// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
 *  Universal interface for Audio Codec '97
 *
 *  For more details look to AC '97 component specification revision 2.2
 *  by Intel Corporation (http://developer.intel.com) and to datasheets
 *  for specific codecs.
 */

#include <linux/delay.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/mutex.h>
#include <linux/export.h>

#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/control.h>
#include <sound/ac97_codec.h>
#include <sound/asoundef.h>
#include "ac97_id.h"
#include "ac97_local.h"

/*
 *  PCM support
 */

static const unsigned char rate_reg_tables[2][4][9] = {
{
  /* standard rates */
  {
        /* 3&4 front, 7&8 rear, 6&9 center/lfe */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 3 */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 4 */
        0xff,                           /* slot 5 */
        AC97_PCM_LFE_DAC_RATE,          /* slot 6 */
        AC97_PCM_SURR_DAC_RATE,         /* slot 7 */
        AC97_PCM_SURR_DAC_RATE,         /* slot 8 */
        AC97_PCM_LFE_DAC_RATE,          /* slot 9 */
        0xff,                           /* slot 10 */
        0xff,                           /* slot 11 */
  },
  {
        /* 7&8 front, 6&9 rear, 10&11 center/lfe */
        0xff,                           /* slot 3 */
        0xff,                           /* slot 4 */
        0xff,                           /* slot 5 */
        AC97_PCM_SURR_DAC_RATE,         /* slot 6 */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 7 */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 8 */
        AC97_PCM_SURR_DAC_RATE,         /* slot 9 */
        AC97_PCM_LFE_DAC_RATE,          /* slot 10 */
        AC97_PCM_LFE_DAC_RATE,          /* slot 11 */
  },
  {
        /* 6&9 front, 10&11 rear, 3&4 center/lfe */
        AC97_PCM_LFE_DAC_RATE,          /* slot 3 */
        AC97_PCM_LFE_DAC_RATE,          /* slot 4 */
        0xff,                           /* slot 5 */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 6 */
        0xff,                           /* slot 7 */
        0xff,                           /* slot 8 */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 9 */
        AC97_PCM_SURR_DAC_RATE,         /* slot 10 */
        AC97_PCM_SURR_DAC_RATE,         /* slot 11 */
  },
  {
        /* 10&11 front, 3&4 rear, 7&8 center/lfe */
        AC97_PCM_SURR_DAC_RATE,         /* slot 3 */
        AC97_PCM_SURR_DAC_RATE,         /* slot 4 */
        0xff,                           /* slot 5 */
        0xff,                           /* slot 6 */
        AC97_PCM_LFE_DAC_RATE,          /* slot 7 */
        AC97_PCM_LFE_DAC_RATE,          /* slot 8 */
        0xff,                           /* slot 9 */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 10 */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 11 */
  },
},
{
  /* double rates */
  {
        /* 3&4 front, 7&8 front (t+1) */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 3 */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 4 */
        0xff,                           /* slot 5 */
        0xff,                           /* slot 6 */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 7 */
        AC97_PCM_FRONT_DAC_RATE,        /* slot 8 */
        0xff,                           /* slot 9 */
        0xff,                           /* slot 10 */
        0xff,                           /* slot 11 */
  },
  {
        /* not specified in the specification */
        0xff,                           /* slot 3 */
        0xff,                           /* slot 4 */
        0xff,                           /* slot 5 */
        0xff,                           /* slot 6 */
        0xff,                           /* slot 7 */
        0xff,                           /* slot 8 */
        0xff,                           /* slot 9 */
        0xff,                           /* slot 10 */
        0xff,                           /* slot 11 */
  },
  {
        0xff,                           /* slot 3 */
        0xff,                           /* slot 4 */
        0xff,                           /* slot 5 */
        0xff,                           /* slot 6 */
        0xff,                           /* slot 7 */
        0xff,                           /* slot 8 */
        0xff,                           /* slot 9 */
        0xff,                           /* slot 10 */
        0xff,                           /* slot 11 */
  },
  {
        0xff,                           /* slot 3 */
        0xff,                           /* slot 4 */
        0xff,                           /* slot 5 */
        0xff,                           /* slot 6 */
        0xff,                           /* slot 7 */
        0xff,                           /* slot 8 */
        0xff,                           /* slot 9 */
        0xff,                           /* slot 10 */
        0xff,                           /* slot 11 */
  }
}};

