// SPDX-License-Identifier: GPL-2.0-only
/* Analog Devices 1889 audio driver
 *
 * This is a driver for the AD1889 PCI audio chipset found
 * on the HP PA-RISC [BCJ]-xxx0 workstations.
 *
 * Copyright (C) 2004-2005, Kyle McMartin <kyle@parisc-linux.org>
 * Copyright (C) 2005, Thibaut Varene <varenet@parisc-linux.org>
 *   Based on the OSS AD1889 driver by Randolph Chung <tausq@debian.org>
 *
 * TODO:
 *      Do we need to take care of CCS register?
 *      Maybe we could use finer grained locking (separate locks for pb/cap)?
 * Wishlist:
 *      Control Interface (mixer) support
 *      Better AC97 support (VSR...)?
 *      PM support
 *      MIDI support
 *      Game Port support
 *      SG DMA support (this will need *a lot* of work)
 */

#include <linux/init.h>
#include <linux/pci.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/compiler.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/io.h>

#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/initval.h>
#include <sound/ac97_codec.h>

#include "ad1889.h"
#include "ac97/ac97_id.h"

#define AD1889_DRVVER   "Version: 1.7"

MODULE_AUTHOR("Kyle McMartin <kyle@parisc-linux.org>, Thibaut Varene <t-bone@parisc-linux.org>");
MODULE_DESCRIPTION("Analog Devices AD1889 ALSA sound driver");
MODULE_LICENSE("GPL");

static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
module_param_array(index, int, NULL, 0444);
MODULE_PARM_DESC(index, "Index value for the AD1889 soundcard.");

static char *id[SNDRV_CARDS] = SNDRV_DEFAULT_STR;
module_param_array(id, charp, NULL, 0444);
MODULE_PARM_DESC(id, "ID string for the AD1889 soundcard.");

static bool enable[SNDRV_CARDS] = SNDRV_DEFAULT_ENABLE_PNP;
module_param_array(enable, bool, NULL, 0444);
MODULE_PARM_DESC(enable, "Enable AD1889 soundcard.");

static char *ac97_quirk[SNDRV_CARDS];
module_param_array(ac97_quirk, charp, NULL, 0444);
MODULE_PARM_DESC(ac97_quirk, "AC'97 workaround for strange hardware.");

#define DEVNAME "ad1889"
#define PFX     DEVNAME ": "

/* keep track of some hw registers */
struct ad1889_register_state {
        u16 reg;        /* reg setup */
        u32 addr;       /* dma base address */
        unsigned long size;     /* DMA buffer size */
};

struct snd_ad1889 {
        struct snd_card *card;
        struct pci_dev *pci;

        int irq;
        unsigned long bar;
        void __iomem *iobase;

        struct snd_ac97 *ac97;
        struct snd_ac97_bus *ac97_bus;
        struct snd_pcm *pcm;
        struct snd_info_entry *proc;

        struct snd_pcm_substream *psubs;
        struct snd_pcm_substream *csubs;

        /* playback register state */
        struct ad1889_register_state wave;
        struct ad1889_register_state ramc;

        spinlock_t lock;
};

static inline u16
ad1889_readw(struct snd_ad1889 *chip, unsigned reg)
{
        return readw(chip->iobase + reg);
}

static inline void
ad1889_writew(struct snd_ad1889 *chip, unsigned reg, u16 val)
{
        writew(val, chip->iobase + reg);
}

static inline u32
ad1889_readl(struct snd_ad1889 *chip, unsigned reg)
{
        return readl(chip->iobase + reg);
}

static inline void
ad1889_writel(struct snd_ad1889 *chip, unsigned reg, u32 val)
{
        writel(val, chip->iobase + reg);
}

static inline void
ad1889_unmute(struct snd_ad1889 *chip)
{
        u16 st;
        st = ad1889_readw(chip, AD_DS_WADA) & 
                ~(AD_DS_WADA_RWAM | AD_DS_WADA_LWAM);
        ad1889_writew(chip, AD_DS_WADA, st);
        ad1889_readw(chip, AD_DS_WADA);
}

static inline void
ad1889_mute(struct snd_ad1889 *chip)
{
        u16 st;
        st = ad1889_readw(chip, AD_DS_WADA) | AD_DS_WADA_RWAM | AD_DS_WADA_LWAM;
        ad1889_writew(chip, AD_DS_WADA, st);
        ad1889_readw(chip, AD_DS_WADA);
}

