kernel / sound / drivers / ml403-ac97cr.c

/*
 * ALSA driver for Xilinx ML403 AC97 Controller Reference
 *   IP: opb_ac97_controller_ref_v1_00_a (EDK 8.1i)
 *   IP: opb_ac97_controller_ref_v1_00_a (EDK 9.1i)
 *
 *  Copyright (c) by 2007  Joachim Foerster <[e-mail]>
 *
 *   This program is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU General Public License as published by
 *   the Free Software Foundation; either version 2 of the License, or
 *   (at your option) any later version.
 *
 *   This program is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *   GNU General Public License for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
 *
 */

/* Some notes / status of this driver:
 *
 * - Don't wonder about some strange implementations of things - especially the
 * (heavy) shadowing of codec registers, with which I tried to reduce read
 * accesses to a minimum, because after a variable amount of accesses, the AC97
 * controller doesn't raise the register access finished bit anymore ...
 *
 * - Playback support seems to be pretty stable - no issues here.
 * - Capture support "works" now, too. Overruns don't happen any longer so often.
 *   But there might still be some ...
 */

#include <linux/init.h>
#include <linux/moduleparam.h>

#include <linux/platform_device.h>

#include <linux/ioport.h>
#include <linux/io.h>
#include <linux/interrupt.h>

/* HZ */
#include <linux/param.h>
/* jiffies, time_*() */
#include <linux/jiffies.h>
/* schedule_timeout*() */
#include <linux/sched.h>
/* spin_lock*() */
#include <linux/spinlock.h>
/* struct mutex, mutex_init(), mutex_*lock() */
#include <linux/mutex.h>

/* snd_printk(), snd_printd() */
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/initval.h>
#include <sound/ac97_codec.h>

#include "pcm-indirect2.h"


#define SND_ML403_AC97CR_DRIVER "ml403-ac97cr"

MODULE_AUTHOR("Joachim Foerster <[e-mail]>");
MODULE_DESCRIPTION("Xilinx ML403 AC97 Controller Reference");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{Xilinx,ML403 AC97 Controller Reference}}");

static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
static int enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE;

module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for ML403 AC97 Controller Reference.");
module_param_array(id, charp, NULL, 0444);
MODULE_PARM_DESC(id, "ID string for ML403 AC97 Controller Reference.");
module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable this ML403 AC97 Controller Reference.");

/* Special feature options */
/*#define CODEC_WRITE_CHECK_RAF*/ /* don't return after a write to a codec
				   * register, while RAF bit is not set
				   */
/* Debug options for code which may be removed completely in a final version */
#ifdef CONFIG_SND_DEBUG
/*#define CODEC_STAT*/            /* turn on some minimal "statistics"
				   * about codec register usage
				   */
#define SND_PCM_INDIRECT2_STAT    /* turn on some "statistics" about the
				   * process of copying bytes from the
				   * intermediate buffer to the hardware
				   * fifo and the other way round
				   */
#endif

/* Definition of a "level/facility dependent" printk(); may be removed
 * completely in a final version
 */
#undef PDEBUG
#ifdef CONFIG_SND_DEBUG
/* "facilities" for PDEBUG */
#define UNKNOWN       (1<<0)
#define CODEC_SUCCESS (1<<1)
#define CODEC_FAKE    (1<<2)
#define INIT_INFO     (1<<3)
#define INIT_FAILURE  (1<<4)
#define WORK_INFO     (1<<5)
#define WORK_FAILURE  (1<<6)

#define PDEBUG_FACILITIES (UNKNOWN | INIT_FAILURE | WORK_FAILURE)

#define PDEBUG(fac, fmt, args...) do { \
		if (fac & PDEBUG_FACILITIES) \
			snd_printd(KERN_DEBUG SND_ML403_AC97CR_DRIVER ": " \
				   fmt, ##args); \
	} while (0)
#else
#define PDEBUG(fac, fmt, args...) /* nothing */
#endif



/* Defines for "waits"/timeouts (portions of HZ=250 on arch/ppc by default) */
#define CODEC_TIMEOUT_ON_INIT       5	/* timeout for checking for codec
					 * readiness (after insmod)
					 */
#ifndef CODEC_WRITE_CHECK_RAF
#define CODEC_WAIT_AFTER_WRITE    100	/* general, static wait after a write
					 * access to a codec register, may be
					 * 0 to completely remove wait
					 */
#else
#define CODEC_TIMEOUT_AFTER_WRITE   5	/* timeout after a write access to a
					 * codec register, if RAF bit is used
					 */
#endif
#define CODEC_TIMEOUT_AFTER_READ    5	/* timeout after a read access to a
					 * codec register (checking RAF bit)
					 */

/* Infrastructure for codec register shadowing */
#define LM4550_REG_OK        (1<<0)   /* register exists */
#define LM4550_REG_DONEREAD  (1<<1)   /* read register once, value should be
				       * the same currently in the register
				       */
#define LM4550_REG_NOSAVE    (1<<2)   /* values written to this register will
				       * not be saved in the register
				       */
#define LM4550_REG_NOSHADOW  (1<<3)   /* don't do register shadowing, use plain
				       * hardware access
				       */
#define LM4550_REG_READONLY  (1<<4)   /* register is read only */
#define LM4550_REG_FAKEPROBE (1<<5)   /* fake write _and_ read actions during
				       * probe() correctly
				       */
#define LM4550_REG_FAKEREAD  (1<<6)   /* fake read access, always return
				       * default value
				       */
#define LM4550_REG_ALLFAKE   (LM4550_REG_FAKEREAD | LM4550_REG_FAKEPROBE)

struct lm4550_reg {
	u16 value;
	u16 flag;
	u16 wmask;
	u16 def;
};

