// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *   ALSA modem driver for VIA VT82xx (South Bridge)
 *
 *   VT82C686A/B/C, VT8233A/C, VT8235
 *
 *      Copyright (c) 2000 Jaroslav Kysela <perex@perex.cz>
 *                         Tjeerd.Mulder <Tjeerd.Mulder@fujitsu-siemens.com>
 *                    2002 Takashi Iwai <tiwai@suse.de>
 */

/*
 * Changes:
 *
 * Sep. 2,  2004  Sasha Khapyorsky <sashak@alsa-project.org>
 *      Modified from original audio driver 'via82xx.c' to support AC97
 *      modems.
 */

#include <linux/io.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/info.h>
#include <sound/ac97_codec.h>
#include <sound/initval.h>

#if 0
#define POINTER_DEBUG
#endif

MODULE_AUTHOR("Jaroslav Kysela <perex@perex.cz>");
MODULE_DESCRIPTION("VIA VT82xx modem");
MODULE_LICENSE("GPL");

static int index = -2; /* Exclude the first card */
static char *id = SNDRV_DEFAULT_STR1;   /* ID for this card */
static int ac97_clock = 48000;

module_param(index, int, 0444);
MODULE_PARM_DESC(index, "Index value for VIA 82xx bridge.");
module_param(id, charp, 0444);
MODULE_PARM_DESC(id, "ID string for VIA 82xx bridge.");
module_param(ac97_clock, int, 0444);
MODULE_PARM_DESC(ac97_clock, "AC'97 codec clock (default 48000Hz).");

/* just for backward compatibility */
static bool enable;
module_param(enable, bool, 0444);


/*
 *  Direct registers
 */

#define VIAREG(via, x) ((via)->port + VIA_REG_##x)
#define VIADEV_REG(viadev, x) ((viadev)->port + VIA_REG_##x)

/* common offsets */
#define VIA_REG_OFFSET_STATUS           0x00    /* byte - channel status */
#define   VIA_REG_STAT_ACTIVE           0x80    /* RO */
#define   VIA_REG_STAT_PAUSED           0x40    /* RO */
#define   VIA_REG_STAT_TRIGGER_QUEUED   0x08    /* RO */
#define   VIA_REG_STAT_STOPPED          0x04    /* RWC */
#define   VIA_REG_STAT_EOL              0x02    /* RWC */
#define   VIA_REG_STAT_FLAG             0x01    /* RWC */
#define VIA_REG_OFFSET_CONTROL          0x01    /* byte - channel control */
#define   VIA_REG_CTRL_START            0x80    /* WO */
#define   VIA_REG_CTRL_TERMINATE        0x40    /* WO */
#define   VIA_REG_CTRL_AUTOSTART        0x20
#define   VIA_REG_CTRL_PAUSE            0x08    /* RW */
#define   VIA_REG_CTRL_INT_STOP         0x04            
#define   VIA_REG_CTRL_INT_EOL          0x02
#define   VIA_REG_CTRL_INT_FLAG         0x01
#define   VIA_REG_CTRL_RESET            0x01    /* RW - probably reset? undocumented */
#define   VIA_REG_CTRL_INT (VIA_REG_CTRL_INT_FLAG | VIA_REG_CTRL_INT_EOL | VIA_REG_CTRL_AUTOSTART)
#define VIA_REG_OFFSET_TYPE             0x02    /* byte - channel type (686 only) */
#define   VIA_REG_TYPE_AUTOSTART        0x80    /* RW - autostart at EOL */
#define   VIA_REG_TYPE_16BIT            0x20    /* RW */
#define   VIA_REG_TYPE_STEREO           0x10    /* RW */
#define   VIA_REG_TYPE_INT_LLINE        0x00
#define   VIA_REG_TYPE_INT_LSAMPLE      0x04
#define   VIA_REG_TYPE_INT_LESSONE      0x08
#define   VIA_REG_TYPE_INT_MASK         0x0c
#define   VIA_REG_TYPE_INT_EOL          0x02
#define   VIA_REG_TYPE_INT_FLAG         0x01
#define VIA_REG_OFFSET_TABLE_PTR        0x04    /* dword - channel table pointer */
#define VIA_REG_OFFSET_CURR_PTR         0x04    /* dword - channel current pointer */
#define VIA_REG_OFFSET_STOP_IDX         0x08    /* dword - stop index, channel type, sample rate */
#define VIA_REG_OFFSET_CURR_COUNT       0x0c    /* dword - channel current count (24 bit) */
#define VIA_REG_OFFSET_CURR_INDEX       0x0f    /* byte - channel current index (for via8233 only) */

#define DEFINE_VIA_REGSET(name,val) \
enum {\
        VIA_REG_##name##_STATUS         = (val),\
        VIA_REG_##name##_CONTROL        = (val) + 0x01,\
        VIA_REG_##name##_TYPE           = (val) + 0x02,\
        VIA_REG_##name##_TABLE_PTR      = (val) + 0x04,\
        VIA_REG_##name##_CURR_PTR       = (val) + 0x04,\
        VIA_REG_##name##_STOP_IDX       = (val) + 0x08,\
        VIA_REG_##name##_CURR_COUNT     = (val) + 0x0c,\
}

/* modem block */
DEFINE_VIA_REGSET(MO, 0x40);
DEFINE_VIA_REGSET(MI, 0x50);