static inline void
ad1889_load_adc_buffer_address(struct snd_ad1889 *chip, u32 address)
{
        ad1889_writel(chip, AD_DMA_ADCBA, address);
        ad1889_writel(chip, AD_DMA_ADCCA, address);
}

static inline void
ad1889_load_adc_buffer_count(struct snd_ad1889 *chip, u32 count)
{
        ad1889_writel(chip, AD_DMA_ADCBC, count);
        ad1889_writel(chip, AD_DMA_ADCCC, count);
}

static inline void
ad1889_load_adc_interrupt_count(struct snd_ad1889 *chip, u32 count)
{
        ad1889_writel(chip, AD_DMA_ADCIB, count);
        ad1889_writel(chip, AD_DMA_ADCIC, count);
}

static inline void
ad1889_load_wave_buffer_address(struct snd_ad1889 *chip, u32 address)
{
        ad1889_writel(chip, AD_DMA_WAVBA, address);
        ad1889_writel(chip, AD_DMA_WAVCA, address);
}

static inline void
ad1889_load_wave_buffer_count(struct snd_ad1889 *chip, u32 count)
{
        ad1889_writel(chip, AD_DMA_WAVBC, count);
        ad1889_writel(chip, AD_DMA_WAVCC, count);
}

static inline void
ad1889_load_wave_interrupt_count(struct snd_ad1889 *chip, u32 count)
{
        ad1889_writel(chip, AD_DMA_WAVIB, count);
        ad1889_writel(chip, AD_DMA_WAVIC, count);
}

static void
ad1889_channel_reset(struct snd_ad1889 *chip, unsigned int channel)
{
        u16 reg;
        
        if (channel & AD_CHAN_WAV) {
                /* Disable wave channel */
                reg = ad1889_readw(chip, AD_DS_WSMC) & ~AD_DS_WSMC_WAEN;
                ad1889_writew(chip, AD_DS_WSMC, reg);
                chip->wave.reg = reg;
                
                /* disable IRQs */
                reg = ad1889_readw(chip, AD_DMA_WAV);
                reg &= AD_DMA_IM_DIS;
                reg &= ~AD_DMA_LOOP;
                ad1889_writew(chip, AD_DMA_WAV, reg);

                /* clear IRQ and address counters and pointers */
                ad1889_load_wave_buffer_address(chip, 0x0);
                ad1889_load_wave_buffer_count(chip, 0x0);
                ad1889_load_wave_interrupt_count(chip, 0x0);

                /* flush */
                ad1889_readw(chip, AD_DMA_WAV);
        }
        
        if (channel & AD_CHAN_ADC) {
                /* Disable ADC channel */
                reg = ad1889_readw(chip, AD_DS_RAMC) & ~AD_DS_RAMC_ADEN;
                ad1889_writew(chip, AD_DS_RAMC, reg);
                chip->ramc.reg = reg;

                reg = ad1889_readw(chip, AD_DMA_ADC);
                reg &= AD_DMA_IM_DIS;
                reg &= ~AD_DMA_LOOP;
                ad1889_writew(chip, AD_DMA_ADC, reg);
        
                ad1889_load_adc_buffer_address(chip, 0x0);
                ad1889_load_adc_buffer_count(chip, 0x0);
                ad1889_load_adc_interrupt_count(chip, 0x0);

                /* flush */
                ad1889_readw(chip, AD_DMA_ADC);
        }
}

static u16
snd_ad1889_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
{
        struct snd_ad1889 *chip = ac97->private_data;
        return ad1889_readw(chip, AD_AC97_BASE + reg);
}

static void
snd_ad1889_ac97_write(struct snd_ac97 *ac97, unsigned short reg, unsigned short val)
{
        struct snd_ad1889 *chip = ac97->private_data;
        ad1889_writew(chip, AD_AC97_BASE + reg, val);
}

static int
snd_ad1889_ac97_ready(struct snd_ad1889 *chip)
{
        int retry = 400; /* average needs 352 msec */
        
        while (!(ad1889_readw(chip, AD_AC97_ACIC) & AD_AC97_ACIC_ACRDY) 
                        && --retry)
                usleep_range(1000, 2000);
        if (!retry) {
                dev_err(chip->card->dev, "[%s] Link is not ready.\n",
                        __func__);
                return -EIO;
        }
        dev_dbg(chip->card->dev, "[%s] ready after %d ms\n", __func__, 400 - retry);