/* FIXME: more various mappings for ADC? */
static const unsigned char rate_cregs[9] = {
        AC97_PCM_LR_ADC_RATE,   /* 3 */
        AC97_PCM_LR_ADC_RATE,   /* 4 */
        0xff,                   /* 5 */
        AC97_PCM_MIC_ADC_RATE,  /* 6 */
        0xff,                   /* 7 */
        0xff,                   /* 8 */
        0xff,                   /* 9 */
        0xff,                   /* 10 */
        0xff,                   /* 11 */
};

static unsigned char get_slot_reg(struct ac97_pcm *pcm, unsigned short cidx,
                                  unsigned short slot, int dbl)
{
        if (slot < 3)
                return 0xff;
        if (slot > 11)
                return 0xff;
        if (pcm->spdif)
                return AC97_SPDIF; /* pseudo register */
        if (pcm->stream == SNDRV_PCM_STREAM_PLAYBACK)
                return rate_reg_tables[dbl][pcm->r[dbl].rate_table[cidx]][slot - 3];
        else
                return rate_cregs[slot - 3];
}

static int set_spdif_rate(struct snd_ac97 *ac97, unsigned short rate)
{
        unsigned short old, bits, reg, mask;
        unsigned int sbits;

        if (! (ac97->ext_id & AC97_EI_SPDIF))
                return -ENODEV;

        /* TODO: double rate support */
        if (ac97->flags & AC97_CS_SPDIF) {
                switch (rate) {
                case 48000: bits = 0; break;
                case 44100: bits = 1 << AC97_SC_SPSR_SHIFT; break;
                default: /* invalid - disable output */
                        snd_ac97_update_bits(ac97, AC97_EXTENDED_STATUS, AC97_EA_SPDIF, 0);
                        return -EINVAL;
                }
                reg = AC97_CSR_SPDIF;
                mask = 1 << AC97_SC_SPSR_SHIFT;
        } else {
                if (ac97->id == AC97_ID_CM9739 && rate != 48000) {
                        snd_ac97_update_bits(ac97, AC97_EXTENDED_STATUS, AC97_EA_SPDIF, 0);
                        return -EINVAL;
                }
                switch (rate) {
                case 44100: bits = AC97_SC_SPSR_44K; break;
                case 48000: bits = AC97_SC_SPSR_48K; break;
                case 32000: bits = AC97_SC_SPSR_32K; break;
                default: /* invalid - disable output */
                        snd_ac97_update_bits(ac97, AC97_EXTENDED_STATUS, AC97_EA_SPDIF, 0);
                        return -EINVAL;
                }
                reg = AC97_SPDIF;
                mask = AC97_SC_SPSR_MASK;
        }

        mutex_lock(&ac97->reg_mutex);
        old = snd_ac97_read(ac97, reg) & mask;
        if (old != bits) {
                snd_ac97_update_bits_nolock(ac97, AC97_EXTENDED_STATUS, AC97_EA_SPDIF, 0);
                snd_ac97_update_bits_nolock(ac97, reg, mask, bits);
                /* update the internal spdif bits */
                sbits = ac97->spdif_status;
                if (sbits & IEC958_AES0_PROFESSIONAL) {
                        sbits &= ~IEC958_AES0_PRO_FS;
                        switch (rate) {
                        case 44100: sbits |= IEC958_AES0_PRO_FS_44100; break;
                        case 48000: sbits |= IEC958_AES0_PRO_FS_48000; break;
                        case 32000: sbits |= IEC958_AES0_PRO_FS_32000; break;
                        }
                } else {
                        sbits &= ~(IEC958_AES3_CON_FS << 24);
                        switch (rate) {
                        case 44100: sbits |= IEC958_AES3_CON_FS_44100<<24; break;
                        case 48000: sbits |= IEC958_AES3_CON_FS_48000<<24; break;
                        case 32000: sbits |= IEC958_AES3_CON_FS_32000<<24; break;
                        }
                }
                ac97->spdif_status = sbits;
        }
        snd_ac97_update_bits_nolock(ac97, AC97_EXTENDED_STATUS, AC97_EA_SPDIF, AC97_EA_SPDIF);
        mutex_unlock(&ac97->reg_mutex);
        return 0;
}

