xref: /linux/drivers/media/pci/cx25821/cx25821-alsa.c (revision e0bf6c5ca2d3281f231c5f0c9bf145e9513644de)
1 /*
2  *  Driver for the Conexant CX25821 PCIe bridge
3  *
4  *  Copyright (C) 2009 Conexant Systems Inc.
5  *  Authors  <shu.lin@conexant.com>, <hiep.huynh@conexant.com>
6  *	Based on SAA713x ALSA driver and CX88 driver
7  *
8  *   This program is free software; you can redistribute it and/or modify
9  *   it under the terms of the GNU General Public License as published by
10  *   the Free Software Foundation, version 2
11  *
12  *   This program is distributed in the hope that it will be useful,
13  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
14  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  *   GNU General Public License for more details.
16  *
17  *   You should have received a copy of the GNU General Public License
18  *   along with this program; if not, write to the Free Software
19  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
20  *
21  */
22 
23 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24 
25 #include <linux/module.h>
26 #include <linux/init.h>
27 #include <linux/device.h>
28 #include <linux/interrupt.h>
29 #include <linux/vmalloc.h>
30 #include <linux/dma-mapping.h>
31 #include <linux/pci.h>
32 #include <linux/slab.h>
33 
34 #include <linux/delay.h>
35 #include <sound/core.h>
36 #include <sound/pcm.h>
37 #include <sound/pcm_params.h>
38 #include <sound/control.h>
39 #include <sound/initval.h>
40 #include <sound/tlv.h>
41 
42 #include "cx25821.h"
43 #include "cx25821-reg.h"
44 
45 #define AUDIO_SRAM_CHANNEL	SRAM_CH08
46 
47 #define dprintk(level, fmt, arg...)				\
48 do {								\
49 	if (debug >= level)					\
50 		pr_info("%s/1: " fmt, chip->dev->name, ##arg);	\
51 } while (0)
52 #define dprintk_core(level, fmt, arg...)				\
53 do {									\
54 	if (debug >= level)						\
55 		printk(KERN_DEBUG "%s/1: " fmt, chip->dev->name, ##arg); \
56 } while (0)
57 
58 /****************************************************************************
59 	Data type declarations - Can be moded to a header file later
60  ****************************************************************************/
61 
62 static int devno;
63 
64 struct cx25821_audio_buffer {
65 	unsigned int bpl;
66 	struct cx25821_riscmem risc;
67 	void			*vaddr;
68 	struct scatterlist	*sglist;
69 	int                     sglen;
70 	int                     nr_pages;
71 };
72 
73 struct cx25821_audio_dev {
74 	struct cx25821_dev *dev;
75 	struct cx25821_dmaqueue q;
76 
77 	/* pci i/o */
78 	struct pci_dev *pci;
79 
80 	/* audio controls */
81 	int irq;
82 
83 	struct snd_card *card;
84 
85 	unsigned long iobase;
86 	spinlock_t reg_lock;
87 	atomic_t count;
88 
89 	unsigned int dma_size;
90 	unsigned int period_size;
91 	unsigned int num_periods;
92 
93 	struct cx25821_audio_buffer *buf;
94 
95 	struct snd_pcm_substream *substream;
96 };
97 
98 
99 /****************************************************************************
100 			Module global static vars
101  ****************************************************************************/