        return 0;
}

static const struct snd_pcm_hardware snd_ad1889_playback_hw = {
        .info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
                SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_BLOCK_TRANSFER,
        .formats = SNDRV_PCM_FMTBIT_S16_LE,
        .rates = SNDRV_PCM_RATE_CONTINUOUS | SNDRV_PCM_RATE_8000_48000,
        .rate_min = 8000,       /* docs say 7000, but we're lazy */
        .rate_max = 48000,
        .channels_min = 1,
        .channels_max = 2,
        .buffer_bytes_max = BUFFER_BYTES_MAX,
        .period_bytes_min = PERIOD_BYTES_MIN,
        .period_bytes_max = PERIOD_BYTES_MAX,
        .periods_min = PERIODS_MIN,
        .periods_max = PERIODS_MAX,
        /*.fifo_size = 0,*/
};

static const struct snd_pcm_hardware snd_ad1889_capture_hw = {
        .info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
                SNDRV_PCM_INFO_MMAP_VALID | SNDRV_PCM_INFO_BLOCK_TRANSFER,
        .formats = SNDRV_PCM_FMTBIT_S16_LE,
        .rates = SNDRV_PCM_RATE_48000,
        .rate_min = 48000,      /* docs say we could to VSR, but we're lazy */
        .rate_max = 48000,
        .channels_min = 1,
        .channels_max = 2,
        .buffer_bytes_max = BUFFER_BYTES_MAX,
        .period_bytes_min = PERIOD_BYTES_MIN,
        .period_bytes_max = PERIOD_BYTES_MAX,
        .periods_min = PERIODS_MIN,
        .periods_max = PERIODS_MAX,
        /*.fifo_size = 0,*/
};

static int
snd_ad1889_playback_open(struct snd_pcm_substream *ss)
{
        struct snd_ad1889 *chip = snd_pcm_substream_chip(ss);
        struct snd_pcm_runtime *rt = ss->runtime;

        chip->psubs = ss;
        rt->hw = snd_ad1889_playback_hw;

        return 0;
}

static int
snd_ad1889_capture_open(struct snd_pcm_substream *ss)
{
        struct snd_ad1889 *chip = snd_pcm_substream_chip(ss);
        struct snd_pcm_runtime *rt = ss->runtime;

        chip->csubs = ss;
        rt->hw = snd_ad1889_capture_hw;

        return 0;
}

static int
snd_ad1889_playback_close(struct snd_pcm_substream *ss)
{
        struct snd_ad1889 *chip = snd_pcm_substream_chip(ss);
        chip->psubs = NULL;
        return 0;
}

static int
snd_ad1889_capture_close(struct snd_pcm_substream *ss)
{
        struct snd_ad1889 *chip = snd_pcm_substream_chip(ss);
        chip->csubs = NULL;
        return 0;
}

static int
snd_ad1889_playback_prepare(struct snd_pcm_substream *ss)
{
        struct snd_ad1889 *chip = snd_pcm_substream_chip(ss);
        struct snd_pcm_runtime *rt = ss->runtime;
        unsigned int size = snd_pcm_lib_buffer_bytes(ss);
        unsigned int count = snd_pcm_lib_period_bytes(ss);
        u16 reg;

        ad1889_channel_reset(chip, AD_CHAN_WAV);

        reg = ad1889_readw(chip, AD_DS_WSMC);
        
        /* Mask out 16-bit / Stereo */
        reg &= ~(AD_DS_WSMC_WA16 | AD_DS_WSMC_WAST);

        if (snd_pcm_format_width(rt->format) == 16)
                reg |= AD_DS_WSMC_WA16;

        if (rt->channels > 1)
                reg |= AD_DS_WSMC_WAST;

        /* let's make sure we don't clobber ourselves */
        spin_lock_irq(&chip->lock);
        
        chip->wave.size = size;
        chip->wave.reg = reg;
        chip->wave.addr = rt->dma_addr;

        ad1889_writew(chip, AD_DS_WSMC, chip->wave.reg);
        
        /* Set sample rates on the codec */
        ad1889_writew(chip, AD_DS_WAS, rt->rate);

        /* Set up DMA */
        ad1889_load_wave_buffer_address(chip, chip->wave.addr);
        ad1889_load_wave_buffer_count(chip, size);
        ad1889_load_wave_interrupt_count(chip, count);