/**
 * snd_ac97_set_rate - change the rate of the given input/output.
 * @ac97: the ac97 instance
 * @reg: the register to change
 * @rate: the sample rate to set
 *
 * Changes the rate of the given input/output on the codec.
 * If the codec doesn't support VAR, the rate must be 48000 (except
 * for SPDIF).
 *
 * The valid registers are AC97_PMC_MIC_ADC_RATE,
 * AC97_PCM_FRONT_DAC_RATE, AC97_PCM_LR_ADC_RATE.
 * AC97_PCM_SURR_DAC_RATE and AC97_PCM_LFE_DAC_RATE are accepted
 * if the codec supports them.
 * AC97_SPDIF is accepted as a pseudo register to modify the SPDIF
 * status bits.
 *
 * Return: Zero if successful, or a negative error code on failure.
 */
int snd_ac97_set_rate(struct snd_ac97 *ac97, int reg, unsigned int rate)
{
        int dbl;
        unsigned int tmp;
        
        dbl = rate > 48000;
        if (dbl) {
                if (!(ac97->flags & AC97_DOUBLE_RATE))
                        return -EINVAL;
                if (reg != AC97_PCM_FRONT_DAC_RATE)
                        return -EINVAL;
        }

        snd_ac97_update_power(ac97, reg, 1);
        switch (reg) {
        case AC97_PCM_MIC_ADC_RATE:
                if ((ac97->regs[AC97_EXTENDED_STATUS] & AC97_EA_VRM) == 0)      /* MIC VRA */
                        if (rate != 48000)
                                return -EINVAL;
                break;
        case AC97_PCM_FRONT_DAC_RATE:
        case AC97_PCM_LR_ADC_RATE:
                if ((ac97->regs[AC97_EXTENDED_STATUS] & AC97_EA_VRA) == 0)      /* VRA */
                        if (rate != 48000 && rate != 96000)
                                return -EINVAL;
                break;
        case AC97_PCM_SURR_DAC_RATE:
                if (! (ac97->scaps & AC97_SCAP_SURROUND_DAC))
                        return -EINVAL;
                break;
        case AC97_PCM_LFE_DAC_RATE:
                if (! (ac97->scaps & AC97_SCAP_CENTER_LFE_DAC))
                        return -EINVAL;
                break;
        case AC97_SPDIF:
                /* special case */
                return set_spdif_rate(ac97, rate);
        default:
                return -EINVAL;
        }
        if (dbl)
                rate /= 2;
        tmp = (rate * ac97->bus->clock) / 48000;
        if (tmp > 65535)
                return -EINVAL;
        if ((ac97->ext_id & AC97_EI_DRA) && reg == AC97_PCM_FRONT_DAC_RATE)
                snd_ac97_update_bits(ac97, AC97_EXTENDED_STATUS,
                                     AC97_EA_DRA, dbl ? AC97_EA_DRA : 0);
        snd_ac97_update(ac97, reg, tmp & 0xffff);
        snd_ac97_read(ac97, reg);
        if ((ac97->ext_id & AC97_EI_DRA) && reg == AC97_PCM_FRONT_DAC_RATE) {
                /* Intel controllers require double rate data to be put in
                 * slots 7+8
                 */
                snd_ac97_update_bits(ac97, AC97_GENERAL_PURPOSE,
                                     AC97_GP_DRSS_MASK,
                                     dbl ? AC97_GP_DRSS_78 : 0);
                snd_ac97_read(ac97, AC97_GENERAL_PURPOSE);
        }
        return 0;
}

EXPORT_SYMBOL(snd_ac97_set_rate);