102 
103 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;	/* Index 0-MAX */
104 static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;	/* ID for this card */
105 static bool enable[SNDRV_CARDS] = { 1, [1 ... (SNDRV_CARDS - 1)] = 1 };
106 
107 module_param_array(enable, bool, NULL, 0444);
108 MODULE_PARM_DESC(enable, "Enable cx25821 soundcard. default enabled.");
109 
110 module_param_array(index, int, NULL, 0444);
111 MODULE_PARM_DESC(index, "Index value for cx25821 capture interface(s).");
112 
113 /****************************************************************************
114 				Module macros
115  ****************************************************************************/
116 
117 MODULE_DESCRIPTION("ALSA driver module for cx25821 based capture cards");
118 MODULE_AUTHOR("Hiep Huynh");
119 MODULE_LICENSE("GPL");
120 MODULE_SUPPORTED_DEVICE("{{Conexant,25821}");	/* "{{Conexant,23881}," */
121 
122 static unsigned int debug;
123 module_param(debug, int, 0644);
124 MODULE_PARM_DESC(debug, "enable debug messages");
125 
126 /****************************************************************************
127 			Module specific funtions
128  ****************************************************************************/
129 /* Constants taken from cx88-reg.h */
130 #define AUD_INT_DN_RISCI1       (1 <<  0)
131 #define AUD_INT_UP_RISCI1       (1 <<  1)
132 #define AUD_INT_RDS_DN_RISCI1   (1 <<  2)
133 #define AUD_INT_DN_RISCI2       (1 <<  4)	/* yes, 3 is skipped */
134 #define AUD_INT_UP_RISCI2       (1 <<  5)
135 #define AUD_INT_RDS_DN_RISCI2   (1 <<  6)
136 #define AUD_INT_DN_SYNC         (1 << 12)
137 #define AUD_INT_UP_SYNC         (1 << 13)
138 #define AUD_INT_RDS_DN_SYNC     (1 << 14)
139 #define AUD_INT_OPC_ERR         (1 << 16)
140 #define AUD_INT_BER_IRQ         (1 << 20)
141 #define AUD_INT_MCHG_IRQ        (1 << 21)
142 #define GP_COUNT_CONTROL_RESET	0x3
143 
144 #define PCI_MSK_AUD_EXT   (1 <<  4)
145 #define PCI_MSK_AUD_INT   (1 <<  3)
146 
147 static int cx25821_alsa_dma_init(struct cx25821_audio_dev *chip, int nr_pages)
148 {
149 	struct cx25821_audio_buffer *buf = chip->buf;
150 	struct page *pg;
151 	int i;
152 
153 	buf->vaddr = vmalloc_32(nr_pages << PAGE_SHIFT);
154 	if (NULL == buf->vaddr) {
155 		dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
156 		return -ENOMEM;
157 	}
158 
159 	dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
160 				(unsigned long)buf->vaddr,
161 				nr_pages << PAGE_SHIFT);
162 
163 	memset(buf->vaddr, 0, nr_pages << PAGE_SHIFT);
164 	buf->nr_pages = nr_pages;
165 
166 	buf->sglist = vzalloc(buf->nr_pages * sizeof(*buf->sglist));
167 	if (NULL == buf->sglist)
168 		goto vzalloc_err;
169 
170 	sg_init_table(buf->sglist, buf->nr_pages);
171 	for (i = 0; i < buf->nr_pages; i++) {
172 		pg = vmalloc_to_page(buf->vaddr + i * PAGE_SIZE);
173 		if (NULL == pg)
174 			goto vmalloc_to_page_err;
175 		sg_set_page(&buf->sglist[i], pg, PAGE_SIZE, 0);
176 	}
177 	return 0;
178 
179 vmalloc_to_page_err:
180 	vfree(buf->sglist);
181 	buf->sglist = NULL;
182 vzalloc_err:
183 	vfree(buf->vaddr);
184 	buf->vaddr = NULL;
185 	return -ENOMEM;
186 }
187 
188 static int cx25821_alsa_dma_map(struct cx25821_audio_dev *dev)
189 {
190 	struct cx25821_audio_buffer *buf = dev->buf;
191 
192 	buf->sglen = dma_map_sg(&dev->pci->dev, buf->sglist,
193 			buf->nr_pages, PCI_DMA_FROMDEVICE);
194 
195 	if (0 == buf->sglen) {
196 		pr_warn("%s: cx25821_alsa_map_sg failed\n", __func__);
197 		return -ENOMEM;
198 	}
199 	return 0;
200 }
201 
202 static int cx25821_alsa_dma_unmap(struct cx25821_audio_dev *dev)
203 {
204 	struct cx25821_audio_buffer *buf = dev->buf;
205 
206 	if (!buf->sglen)
207 		return 0;
208 
209 	dma_unmap_sg(&dev->pci->dev, buf->sglist, buf->sglen, PCI_DMA_FROMDEVICE);
210 	buf->sglen = 0;
211 	return 0;
212 }
213 
214 static int cx25821_alsa_dma_free(struct cx25821_audio_buffer *buf)
215 {
216 	vfree(buf->sglist);
217 	buf->sglist = NULL;
218 	vfree(buf->vaddr);
219 	buf->vaddr = NULL;
220 	return 0;
221 }
222 
223 /*
224  * BOARD Specific: Sets audio DMA
225  */
226 
227 static int _cx25821_start_audio_dma(struct cx25821_audio_dev *chip)
228 {
229 	struct cx25821_audio_buffer *buf = chip->buf;
230 	struct cx25821_dev *dev = chip->dev;
231 	const struct sram_channel *audio_ch =
232 	    &cx25821_sram_channels[AUDIO_SRAM_CHANNEL];
233 	u32 tmp = 0;
234 
235 	/* enable output on the GPIO 0 for the MCLK ADC (Audio) */
236 	cx25821_set_gpiopin_direction(chip->dev, 0, 0);
237 
238 	/* Make sure RISC/FIFO are off before changing FIFO/RISC settings */
239 	cx_clear(AUD_INT_DMA_CTL,
240 		 FLD_AUD_DST_A_RISC_EN | FLD_AUD_DST_A_FIFO_EN);
241 
242 	/* setup fifo + format - out channel */
243 	cx25821_sram_channel_setup_audio(chip->dev, audio_ch, buf->bpl,
244 					 buf->risc.dma);
245 
246 	/* sets bpl size */
247 	cx_write(AUD_A_LNGTH, buf->bpl);
248 
249 	/* reset counter */
250 	/* GP_COUNT_CONTROL_RESET = 0x3 */
251 	cx_write(AUD_A_GPCNT_CTL, GP_COUNT_CONTROL_RESET);
252 	atomic_set(&chip->count, 0);
253 
254 	/* Set the input mode to 16-bit */
255 	tmp = cx_read(AUD_A_CFG);
256 	cx_write(AUD_A_CFG, tmp | FLD_AUD_DST_PK_MODE | FLD_AUD_DST_ENABLE |
257 		 FLD_AUD_CLK_ENABLE);
258 
259 	/*
260 	pr_info("DEBUG: Start audio DMA, %d B/line, cmds_start(0x%x)= %d lines/FIFO, %d periods, %d byte buffer\n",
261 		buf->bpl, audio_ch->cmds_start,
262 		cx_read(audio_ch->cmds_start + 12)>>1,
263 		chip->num_periods, buf->bpl * chip->num_periods);
264 	*/
265 
266 	/* Enables corresponding bits at AUD_INT_STAT */
267 	cx_write(AUD_A_INT_MSK, FLD_AUD_DST_RISCI1 | FLD_AUD_DST_OF |
268 		 FLD_AUD_DST_SYNC | FLD_AUD_DST_OPC_ERR);
269 
270 	/* Clean any pending interrupt bits already set */
271 	cx_write(AUD_A_INT_STAT, ~0);
272 
273 	/* enable audio irqs */
274 	cx_set(PCI_INT_MSK, chip->dev->pci_irqmask | PCI_MSK_AUD_INT);
275 
276 	/* Turn on audio downstream fifo and risc enable 0x101 */
277 	tmp = cx_read(AUD_INT_DMA_CTL);
278 	cx_set(AUD_INT_DMA_CTL, tmp |
279 	       (FLD_AUD_DST_A_RISC_EN | FLD_AUD_DST_A_FIFO_EN));
280 