struct lm4550_reg lm4550_regfile[64] = {
	[AC97_RESET / 2]              = {.flag = LM4550_REG_OK \
						| LM4550_REG_NOSAVE \
						| LM4550_REG_FAKEREAD,
					 .def = 0x0D50},
	[AC97_MASTER / 2]             = {.flag = LM4550_REG_OK
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x9F1F,
					 .def = 0x8000},
	[AC97_HEADPHONE / 2]          = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x9F1F,
					 .def = 0x8000},
	[AC97_MASTER_MONO / 2]        = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x801F,
					 .def = 0x8000},
	[AC97_PC_BEEP / 2]            = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x801E,
					 .def = 0x0},
	[AC97_PHONE / 2]              = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x801F,
					 .def = 0x8008},
	[AC97_MIC / 2]                = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x805F,
					 .def = 0x8008},
	[AC97_LINE / 2]               = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x9F1F,
					 .def = 0x8808},
	[AC97_CD / 2]                 = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x9F1F,
					 .def = 0x8808},
	[AC97_VIDEO / 2]              = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x9F1F,
					 .def = 0x8808},
	[AC97_AUX / 2]                = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x9F1F,
					 .def = 0x8808},
	[AC97_PCM / 2]                = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x9F1F,
					 .def = 0x8008},
	[AC97_REC_SEL / 2]            = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x707,
					 .def = 0x0},
	[AC97_REC_GAIN / 2]           = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .wmask = 0x8F0F,
					 .def = 0x8000},
	[AC97_GENERAL_PURPOSE / 2]    = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .def = 0x0,
					 .wmask = 0xA380},
	[AC97_3D_CONTROL / 2]         = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEREAD \
						| LM4550_REG_READONLY,
					 .def = 0x0101},
	[AC97_POWERDOWN / 2]          = {.flag = LM4550_REG_OK \
						| LM4550_REG_NOSHADOW \
						| LM4550_REG_NOSAVE,
					 .wmask = 0xFF00},
					/* may not write ones to
					 * REF/ANL/DAC/ADC bits
					 * FIXME: Is this ok?
					 */
	[AC97_EXTENDED_ID / 2]        = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEREAD \
						| LM4550_REG_READONLY,
					 .def = 0x0201}, /* primary codec */
	[AC97_EXTENDED_STATUS / 2]    = {.flag = LM4550_REG_OK \
						| LM4550_REG_NOSHADOW \
						| LM4550_REG_NOSAVE,
					 .wmask = 0x1},
	[AC97_PCM_FRONT_DAC_RATE / 2] = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .def = 0xBB80,
					 .wmask = 0xFFFF},
	[AC97_PCM_LR_ADC_RATE / 2]    = {.flag = LM4550_REG_OK \
						| LM4550_REG_FAKEPROBE,
					 .def = 0xBB80,
					 .wmask = 0xFFFF},
	[AC97_VENDOR_ID1 / 2]         = {.flag = LM4550_REG_OK \
						| LM4550_REG_READONLY \
						| LM4550_REG_FAKEREAD,
					 .def = 0x4E53},
	[AC97_VENDOR_ID2 / 2]         = {.flag = LM4550_REG_OK \
						| LM4550_REG_READONLY \
						| LM4550_REG_FAKEREAD,
					 .def = 0x4350}
};

#define LM4550_RF_OK(reg)    (lm4550_regfile[reg / 2].flag & LM4550_REG_OK)

static void lm4550_regfile_init(void)
{
	int i;
	for (i = 0; i < 64; i++)
		if (lm4550_regfile[i].flag & LM4550_REG_FAKEPROBE)
			lm4550_regfile[i].value = lm4550_regfile[i].def;
}

static void lm4550_regfile_write_values_after_init(struct snd_ac97 *ac97)
{
	int i;
	for (i = 0; i < 64; i++)
		if ((lm4550_regfile[i].flag & LM4550_REG_FAKEPROBE) &&
		    (lm4550_regfile[i].value != lm4550_regfile[i].def)) {
			PDEBUG(CODEC_FAKE, "lm4550_regfile_write_values_after_"
			       "init(): reg=0x%x value=0x%x / %d is different "
			       "from def=0x%x / %d\n",
			       i, lm4550_regfile[i].value,
			       lm4550_regfile[i].value, lm4550_regfile[i].def,
			       lm4550_regfile[i].def);
			snd_ac97_write(ac97, i * 2, lm4550_regfile[i].value);
			lm4550_regfile[i].flag |= LM4550_REG_DONEREAD;
		}
}


/* direct registers */
#define CR_REG(ml403_ac97cr, x) ((ml403_ac97cr)->port + CR_REG_##x)

#define CR_REG_PLAYFIFO         0x00
#define   CR_PLAYDATA(a)        ((a) & 0xFFFF)

#define CR_REG_RECFIFO          0x04
#define   CR_RECDATA(a)         ((a) & 0xFFFF)

#define CR_REG_STATUS           0x08
#define   CR_RECOVER            (1<<7)
#define   CR_PLAYUNDER          (1<<6)
#define   CR_CODECREADY         (1<<5)
#define   CR_RAF                (1<<4)
#define   CR_RECEMPTY           (1<<3)
#define   CR_RECFULL            (1<<2)
#define   CR_PLAYHALF           (1<<1)
#define   CR_PLAYFULL           (1<<0)

#define CR_REG_RESETFIFO        0x0C
#define   CR_RECRESET           (1<<1)
#define   CR_PLAYRESET          (1<<0)

#define CR_REG_CODEC_ADDR       0x10
/* UG082 says:
 * #define   CR_CODEC_ADDR(a)  ((a) << 1)
 * #define   CR_CODEC_READ     (1<<0)
 * #define   CR_CODEC_WRITE    (0<<0)
 */
/* RefDesign example says: */
#define   CR_CODEC_ADDR(a)      ((a) << 0)
#define   CR_CODEC_READ         (1<<7)
#define   CR_CODEC_WRITE        (0<<7)

#define CR_REG_CODEC_DATAREAD   0x14
#define   CR_CODEC_DATAREAD(v)  ((v) & 0xFFFF)

#define CR_REG_CODEC_DATAWRITE  0x18
#define   CR_CODEC_DATAWRITE(v) ((v) & 0xFFFF)

#define CR_FIFO_SIZE            32

struct snd_ml403_ac97cr {
	/* lock for access to (controller) registers */
	spinlock_t reg_lock;
	/* mutex for the whole sequence of accesses to (controller) registers
	 * which affect codec registers
	 */
	struct mutex cdc_mutex;

	int irq; /* for playback */
	int enable_irq;	/* for playback */

	int capture_irq;
	int enable_capture_irq;

	struct resource *res_port;
	void *port;

	struct snd_ac97 *ac97;
	int ac97_fake;
#ifdef CODEC_STAT
	int ac97_read;
	int ac97_write;
#endif

	struct platform_device *pfdev;
	struct snd_card *card;
	struct snd_pcm *pcm;
	struct snd_pcm_substream *playback_substream;
	struct snd_pcm_substream *capture_substream;

	struct snd_pcm_indirect2 ind_rec; /* for playback */
	struct snd_pcm_indirect2 capture_ind2_rec;
};

static struct snd_pcm_hardware snd_ml403_ac97cr_playback = {
	.info =	            (SNDRV_PCM_INFO_MMAP |
			     SNDRV_PCM_INFO_INTERLEAVED |
			     SNDRV_PCM_INFO_MMAP_VALID),
	.formats =          SNDRV_PCM_FMTBIT_S16_BE,
	.rates =	    (SNDRV_PCM_RATE_CONTINUOUS |
			     SNDRV_PCM_RATE_8000_48000),
	.rate_min =	    4000,
	.rate_max =	    48000,
	.channels_min =     2,
	.channels_max =     2,
	.buffer_bytes_max = (128*1024),
	.period_bytes_min = CR_FIFO_SIZE/2,
	.period_bytes_max = (64*1024),
	.periods_min =      2,
	.periods_max =      (128*1024)/(CR_FIFO_SIZE/2),
	.fifo_size =	    0,
};