/* AC'97 */
#define VIA_REG_AC97                    0x80    /* dword */
#define   VIA_REG_AC97_CODEC_ID_MASK    (3<<30)
#define   VIA_REG_AC97_CODEC_ID_SHIFT   30
#define   VIA_REG_AC97_CODEC_ID_PRIMARY 0x00
#define   VIA_REG_AC97_CODEC_ID_SECONDARY 0x01
#define   VIA_REG_AC97_SECONDARY_VALID  (1<<27)
#define   VIA_REG_AC97_PRIMARY_VALID    (1<<25)
#define   VIA_REG_AC97_BUSY             (1<<24)
#define   VIA_REG_AC97_READ             (1<<23)
#define   VIA_REG_AC97_CMD_SHIFT        16
#define   VIA_REG_AC97_CMD_MASK         0x7e
#define   VIA_REG_AC97_DATA_SHIFT       0
#define   VIA_REG_AC97_DATA_MASK        0xffff

#define VIA_REG_SGD_SHADOW              0x84    /* dword */
#define   VIA_REG_SGD_STAT_PB_FLAG      (1<<0)
#define   VIA_REG_SGD_STAT_CP_FLAG      (1<<1)
#define   VIA_REG_SGD_STAT_FM_FLAG      (1<<2)
#define   VIA_REG_SGD_STAT_PB_EOL       (1<<4)
#define   VIA_REG_SGD_STAT_CP_EOL       (1<<5)
#define   VIA_REG_SGD_STAT_FM_EOL       (1<<6)
#define   VIA_REG_SGD_STAT_PB_STOP      (1<<8)
#define   VIA_REG_SGD_STAT_CP_STOP      (1<<9)
#define   VIA_REG_SGD_STAT_FM_STOP      (1<<10)
#define   VIA_REG_SGD_STAT_PB_ACTIVE    (1<<12)
#define   VIA_REG_SGD_STAT_CP_ACTIVE    (1<<13)
#define   VIA_REG_SGD_STAT_FM_ACTIVE    (1<<14)
#define   VIA_REG_SGD_STAT_MR_FLAG      (1<<16)
#define   VIA_REG_SGD_STAT_MW_FLAG      (1<<17)
#define   VIA_REG_SGD_STAT_MR_EOL       (1<<20)
#define   VIA_REG_SGD_STAT_MW_EOL       (1<<21)
#define   VIA_REG_SGD_STAT_MR_STOP      (1<<24)
#define   VIA_REG_SGD_STAT_MW_STOP      (1<<25)
#define   VIA_REG_SGD_STAT_MR_ACTIVE    (1<<28)
#define   VIA_REG_SGD_STAT_MW_ACTIVE    (1<<29)

#define VIA_REG_GPI_STATUS              0x88
#define VIA_REG_GPI_INTR                0x8c

#define VIA_TBL_BIT_FLAG        0x40000000
#define VIA_TBL_BIT_EOL         0x80000000

/* pci space */
#define VIA_ACLINK_STAT         0x40
#define  VIA_ACLINK_C11_READY   0x20
#define  VIA_ACLINK_C10_READY   0x10
#define  VIA_ACLINK_C01_READY   0x04 /* secondary codec ready */
#define  VIA_ACLINK_LOWPOWER    0x02 /* low-power state */
#define  VIA_ACLINK_C00_READY   0x01 /* primary codec ready */
#define VIA_ACLINK_CTRL         0x41
#define  VIA_ACLINK_CTRL_ENABLE 0x80 /* 0: disable, 1: enable */
#define  VIA_ACLINK_CTRL_RESET  0x40 /* 0: assert, 1: de-assert */
#define  VIA_ACLINK_CTRL_SYNC   0x20 /* 0: release SYNC, 1: force SYNC hi */
#define  VIA_ACLINK_CTRL_SDO    0x10 /* 0: release SDO, 1: force SDO hi */
#define  VIA_ACLINK_CTRL_VRA    0x08 /* 0: disable VRA, 1: enable VRA */
#define  VIA_ACLINK_CTRL_PCM    0x04 /* 0: disable PCM, 1: enable PCM */
#define  VIA_ACLINK_CTRL_FM     0x02 /* via686 only */
#define  VIA_ACLINK_CTRL_SB     0x01 /* via686 only */
#define  VIA_ACLINK_CTRL_INIT   (VIA_ACLINK_CTRL_ENABLE|\
                                 VIA_ACLINK_CTRL_RESET|\
                                 VIA_ACLINK_CTRL_PCM)
#define VIA_FUNC_ENABLE         0x42
#define  VIA_FUNC_MIDI_PNP      0x80 /* FIXME: it's 0x40 in the datasheet! */
#define  VIA_FUNC_MIDI_IRQMASK  0x40 /* FIXME: not documented! */
#define  VIA_FUNC_RX2C_WRITE    0x20
#define  VIA_FUNC_SB_FIFO_EMPTY 0x10
#define  VIA_FUNC_ENABLE_GAME   0x08
#define  VIA_FUNC_ENABLE_FM     0x04
#define  VIA_FUNC_ENABLE_MIDI   0x02
#define  VIA_FUNC_ENABLE_SB     0x01
#define VIA_PNP_CONTROL         0x43
#define VIA_MC97_CTRL           0x44
#define  VIA_MC97_CTRL_ENABLE   0x80
#define  VIA_MC97_CTRL_SECONDARY 0x40
#define  VIA_MC97_CTRL_INIT     (VIA_MC97_CTRL_ENABLE|\
                                 VIA_MC97_CTRL_SECONDARY)


/*
 * pcm stream
 */

struct snd_via_sg_table {
        unsigned int offset;
        unsigned int size;
} ;