        /* writes flush */
        ad1889_readw(chip, AD_DS_WSMC);
        
        spin_unlock_irq(&chip->lock);
        
        dev_dbg(chip->card->dev,
                "prepare playback: addr = 0x%x, count = %u, size = %u, reg = 0x%x, rate = %u\n",
                chip->wave.addr, count, size, reg, rt->rate);
        return 0;
}

static int
snd_ad1889_capture_prepare(struct snd_pcm_substream *ss)
{
        struct snd_ad1889 *chip = snd_pcm_substream_chip(ss);
        struct snd_pcm_runtime *rt = ss->runtime;
        unsigned int size = snd_pcm_lib_buffer_bytes(ss);
        unsigned int count = snd_pcm_lib_period_bytes(ss);
        u16 reg;

        ad1889_channel_reset(chip, AD_CHAN_ADC);
        
        reg = ad1889_readw(chip, AD_DS_RAMC);

        /* Mask out 16-bit / Stereo */
        reg &= ~(AD_DS_RAMC_AD16 | AD_DS_RAMC_ADST);

        if (snd_pcm_format_width(rt->format) == 16)
                reg |= AD_DS_RAMC_AD16;

        if (rt->channels > 1)
                reg |= AD_DS_RAMC_ADST;

        /* let's make sure we don't clobber ourselves */
        spin_lock_irq(&chip->lock);
        
        chip->ramc.size = size;
        chip->ramc.reg = reg;
        chip->ramc.addr = rt->dma_addr;

        ad1889_writew(chip, AD_DS_RAMC, chip->ramc.reg);

        /* Set up DMA */
        ad1889_load_adc_buffer_address(chip, chip->ramc.addr);
        ad1889_load_adc_buffer_count(chip, size);
        ad1889_load_adc_interrupt_count(chip, count);

        /* writes flush */
        ad1889_readw(chip, AD_DS_RAMC);
        
        spin_unlock_irq(&chip->lock);
        
        dev_dbg(chip->card->dev,
                "prepare capture: addr = 0x%x, count = %u, size = %u, reg = 0x%x, rate = %u\n",
                chip->ramc.addr, count, size, reg, rt->rate);
        return 0;
}

/* this is called in atomic context with IRQ disabled.
   Must be as fast as possible and not sleep.
   DMA should be *triggered* by this call.
   The WSMC "WAEN" bit triggers DMA Wave On/Off */
static int
snd_ad1889_playback_trigger(struct snd_pcm_substream *ss, int cmd)
{
        u16 wsmc;
        struct snd_ad1889 *chip = snd_pcm_substream_chip(ss);
        
        wsmc = ad1889_readw(chip, AD_DS_WSMC);

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
                /* enable DMA loop & interrupts */
                ad1889_writew(chip, AD_DMA_WAV, AD_DMA_LOOP | AD_DMA_IM_CNT);
                wsmc |= AD_DS_WSMC_WAEN;
                /* 1 to clear CHSS bit */
                ad1889_writel(chip, AD_DMA_CHSS, AD_DMA_CHSS_WAVS);
                ad1889_unmute(chip);
                break;
        case SNDRV_PCM_TRIGGER_STOP:
                ad1889_mute(chip);
                wsmc &= ~AD_DS_WSMC_WAEN;
                break;
        default:
                snd_BUG();
                return -EINVAL;
        }
        
        chip->wave.reg = wsmc;
        ad1889_writew(chip, AD_DS_WSMC, wsmc);  
        ad1889_readw(chip, AD_DS_WSMC); /* flush */

        /* reset the chip when STOP - will disable IRQs */
        if (cmd == SNDRV_PCM_TRIGGER_STOP)
                ad1889_channel_reset(chip, AD_CHAN_WAV);

        return 0;
}

/* this is called in atomic context with IRQ disabled.
   Must be as fast as possible and not sleep.
   DMA should be *triggered* by this call.
   The RAMC "ADEN" bit triggers DMA ADC On/Off */
static int
snd_ad1889_capture_trigger(struct snd_pcm_substream *ss, int cmd)
{
        u16 ramc;
        struct snd_ad1889 *chip = snd_pcm_substream_chip(ss);

        ramc = ad1889_readw(chip, AD_DS_RAMC);
        
        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
                /* enable DMA loop & interrupts */
                ad1889_writew(chip, AD_DMA_ADC, AD_DMA_LOOP | AD_DMA_IM_CNT);
                ramc |= AD_DS_RAMC_ADEN;
                /* 1 to clear CHSS bit */
                ad1889_writel(chip, AD_DMA_CHSS, AD_DMA_CHSS_ADCS);
                break;
        case SNDRV_PCM_TRIGGER_STOP:
                ramc &= ~AD_DS_RAMC_ADEN;
                break;
        default:
                return -EINVAL;
        }
        
        chip->ramc.reg = ramc;
        ad1889_writew(chip, AD_DS_RAMC, ramc);  
        ad1889_readw(chip, AD_DS_RAMC); /* flush */
        