static unsigned short get_pslots(struct snd_ac97 *ac97, unsigned char *rate_table, unsigned short *spdif_slots)
{
        if (!ac97_is_audio(ac97))
                return 0;
        if (ac97_is_rev22(ac97) || ac97_can_amap(ac97)) {
                unsigned short slots = 0;
                if (ac97_is_rev22(ac97)) {
                        /* Note: it's simply emulation of AMAP behaviour */
                        u16 es;
                        es = ac97->regs[AC97_EXTENDED_ID] &= ~AC97_EI_DACS_SLOT_MASK;
                        switch (ac97->addr) {
                        case 1:
                        case 2: es |= (1<<AC97_EI_DACS_SLOT_SHIFT); break;
                        case 3: es |= (2<<AC97_EI_DACS_SLOT_SHIFT); break;
                        }
                        snd_ac97_write_cache(ac97, AC97_EXTENDED_ID, es);
                }
                switch (ac97->addr) {
                case 0:
                        slots |= (1<<AC97_SLOT_PCM_LEFT)|(1<<AC97_SLOT_PCM_RIGHT);
                        if (ac97->scaps & AC97_SCAP_SURROUND_DAC)
                                slots |= (1<<AC97_SLOT_PCM_SLEFT)|(1<<AC97_SLOT_PCM_SRIGHT);
                        if (ac97->scaps & AC97_SCAP_CENTER_LFE_DAC)
                                slots |= (1<<AC97_SLOT_PCM_CENTER)|(1<<AC97_SLOT_LFE);
                        if (ac97->ext_id & AC97_EI_SPDIF) {
                                if (!(ac97->scaps & AC97_SCAP_SURROUND_DAC))
                                        *spdif_slots = (1<<AC97_SLOT_SPDIF_LEFT)|(1<<AC97_SLOT_SPDIF_RIGHT);
                                else if (!(ac97->scaps & AC97_SCAP_CENTER_LFE_DAC))
                                        *spdif_slots = (1<<AC97_SLOT_SPDIF_LEFT1)|(1<<AC97_SLOT_SPDIF_RIGHT1);
                                else
                                        *spdif_slots = (1<<AC97_SLOT_SPDIF_LEFT2)|(1<<AC97_SLOT_SPDIF_RIGHT2);
                        }
                        *rate_table = 0;
                        break;
                case 1:
                case 2:
                        slots |= (1<<AC97_SLOT_PCM_SLEFT)|(1<<AC97_SLOT_PCM_SRIGHT);
                        if (ac97->scaps & AC97_SCAP_SURROUND_DAC)
                                slots |= (1<<AC97_SLOT_PCM_CENTER)|(1<<AC97_SLOT_LFE);
                        if (ac97->ext_id & AC97_EI_SPDIF) {
                                if (!(ac97->scaps & AC97_SCAP_SURROUND_DAC))
                                        *spdif_slots = (1<<AC97_SLOT_SPDIF_LEFT1)|(1<<AC97_SLOT_SPDIF_RIGHT1);
                                else
                                        *spdif_slots = (1<<AC97_SLOT_SPDIF_LEFT2)|(1<<AC97_SLOT_SPDIF_RIGHT2);
                        }
                        *rate_table = 1;
                        break;
                case 3:
                        slots |= (1<<AC97_SLOT_PCM_CENTER)|(1<<AC97_SLOT_LFE);
                        if (ac97->ext_id & AC97_EI_SPDIF)
                                *spdif_slots = (1<<AC97_SLOT_SPDIF_LEFT2)|(1<<AC97_SLOT_SPDIF_RIGHT2);
                        *rate_table = 2;
                        break;
                }
                return slots;
        } else {
                unsigned short slots;
                slots = (1<<AC97_SLOT_PCM_LEFT)|(1<<AC97_SLOT_PCM_RIGHT);
                if (ac97->scaps & AC97_SCAP_SURROUND_DAC)
                        slots |= (1<<AC97_SLOT_PCM_SLEFT)|(1<<AC97_SLOT_PCM_SRIGHT);
                if (ac97->scaps & AC97_SCAP_CENTER_LFE_DAC)
                        slots |= (1<<AC97_SLOT_PCM_CENTER)|(1<<AC97_SLOT_LFE);
                if (ac97->ext_id & AC97_EI_SPDIF) {
                        if (!(ac97->scaps & AC97_SCAP_SURROUND_DAC))
                                *spdif_slots = (1<<AC97_SLOT_SPDIF_LEFT)|(1<<AC97_SLOT_SPDIF_RIGHT);
                        else if (!(ac97->scaps & AC97_SCAP_CENTER_LFE_DAC))
                                *spdif_slots = (1<<AC97_SLOT_SPDIF_LEFT1)|(1<<AC97_SLOT_SPDIF_RIGHT1);
                        else
                                *spdif_slots = (1<<AC97_SLOT_SPDIF_LEFT2)|(1<<AC97_SLOT_SPDIF_RIGHT2);
                }
                *rate_table = 0;
                return slots;
        }
}

static unsigned short get_cslots(struct snd_ac97 *ac97)
{
        unsigned short slots;

        if (!ac97_is_audio(ac97))
                return 0;
        slots = (1<<AC97_SLOT_PCM_LEFT)|(1<<AC97_SLOT_PCM_RIGHT);
        slots |= (1<<AC97_SLOT_MIC);
        return slots;
}