#define VIA_TABLE_SIZE  255

struct viadev {
        unsigned int reg_offset;
        unsigned long port;
        int direction;  /* playback = 0, capture = 1 */
        struct snd_pcm_substream *substream;
        int running;
        unsigned int tbl_entries; /* # descriptors */
        struct snd_dma_buffer table;
        struct snd_via_sg_table *idx_table;
        /* for recovery from the unexpected pointer */
        unsigned int lastpos;
        unsigned int bufsize;
        unsigned int bufsize2;
};

enum { TYPE_CARD_VIA82XX_MODEM = 1 };

#define VIA_MAX_MODEM_DEVS      2

struct via82xx_modem {
        int irq;

        unsigned long port;

        unsigned int intr_mask; /* SGD_SHADOW mask to check interrupts */

        struct pci_dev *pci;
        struct snd_card *card;

        unsigned int num_devs;
        unsigned int playback_devno, capture_devno;
        struct viadev devs[VIA_MAX_MODEM_DEVS];

        struct snd_pcm *pcms[2];

        struct snd_ac97_bus *ac97_bus;
        struct snd_ac97 *ac97;
        unsigned int ac97_clock;
        unsigned int ac97_secondary;    /* secondary AC'97 codec is present */

        spinlock_t reg_lock;
        struct snd_info_entry *proc_entry;
};

static const struct pci_device_id snd_via82xx_modem_ids[] = {
        { PCI_VDEVICE(VIA, 0x3068), TYPE_CARD_VIA82XX_MODEM, },
        { 0, }
};

MODULE_DEVICE_TABLE(pci, snd_via82xx_modem_ids);

/*
 */

/*
 * allocate and initialize the descriptor buffers
 * periods = number of periods
 * fragsize = period size in bytes
 */
static int build_via_table(struct viadev *dev, struct snd_pcm_substream *substream,
                           struct pci_dev *pci,
                           unsigned int periods, unsigned int fragsize)
{
        unsigned int i, idx, ofs, rest;
        struct via82xx_modem *chip = snd_pcm_substream_chip(substream);
        __le32 *pgtbl;

        if (dev->table.area == NULL) {
                /* the start of each lists must be aligned to 8 bytes,
                 * but the kernel pages are much bigger, so we don't care
                 */
                if (snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, &chip->pci->dev,
                                        PAGE_ALIGN(VIA_TABLE_SIZE * 2 * 8),
                                        &dev->table) < 0)
                        return -ENOMEM;
        }
        if (! dev->idx_table) {
                dev->idx_table = kmalloc_objs(*dev->idx_table, VIA_TABLE_SIZE);
                if (! dev->idx_table)
                        return -ENOMEM;
        }

        /* fill the entries */
        idx = 0;
        ofs = 0;
        pgtbl = (__le32 *)dev->table.area;
        for (i = 0; i < periods; i++) {
                rest = fragsize;
                /* fill descriptors for a period.
                 * a period can be split to several descriptors if it's
                 * over page boundary.
                 */
                do {
                        unsigned int r;
                        unsigned int flag;
                        unsigned int addr;

                        if (idx >= VIA_TABLE_SIZE) {
                                dev_err(&pci->dev, "too much table size!\n");
                                return -EINVAL;
                        }
                        addr = snd_pcm_sgbuf_get_addr(substream, ofs);
                        pgtbl[idx << 1] = cpu_to_le32(addr);
                        r = PAGE_SIZE - (ofs % PAGE_SIZE);
                        if (rest < r)
                                r = rest;
                        rest -= r;
                        if (! rest) {
                                if (i == periods - 1)
                                        flag = VIA_TBL_BIT_EOL; /* buffer boundary */
                                else
                                        flag = VIA_TBL_BIT_FLAG; /* period boundary */
                        } else
                                flag = 0; /* period continues to the next */
                        /*
                        dev_dbg(&pci->dev,
                                "tbl %d: at %d  size %d (rest %d)\n",
                                idx, ofs, r, rest);
                        */
                        pgtbl[(idx<<1) + 1] = cpu_to_le32(r | flag);
                        dev->idx_table[idx].offset = ofs;
                        dev->idx_table[idx].size = r;
                        ofs += r;
                        idx++;
                } while (rest > 0);
        }
        dev->tbl_entries = idx;
        dev->bufsize = periods * fragsize;
        dev->bufsize2 = dev->bufsize / 2;
        return 0;
}


static int clean_via_table(struct viadev *dev, struct snd_pcm_substream *substream,
                           struct pci_dev *pci)
{
        if (dev->table.area) {
                snd_dma_free_pages(&dev->table);
                dev->table.area = NULL;
        }
        kfree(dev->idx_table);
        dev->idx_table = NULL;
        return 0;
}

/*
 *  Basic I/O
 */

static inline unsigned int snd_via82xx_codec_xread(struct via82xx_modem *chip)
{
        return inl(VIAREG(chip, AC97));
}
 
static inline void snd_via82xx_codec_xwrite(struct via82xx_modem *chip, unsigned int val)
{
        outl(val, VIAREG(chip, AC97));
}
 
static int snd_via82xx_codec_ready(struct via82xx_modem *chip, int secondary)
{
        unsigned int timeout = 1000;    /* 1ms */
        unsigned int val;
        
        while (timeout-- > 0) {
                udelay(1);
                val = snd_via82xx_codec_xread(chip);
                if (!(val & VIA_REG_AC97_BUSY))
                        return val & 0xffff;
        }
        dev_err(chip->card->dev, "codec_ready: codec %i is not ready [0x%x]\n",
                   secondary, snd_via82xx_codec_xread(chip));
        return -EIO;
}
 