        /* reset the chip when STOP - will disable IRQs */
        if (cmd == SNDRV_PCM_TRIGGER_STOP)
                ad1889_channel_reset(chip, AD_CHAN_ADC);
                
        return 0;
}

/* Called in atomic context with IRQ disabled */
static snd_pcm_uframes_t
snd_ad1889_playback_pointer(struct snd_pcm_substream *ss)
{
        size_t ptr = 0;
        struct snd_ad1889 *chip = snd_pcm_substream_chip(ss);

        if (unlikely(!(chip->wave.reg & AD_DS_WSMC_WAEN)))
                return 0;

        ptr = ad1889_readl(chip, AD_DMA_WAVCA);
        ptr -= chip->wave.addr;
        
        if (snd_BUG_ON(ptr >= chip->wave.size))
                return 0;
        
        return bytes_to_frames(ss->runtime, ptr);
}

/* Called in atomic context with IRQ disabled */
static snd_pcm_uframes_t
snd_ad1889_capture_pointer(struct snd_pcm_substream *ss)
{
        size_t ptr = 0;
        struct snd_ad1889 *chip = snd_pcm_substream_chip(ss);

        if (unlikely(!(chip->ramc.reg & AD_DS_RAMC_ADEN)))
                return 0;

        ptr = ad1889_readl(chip, AD_DMA_ADCCA);
        ptr -= chip->ramc.addr;

        if (snd_BUG_ON(ptr >= chip->ramc.size))
                return 0;
        
        return bytes_to_frames(ss->runtime, ptr);
}

static const struct snd_pcm_ops snd_ad1889_playback_ops = {
        .open = snd_ad1889_playback_open,
        .close = snd_ad1889_playback_close,
        .prepare = snd_ad1889_playback_prepare,
        .trigger = snd_ad1889_playback_trigger,
        .pointer = snd_ad1889_playback_pointer, 
};

static const struct snd_pcm_ops snd_ad1889_capture_ops = {
        .open = snd_ad1889_capture_open,
        .close = snd_ad1889_capture_close,
        .prepare = snd_ad1889_capture_prepare,
        .trigger = snd_ad1889_capture_trigger,
        .pointer = snd_ad1889_capture_pointer, 
};

static irqreturn_t
snd_ad1889_interrupt(int irq, void *dev_id)
{
        unsigned long st;
        struct snd_ad1889 *chip = dev_id;

        st = ad1889_readl(chip, AD_DMA_DISR);

        /* clear ISR */
        ad1889_writel(chip, AD_DMA_DISR, st);

        st &= AD_INTR_MASK;

        if (unlikely(!st))
                return IRQ_NONE;

        if (st & (AD_DMA_DISR_PMAI|AD_DMA_DISR_PTAI))
                dev_dbg(chip->card->dev,
                        "Unexpected master or target abort interrupt!\n");

        if ((st & AD_DMA_DISR_WAVI) && chip->psubs)
                snd_pcm_period_elapsed(chip->psubs);
        if ((st & AD_DMA_DISR_ADCI) && chip->csubs)
                snd_pcm_period_elapsed(chip->csubs);

        return IRQ_HANDLED;
}

static int
snd_ad1889_pcm_init(struct snd_ad1889 *chip, int device)
{
        int err;
        struct snd_pcm *pcm;

        err = snd_pcm_new(chip->card, chip->card->driver, device, 1, 1, &pcm);
        if (err < 0)
                return err;

        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, 
                        &snd_ad1889_playback_ops);
        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE,
                        &snd_ad1889_capture_ops);

        pcm->private_data = chip;
        pcm->info_flags = 0;
        strcpy(pcm->name, chip->card->shortname);
        
        chip->pcm = pcm;
        chip->psubs = NULL;
        chip->csubs = NULL;

        snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV, &chip->pci->dev,
                                       BUFFER_BYTES_MAX / 2, BUFFER_BYTES_MAX);

        return 0;
}

static void
snd_ad1889_proc_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
{
        struct snd_ad1889 *chip = entry->private_data;
        u16 reg;
        int tmp;

        reg = ad1889_readw(chip, AD_DS_WSMC);
        snd_iprintf(buffer, "Wave output: %s\n",
                        (reg & AD_DS_WSMC_WAEN) ? "enabled" : "disabled");
        snd_iprintf(buffer, "Wave Channels: %s\n",
                        (reg & AD_DS_WSMC_WAST) ? "stereo" : "mono");
        snd_iprintf(buffer, "Wave Quality: %d-bit linear\n",
                        (reg & AD_DS_WSMC_WA16) ? 16 : 8);
        