static struct snd_pcm_hardware snd_ml403_ac97cr_capture = {
	.info =	            (SNDRV_PCM_INFO_MMAP |
			     SNDRV_PCM_INFO_INTERLEAVED |
			     SNDRV_PCM_INFO_MMAP_VALID),
	.formats =          SNDRV_PCM_FMTBIT_S16_BE,
	.rates =            (SNDRV_PCM_RATE_CONTINUOUS |
			     SNDRV_PCM_RATE_8000_48000),
	.rate_min =         4000,
	.rate_max =         48000,
	.channels_min =     2,
	.channels_max =     2,
	.buffer_bytes_max = (128*1024),
	.period_bytes_min = CR_FIFO_SIZE/2,
	.period_bytes_max = (64*1024),
	.periods_min =      2,
	.periods_max =      (128*1024)/(CR_FIFO_SIZE/2),
	.fifo_size =	    0,
};

static size_t
snd_ml403_ac97cr_playback_ind2_zero(struct snd_pcm_substream *substream,
				    struct snd_pcm_indirect2 *rec)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	int copied_words = 0;
	u32 full = 0;

	ml403_ac97cr = snd_pcm_substream_chip(substream);

	spin_lock(&ml403_ac97cr->reg_lock);
	while ((full = (in_be32(CR_REG(ml403_ac97cr, STATUS)) &
			CR_PLAYFULL)) != CR_PLAYFULL) {
		out_be32(CR_REG(ml403_ac97cr, PLAYFIFO), 0);
		copied_words++;
	}
	rec->hw_ready = 0;
	spin_unlock(&ml403_ac97cr->reg_lock);

	return (size_t) (copied_words * 2);
}

static size_t
snd_ml403_ac97cr_playback_ind2_copy(struct snd_pcm_substream *substream,
				    struct snd_pcm_indirect2 *rec,
				    size_t bytes)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	u16 *src;
	int copied_words = 0;
	u32 full = 0;

	ml403_ac97cr = snd_pcm_substream_chip(substream);
	src = (u16 *)(substream->runtime->dma_area + rec->sw_data);

	spin_lock(&ml403_ac97cr->reg_lock);
	while (((full = (in_be32(CR_REG(ml403_ac97cr, STATUS)) &
			 CR_PLAYFULL)) != CR_PLAYFULL) && (bytes > 1)) {
		out_be32(CR_REG(ml403_ac97cr, PLAYFIFO),
			 CR_PLAYDATA(src[copied_words]));
		copied_words++;
		bytes = bytes - 2;
	}
	if (full != CR_PLAYFULL)
		rec->hw_ready = 1;
	else
		rec->hw_ready = 0;
	spin_unlock(&ml403_ac97cr->reg_lock);

	return (size_t) (copied_words * 2);
}

static size_t
snd_ml403_ac97cr_capture_ind2_null(struct snd_pcm_substream *substream,
				   struct snd_pcm_indirect2 *rec)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	int copied_words = 0;
	u32 empty = 0;

	ml403_ac97cr = snd_pcm_substream_chip(substream);

	spin_lock(&ml403_ac97cr->reg_lock);
	while ((empty = (in_be32(CR_REG(ml403_ac97cr, STATUS)) &
			 CR_RECEMPTY)) != CR_RECEMPTY) {
		volatile u32 trash;

		trash = CR_RECDATA(in_be32(CR_REG(ml403_ac97cr, RECFIFO)));
		/* Hmmmm, really necessary? Don't want call to in_be32()
		 * to be optimised away!
		 */
		trash++;
		copied_words++;
	}
	rec->hw_ready = 0;
	spin_unlock(&ml403_ac97cr->reg_lock);

	return (size_t) (copied_words * 2);
}

static size_t
snd_ml403_ac97cr_capture_ind2_copy(struct snd_pcm_substream *substream,
				   struct snd_pcm_indirect2 *rec, size_t bytes)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	u16 *dst;
	int copied_words = 0;
	u32 empty = 0;

	ml403_ac97cr = snd_pcm_substream_chip(substream);
	dst = (u16 *)(substream->runtime->dma_area + rec->sw_data);

	spin_lock(&ml403_ac97cr->reg_lock);
	while (((empty = (in_be32(CR_REG(ml403_ac97cr, STATUS)) &
			  CR_RECEMPTY)) != CR_RECEMPTY) && (bytes > 1)) {
		dst[copied_words] = CR_RECDATA(in_be32(CR_REG(ml403_ac97cr,
							      RECFIFO)));
		copied_words++;
		bytes = bytes - 2;
	}
	if (empty != CR_RECEMPTY)
		rec->hw_ready = 1;
	else
		rec->hw_ready = 0;
	spin_unlock(&ml403_ac97cr->reg_lock);

	return (size_t) (copied_words * 2);
}

static snd_pcm_uframes_t
snd_ml403_ac97cr_pcm_pointer(struct snd_pcm_substream *substream)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	struct snd_pcm_indirect2 *ind2_rec = NULL;

	ml403_ac97cr = snd_pcm_substream_chip(substream);

	if (substream == ml403_ac97cr->playback_substream)
		ind2_rec = &ml403_ac97cr->ind_rec;
	if (substream == ml403_ac97cr->capture_substream)
		ind2_rec = &ml403_ac97cr->capture_ind2_rec;

	if (ind2_rec != NULL)
		return snd_pcm_indirect2_pointer(substream, ind2_rec);
	return (snd_pcm_uframes_t) 0;
}

static int
snd_ml403_ac97cr_pcm_playback_trigger(struct snd_pcm_substream *substream,
				      int cmd)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	int err = 0;

	ml403_ac97cr = snd_pcm_substream_chip(substream);

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
		PDEBUG(WORK_INFO, "trigger(playback): START\n");
		ml403_ac97cr->ind_rec.hw_ready = 1;

		/* clear play FIFO */
		out_be32(CR_REG(ml403_ac97cr, RESETFIFO), CR_PLAYRESET);