static int snd_via82xx_codec_valid(struct via82xx_modem *chip, int secondary)
{
        unsigned int timeout = 1000;    /* 1ms */
        unsigned int val, val1;
        unsigned int stat = !secondary ? VIA_REG_AC97_PRIMARY_VALID :
                                         VIA_REG_AC97_SECONDARY_VALID;
        
        while (timeout-- > 0) {
                val = snd_via82xx_codec_xread(chip);
                val1 = val & (VIA_REG_AC97_BUSY | stat);
                if (val1 == stat)
                        return val & 0xffff;
                udelay(1);
        }
        return -EIO;
}
 
static void snd_via82xx_codec_wait(struct snd_ac97 *ac97)
{
        struct via82xx_modem *chip = ac97->private_data;
        __always_unused int err;
        err = snd_via82xx_codec_ready(chip, ac97->num);
        /* here we need to wait fairly for long time.. */
        msleep(500);
}

static void snd_via82xx_codec_write(struct snd_ac97 *ac97,
                                    unsigned short reg,
                                    unsigned short val)
{
        struct via82xx_modem *chip = ac97->private_data;
        unsigned int xval;
        if(reg == AC97_GPIO_STATUS) {
                outl(val, VIAREG(chip, GPI_STATUS));
                return;
        }       
        xval = !ac97->num ? VIA_REG_AC97_CODEC_ID_PRIMARY : VIA_REG_AC97_CODEC_ID_SECONDARY;
        xval <<= VIA_REG_AC97_CODEC_ID_SHIFT;
        xval |= reg << VIA_REG_AC97_CMD_SHIFT;
        xval |= val << VIA_REG_AC97_DATA_SHIFT;
        snd_via82xx_codec_xwrite(chip, xval);
        snd_via82xx_codec_ready(chip, ac97->num);
}

static unsigned short snd_via82xx_codec_read(struct snd_ac97 *ac97, unsigned short reg)
{
        struct via82xx_modem *chip = ac97->private_data;
        unsigned int xval, val = 0xffff;
        int again = 0;

        xval = ac97->num << VIA_REG_AC97_CODEC_ID_SHIFT;
        xval |= ac97->num ? VIA_REG_AC97_SECONDARY_VALID : VIA_REG_AC97_PRIMARY_VALID;
        xval |= VIA_REG_AC97_READ;
        xval |= (reg & 0x7f) << VIA_REG_AC97_CMD_SHIFT;
        while (1) {
                if (again++ > 3) {
                        dev_err(chip->card->dev,
                                "codec_read: codec %i is not valid [0x%x]\n",
                                   ac97->num, snd_via82xx_codec_xread(chip));
                        return 0xffff;
                }
                snd_via82xx_codec_xwrite(chip, xval);
                udelay (20);
                if (snd_via82xx_codec_valid(chip, ac97->num) >= 0) {
                        udelay(25);
                        val = snd_via82xx_codec_xread(chip);
                        break;
                }
        }
        return val & 0xffff;
}

static void snd_via82xx_channel_reset(struct via82xx_modem *chip, struct viadev *viadev)
{
        outb(VIA_REG_CTRL_PAUSE | VIA_REG_CTRL_TERMINATE | VIA_REG_CTRL_RESET,
             VIADEV_REG(viadev, OFFSET_CONTROL));
        inb(VIADEV_REG(viadev, OFFSET_CONTROL));
        udelay(50);
        /* disable interrupts */
        outb(0x00, VIADEV_REG(viadev, OFFSET_CONTROL));
        /* clear interrupts */
        outb(0x03, VIADEV_REG(viadev, OFFSET_STATUS));
        outb(0x00, VIADEV_REG(viadev, OFFSET_TYPE)); /* for via686 */
        // outl(0, VIADEV_REG(viadev, OFFSET_CURR_PTR));
        viadev->lastpos = 0;
}


/*
 *  Interrupt handler
 */

static irqreturn_t snd_via82xx_interrupt(int irq, void *dev_id)
{
        struct via82xx_modem *chip = dev_id;
        unsigned int status;
        unsigned int i;

        status = inl(VIAREG(chip, SGD_SHADOW));
        if (! (status & chip->intr_mask)) {
                return IRQ_NONE;
        }
// _skip_sgd:

        /* check status for each stream */
        guard(spinlock)(&chip->reg_lock);
        for (i = 0; i < chip->num_devs; i++) {
                struct viadev *viadev = &chip->devs[i];
                unsigned char c_status = inb(VIADEV_REG(viadev, OFFSET_STATUS));
                c_status &= (VIA_REG_STAT_EOL|VIA_REG_STAT_FLAG|VIA_REG_STAT_STOPPED);
                if (! c_status)
                        continue;
                if (viadev->substream && viadev->running) {
                        spin_unlock(&chip->reg_lock);
                        snd_pcm_period_elapsed(viadev->substream);
                        spin_lock(&chip->reg_lock);
                }
                outb(c_status, VIADEV_REG(viadev, OFFSET_STATUS)); /* ack */
        }
        return IRQ_HANDLED;
}

/*
 *  PCM callbacks
 */

/*
 * trigger callback
 */
static int snd_via82xx_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct via82xx_modem *chip = snd_pcm_substream_chip(substream);
        struct viadev *viadev = substream->runtime->private_data;
        unsigned char val = 0;

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_SUSPEND:
                val |= VIA_REG_CTRL_START;
                viadev->running = 1;
                break;
        case SNDRV_PCM_TRIGGER_STOP:
                val = VIA_REG_CTRL_TERMINATE;
                viadev->running = 0;
                break;
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                val |= VIA_REG_CTRL_PAUSE;
                viadev->running = 0;
                break;
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                viadev->running = 1;
                break;
        default:
                return -EINVAL;
        }
        outb(val, VIADEV_REG(viadev, OFFSET_CONTROL));
        if (cmd == SNDRV_PCM_TRIGGER_STOP)
                snd_via82xx_channel_reset(chip, viadev);
        return 0;
}