        /* WARQ is at offset 12 */
        tmp = (reg & AD_DS_WSMC_WARQ) ?
                ((((reg & AD_DS_WSMC_WARQ) >> 12) & 0x01) ? 12 : 18) : 4;
        tmp /= (reg & AD_DS_WSMC_WAST) ? 2 : 1;
        
        snd_iprintf(buffer, "Wave FIFO: %d %s words\n\n", tmp,
                        (reg & AD_DS_WSMC_WAST) ? "stereo" : "mono");
                                
        
        snd_iprintf(buffer, "Synthesis output: %s\n",
                        reg & AD_DS_WSMC_SYEN ? "enabled" : "disabled");
        
        /* SYRQ is at offset 4 */
        tmp = (reg & AD_DS_WSMC_SYRQ) ?
                ((((reg & AD_DS_WSMC_SYRQ) >> 4) & 0x01) ? 12 : 18) : 4;
        tmp /= (reg & AD_DS_WSMC_WAST) ? 2 : 1;
        
        snd_iprintf(buffer, "Synthesis FIFO: %d %s words\n\n", tmp,
                        (reg & AD_DS_WSMC_WAST) ? "stereo" : "mono");

        reg = ad1889_readw(chip, AD_DS_RAMC);
        snd_iprintf(buffer, "ADC input: %s\n",
                        (reg & AD_DS_RAMC_ADEN) ? "enabled" : "disabled");
        snd_iprintf(buffer, "ADC Channels: %s\n",
                        (reg & AD_DS_RAMC_ADST) ? "stereo" : "mono");
        snd_iprintf(buffer, "ADC Quality: %d-bit linear\n",
                        (reg & AD_DS_RAMC_AD16) ? 16 : 8);
        
        /* ACRQ is at offset 4 */
        tmp = (reg & AD_DS_RAMC_ACRQ) ?
                ((((reg & AD_DS_RAMC_ACRQ) >> 4) & 0x01) ? 12 : 18) : 4;
        tmp /= (reg & AD_DS_RAMC_ADST) ? 2 : 1;
        
        snd_iprintf(buffer, "ADC FIFO: %d %s words\n\n", tmp,
                        (reg & AD_DS_RAMC_ADST) ? "stereo" : "mono");
        
        snd_iprintf(buffer, "Resampler input: %s\n",
                        reg & AD_DS_RAMC_REEN ? "enabled" : "disabled");
                        
        /* RERQ is at offset 12 */
        tmp = (reg & AD_DS_RAMC_RERQ) ?
                ((((reg & AD_DS_RAMC_RERQ) >> 12) & 0x01) ? 12 : 18) : 4;
        tmp /= (reg & AD_DS_RAMC_ADST) ? 2 : 1;
        
        snd_iprintf(buffer, "Resampler FIFO: %d %s words\n\n", tmp,
                        (reg & AD_DS_WSMC_WAST) ? "stereo" : "mono");
                                
        
        /* doc says LSB represents -1.5dB, but the max value (-94.5dB)
        suggests that LSB is -3dB, which is more coherent with the logarithmic
        nature of the dB scale */
        reg = ad1889_readw(chip, AD_DS_WADA);
        snd_iprintf(buffer, "Left: %s, -%d dB\n",
                        (reg & AD_DS_WADA_LWAM) ? "mute" : "unmute",
                        ((reg & AD_DS_WADA_LWAA) >> 8) * 3);
        reg = ad1889_readw(chip, AD_DS_WADA);
        snd_iprintf(buffer, "Right: %s, -%d dB\n",
                        (reg & AD_DS_WADA_RWAM) ? "mute" : "unmute",
                        (reg & AD_DS_WADA_RWAA) * 3);
        
        reg = ad1889_readw(chip, AD_DS_WAS);
        snd_iprintf(buffer, "Wave samplerate: %u Hz\n", reg);
        reg = ad1889_readw(chip, AD_DS_RES);
        snd_iprintf(buffer, "Resampler samplerate: %u Hz\n", reg);
}

static void
snd_ad1889_proc_init(struct snd_ad1889 *chip)
{
        snd_card_ro_proc_new(chip->card, chip->card->driver,
                             chip, snd_ad1889_proc_read);
}