281 	mdelay(100);
282 	return 0;
283 }
284 
285 /*
286  * BOARD Specific: Resets audio DMA
287  */
288 static int _cx25821_stop_audio_dma(struct cx25821_audio_dev *chip)
289 {
290 	struct cx25821_dev *dev = chip->dev;
291 
292 	/* stop dma */
293 	cx_clear(AUD_INT_DMA_CTL,
294 		 FLD_AUD_DST_A_RISC_EN | FLD_AUD_DST_A_FIFO_EN);
295 
296 	/* disable irqs */
297 	cx_clear(PCI_INT_MSK, PCI_MSK_AUD_INT);
298 	cx_clear(AUD_A_INT_MSK, AUD_INT_OPC_ERR | AUD_INT_DN_SYNC |
299 		 AUD_INT_DN_RISCI2 | AUD_INT_DN_RISCI1);
300 
301 	return 0;
302 }
303 
304 #define MAX_IRQ_LOOP 50
305 
306 /*
307  * BOARD Specific: IRQ dma bits
308  */
309 static char *cx25821_aud_irqs[32] = {
310 	"dn_risci1", "up_risci1", "rds_dn_risc1",	/* 0-2 */
311 	NULL,						/* reserved */
312 	"dn_risci2", "up_risci2", "rds_dn_risc2",	/* 4-6 */
313 	NULL,						/* reserved */
314 	"dnf_of", "upf_uf", "rds_dnf_uf",		/* 8-10 */
315 	NULL,						/* reserved */
316 	"dn_sync", "up_sync", "rds_dn_sync",		/* 12-14 */
317 	NULL,						/* reserved */
318 	"opc_err", "par_err", "rip_err",		/* 16-18 */
319 	"pci_abort", "ber_irq", "mchg_irq"		/* 19-21 */
320 };
321 
322 /*
323  * BOARD Specific: Threats IRQ audio specific calls
324  */
325 static void cx25821_aud_irq(struct cx25821_audio_dev *chip, u32 status,
326 			    u32 mask)
327 {
328 	struct cx25821_dev *dev = chip->dev;
329 
330 	if (0 == (status & mask))
331 		return;
332 
333 	cx_write(AUD_A_INT_STAT, status);
334 	if (debug > 1 || (status & mask & ~0xff))
335 		cx25821_print_irqbits(dev->name, "irq aud", cx25821_aud_irqs,
336 				ARRAY_SIZE(cx25821_aud_irqs), status, mask);
337 
338 	/* risc op code error */
339 	if (status & AUD_INT_OPC_ERR) {
340 		pr_warn("WARNING %s/1: Audio risc op code error\n", dev->name);
341 
342 		cx_clear(AUD_INT_DMA_CTL,
343 			 FLD_AUD_DST_A_RISC_EN | FLD_AUD_DST_A_FIFO_EN);
344 		cx25821_sram_channel_dump_audio(dev,
345 				&cx25821_sram_channels[AUDIO_SRAM_CHANNEL]);
346 	}
347 	if (status & AUD_INT_DN_SYNC) {
348 		pr_warn("WARNING %s: Downstream sync error!\n", dev->name);
349 		cx_write(AUD_A_GPCNT_CTL, GP_COUNT_CONTROL_RESET);
350 		return;
351 	}
352 
353 	/* risc1 downstream */
354 	if (status & AUD_INT_DN_RISCI1) {
355 		atomic_set(&chip->count, cx_read(AUD_A_GPCNT));
356 		snd_pcm_period_elapsed(chip->substream);
357 	}
358 }
359 
360 /*
361  * BOARD Specific: Handles IRQ calls
362  */
363 static irqreturn_t cx25821_irq(int irq, void *dev_id)
364 {
365 	struct cx25821_audio_dev *chip = dev_id;
366 	struct cx25821_dev *dev = chip->dev;
367 	u32 status, pci_status;
368 	u32 audint_status, audint_mask;
369 	int loop, handled = 0;
370 
371 	audint_status = cx_read(AUD_A_INT_STAT);
372 	audint_mask = cx_read(AUD_A_INT_MSK);
373 	status = cx_read(PCI_INT_STAT);
374 
375 	for (loop = 0; loop < 1; loop++) {
376 		status = cx_read(PCI_INT_STAT);
377 		if (0 == status) {
378 			status = cx_read(PCI_INT_STAT);
379 			audint_status = cx_read(AUD_A_INT_STAT);
380 			audint_mask = cx_read(AUD_A_INT_MSK);
381 
382 			if (status) {
383 				handled = 1;