/*
 * pointer callbacks
 */

/*
 * calculate the linear position at the given sg-buffer index and the rest count
 */

#define check_invalid_pos(viadev,pos) \
        ((pos) < viadev->lastpos && ((pos) >= viadev->bufsize2 ||\
                                     viadev->lastpos < viadev->bufsize2))

static inline unsigned int calc_linear_pos(struct via82xx_modem *chip,
                                           struct viadev *viadev,
                                           unsigned int idx,
                                           unsigned int count)
{
        unsigned int size, res;

        size = viadev->idx_table[idx].size;
        res = viadev->idx_table[idx].offset + size - count;

        /* check the validity of the calculated position */
        if (size < count) {
                dev_err(chip->card->dev,
                        "invalid via82xx_cur_ptr (size = %d, count = %d)\n",
                           (int)size, (int)count);
                res = viadev->lastpos;
        } else if (check_invalid_pos(viadev, res)) {
#ifdef POINTER_DEBUG
                dev_dbg(chip->card->dev,
                        "fail: idx = %i/%i, lastpos = 0x%x, bufsize2 = 0x%x, offsize = 0x%x, size = 0x%x, count = 0x%x\n",
                        idx, viadev->tbl_entries, viadev->lastpos,
                       viadev->bufsize2, viadev->idx_table[idx].offset,
                       viadev->idx_table[idx].size, count);
#endif
                if (count && size < count) {
                        dev_dbg(chip->card->dev,
                                "invalid via82xx_cur_ptr, using last valid pointer\n");
                        res = viadev->lastpos;
                } else {
                        if (! count)
                                /* bogus count 0 on the DMA boundary? */
                                res = viadev->idx_table[idx].offset;
                        else
                                /* count register returns full size
                                 * when end of buffer is reached
                                 */
                                res = viadev->idx_table[idx].offset + size;
                        if (check_invalid_pos(viadev, res)) {
                                dev_dbg(chip->card->dev,
                                        "invalid via82xx_cur_ptr (2), using last valid pointer\n");
                                res = viadev->lastpos;
                        }
                }
        }
        viadev->lastpos = res; /* remember the last position */
        if (res >= viadev->bufsize)
                res -= viadev->bufsize;
        return res;
}

/*
 * get the current pointer on via686
 */
static snd_pcm_uframes_t snd_via686_pcm_pointer(struct snd_pcm_substream *substream)
{
        struct via82xx_modem *chip = snd_pcm_substream_chip(substream);
        struct viadev *viadev = substream->runtime->private_data;
        unsigned int idx, ptr, count, res;

        if (snd_BUG_ON(!viadev->tbl_entries))
                return 0;
        if (!(inb(VIADEV_REG(viadev, OFFSET_STATUS)) & VIA_REG_STAT_ACTIVE))
                return 0;

        guard(spinlock)(&chip->reg_lock);
        count = inl(VIADEV_REG(viadev, OFFSET_CURR_COUNT)) & 0xffffff;
        /* The via686a does not have the current index register,
         * so we need to calculate the index from CURR_PTR.
         */
        ptr = inl(VIADEV_REG(viadev, OFFSET_CURR_PTR));
        if (ptr <= (unsigned int)viadev->table.addr)
                idx = 0;
        else /* CURR_PTR holds the address + 8 */
                idx = ((ptr - (unsigned int)viadev->table.addr) / 8 - 1) %
                        viadev->tbl_entries;
        res = calc_linear_pos(chip, viadev, idx, count);

        return bytes_to_frames(substream->runtime, res);
}

/*
 * hw_params callback:
 * allocate the buffer and build up the buffer description table
 */
static int snd_via82xx_hw_params(struct snd_pcm_substream *substream,
                                 struct snd_pcm_hw_params *hw_params)
{
        struct via82xx_modem *chip = snd_pcm_substream_chip(substream);
        struct viadev *viadev = substream->runtime->private_data;
        int err;

        err = build_via_table(viadev, substream, chip->pci,
                              params_periods(hw_params),
                              params_period_bytes(hw_params));
        if (err < 0)
                return err;

        snd_ac97_write(chip->ac97, AC97_LINE1_RATE, params_rate(hw_params));
        snd_ac97_write(chip->ac97, AC97_LINE1_LEVEL, 0);

        return 0;
}

/*
 * hw_free callback:
 * clean up the buffer description table and release the buffer
 */
static int snd_via82xx_hw_free(struct snd_pcm_substream *substream)
{
        struct via82xx_modem *chip = snd_pcm_substream_chip(substream);
        struct viadev *viadev = substream->runtime->private_data;

        clean_via_table(viadev, substream, chip->pci);
        return 0;
}


/*
 * set up the table pointer
 */
static void snd_via82xx_set_table_ptr(struct via82xx_modem *chip, struct viadev *viadev)
{
        snd_via82xx_codec_ready(chip, chip->ac97_secondary);
        outl((u32)viadev->table.addr, VIADEV_REG(viadev, OFFSET_TABLE_PTR));
        udelay(20);
        snd_via82xx_codec_ready(chip, chip->ac97_secondary);
}