static unsigned int get_rates(struct ac97_pcm *pcm, unsigned int cidx, unsigned short slots, int dbl)
{
        int i, idx;
        unsigned int rates = ~0;
        unsigned char reg;

        for (i = 3; i < 12; i++) {
                if (!(slots & (1 << i)))
                        continue;
                reg = get_slot_reg(pcm, cidx, i, dbl);
                switch (reg) {
                case AC97_PCM_FRONT_DAC_RATE:   idx = AC97_RATES_FRONT_DAC; break;
                case AC97_PCM_SURR_DAC_RATE:    idx = AC97_RATES_SURR_DAC; break;
                case AC97_PCM_LFE_DAC_RATE:     idx = AC97_RATES_LFE_DAC; break;
                case AC97_PCM_LR_ADC_RATE:      idx = AC97_RATES_ADC; break;
                case AC97_PCM_MIC_ADC_RATE:     idx = AC97_RATES_MIC_ADC; break;
                default:                        idx = AC97_RATES_SPDIF; break;
                }
                rates &= pcm->r[dbl].codec[cidx]->rates[idx];
        }
        if (!dbl)
                rates &= ~(SNDRV_PCM_RATE_64000 | SNDRV_PCM_RATE_88200 |
                           SNDRV_PCM_RATE_96000);
        return rates;
}

/**
 * snd_ac97_pcm_assign - assign AC97 slots to given PCM streams
 * @bus: the ac97 bus instance
 * @pcms_count: count of PCMs to be assigned
 * @pcms: PCMs to be assigned
 *
 * It assigns available AC97 slots for given PCMs. If none or only
 * some slots are available, pcm->xxx.slots and pcm->xxx.rslots[] members
 * are reduced and might be zero.
 *
 * Return: Zero if successful, or a negative error code on failure.
 */
int snd_ac97_pcm_assign(struct snd_ac97_bus *bus,
                        unsigned short pcms_count,
                        const struct ac97_pcm *pcms)
{
        int i, j, k;
        const struct ac97_pcm *pcm;
        struct ac97_pcm *rpcms, *rpcm;
        unsigned short avail_slots[2][4];
        unsigned char rate_table[2][4];
        unsigned short tmp, slots;
        unsigned short spdif_slots[4];
        unsigned int rates;
        struct snd_ac97 *codec;