384 				cx_write(PCI_INT_STAT, status);
385 
386 				cx25821_aud_irq(chip, audint_status,
387 						audint_mask);
388 				break;
389 			} else {
390 				goto out;
391 			}
392 		}
393 
394 		handled = 1;
395 		cx_write(PCI_INT_STAT, status);
396 
397 		cx25821_aud_irq(chip, audint_status, audint_mask);
398 	}
399 
400 	pci_status = cx_read(PCI_INT_STAT);
401 
402 	if (handled)
403 		cx_write(PCI_INT_STAT, pci_status);
404 
405 out:
406 	return IRQ_RETVAL(handled);
407 }
408 
409 static int dsp_buffer_free(struct cx25821_audio_dev *chip)
410 {
411 	struct cx25821_riscmem *risc = &chip->buf->risc;
412 
413 	BUG_ON(!chip->dma_size);
414 
415 	dprintk(2, "Freeing buffer\n");
416 	cx25821_alsa_dma_unmap(chip);
417 	cx25821_alsa_dma_free(chip->buf);
418 	pci_free_consistent(chip->pci, risc->size, risc->cpu, risc->dma);
419 	kfree(chip->buf);
420 
421 	chip->buf = NULL;
422 	chip->dma_size = 0;
423 
424 	return 0;
425 }
426 
427 /****************************************************************************
428 				ALSA PCM Interface
429  ****************************************************************************/
430 
431 /*
432  * Digital hardware definition
433  */
434 #define DEFAULT_FIFO_SIZE	384
435 static struct snd_pcm_hardware snd_cx25821_digital_hw = {
436 	.info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
437 		SNDRV_PCM_INFO_BLOCK_TRANSFER | SNDRV_PCM_INFO_MMAP_VALID,
438 	.formats = SNDRV_PCM_FMTBIT_S16_LE,
439 
440 	.rates = SNDRV_PCM_RATE_48000,
441 	.rate_min = 48000,
442 	.rate_max = 48000,
443 	.channels_min = 2,
444 	.channels_max = 2,
445 	/* Analog audio output will be full of clicks and pops if there
446 	   are not exactly four lines in the SRAM FIFO buffer.  */
447 	.period_bytes_min = DEFAULT_FIFO_SIZE / 3,
448 	.period_bytes_max = DEFAULT_FIFO_SIZE / 3,
449 	.periods_min = 1,
450 	.periods_max = AUDIO_LINE_SIZE,
451 	/* 128 * 128 = 16384 = 1024 * 16 */
452 	.buffer_bytes_max = (AUDIO_LINE_SIZE * AUDIO_LINE_SIZE),
453 };
454 
455 /*
456  * audio pcm capture open callback
457  */
458 static int snd_cx25821_pcm_open(struct snd_pcm_substream *substream)
459 {
460 	struct cx25821_audio_dev *chip = snd_pcm_substream_chip(substream);
461 	struct snd_pcm_runtime *runtime = substream->runtime;
462 	int err;
463 	unsigned int bpl = 0;
464 
465 	if (!chip) {
466 		pr_err("DEBUG: cx25821 can't find device struct. Can't proceed with open\n");
467 		return -ENODEV;
468 	}
469 
470 	err = snd_pcm_hw_constraint_pow2(runtime, 0,
471 					 SNDRV_PCM_HW_PARAM_PERIODS);
472 	if (err < 0)
473 		goto _error;
474 
475 	chip->substream = substream;
476 
477 	runtime->hw = snd_cx25821_digital_hw;
478 
479 	if (cx25821_sram_channels[AUDIO_SRAM_CHANNEL].fifo_size !=
480 	    DEFAULT_FIFO_SIZE) {
481 		/* since there are 3 audio Clusters */
482 		bpl = cx25821_sram_channels[AUDIO_SRAM_CHANNEL].fifo_size / 3;
483 		bpl &= ~7;	/* must be multiple of 8 */
484 
485 		if (bpl > AUDIO_LINE_SIZE)
486 			bpl = AUDIO_LINE_SIZE;
487 
488 		runtime->hw.period_bytes_min = bpl;
489 		runtime->hw.period_bytes_max = bpl;
490 	}
491 