/*
 * prepare callback for playback and capture
 */
static int snd_via82xx_pcm_prepare(struct snd_pcm_substream *substream)
{
        struct via82xx_modem *chip = snd_pcm_substream_chip(substream);
        struct viadev *viadev = substream->runtime->private_data;

        snd_via82xx_channel_reset(chip, viadev);
        /* this must be set after channel_reset */
        snd_via82xx_set_table_ptr(chip, viadev);
        outb(VIA_REG_TYPE_AUTOSTART|VIA_REG_TYPE_INT_EOL|VIA_REG_TYPE_INT_FLAG,
             VIADEV_REG(viadev, OFFSET_TYPE));
        return 0;
}

/*
 * pcm hardware definition, identical for both playback and capture
 */
static const struct snd_pcm_hardware snd_via82xx_hw =
{
        .info =                 (SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_INTERLEAVED |
                                 SNDRV_PCM_INFO_BLOCK_TRANSFER |
                                 SNDRV_PCM_INFO_MMAP_VALID |
                                 /* SNDRV_PCM_INFO_RESUME | */
                                 SNDRV_PCM_INFO_PAUSE),
        .formats =              SNDRV_PCM_FMTBIT_U8 | SNDRV_PCM_FMTBIT_S16_LE,
        .rates =                SNDRV_PCM_RATE_8000 | SNDRV_PCM_RATE_16000 | SNDRV_PCM_RATE_KNOT,
        .rate_min =             8000,
        .rate_max =             16000,
        .channels_min =         1,
        .channels_max =         1,
        .buffer_bytes_max =     128 * 1024,
        .period_bytes_min =     32,
        .period_bytes_max =     128 * 1024,
        .periods_min =          2,
        .periods_max =          VIA_TABLE_SIZE / 2,
        .fifo_size =            0,
};


/*
 * open callback skeleton
 */
static int snd_via82xx_modem_pcm_open(struct via82xx_modem *chip, struct viadev *viadev,
                                      struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        int err;
        static const unsigned int rates[] = { 8000,  9600, 12000, 16000 };
        static const struct snd_pcm_hw_constraint_list hw_constraints_rates = {
                .count = ARRAY_SIZE(rates),
                .list = rates,
                .mask = 0,
        };

        runtime->hw = snd_via82xx_hw;
        
        err = snd_pcm_hw_constraint_list(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
                                         &hw_constraints_rates);
        if (err < 0)
                return err;

        /* we may remove following constaint when we modify table entries
           in interrupt */
        err = snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
        if (err < 0)
                return err;

        runtime->private_data = viadev;
        viadev->substream = substream;

        return 0;
}


/*
 * open callback for playback
 */
static int snd_via82xx_playback_open(struct snd_pcm_substream *substream)
{
        struct via82xx_modem *chip = snd_pcm_substream_chip(substream);
        struct viadev *viadev = &chip->devs[chip->playback_devno + substream->number];

        return snd_via82xx_modem_pcm_open(chip, viadev, substream);
}

/*
 * open callback for capture
 */
static int snd_via82xx_capture_open(struct snd_pcm_substream *substream)
{
        struct via82xx_modem *chip = snd_pcm_substream_chip(substream);
        struct viadev *viadev = &chip->devs[chip->capture_devno + substream->pcm->device];

        return snd_via82xx_modem_pcm_open(chip, viadev, substream);
}

/*
 * close callback
 */
static int snd_via82xx_pcm_close(struct snd_pcm_substream *substream)
{
        struct viadev *viadev = substream->runtime->private_data;

        viadev->substream = NULL;
        return 0;
}


/* via686 playback callbacks */
static const struct snd_pcm_ops snd_via686_playback_ops = {
        .open =         snd_via82xx_playback_open,
        .close =        snd_via82xx_pcm_close,
        .hw_params =    snd_via82xx_hw_params,
        .hw_free =      snd_via82xx_hw_free,
        .prepare =      snd_via82xx_pcm_prepare,
        .trigger =      snd_via82xx_pcm_trigger,
        .pointer =      snd_via686_pcm_pointer,
};

/* via686 capture callbacks */
static const struct snd_pcm_ops snd_via686_capture_ops = {
        .open =         snd_via82xx_capture_open,
        .close =        snd_via82xx_pcm_close,
        .hw_params =    snd_via82xx_hw_params,
        .hw_free =      snd_via82xx_hw_free,
        .prepare =      snd_via82xx_pcm_prepare,
        .trigger =      snd_via82xx_pcm_trigger,
        .pointer =      snd_via686_pcm_pointer,
};


static void init_viadev(struct via82xx_modem *chip, int idx, unsigned int reg_offset,
                        int direction)
{
        chip->devs[idx].reg_offset = reg_offset;
        chip->devs[idx].direction = direction;
        chip->devs[idx].port = chip->port + reg_offset;
}

/*
 * create a pcm instance for via686a/b
 */
static int snd_via686_pcm_new(struct via82xx_modem *chip)
{
        struct snd_pcm *pcm;
        int err;

        chip->playback_devno = 0;
        chip->capture_devno = 1;
        chip->num_devs = 2;
        chip->intr_mask = 0x330000; /* FLAGS | EOL for MR, MW */

        err = snd_pcm_new(chip->card, chip->card->shortname, 0, 1, 1, &pcm);
        if (err < 0)
                return err;
        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &snd_via686_playback_ops);
        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &snd_via686_capture_ops);
        pcm->dev_class = SNDRV_PCM_CLASS_MODEM;
        pcm->private_data = chip;
        strscpy(pcm->name, chip->card->shortname);
        chip->pcms[0] = pcm;
        init_viadev(chip, 0, VIA_REG_MO_STATUS, 0);
        init_viadev(chip, 1, VIA_REG_MI_STATUS, 1);

        snd_pcm_set_managed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV_SG,
                                       &chip->pci->dev, 64*1024, 128*1024);
        return 0;
}