		/* enable play irq */
		ml403_ac97cr->enable_irq = 1;
		enable_irq(ml403_ac97cr->irq);
		break;
	case SNDRV_PCM_TRIGGER_STOP:
		PDEBUG(WORK_INFO, "trigger(playback): STOP\n");
		ml403_ac97cr->ind_rec.hw_ready = 0;
#ifdef SND_PCM_INDIRECT2_STAT
		snd_pcm_indirect2_stat(substream, &ml403_ac97cr->ind_rec);
#endif
		/* disable play irq */
		disable_irq_nosync(ml403_ac97cr->irq);
		ml403_ac97cr->enable_irq = 0;
		break;
	default:
		err = -EINVAL;
		break;
	}
	PDEBUG(WORK_INFO, "trigger(playback): (done)\n");
	return err;
}

static int
snd_ml403_ac97cr_pcm_capture_trigger(struct snd_pcm_substream *substream,
				      int cmd)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	int err = 0;

	ml403_ac97cr = snd_pcm_substream_chip(substream);

	switch (cmd) {
	case SNDRV_PCM_TRIGGER_START:
		PDEBUG(WORK_INFO, "trigger(capture): START\n");
		ml403_ac97cr->capture_ind2_rec.hw_ready = 0;

		/* clear record FIFO */
		out_be32(CR_REG(ml403_ac97cr, RESETFIFO), CR_RECRESET);

		/* enable record irq */
		ml403_ac97cr->enable_capture_irq = 1;
		enable_irq(ml403_ac97cr->capture_irq);
		break;
	case SNDRV_PCM_TRIGGER_STOP:
		PDEBUG(WORK_INFO, "trigger(capture): STOP\n");
		ml403_ac97cr->capture_ind2_rec.hw_ready = 0;
#ifdef SND_PCM_INDIRECT2_STAT
		snd_pcm_indirect2_stat(substream,
				       &ml403_ac97cr->capture_ind2_rec);
#endif
		/* disable capture irq */
		disable_irq_nosync(ml403_ac97cr->capture_irq);
		ml403_ac97cr->enable_capture_irq = 0;
		break;
	default:
		err = -EINVAL;
		break;
	}
	PDEBUG(WORK_INFO, "trigger(capture): (done)\n");
	return err;
}

static int
snd_ml403_ac97cr_pcm_playback_prepare(struct snd_pcm_substream *substream)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	struct snd_pcm_runtime *runtime;

	ml403_ac97cr = snd_pcm_substream_chip(substream);
	runtime = substream->runtime;

	PDEBUG(WORK_INFO,
	       "prepare(): period_bytes=%d, minperiod_bytes=%d\n",
	       snd_pcm_lib_period_bytes(substream), CR_FIFO_SIZE / 2);

	/* set sampling rate */
	snd_ac97_set_rate(ml403_ac97cr->ac97, AC97_PCM_FRONT_DAC_RATE,
			  runtime->rate);
	PDEBUG(WORK_INFO, "prepare(): rate=%d\n", runtime->rate);

	/* init struct for intermediate buffer */
	memset(&ml403_ac97cr->ind_rec, 0,
	       sizeof(struct snd_pcm_indirect2));
	ml403_ac97cr->ind_rec.hw_buffer_size = CR_FIFO_SIZE;
	ml403_ac97cr->ind_rec.sw_buffer_size =
		snd_pcm_lib_buffer_bytes(substream);
	ml403_ac97cr->ind_rec.min_periods = -1;
	ml403_ac97cr->ind_rec.min_multiple =
		snd_pcm_lib_period_bytes(substream) / (CR_FIFO_SIZE / 2);
	PDEBUG(WORK_INFO, "prepare(): hw_buffer_size=%d, "
	       "sw_buffer_size=%d, min_multiple=%d\n",
	       CR_FIFO_SIZE, ml403_ac97cr->ind_rec.sw_buffer_size,
	       ml403_ac97cr->ind_rec.min_multiple);
	return 0;
}

static int
snd_ml403_ac97cr_pcm_capture_prepare(struct snd_pcm_substream *substream)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	struct snd_pcm_runtime *runtime;

	ml403_ac97cr = snd_pcm_substream_chip(substream);
	runtime = substream->runtime;

	PDEBUG(WORK_INFO,
	       "prepare(capture): period_bytes=%d, minperiod_bytes=%d\n",
	       snd_pcm_lib_period_bytes(substream), CR_FIFO_SIZE / 2);

	/* set sampling rate */
	snd_ac97_set_rate(ml403_ac97cr->ac97, AC97_PCM_LR_ADC_RATE,
			  runtime->rate);
	PDEBUG(WORK_INFO, "prepare(capture): rate=%d\n", runtime->rate);

	/* init struct for intermediate buffer */
	memset(&ml403_ac97cr->capture_ind2_rec, 0,
	       sizeof(struct snd_pcm_indirect2));
	ml403_ac97cr->capture_ind2_rec.hw_buffer_size = CR_FIFO_SIZE;
	ml403_ac97cr->capture_ind2_rec.sw_buffer_size =
		snd_pcm_lib_buffer_bytes(substream);
	ml403_ac97cr->capture_ind2_rec.min_multiple =
		snd_pcm_lib_period_bytes(substream) / (CR_FIFO_SIZE / 2);
	PDEBUG(WORK_INFO, "prepare(capture): hw_buffer_size=%d, "
	       "sw_buffer_size=%d, min_multiple=%d\n", CR_FIFO_SIZE,
	       ml403_ac97cr->capture_ind2_rec.sw_buffer_size,
	       ml403_ac97cr->capture_ind2_rec.min_multiple);
	return 0;
}

static int snd_ml403_ac97cr_hw_free(struct snd_pcm_substream *substream)
{
	PDEBUG(WORK_INFO, "hw_free()\n");
	return snd_pcm_lib_free_pages(substream);
}

static int
snd_ml403_ac97cr_hw_params(struct snd_pcm_substream *substream,
			   struct snd_pcm_hw_params *hw_params)
{
	PDEBUG(WORK_INFO, "hw_params(): desired buffer bytes=%d, desired "
	       "period bytes=%d\n",
	       params_buffer_bytes(hw_params), params_period_bytes(hw_params));
	return snd_pcm_lib_malloc_pages(substream,
					params_buffer_bytes(hw_params));
}

static int snd_ml403_ac97cr_playback_open(struct snd_pcm_substream *substream)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	struct snd_pcm_runtime *runtime;

	ml403_ac97cr = snd_pcm_substream_chip(substream);
	runtime = substream->runtime;

	PDEBUG(WORK_INFO, "open(playback)\n");
	ml403_ac97cr->playback_substream = substream;
	runtime->hw = snd_ml403_ac97cr_playback;

	snd_pcm_hw_constraint_step(runtime, 0,
				   SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
				   CR_FIFO_SIZE / 2);
	return 0;
}

static int snd_ml403_ac97cr_capture_open(struct snd_pcm_substream *substream)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	struct snd_pcm_runtime *runtime;

	ml403_ac97cr = snd_pcm_substream_chip(substream);
	runtime = substream->runtime;