492 	return 0;
493 _error:
494 	dprintk(1, "Error opening PCM!\n");
495 	return err;
496 }
497 
498 /*
499  * audio close callback
500  */
501 static int snd_cx25821_close(struct snd_pcm_substream *substream)
502 {
503 	return 0;
504 }
505 
506 /*
507  * hw_params callback
508  */
509 static int snd_cx25821_hw_params(struct snd_pcm_substream *substream,
510 				 struct snd_pcm_hw_params *hw_params)
511 {
512 	struct cx25821_audio_dev *chip = snd_pcm_substream_chip(substream);
513 	struct cx25821_audio_buffer *buf;
514 	int ret;
515 
516 	if (substream->runtime->dma_area) {
517 		dsp_buffer_free(chip);
518 		substream->runtime->dma_area = NULL;
519 	}
520 
521 	chip->period_size = params_period_bytes(hw_params);
522 	chip->num_periods = params_periods(hw_params);
523 	chip->dma_size = chip->period_size * params_periods(hw_params);
524 
525 	BUG_ON(!chip->dma_size);
526 	BUG_ON(chip->num_periods & (chip->num_periods - 1));
527 
528 	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
529 	if (NULL == buf)
530 		return -ENOMEM;
531 
532 	if (chip->period_size > AUDIO_LINE_SIZE)
533 		chip->period_size = AUDIO_LINE_SIZE;
534 
535 	buf->bpl = chip->period_size;
536 	chip->buf = buf;
537 
538 	ret = cx25821_alsa_dma_init(chip,
539 			(PAGE_ALIGN(chip->dma_size) >> PAGE_SHIFT));
540 	if (ret < 0)
541 		goto error;
542 
543 	ret = cx25821_alsa_dma_map(chip);
544 	if (ret < 0)
545 		goto error;
546 
547 	ret = cx25821_risc_databuffer_audio(chip->pci, &buf->risc, buf->sglist,
548 			chip->period_size, chip->num_periods, 1);
549 	if (ret < 0) {
550 		pr_info("DEBUG: ERROR after cx25821_risc_databuffer_audio()\n");
551 		goto error;
552 	}
553 
554 	/* Loop back to start of program */
555 	buf->risc.jmp[0] = cpu_to_le32(RISC_JUMP | RISC_IRQ1 | RISC_CNT_INC);
556 	buf->risc.jmp[1] = cpu_to_le32(buf->risc.dma);
557 	buf->risc.jmp[2] = cpu_to_le32(0);	/* bits 63-32 */
558 
559 	substream->runtime->dma_area = chip->buf->vaddr;
560 	substream->runtime->dma_bytes = chip->dma_size;
561 	substream->runtime->dma_addr = 0;
562 
563 	return 0;
564 
565 error:
566 	chip->buf = NULL;
567 	kfree(buf);
568 	return ret;
569 }
570 
571 /*
572  * hw free callback
573  */
574 static int snd_cx25821_hw_free(struct snd_pcm_substream *substream)
575 {
576 	struct cx25821_audio_dev *chip = snd_pcm_substream_chip(substream);
577 
578 	if (substream->runtime->dma_area) {
579 		dsp_buffer_free(chip);
580 		substream->runtime->dma_area = NULL;
581 	}
582 
583 	return 0;
584 }
585 
586 /*
587  * prepare callback
588  */
589 static int snd_cx25821_prepare(struct snd_pcm_substream *substream)
590 {
591 	return 0;
592 }
593 
594 /*
595  * trigger callback
596  */
597 static int snd_cx25821_card_trigger(struct snd_pcm_substream *substream,
598 				    int cmd)
599 {
600 	struct cx25821_audio_dev *chip = snd_pcm_substream_chip(substream);
601 	int err = 0;
602 
603 	/* Local interrupts are already disabled by ALSA */
604 	spin_lock(&chip->reg_lock);
605 
606 	switch (cmd) {
607 	case SNDRV_PCM_TRIGGER_START:
608 		err = _cx25821_start_audio_dma(chip);