        rpcms = kcalloc(pcms_count, sizeof(struct ac97_pcm), GFP_KERNEL);
        if (rpcms == NULL)
                return -ENOMEM;
        memset(avail_slots, 0, sizeof(avail_slots));
        memset(rate_table, 0, sizeof(rate_table));
        memset(spdif_slots, 0, sizeof(spdif_slots));
        for (i = 0; i < 4; i++) {
                codec = bus->codec[i];
                if (!codec)
                        continue;
                avail_slots[0][i] = get_pslots(codec, &rate_table[0][i], &spdif_slots[i]);
                avail_slots[1][i] = get_cslots(codec);
                if (!(codec->scaps & AC97_SCAP_INDEP_SDIN)) {
                        for (j = 0; j < i; j++) {
                                if (bus->codec[j])
                                        avail_slots[1][i] &= ~avail_slots[1][j];
                        }
                }
        }
        /* first step - exclusive devices */
        for (i = 0; i < pcms_count; i++) {
                pcm = &pcms[i];
                rpcm = &rpcms[i];
                /* low-level driver thinks that it's more clever */
                if (pcm->copy_flag) {
                        *rpcm = *pcm;
                        continue;
                }
                rpcm->stream = pcm->stream;
                rpcm->exclusive = pcm->exclusive;
                rpcm->spdif = pcm->spdif;
                rpcm->private_value = pcm->private_value;
                rpcm->bus = bus;
                rpcm->rates = ~0;
                slots = pcm->r[0].slots;
                for (j = 0; j < 4 && slots; j++) {
                        if (!bus->codec[j])
                                continue;
                        rates = ~0;
                        if (pcm->spdif && pcm->stream == 0)
                                tmp = spdif_slots[j];
                        else
                                tmp = avail_slots[pcm->stream][j];
                        if (pcm->exclusive) {
                                /* exclusive access */
                                tmp &= slots;
                                for (k = 0; k < i; k++) {
                                        if (rpcm->stream == rpcms[k].stream)
                                                tmp &= ~rpcms[k].r[0].rslots[j];
                                }
                        } else {
                                /* non-exclusive access */
                                tmp &= pcm->r[0].slots;
                        }
                        if (tmp) {
                                rpcm->r[0].rslots[j] = tmp;
                                rpcm->r[0].codec[j] = bus->codec[j];
                                rpcm->r[0].rate_table[j] = rate_table[pcm->stream][j];
                                if (bus->no_vra)
                                        rates = SNDRV_PCM_RATE_48000;
                                else
                                        rates = get_rates(rpcm, j, tmp, 0);
                                if (pcm->exclusive)
                                        avail_slots[pcm->stream][j] &= ~tmp;
                        }
                        slots &= ~tmp;
                        rpcm->r[0].slots |= tmp;
                        rpcm->rates &= rates;
                }
                /* for double rate, we check the first codec only */
                if (pcm->stream == SNDRV_PCM_STREAM_PLAYBACK &&
                    bus->codec[0] && (bus->codec[0]->flags & AC97_DOUBLE_RATE) &&
                    rate_table[pcm->stream][0] == 0) {
                        tmp = (1<<AC97_SLOT_PCM_LEFT) | (1<<AC97_SLOT_PCM_RIGHT) |
                              (1<<AC97_SLOT_PCM_LEFT_0) | (1<<AC97_SLOT_PCM_RIGHT_0);
                        if ((tmp & pcm->r[1].slots) == tmp) {
                                rpcm->r[1].slots = tmp;
                                rpcm->r[1].rslots[0] = tmp;
                                rpcm->r[1].rate_table[0] = 0;
                                rpcm->r[1].codec[0] = bus->codec[0];
                                if (pcm->exclusive)
                                        avail_slots[pcm->stream][0] &= ~tmp;
                                if (bus->no_vra)
                                        rates = SNDRV_PCM_RATE_96000;
                                else
                                        rates = get_rates(rpcm, 0, tmp, 1);
                                rpcm->rates |= rates;
                        }
                }
                if (rpcm->rates == ~0)
                        rpcm->rates = 0; /* not used */
        }
        bus->pcms_count = pcms_count;
        bus->pcms = rpcms;
        return 0;
}

EXPORT_SYMBOL(snd_ac97_pcm_assign);

/**
 * snd_ac97_pcm_open - opens the given AC97 pcm
 * @pcm: the ac97 pcm instance
 * @rate: rate in Hz, if codec does not support VRA, this value must be 48000Hz
 * @cfg: output stream characteristics
 * @slots: a subset of allocated slots (snd_ac97_pcm_assign) for this pcm
 *
 * It locks the specified slots and sets the given rate to AC97 registers.
 *
 * Return: Zero if successful, or a negative error code on failure.
 */
int snd_ac97_pcm_open(struct ac97_pcm *pcm, unsigned int rate,
                      enum ac97_pcm_cfg cfg, unsigned short slots)
{
        struct snd_ac97_bus *bus;
        int i, cidx, r, ok_flag;
        unsigned int reg_ok[4] = {0,0,0,0};
        unsigned char reg;
        int err = 0;