/*
 *  Mixer part
 */


static void snd_via82xx_mixer_free_ac97_bus(struct snd_ac97_bus *bus)
{
        struct via82xx_modem *chip = bus->private_data;
        chip->ac97_bus = NULL;
}

static void snd_via82xx_mixer_free_ac97(struct snd_ac97 *ac97)
{
        struct via82xx_modem *chip = ac97->private_data;
        chip->ac97 = NULL;
}


static int snd_via82xx_mixer_new(struct via82xx_modem *chip)
{
        struct snd_ac97_template ac97;
        int err;
        static const struct snd_ac97_bus_ops ops = {
                .write = snd_via82xx_codec_write,
                .read = snd_via82xx_codec_read,
                .wait = snd_via82xx_codec_wait,
        };

        err = snd_ac97_bus(chip->card, 0, &ops, chip, &chip->ac97_bus);
        if (err < 0)
                return err;
        chip->ac97_bus->private_free = snd_via82xx_mixer_free_ac97_bus;
        chip->ac97_bus->clock = chip->ac97_clock;

        memset(&ac97, 0, sizeof(ac97));
        ac97.private_data = chip;
        ac97.private_free = snd_via82xx_mixer_free_ac97;
        ac97.pci = chip->pci;
        ac97.scaps = AC97_SCAP_SKIP_AUDIO | AC97_SCAP_POWER_SAVE;
        ac97.num = chip->ac97_secondary;

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

        return 0;
}


/*
 * proc interface
 */
static void snd_via82xx_proc_read(struct snd_info_entry *entry, struct snd_info_buffer *buffer)
{
        struct via82xx_modem *chip = entry->private_data;
        int i;
        
        snd_iprintf(buffer, "%s\n\n", chip->card->longname);
        for (i = 0; i < 0xa0; i += 4) {
                snd_iprintf(buffer, "%02x: %08x\n", i, inl(chip->port + i));
        }
}

static void snd_via82xx_proc_init(struct via82xx_modem *chip)
{
        snd_card_ro_proc_new(chip->card, "via82xx", chip,
                             snd_via82xx_proc_read);
}

/*
 *
 */

static int snd_via82xx_chip_init(struct via82xx_modem *chip)
{
        unsigned int val;
        unsigned long end_time;
        unsigned char pval;

        pci_read_config_byte(chip->pci, VIA_MC97_CTRL, &pval);
        if((pval & VIA_MC97_CTRL_INIT) != VIA_MC97_CTRL_INIT) {
                pci_write_config_byte(chip->pci, 0x44, pval|VIA_MC97_CTRL_INIT);
                udelay(100);
        }

        pci_read_config_byte(chip->pci, VIA_ACLINK_STAT, &pval);
        if (! (pval & VIA_ACLINK_C00_READY)) { /* codec not ready? */
                /* deassert ACLink reset, force SYNC */
                pci_write_config_byte(chip->pci, VIA_ACLINK_CTRL,
                                      VIA_ACLINK_CTRL_ENABLE |
                                      VIA_ACLINK_CTRL_RESET |
                                      VIA_ACLINK_CTRL_SYNC);
                udelay(100);
#if 1 /* FIXME: should we do full reset here for all chip models? */
                pci_write_config_byte(chip->pci, VIA_ACLINK_CTRL, 0x00);
                udelay(100);
#else
                /* deassert ACLink reset, force SYNC (warm AC'97 reset) */
                pci_write_config_byte(chip->pci, VIA_ACLINK_CTRL,
                                      VIA_ACLINK_CTRL_RESET|VIA_ACLINK_CTRL_SYNC);
                udelay(2);
#endif
                /* ACLink on, deassert ACLink reset, VSR, SGD data out */
                pci_write_config_byte(chip->pci, VIA_ACLINK_CTRL, VIA_ACLINK_CTRL_INIT);
                udelay(100);
        }
        
        pci_read_config_byte(chip->pci, VIA_ACLINK_CTRL, &pval);
        if ((pval & VIA_ACLINK_CTRL_INIT) != VIA_ACLINK_CTRL_INIT) {
                /* ACLink on, deassert ACLink reset, VSR, SGD data out */
                pci_write_config_byte(chip->pci, VIA_ACLINK_CTRL, VIA_ACLINK_CTRL_INIT);
                udelay(100);
        }

        /* wait until codec ready */
        end_time = jiffies + msecs_to_jiffies(750);
        do {
                pci_read_config_byte(chip->pci, VIA_ACLINK_STAT, &pval);
                if (pval & VIA_ACLINK_C00_READY) /* primary codec ready */
                        break;
                schedule_timeout_uninterruptible(1);
        } while (time_before(jiffies, end_time));

        val = snd_via82xx_codec_xread(chip);
        if (val & VIA_REG_AC97_BUSY)
                dev_err(chip->card->dev,
                        "AC'97 codec is not ready [0x%x]\n", val);

        snd_via82xx_codec_xwrite(chip, VIA_REG_AC97_READ |
                                 VIA_REG_AC97_SECONDARY_VALID |
                                 (VIA_REG_AC97_CODEC_ID_SECONDARY << VIA_REG_AC97_CODEC_ID_SHIFT));
        end_time = jiffies + msecs_to_jiffies(750);
        snd_via82xx_codec_xwrite(chip, VIA_REG_AC97_READ |
                                 VIA_REG_AC97_SECONDARY_VALID |
                                 (VIA_REG_AC97_CODEC_ID_SECONDARY << VIA_REG_AC97_CODEC_ID_SHIFT));
        do {
                val = snd_via82xx_codec_xread(chip);
                if (val & VIA_REG_AC97_SECONDARY_VALID) {
                        chip->ac97_secondary = 1;
                        goto __ac97_ok2;
                }
                schedule_timeout_uninterruptible(1);
        } while (time_before(jiffies, end_time));
        /* This is ok, the most of motherboards have only one codec */