609 		break;
610 	case SNDRV_PCM_TRIGGER_STOP:
611 		err = _cx25821_stop_audio_dma(chip);
612 		break;
613 	default:
614 		err = -EINVAL;
615 		break;
616 	}
617 
618 	spin_unlock(&chip->reg_lock);
619 
620 	return err;
621 }
622 
623 /*
624  * pointer callback
625  */
626 static snd_pcm_uframes_t snd_cx25821_pointer(struct snd_pcm_substream
627 					     *substream)
628 {
629 	struct cx25821_audio_dev *chip = snd_pcm_substream_chip(substream);
630 	struct snd_pcm_runtime *runtime = substream->runtime;
631 	u16 count;
632 
633 	count = atomic_read(&chip->count);
634 
635 	return runtime->period_size * (count & (runtime->periods - 1));
636 }
637 
638 /*
639  * page callback (needed for mmap)
640  */
641 static struct page *snd_cx25821_page(struct snd_pcm_substream *substream,
642 				     unsigned long offset)
643 {
644 	void *pageptr = substream->runtime->dma_area + offset;
645 
646 	return vmalloc_to_page(pageptr);
647 }
648 
649 /*
650  * operators
651  */
652 static struct snd_pcm_ops snd_cx25821_pcm_ops = {
653 	.open = snd_cx25821_pcm_open,
654 	.close = snd_cx25821_close,
655 	.ioctl = snd_pcm_lib_ioctl,
656 	.hw_params = snd_cx25821_hw_params,
657 	.hw_free = snd_cx25821_hw_free,
658 	.prepare = snd_cx25821_prepare,
659 	.trigger = snd_cx25821_card_trigger,
660 	.pointer = snd_cx25821_pointer,
661 	.page = snd_cx25821_page,
662 };
663 
664 /*
665  * ALSA create a PCM device:  Called when initializing the board.
666  * Sets up the name and hooks up the callbacks
667  */
668 static int snd_cx25821_pcm(struct cx25821_audio_dev *chip, int device,
669 			   char *name)
670 {
671 	struct snd_pcm *pcm;
672 	int err;
673 
674 	err = snd_pcm_new(chip->card, name, device, 0, 1, &pcm);
675 	if (err < 0) {
676 		pr_info("ERROR: FAILED snd_pcm_new() in %s\n", __func__);
677 		return err;
678 	}
679 	pcm->private_data = chip;
680 	pcm->info_flags = 0;
681 	strcpy(pcm->name, name);
682 	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_cx25821_pcm_ops);
683 
684 	return 0;
685 }
686 
687 /****************************************************************************
688 			Basic Flow for Sound Devices
689  ****************************************************************************/
690 
691 /*
692  * PCI ID Table - 14f1:8801 and 14f1:8811 means function 1: Audio
693  * Only boards with eeprom and byte 1 at eeprom=1 have it
694  */
695 
696 static const struct pci_device_id cx25821_audio_pci_tbl[] = {
697 	{0x14f1, 0x0920, PCI_ANY_ID, PCI_ANY_ID, 0, 0, 0},
698 	{0,}
699 };
700 
701 MODULE_DEVICE_TABLE(pci, cx25821_audio_pci_tbl);
702 
703 /*
704  * Alsa Constructor - Component probe
705  */
706 static int cx25821_audio_initdev(struct cx25821_dev *dev)
707 {
708 	struct snd_card *card;
709 	struct cx25821_audio_dev *chip;
710 	int err;
711 
712 	if (devno >= SNDRV_CARDS) {
713 		pr_info("DEBUG ERROR: devno >= SNDRV_CARDS %s\n", __func__);
714 		return -ENODEV;
715 	}
716 
717 	if (!enable[devno]) {
718 		++devno;
719 		pr_info("DEBUG ERROR: !enable[devno] %s\n", __func__);
720 		return -ENOENT;
721 	}