	PDEBUG(WORK_INFO, "open(capture)\n");
	ml403_ac97cr->capture_substream = substream;
	runtime->hw = snd_ml403_ac97cr_capture;

	snd_pcm_hw_constraint_step(runtime, 0,
				   SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
				   CR_FIFO_SIZE / 2);
	return 0;
}

static int snd_ml403_ac97cr_playback_close(struct snd_pcm_substream *substream)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;

	ml403_ac97cr = snd_pcm_substream_chip(substream);

	PDEBUG(WORK_INFO, "close(playback)\n");
	ml403_ac97cr->playback_substream = NULL;
	return 0;
}

static int snd_ml403_ac97cr_capture_close(struct snd_pcm_substream *substream)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;

	ml403_ac97cr = snd_pcm_substream_chip(substream);

	PDEBUG(WORK_INFO, "close(capture)\n");
	ml403_ac97cr->capture_substream = NULL;
	return 0;
}

static struct snd_pcm_ops snd_ml403_ac97cr_playback_ops = {
	.open = snd_ml403_ac97cr_playback_open,
	.close = snd_ml403_ac97cr_playback_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = snd_ml403_ac97cr_hw_params,
	.hw_free = snd_ml403_ac97cr_hw_free,
	.prepare = snd_ml403_ac97cr_pcm_playback_prepare,
	.trigger = snd_ml403_ac97cr_pcm_playback_trigger,
	.pointer = snd_ml403_ac97cr_pcm_pointer,
};

static struct snd_pcm_ops snd_ml403_ac97cr_capture_ops = {
	.open = snd_ml403_ac97cr_capture_open,
	.close = snd_ml403_ac97cr_capture_close,
	.ioctl = snd_pcm_lib_ioctl,
	.hw_params = snd_ml403_ac97cr_hw_params,
	.hw_free = snd_ml403_ac97cr_hw_free,
	.prepare = snd_ml403_ac97cr_pcm_capture_prepare,
	.trigger = snd_ml403_ac97cr_pcm_capture_trigger,
	.pointer = snd_ml403_ac97cr_pcm_pointer,
};

static irqreturn_t snd_ml403_ac97cr_irq(int irq, void *dev_id)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	struct platform_device *pfdev;
	int cmp_irq;

	ml403_ac97cr = (struct snd_ml403_ac97cr *)dev_id;
	if (ml403_ac97cr == NULL)
		return IRQ_NONE;

	pfdev = ml403_ac97cr->pfdev;

	/* playback interrupt */
	cmp_irq = platform_get_irq(pfdev, 0);
	if (irq == cmp_irq) {
		if (ml403_ac97cr->enable_irq)
			snd_pcm_indirect2_playback_interrupt(
				ml403_ac97cr->playback_substream,
				&ml403_ac97cr->ind_rec,
				snd_ml403_ac97cr_playback_ind2_copy,
				snd_ml403_ac97cr_playback_ind2_zero);
		else
			goto __disable_irq;
	} else {
		/* record interrupt */
		cmp_irq = platform_get_irq(pfdev, 1);
		if (irq == cmp_irq) {
			if (ml403_ac97cr->enable_capture_irq)
				snd_pcm_indirect2_capture_interrupt(
					ml403_ac97cr->capture_substream,
					&ml403_ac97cr->capture_ind2_rec,
					snd_ml403_ac97cr_capture_ind2_copy,
					snd_ml403_ac97cr_capture_ind2_null);
			else
				goto __disable_irq;
		} else
			return IRQ_NONE;
	}
	return IRQ_HANDLED;

__disable_irq:
	PDEBUG(INIT_INFO, "irq(): irq %d is meant to be disabled! So, now try "
	       "to disable it _really_!\n", irq);
	disable_irq_nosync(irq);
	return IRQ_HANDLED;
}

static unsigned short
snd_ml403_ac97cr_codec_read(struct snd_ac97 *ac97, unsigned short reg)
{
	struct snd_ml403_ac97cr *ml403_ac97cr = ac97->private_data;
#ifdef CODEC_STAT
	u32 stat;
	u32 rafaccess = 0;
#endif
	unsigned long end_time;
	u16 value = 0;

	if (!LM4550_RF_OK(reg)) {
		snd_printk(KERN_WARNING SND_ML403_AC97CR_DRIVER ": "
			   "access to unknown/unused codec register 0x%x "
			   "ignored!\n", reg);
		return 0;
	}
	/* check if we can fake/answer this access from our shadow register */
	if ((lm4550_regfile[reg / 2].flag &
	     (LM4550_REG_DONEREAD | LM4550_REG_ALLFAKE)) &&
	    !(lm4550_regfile[reg / 2].flag & LM4550_REG_NOSHADOW)) {
		if (lm4550_regfile[reg / 2].flag & LM4550_REG_FAKEREAD) {
			PDEBUG(CODEC_FAKE, "codec_read(): faking read from "
			       "reg=0x%x, val=0x%x / %d\n",
			       reg, lm4550_regfile[reg / 2].def,
			       lm4550_regfile[reg / 2].def);
			return lm4550_regfile[reg / 2].def;
		} else if ((lm4550_regfile[reg / 2].flag &
			    LM4550_REG_FAKEPROBE) &&
			   ml403_ac97cr->ac97_fake) {
			PDEBUG(CODEC_FAKE, "codec_read(): faking read from "
			       "reg=0x%x, val=0x%x / %d (probe)\n",
			       reg, lm4550_regfile[reg / 2].value,
			       lm4550_regfile[reg / 2].value);
			return lm4550_regfile[reg / 2].value;
		} else {
#ifdef CODEC_STAT
			PDEBUG(CODEC_FAKE, "codec_read(): read access "
			       "answered by shadow register 0x%x (value=0x%x "
			       "/ %d) (cw=%d cr=%d)\n",
			       reg, lm4550_regfile[reg / 2].value,
			       lm4550_regfile[reg / 2].value,
			       ml403_ac97cr->ac97_write,
			       ml403_ac97cr->ac97_read);
#else
			PDEBUG(CODEC_FAKE, "codec_read(): read access "
			       "answered by shadow register 0x%x (value=0x%x "
			       "/ %d)\n",
			       reg, lm4550_regfile[reg / 2].value,
			       lm4550_regfile[reg / 2].value);
#endif
			return lm4550_regfile[reg / 2].value;
		}
	}
	/* if we are here, we _have_ to access the codec really, no faking */
	if (mutex_lock_interruptible(&ml403_ac97cr->cdc_mutex) != 0)
		return 0;
#ifdef CODEC_STAT
	ml403_ac97cr->ac97_read++;
#endif
	spin_lock(&ml403_ac97cr->reg_lock);
	out_be32(CR_REG(ml403_ac97cr, CODEC_ADDR),
		 CR_CODEC_ADDR(reg) | CR_CODEC_READ);
	spin_unlock(&ml403_ac97cr->reg_lock);
	end_time = jiffies + (HZ / CODEC_TIMEOUT_AFTER_READ);
	do {
		spin_lock(&ml403_ac97cr->reg_lock);
#ifdef CODEC_STAT
		rafaccess++;
		stat = in_be32(CR_REG(ml403_ac97cr, STATUS));
		if ((stat & CR_RAF) == CR_RAF) {
			value = CR_CODEC_DATAREAD(
				in_be32(CR_REG(ml403_ac97cr, CODEC_DATAREAD)));
			PDEBUG(CODEC_SUCCESS, "codec_read(): (done) reg=0x%x, "
			       "value=0x%x / %d (STATUS=0x%x)\n",
			       reg, value, value, stat);
#else
		if ((in_be32(CR_REG(ml403_ac97cr, STATUS)) &
		     CR_RAF) == CR_RAF) {
			value = CR_CODEC_DATAREAD(
				in_be32(CR_REG(ml403_ac97cr, CODEC_DATAREAD)));
			PDEBUG(CODEC_SUCCESS, "codec_read(): (done) "
			       "reg=0x%x, value=0x%x / %d\n",
			       reg, value, value);
#endif
			lm4550_regfile[reg / 2].value = value;
			lm4550_regfile[reg / 2].flag |= LM4550_REG_DONEREAD;
			spin_unlock(&ml403_ac97cr->reg_lock);
			mutex_unlock(&ml403_ac97cr->cdc_mutex);
			return value;
		}
		spin_unlock(&ml403_ac97cr->reg_lock);
		schedule_timeout_uninterruptible(1);
	} while (time_after(end_time, jiffies));
	/* read the DATAREAD register anyway, see comment below */
	spin_lock(&ml403_ac97cr->reg_lock);
	value =
	    CR_CODEC_DATAREAD(in_be32(CR_REG(ml403_ac97cr, CODEC_DATAREAD)));
	spin_unlock(&ml403_ac97cr->reg_lock);
#ifdef CODEC_STAT
	snd_printk(KERN_WARNING SND_ML403_AC97CR_DRIVER ": "
		   "timeout while codec read! "
		   "(reg=0x%x, last STATUS=0x%x, DATAREAD=0x%x / %d, %d) "
		   "(cw=%d, cr=%d)\n",
		   reg, stat, value, value, rafaccess,
		   ml403_ac97cr->ac97_write, ml403_ac97cr->ac97_read);
#else
	snd_printk(KERN_WARNING SND_ML403_AC97CR_DRIVER ": "
		   "timeout while codec read! "
		   "(reg=0x%x, DATAREAD=0x%x / %d)\n",
		   reg, value, value);
#endif
	/* BUG: This is PURE speculation! But after _most_ read timeouts the
	 * value in the register is ok!
	 */
	lm4550_regfile[reg / 2].value = value;
	lm4550_regfile[reg / 2].flag |= LM4550_REG_DONEREAD;
	mutex_unlock(&ml403_ac97cr->cdc_mutex);
	return value;
}

