1 << azx_dev->index;
581 			if (!azx_dev->substream || !azx_dev->running ||
582 			    !(sd_status & SD_INT_COMPLETE))
583 				continue;
584 			if (ack)
585 				ack(bus, azx_dev);
586 		}
587 	}
588 	return handled;
589 }
590 EXPORT_SYMBOL_GPL(snd_hdac_bus_handle_stream_irq);
591 
592 /**
593  * snd_hdac_bus_alloc_stream_pages - allocate BDL and other buffers
594  * @bus: HD-audio core bus
595  *
596  * Call this after assigning the all streams.
597  * Returns zero for success, or a negative error code.
598  */
599 int snd_hdac_bus_alloc_stream_pages(struct hdac_bus *bus)
600 {
601 	struct hdac_stream *s;
602 	int num_streams = 0;
603 	int dma_type = bus->dma_type ? bus->dma_type : SNDRV_DMA_TYPE_DEV;
604 	int err;
605 
606 	list_for_each_entry(s, &bus->stream_list, list) {
607 		/* allocate memory for the BDL for each stream */
608 		err = snd_dma_alloc_pages(dma_type, bus->dev,
609 					  BDL_SIZE, &s->bdl);
610 		num_streams++;
611 		if (err < 0)
612 			return -ENOMEM;
613 	}
614 
615 	if (WARN_ON(!num_streams))
616 		return -EINVAL;
617 	/* allocate memory for the position buffer */
618 	err = snd_dma_alloc_pages(dma_type, bus->dev,
619 				  num_streams * 8, &bus->posbuf);
620 	if (err < 0)
621 		return -ENOMEM;
622 	list_for_each_entry(s, &bus->stream_list, list)
623 		s->posbuf = (__le32 *)(bus->posbuf.area + s->index * 8);
624 
625 	/* single page (at least 4096 bytes) must suffice for both ringbuffes */
626 	return snd_dma_alloc_pages(dma_type, bus->dev, PAGE_SIZE, &bus->rb);
627 }
628 EXPORT_SYMBOL_GPL(snd_hdac_bus_alloc_stream_pages);
629 
630 /**
631  * snd_hdac_bus_free_stream_pages - release BDL and other buffers
632  * @bus: HD-audio core bus
633  */
634 void snd_hdac_bus_free_stream_pages(struct hdac_bus *bus)
635 {
636 	struct hdac_stream *s;
637 
638 	list_for_each_entry(s, &bus->stream_list, list) {
639 		if (s->bdl.area)
640 			snd_dma_free_pages(&s->bdl);
641 	}
642 
643 	if (bus->rb.area)
644 		snd_dma_free_pages(&bus->rb);
645 	if (bus->posbuf.area)
646 		snd_dma_free_pages(&bus->posbuf);
647 }
648 EXPORT_SYMBOL_GPL(snd_hdac_bus_free_stream_pages);
649 
650 /**
651  * snd_hdac_bus_link_power - power up/down codec link
652  * @codec: HD-audio device
653  * @enable: whether to power-up the link
654  */
655 void snd_hdac_bus_link_power(struct hdac_device *codec, bool enable)
656 {
657 	if (enable)
658 		set_bit(codec->addr, &codec->bus->codec_powered);
659 	else
660 		clear_bit(codec->addr, &codec->bus->codec_powered);
661 }
662 EXPORT_SYMBOL_GPL(snd_hdac_bus_link_power);
663