722 
723 	err = snd_card_new(&dev->pci->dev, index[devno], id[devno],
724 			   THIS_MODULE,
725 			   sizeof(struct cx25821_audio_dev), &card);
726 	if (err < 0) {
727 		pr_info("DEBUG ERROR: cannot create snd_card_new in %s\n",
728 			__func__);
729 		return err;
730 	}
731 
732 	strcpy(card->driver, "cx25821");
733 
734 	/* Card "creation" */
735 	chip = card->private_data;
736 	spin_lock_init(&chip->reg_lock);
737 
738 	chip->dev = dev;
739 	chip->card = card;
740 	chip->pci = dev->pci;
741 	chip->iobase = pci_resource_start(dev->pci, 0);
742 
743 	chip->irq = dev->pci->irq;
744 
745 	err = request_irq(dev->pci->irq, cx25821_irq,
746 			  IRQF_SHARED, chip->dev->name, chip);
747 
748 	if (err < 0) {
749 		pr_err("ERROR %s: can't get IRQ %d for ALSA\n", chip->dev->name,
750 			dev->pci->irq);
751 		goto error;
752 	}
753 
754 	err = snd_cx25821_pcm(chip, 0, "cx25821 Digital");
755 	if (err < 0) {
756 		pr_info("DEBUG ERROR: cannot create snd_cx25821_pcm %s\n",
757 			__func__);
758 		goto error;
759 	}
760 
761 	strcpy(card->shortname, "cx25821");
762 	sprintf(card->longname, "%s at 0x%lx irq %d", chip->dev->name,
763 		chip->iobase, chip->irq);
764 	strcpy(card->mixername, "CX25821");
765 
766 	pr_info("%s/%i: ALSA support for cx25821 boards\n", card->driver,
767 		devno);
768 
769 	err = snd_card_register(card);
770 	if (err < 0) {
771 		pr_info("DEBUG ERROR: cannot register sound card %s\n",
772 			__func__);
773 		goto error;
774 	}
775 
776 	dev->card = card;
777 	devno++;
778 	return 0;
779 
780 error:
781 	snd_card_free(card);
782 	return err;
783 }
784 
785 /****************************************************************************
786 				LINUX MODULE INIT
787  ****************************************************************************/
788 
789 static int cx25821_alsa_exit_callback(struct device *dev, void *data)
790 {
791 	struct v4l2_device *v4l2_dev = dev_get_drvdata(dev);
792 	struct cx25821_dev *cxdev = get_cx25821(v4l2_dev);
793 
794 	snd_card_free(cxdev->card);
795 	return 0;
796 }
797 
798 static void cx25821_audio_fini(void)
799 {
800 	struct device_driver *drv = driver_find("cx25821", &pci_bus_type);
801 	int ret;
802 
803 	ret = driver_for_each_device(drv, NULL, NULL, cx25821_alsa_exit_callback);
804 	if (ret)
805 		pr_err("%s failed to find a cx25821 driver.\n", __func__);
806 }
807 
808 static int cx25821_alsa_init_callback(struct device *dev, void *data)
809 {
810 	struct v4l2_device *v4l2_dev = dev_get_drvdata(dev);
811 	struct cx25821_dev *cxdev = get_cx25821(v4l2_dev);
812 
813 	cx25821_audio_initdev(cxdev);
814 	return 0;
815 }
816 
817 /*
818  * Module initializer
819  *
820  * Loops through present saa7134 cards, and assigns an ALSA device
821  * to each one
822  *
823  */
824 static int cx25821_alsa_init(void)
825 {
826 	struct device_driver *drv = driver_find("cx25821", &pci_bus_type);
827 
828 	return driver_for_each_device(drv, NULL, NULL, cx25821_alsa_init_callback);
829 
830 }
831 
832 late_initcall(cx25821_alsa_init);
833 module_exit(cx25821_audio_fini);
834