static void
snd_ml403_ac97cr_codec_write(struct snd_ac97 *ac97, unsigned short reg,
			     unsigned short val)
{
	struct snd_ml403_ac97cr *ml403_ac97cr = ac97->private_data;

#ifdef CODEC_STAT
	u32 stat;
	u32 rafaccess = 0;
#endif
#ifdef CODEC_WRITE_CHECK_RAF
	unsigned long end_time;
#endif

	if (!LM4550_RF_OK(reg)) {
		snd_printk(KERN_WARNING SND_ML403_AC97CR_DRIVER ": "
			   "access to unknown/unused codec register 0x%x "
			   "ignored!\n", reg);
		return;
	}
	if (lm4550_regfile[reg / 2].flag & LM4550_REG_READONLY) {
		snd_printk(KERN_WARNING SND_ML403_AC97CR_DRIVER ": "
			   "write access to read only codec register 0x%x "
			   "ignored!\n", reg);
		return;
	}
	if ((val & lm4550_regfile[reg / 2].wmask) != val) {
		snd_printk(KERN_WARNING SND_ML403_AC97CR_DRIVER ": "
			   "write access to codec register 0x%x "
			   "with bad value 0x%x / %d!\n",
			   reg, val, val);
		val = val & lm4550_regfile[reg / 2].wmask;
	}
	if (((lm4550_regfile[reg / 2].flag & LM4550_REG_FAKEPROBE) &&
	     ml403_ac97cr->ac97_fake) &&
	    !(lm4550_regfile[reg / 2].flag & LM4550_REG_NOSHADOW)) {
		PDEBUG(CODEC_FAKE, "codec_write(): faking write to reg=0x%x, "
		       "val=0x%x / %d\n", reg, val, val);
		lm4550_regfile[reg / 2].value = (val &
						lm4550_regfile[reg / 2].wmask);
		return;
	}
	if (mutex_lock_interruptible(&ml403_ac97cr->cdc_mutex) != 0)
		return;
#ifdef CODEC_STAT
	ml403_ac97cr->ac97_write++;
#endif
	spin_lock(&ml403_ac97cr->reg_lock);
	out_be32(CR_REG(ml403_ac97cr, CODEC_DATAWRITE),
		 CR_CODEC_DATAWRITE(val));
	out_be32(CR_REG(ml403_ac97cr, CODEC_ADDR),
		 CR_CODEC_ADDR(reg) | CR_CODEC_WRITE);
	spin_unlock(&ml403_ac97cr->reg_lock);
#ifdef CODEC_WRITE_CHECK_RAF
	/* check CR_CODEC_RAF bit to see if write access to register is done;
	 * loop until bit is set or timeout happens
	 */
	end_time = jiffies + HZ / CODEC_TIMEOUT_AFTER_WRITE;
	do {
		spin_lock(&ml403_ac97cr->reg_lock);
#ifdef CODEC_STAT
		rafaccess++;
		stat = in_be32(CR_REG(ml403_ac97cr, STATUS))
		if ((stat & CR_RAF) == CR_RAF) {
#else
		if ((in_be32(CR_REG(ml403_ac97cr, STATUS)) &
		     CR_RAF) == CR_RAF) {
#endif
			PDEBUG(CODEC_SUCCESS, "codec_write(): (done) "
			       "reg=0x%x, value=%d / 0x%x\n",
			       reg, val, val);
			if (!(lm4550_regfile[reg / 2].flag &
			      LM4550_REG_NOSHADOW) &&
			    !(lm4550_regfile[reg / 2].flag &
			      LM4550_REG_NOSAVE))
				lm4550_regfile[reg / 2].value = val;
			lm4550_regfile[reg / 2].flag |= LM4550_REG_DONEREAD;
			spin_unlock(&ml403_ac97cr->reg_lock);
			mutex_unlock(&ml403_ac97cr->cdc_mutex);
			return;
		}
		spin_unlock(&ml403_ac97cr->reg_lock);
		schedule_timeout_uninterruptible(1);
	} while (time_after(end_time, jiffies));
#ifdef CODEC_STAT
	snd_printk(KERN_WARNING SND_ML403_AC97CR_DRIVER ": "
		   "timeout while codec write "
		   "(reg=0x%x, val=0x%x / %d, last STATUS=0x%x, %d) "
		   "(cw=%d, cr=%d)\n",
		   reg, val, val, stat, rafaccess, ml403_ac97cr->ac97_write,
		   ml403_ac97cr->ac97_read);
#else
	snd_printk(KERN_WARNING SND_ML403_AC97CR_DRIVER ": "
		   "timeout while codec write (reg=0x%x, val=0x%x / %d)\n",
		   reg, val, val);
#endif
#else /* CODEC_WRITE_CHECK_RAF */
#if CODEC_WAIT_AFTER_WRITE > 0
	/* officially, in AC97 spec there is no possibility for a AC97
	 * controller to determine, if write access is done or not - so: How
	 * is Xilinx able to provide a RAF bit for write access?
	 * => very strange, thus just don't check RAF bit (compare with
	 * Xilinx's example app in EDK 8.1i) and wait
	 */
	schedule_timeout_uninterruptible(HZ / CODEC_WAIT_AFTER_WRITE);
#endif
	PDEBUG(CODEC_SUCCESS, "codec_write(): (done) "
	       "reg=0x%x, value=%d / 0x%x (no RAF check)\n",
	       reg, val, val);
#endif
	mutex_unlock(&ml403_ac97cr->cdc_mutex);
	return;
}