      __ac97_ok2:

        /* route FM trap to IRQ, disable FM trap */
        // pci_write_config_byte(chip->pci, VIA_FM_NMI_CTRL, 0);
        /* disable all GPI interrupts */
        outl(0, VIAREG(chip, GPI_INTR));

        return 0;
}

/*
 * power management
 */
static int snd_via82xx_suspend(struct device *dev)
{
        struct snd_card *card = dev_get_drvdata(dev);
        struct via82xx_modem *chip = card->private_data;
        int i;

        snd_power_change_state(card, SNDRV_CTL_POWER_D3hot);
        for (i = 0; i < chip->num_devs; i++)
                snd_via82xx_channel_reset(chip, &chip->devs[i]);
        snd_ac97_suspend(chip->ac97);
        return 0;
}

static int snd_via82xx_resume(struct device *dev)
{
        struct snd_card *card = dev_get_drvdata(dev);
        struct via82xx_modem *chip = card->private_data;
        int i;

        snd_via82xx_chip_init(chip);

        snd_ac97_resume(chip->ac97);

        for (i = 0; i < chip->num_devs; i++)
                snd_via82xx_channel_reset(chip, &chip->devs[i]);

        snd_power_change_state(card, SNDRV_CTL_POWER_D0);
        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(snd_via82xx_pm, snd_via82xx_suspend, snd_via82xx_resume);

static void snd_via82xx_free(struct snd_card *card)
{
        struct via82xx_modem *chip = card->private_data;
        unsigned int i;

        /* disable interrupts */
        for (i = 0; i < chip->num_devs; i++)
                snd_via82xx_channel_reset(chip, &chip->devs[i]);
}

static int snd_via82xx_create(struct snd_card *card,
                              struct pci_dev *pci,
                              int chip_type,
                              int revision,
                              unsigned int ac97_clock)
{
        struct via82xx_modem *chip = card->private_data;
        int err;

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

        spin_lock_init(&chip->reg_lock);
        chip->card = card;
        chip->pci = pci;
        chip->irq = -1;

        err = pcim_request_all_regions(pci, card->driver);
        if (err < 0)
                return err;
        chip->port = pci_resource_start(pci, 0);
        if (devm_request_irq(&pci->dev, pci->irq, snd_via82xx_interrupt,
                             IRQF_SHARED, KBUILD_MODNAME, chip)) {
                dev_err(card->dev, "unable to grab IRQ %d\n", pci->irq);
                return -EBUSY;
        }
        chip->irq = pci->irq;
        card->sync_irq = chip->irq;
        card->private_free = snd_via82xx_free;
        if (ac97_clock >= 8000 && ac97_clock <= 48000)
                chip->ac97_clock = ac97_clock;

        err = snd_via82xx_chip_init(chip);
        if (err < 0)
                return err;

        /* The 8233 ac97 controller does not implement the master bit
         * in the pci command register. IMHO this is a violation of the PCI spec.
         * We call pci_set_master here because it does not hurt. */
        pci_set_master(pci);
        return 0;
}


static int __snd_via82xx_probe(struct pci_dev *pci,
                               const struct pci_device_id *pci_id)
{
        struct snd_card *card;
        struct via82xx_modem *chip;
        int chip_type = 0, card_type;
        unsigned int i;
        int err;

        err = snd_devm_card_new(&pci->dev, index, id, THIS_MODULE,
                                sizeof(*chip), &card);
        if (err < 0)
                return err;
        chip = card->private_data;

        card_type = pci_id->driver_data;
        switch (card_type) {
        case TYPE_CARD_VIA82XX_MODEM:
                strscpy(card->driver, "VIA82XX-MODEM");
                sprintf(card->shortname, "VIA 82XX modem");
                break;
        default:
                dev_err(card->dev, "invalid card type %d\n", card_type);
                return -EINVAL;
        }
                
        err = snd_via82xx_create(card, pci, chip_type, pci->revision,
                                 ac97_clock);
        if (err < 0)
                return err;
        err = snd_via82xx_mixer_new(chip);
        if (err < 0)
                return err;

        err = snd_via686_pcm_new(chip);
        if (err < 0)
                return err;

        /* disable interrupts */
        for (i = 0; i < chip->num_devs; i++)
                snd_via82xx_channel_reset(chip, &chip->devs[i]);

        sprintf(card->longname, "%s at 0x%lx, irq %d",
                card->shortname, chip->port, chip->irq);

        snd_via82xx_proc_init(chip);

        err = snd_card_register(card);
        if (err < 0)
                return err;
        pci_set_drvdata(pci, card);
        return 0;
}

static int snd_via82xx_probe(struct pci_dev *pci,
                             const struct pci_device_id *pci_id)
{
        return snd_card_free_on_error(&pci->dev, __snd_via82xx_probe(pci, pci_id));
}

static struct pci_driver via82xx_modem_driver = {
        .name = KBUILD_MODNAME,
        .id_table = snd_via82xx_modem_ids,
        .probe = snd_via82xx_probe,
        .driver = {
                .pm = &snd_via82xx_pm,
        },
};

module_pci_driver(via82xx_modem_driver);