static const struct ac97_quirk ac97_quirks[] = {
        {
                .subvendor = 0x11d4,    /* AD */
                .subdevice = 0x1889,    /* AD1889 */
                .codec_id = AC97_ID_AD1819,
                .name = "AD1889",
                .type = AC97_TUNE_HP_ONLY
        },
        { } /* terminator */
};

static void
snd_ad1889_ac97_xinit(struct snd_ad1889 *chip)
{
        u16 reg;

        reg = ad1889_readw(chip, AD_AC97_ACIC);
        reg |= AD_AC97_ACIC_ACRD;               /* Reset Disable */
        ad1889_writew(chip, AD_AC97_ACIC, reg);
        ad1889_readw(chip, AD_AC97_ACIC);       /* flush posted write */
        udelay(10);
        /* Interface Enable */
        reg |= AD_AC97_ACIC_ACIE;
        ad1889_writew(chip, AD_AC97_ACIC, reg);
        
        snd_ad1889_ac97_ready(chip);

        /* Audio Stream Output | Variable Sample Rate Mode */
        reg = ad1889_readw(chip, AD_AC97_ACIC);
        reg |= AD_AC97_ACIC_ASOE | AD_AC97_ACIC_VSRM;
        ad1889_writew(chip, AD_AC97_ACIC, reg);
        ad1889_readw(chip, AD_AC97_ACIC); /* flush posted write */

}

static void
snd_ad1889_ac97_bus_free(struct snd_ac97_bus *bus)
{
        struct snd_ad1889 *chip = bus->private_data;
        chip->ac97_bus = NULL;
}

static void
snd_ad1889_ac97_free(struct snd_ac97 *ac97)
{
        struct snd_ad1889 *chip = ac97->private_data;
        chip->ac97 = NULL;
}

static int
snd_ad1889_ac97_init(struct snd_ad1889 *chip, const char *quirk_override)
{
        int err;
        struct snd_ac97_template ac97;
        static const struct snd_ac97_bus_ops ops = {
                .write = snd_ad1889_ac97_write,
                .read = snd_ad1889_ac97_read,
        };

        /* doing that here, it works. */
        snd_ad1889_ac97_xinit(chip);

        err = snd_ac97_bus(chip->card, 0, &ops, chip, &chip->ac97_bus);
        if (err < 0)
                return err;
        
        chip->ac97_bus->private_free = snd_ad1889_ac97_bus_free;

        memset(&ac97, 0, sizeof(ac97));
        ac97.private_data = chip;
        ac97.private_free = snd_ad1889_ac97_free;
        ac97.pci = chip->pci;

        err = snd_ac97_mixer(chip->ac97_bus, &ac97, &chip->ac97);
        if (err < 0)
                return err;
                
        snd_ac97_tune_hardware(chip->ac97, ac97_quirks, quirk_override);
        
        return 0;
}

static int
snd_ad1889_free(struct snd_ad1889 *chip)
{
        if (chip->irq < 0)
                goto skip_hw;

        spin_lock_irq(&chip->lock);

        ad1889_mute(chip);

        /* Turn off interrupt on count and zero DMA registers */
        ad1889_channel_reset(chip, AD_CHAN_WAV | AD_CHAN_ADC);

        /* clear DISR. If we don't, we'd better jump off the Eiffel Tower */
        ad1889_writel(chip, AD_DMA_DISR, AD_DMA_DISR_PTAI | AD_DMA_DISR_PMAI);
        ad1889_readl(chip, AD_DMA_DISR);        /* flush, dammit! */

        spin_unlock_irq(&chip->lock);

        if (chip->irq >= 0)
                free_irq(chip->irq, chip);

skip_hw:
        iounmap(chip->iobase);
        pci_release_regions(chip->pci);
        pci_disable_device(chip->pci);
        kfree(chip);
        return 0;
}

static int
snd_ad1889_dev_free(struct snd_device *device) 
{
        struct snd_ad1889 *chip = device->device_data;
        return snd_ad1889_free(chip);
}

static int
snd_ad1889_init(struct snd_ad1889 *chip) 
{
        ad1889_writew(chip, AD_DS_CCS, AD_DS_CCS_CLKEN); /* turn on clock */
        ad1889_readw(chip, AD_DS_CCS);  /* flush posted write */

        usleep_range(10000, 11000);

        /* enable Master and Target abort interrupts */
        ad1889_writel(chip, AD_DMA_DISR, AD_DMA_DISR_PMAE | AD_DMA_DISR_PTAE);

        return 0;
}

static int
snd_ad1889_create(struct snd_card *card,
                  struct pci_dev *pci,
                  struct snd_ad1889 **rchip)
{
        int err;

        struct snd_ad1889 *chip;
        static const struct snd_device_ops ops = {
                .dev_free = snd_ad1889_dev_free,
        };