static int __devinit
snd_ml403_ac97cr_chip_init(struct snd_ml403_ac97cr *ml403_ac97cr)
{
	unsigned long end_time;
	PDEBUG(INIT_INFO, "chip_init():\n");
	end_time = jiffies + HZ / CODEC_TIMEOUT_ON_INIT;
	do {
		if (in_be32(CR_REG(ml403_ac97cr, STATUS)) & CR_CODECREADY) {
			/* clear both hardware FIFOs */
			out_be32(CR_REG(ml403_ac97cr, RESETFIFO),
				 CR_RECRESET | CR_PLAYRESET);
			PDEBUG(INIT_INFO, "chip_init(): (done)\n");
			return 0;
		}
		schedule_timeout_uninterruptible(1);
	} while (time_after(end_time, jiffies));
	snd_printk(KERN_ERR SND_ML403_AC97CR_DRIVER ": "
		   "timeout while waiting for codec, "
		   "not ready!\n");
	return -EBUSY;
}

static int snd_ml403_ac97cr_free(struct snd_ml403_ac97cr *ml403_ac97cr)
{
	PDEBUG(INIT_INFO, "free():\n");
	/* irq release */
	if (ml403_ac97cr->irq >= 0)
		free_irq(ml403_ac97cr->irq, ml403_ac97cr);
	if (ml403_ac97cr->capture_irq >= 0)
		free_irq(ml403_ac97cr->capture_irq, ml403_ac97cr);
	/* give back "port" */
	if (ml403_ac97cr->port != NULL)
		iounmap(ml403_ac97cr->port);
	kfree(ml403_ac97cr);
	PDEBUG(INIT_INFO, "free(): (done)\n");
	return 0;
}

static int snd_ml403_ac97cr_dev_free(struct snd_device *snddev)
{
	struct snd_ml403_ac97cr *ml403_ac97cr = snddev->device_data;
	PDEBUG(INIT_INFO, "dev_free():\n");
	return snd_ml403_ac97cr_free(ml403_ac97cr);
}

static int __devinit
snd_ml403_ac97cr_create(struct snd_card *card, struct platform_device *pfdev,
			struct snd_ml403_ac97cr **rml403_ac97cr)
{
	struct snd_ml403_ac97cr *ml403_ac97cr;
	int err;
	static struct snd_device_ops ops = {
		.dev_free = snd_ml403_ac97cr_dev_free,
	};
	struct resource *resource;
	int irq;

	*rml403_ac97cr = NULL;
	ml403_ac97cr = kzalloc(sizeof(*ml403_ac97cr), GFP_KERNEL);
	if (ml403_ac97cr == NULL)
		return -ENOMEM;
	spin_lock_init(&ml403_ac97cr->reg_lock);
	mutex_init(&ml403_ac97cr->cdc_mutex);
	ml403_ac97cr->card = card;
	ml403_ac97cr->pfdev = pfdev;
	ml403_ac97cr->irq = -1;
	ml403_ac97cr->enable_irq = 0;
	ml403_ac97cr->capture_irq = -1;
	ml403_ac97cr->enable_capture_irq = 0;
	ml403_ac97cr->port = NULL;
	ml403_ac97cr->res_port = NULL;

	PDEBUG(INIT_INFO, "Trying to reserve resources now ...\n");
	resource = platform_get_resource(pfdev, IORESOURCE_MEM, 0);
	/* get "port" */
	ml403_ac97cr->port = ioremap_nocache(resource->start,
					     (resource->end) -
					     (resource->start) + 1);
	if (ml403_ac97cr->port == NULL) {
		snd_printk(KERN_ERR SND_ML403_AC97CR_DRIVER ": "
			   "unable to remap memory region (%x to %x)\n",
			   resource->start, resource->end);
		snd_ml403_ac97cr_free(ml403_ac97cr);
		return -EBUSY;
	}
	snd_printk(KERN_INFO SND_ML403_AC97CR_DRIVER ": "
		   "remap controller memory region to "
		   "0x%x done\n", (unsigned int)ml403_ac97cr->port);
	/* get irq */
	irq = platform_get_irq(pfdev, 0);
	if (request_irq(irq, snd_ml403_ac97cr_irq, IRQF_DISABLED,
			dev_name(&pfdev->dev), (void *)ml403_ac97cr)) {
		snd_printk(KERN_ERR SND_ML403_AC97CR_DRIVER ": "
			   "unable to grab IRQ %d\n",
			   irq);
		snd_ml403_ac97cr_free(ml403_ac97cr);
		return -EBUSY;
	}
	ml403_ac97cr->irq = irq;
	snd_printk(KERN_INFO SND_ML403_AC97CR_DRIVER ": "
		   "request (playback) irq %d done\n",
		   ml403_ac97cr->irq);
	irq = platform_get_irq(pfdev, 1);
	if (request_irq(irq, snd_ml403_ac97cr_irq, IRQF_DISABLED,
			dev_name(&pfdev->dev), (void *)ml403_ac97cr)) {
		snd_printk(KERN_ERR SND_ML403_AC97CR_DRIVER ": "
			   "unable to grab IRQ %d\n",
			   irq);
		snd_ml403_ac97cr_free(ml403_ac97cr);
		return -EBUSY;
	}
	ml403_ac97cr->capture_irq = irq;
	snd_printk(KERN_INFO SND_ML403_AC97CR_DRIVER ": "
		   "request (capture) irq %d done\n",
		   ml403_ac97cr->capture_irq);

	err = snd_ml403_ac97cr_chip_init(ml403_ac97cr);
	if (err < 0) {
		snd_ml403_ac97cr_free(ml403_ac97cr);
		return err;
	}

	err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, ml403_ac97cr, &ops);
	if (err < 0) {
		PDEBUG(INIT_FAILURE, "probe(): snd_device_new() failed!\n");
		snd_ml403_ac97cr_free(ml403_ac97cr);
		return err;
	}

	*rml403_ac97cr = ml403_ac97cr;
	return 0;
}

static void snd_ml403_ac97cr_mixer_free(struct snd_ac97 *ac97)
{
	struct snd_ml403_ac97cr *ml403_ac97cr = ac97->private_data;
	PDEBUG(INIT_INFO, "mixer_free():\n");
	ml403_ac97cr->ac97 = NULL;
	PDEBUG(INIT_INFO, "mixer_free(): (done)\n");
}

static int __devinit
snd_ml403_ac97cr_mixer(struct snd_ml403_ac97cr *ml403_ac97cr)
{
	struct snd_ac97_bus *bus;
	struct snd_ac97_template ac97;
	int err;
	static struct snd_ac97_bus_ops ops = {
		.write = snd_ml403_ac97cr_codec_write,
		.read = snd_ml403_ac97cr_codec_read,
	};
	PDEBUG(INIT_INFO, "mixer():\n");
	err = snd_ac97_bus(ml403_ac97cr->card, 0, &ops, NULL, &bus);
	if (err < 0)
		return err;

	memset(&ac97, 0, sizeof(ac97));
	ml403_ac97cr->ac97_fake = 1;
	lm4550_regfile_init();
#ifdef CODEC_STAT
	ml403_ac97cr->ac97_read = 0;
	ml403_ac97cr->ac97_write = 0;
#endif
	ac97.private_data = ml403_ac97cr;
	ac97.private_free = snd_ml403_ac97cr_mixer_free;
	ac97.scaps = AC97_SCAP_AUDIO | AC97_SCAP_SKIP_MODEM |
	    AC97_SCAP_NO_SPDIF;
	err = snd_ac97_mixer(bus, &ac97, &ml403_ac97cr->ac97);
	ml403_ac97cr->ac97_fake = 0;
	lm4550_regfile_write_values_after_init(ml403_ac97cr->ac97);
	PDEBUG(INIT_INFO, "mixer(): (done) snd_ac97_mixer()=%d\n", err);
	return err;
}

static int __devinit
snd_ml403_ac97cr_pcm(struct snd_ml403_ac97cr *ml403_ac97cr, int device,
		     struct snd_pcm **rpcm)
{
	struct snd_pcm *pcm;
	int err;

	if (rpcm)
		*rpcm = NULL;
	err = snd_pcm_new(ml403_ac97cr->card, "ML403AC97CR/1", device, 1, 1,
			  &pcm);
	if (err < 0)
		return err;
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK,
			&snd_ml403_ac97cr_playback_ops);
	snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE,
			&snd_ml403_ac97cr_capture_ops);
	pcm->private_data = ml403_ac97cr;
	pcm->info_flags = 0;
	strcpy(pcm->name, "ML403AC97CR DAC/ADC");
	ml403_ac97cr->pcm = pcm;

	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_CONTINUOUS,
					  snd_dma_continuous_data(GFP_KERNEL),
					  64 * 1024,
					  128 * 1024);
	if (rpcm)
		*rpcm = pcm;
	return 0;
}

static int __devinit snd_ml403_ac97cr_probe(struct platform_device *pfdev)
{
	struct snd_card *card;
	struct snd_ml403_ac97cr *ml403_ac97cr = NULL;
	int err;
	int dev = pfdev->id;

	if (dev >= SNDRV_CARDS)
		return -ENODEV;
	if (!enable[dev])
		return -ENOENT;

	card = snd_card_new(index[dev], id[dev], THIS_MODULE, 0);
	if (card == NULL)
		return -ENOMEM;
	err = snd_ml403_ac97cr_create(card, pfdev, &ml403_ac97cr);
	if (err < 0) {
		PDEBUG(INIT_FAILURE, "probe(): create failed!\n");
		snd_card_free(card);
		return err;
	}
	PDEBUG(INIT_INFO, "probe(): create done\n");
	card->private_data = ml403_ac97cr;
	err = snd_ml403_ac97cr_mixer(ml403_ac97cr);
	if (err < 0) {
		snd_card_free(card);
		return err;
	}
	PDEBUG(INIT_INFO, "probe(): mixer done\n");
	err = snd_ml403_ac97cr_pcm(ml403_ac97cr, 0, NULL);
	if (err < 0) {
		snd_card_free(card);
		return err;
	}
	PDEBUG(INIT_INFO, "probe(): PCM done\n");
	strcpy(card->driver, SND_ML403_AC97CR_DRIVER);
	strcpy(card->shortname, "ML403 AC97 Controller Reference");
	sprintf(card->longname, "%s %s at 0x%lx, irq %i & %i, device %i",
		card->shortname, card->driver,
		(unsigned long)ml403_ac97cr->port, ml403_ac97cr->irq,
		ml403_ac97cr->capture_irq, dev + 1);

	snd_card_set_dev(card, &pfdev->dev);

	err = snd_card_register(card);
	if (err < 0) {
		snd_card_free(card);
		return err;
	}
	platform_set_drvdata(pfdev, card);
	PDEBUG(INIT_INFO, "probe(): (done)\n");
	return 0;
}

static int snd_ml403_ac97cr_remove(struct platform_device *pfdev)
{
	snd_card_free(platform_get_drvdata(pfdev));
	platform_set_drvdata(pfdev, NULL);
	return 0;
}

/* work with hotplug and coldplug */
MODULE_ALIAS("platform:" SND_ML403_AC97CR_DRIVER);

static struct platform_driver snd_ml403_ac97cr_driver = {
	.probe = snd_ml403_ac97cr_probe,
	.remove = snd_ml403_ac97cr_remove,
	.driver = {
		.name = SND_ML403_AC97CR_DRIVER,
		.owner = THIS_MODULE,
	},
};

static int __init alsa_card_ml403_ac97cr_init(void)
{
	return platform_driver_register(&snd_ml403_ac97cr_driver);
}

static void __exit alsa_card_ml403_ac97cr_exit(void)
{
	platform_driver_unregister(&snd_ml403_ac97cr_driver);
}

module_init(alsa_card_ml403_ac97cr_init)
module_exit(alsa_card_ml403_ac97cr_exit)