        *rchip = NULL;

        err = pci_enable_device(pci);
        if (err < 0)
                return err;

        /* check PCI availability (32bit DMA) */
        if (dma_set_mask_and_coherent(&pci->dev, DMA_BIT_MASK(32))) {
                dev_err(card->dev, "error setting 32-bit DMA mask.\n");
                pci_disable_device(pci);
                return -ENXIO;
        }

        /* allocate chip specific data with zero-filled memory */
        chip = kzalloc(sizeof(*chip), GFP_KERNEL);
        if (!chip) {
                pci_disable_device(pci);
                return -ENOMEM;
        }

        chip->card = card;
        card->private_data = chip;
        chip->pci = pci;
        chip->irq = -1;

        /* (1) PCI resource allocation */
        err = pci_request_regions(pci, card->driver);
        if (err < 0)
                goto free_and_ret;

        chip->bar = pci_resource_start(pci, 0);
        chip->iobase = pci_ioremap_bar(pci, 0);
        if (chip->iobase == NULL) {
                dev_err(card->dev, "unable to reserve region.\n");
                err = -EBUSY;
                goto free_and_ret;
        }
        
        pci_set_master(pci);

        spin_lock_init(&chip->lock);    /* only now can we call ad1889_free */

        if (request_irq(pci->irq, snd_ad1889_interrupt,
                        IRQF_SHARED, KBUILD_MODNAME, chip)) {
                dev_err(card->dev, "cannot obtain IRQ %d\n", pci->irq);
                snd_ad1889_free(chip);
                return -EBUSY;
        }

        chip->irq = pci->irq;
        card->sync_irq = chip->irq;

        /* (2) initialization of the chip hardware */
        err = snd_ad1889_init(chip);
        if (err < 0) {
                snd_ad1889_free(chip);
                return err;
        }

        err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops);
        if (err < 0) {
                snd_ad1889_free(chip);
                return err;
        }

        *rchip = chip;

        return 0;

free_and_ret:
        kfree(chip);
        pci_disable_device(pci);

        return err;
}

static int
snd_ad1889_probe(struct pci_dev *pci,
                 const struct pci_device_id *pci_id)
{
        int err;
        static int devno;
        struct snd_card *card;
        struct snd_ad1889 *chip;

        /* (1) */
        if (devno >= SNDRV_CARDS)
                return -ENODEV;
        if (!enable[devno]) {
                devno++;
                return -ENOENT;
        }

        /* (2) */
        err = snd_card_new(&pci->dev, index[devno], id[devno], THIS_MODULE,
                           0, &card);
        /* XXX REVISIT: we can probably allocate chip in this call */
        if (err < 0)
                return err;

        strcpy(card->driver, "AD1889");
        strcpy(card->shortname, "Analog Devices AD1889");

        /* (3) */
        err = snd_ad1889_create(card, pci, &chip);
        if (err < 0)
                goto free_and_ret;

        /* (4) */
        sprintf(card->longname, "%s at 0x%lx irq %i",
                card->shortname, chip->bar, chip->irq);

        /* (5) */
        /* register AC97 mixer */
        err = snd_ad1889_ac97_init(chip, ac97_quirk[devno]);
        if (err < 0)
                goto free_and_ret;
        
        err = snd_ad1889_pcm_init(chip, 0);
        if (err < 0)
                goto free_and_ret;

        /* register proc interface */
        snd_ad1889_proc_init(chip);

        /* (6) */
        err = snd_card_register(card);
        if (err < 0)
                goto free_and_ret;

        /* (7) */
        pci_set_drvdata(pci, card);

        devno++;
        return 0;

free_and_ret:
        snd_card_free(card);
        return err;
}

static void
snd_ad1889_remove(struct pci_dev *pci)
{
        snd_card_free(pci_get_drvdata(pci));
}

static const struct pci_device_id snd_ad1889_ids[] = {

        { PCI_DEVICE(PCI_VENDOR_ID_ANALOG_DEVICES, PCI_DEVICE_ID_AD1889JS) },
        { 0, },
};
MODULE_DEVICE_TABLE(pci, snd_ad1889_ids);

static struct pci_driver ad1889_pci_driver = {
        .name = KBUILD_MODNAME,
        .id_table = snd_ad1889_ids,
        .probe = snd_ad1889_probe,
        .remove = snd_ad1889_remove,
};

module_pci_driver(ad1889_pci_driver);