        r = rate > 48000;
        bus = pcm->bus;
        if (cfg == AC97_PCM_CFG_SPDIF) {
                for (cidx = 0; cidx < 4; cidx++)
                        if (bus->codec[cidx] && (bus->codec[cidx]->ext_id & AC97_EI_SPDIF)) {
                                err = set_spdif_rate(bus->codec[cidx], rate);
                                if (err < 0)
                                        return err;
                        }
        }
        spin_lock_irq(&pcm->bus->bus_lock);
        for (i = 3; i < 12; i++) {
                if (!(slots & (1 << i)))
                        continue;
                ok_flag = 0;
                for (cidx = 0; cidx < 4; cidx++) {
                        if (bus->used_slots[pcm->stream][cidx] & (1 << i)) {
                                spin_unlock_irq(&pcm->bus->bus_lock);
                                err = -EBUSY;
                                goto error;
                        }
                        if (pcm->r[r].rslots[cidx] & (1 << i)) {
                                bus->used_slots[pcm->stream][cidx] |= (1 << i);
                                ok_flag++;
                        }
                }
                if (!ok_flag) {
                        spin_unlock_irq(&pcm->bus->bus_lock);
                        dev_err(bus->card->dev,
                                "cannot find configuration for AC97 slot %i\n",
                                i);
                        err = -EAGAIN;
                        goto error;
                }
        }
        pcm->cur_dbl = r;
        spin_unlock_irq(&pcm->bus->bus_lock);
        for (i = 3; i < 12; i++) {
                if (!(slots & (1 << i)))
                        continue;
                for (cidx = 0; cidx < 4; cidx++) {
                        if (pcm->r[r].rslots[cidx] & (1 << i)) {
                                reg = get_slot_reg(pcm, cidx, i, r);
                                if (reg == 0xff) {
                                        dev_err(bus->card->dev,
                                                "invalid AC97 slot %i?\n", i);
                                        continue;
                                }
                                if (reg_ok[cidx] & (1 << (reg - AC97_PCM_FRONT_DAC_RATE)))
                                        continue;
                                dev_dbg(bus->card->dev,
                                        "setting ac97 reg 0x%x to rate %d\n",
                                        reg, rate);
                                err = snd_ac97_set_rate(pcm->r[r].codec[cidx], reg, rate);
                                if (err < 0)
                                        dev_err(bus->card->dev,
                                                "error in snd_ac97_set_rate: cidx=%d, reg=0x%x, rate=%d, err=%d\n",
                                                cidx, reg, rate, err);
                                else
                                        reg_ok[cidx] |= (1 << (reg - AC97_PCM_FRONT_DAC_RATE));
                        }
                }
        }
        pcm->aslots = slots;
        return 0;

 error:
        pcm->aslots = slots;
        snd_ac97_pcm_close(pcm);
        return err;
}

EXPORT_SYMBOL(snd_ac97_pcm_open);

/**
 * snd_ac97_pcm_close - closes the given AC97 pcm
 * @pcm: the ac97 pcm instance
 *
 * It frees the locked AC97 slots.
 *
 * Return: Zero.
 */
int snd_ac97_pcm_close(struct ac97_pcm *pcm)
{
        struct snd_ac97_bus *bus;
        unsigned short slots = pcm->aslots;
        int i, cidx;

#ifdef CONFIG_SND_AC97_POWER_SAVE
        int r = pcm->cur_dbl;
        for (i = 3; i < 12; i++) {
                if (!(slots & (1 << i)))
                        continue;
                for (cidx = 0; cidx < 4; cidx++) {
                        if (pcm->r[r].rslots[cidx] & (1 << i)) {
                                int reg = get_slot_reg(pcm, cidx, i, r);
                                snd_ac97_update_power(pcm->r[r].codec[cidx],
                                                      reg, 0);
                        }
                }
        }
#endif

        bus = pcm->bus;
        spin_lock_irq(&pcm->bus->bus_lock);
        for (i = 3; i < 12; i++) {
                if (!(slots & (1 << i)))
                        continue;
                for (cidx = 0; cidx < 4; cidx++)
                        bus->used_slots[pcm->stream][cidx] &= ~(1 << i);
        }
        pcm->aslots = 0;
        pcm->cur_dbl = 0;
        spin_unlock_irq(&pcm->bus->bus_lock);
        return 0;
}

EXPORT_SYMBOL(snd_ac97_pcm_close);

static int double_rate_hw_constraint_rate(struct snd_pcm_hw_params *params,
                                          struct snd_pcm_hw_rule *rule)
{
        struct snd_interval *channels = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
        if (channels->min > 2) {
                static const struct snd_interval single_rates = {
                        .min = 1,
                        .max = 48000,
                };
                struct snd_interval *rate = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
                return snd_interval_refine(rate, &single_rates);
        }
        return 0;
}

static int double_rate_hw_constraint_channels(struct snd_pcm_hw_params *params,
                                              struct snd_pcm_hw_rule *rule)
{
        struct snd_interval *rate = hw_param_interval(params, SNDRV_PCM_HW_PARAM_RATE);
        if (rate->min > 48000) {
                static const struct snd_interval double_rate_channels = {
                        .min = 2,
                        .max = 2,
                };
                struct snd_interval *channels = hw_param_interval(params, SNDRV_PCM_HW_PARAM_CHANNELS);
                return snd_interval_refine(channels, &double_rate_channels);
        }
        return 0;
}

/**
 * snd_ac97_pcm_double_rate_rules - set double rate constraints
 * @runtime: the runtime of the ac97 front playback pcm
 *
 * Installs the hardware constraint rules to prevent using double rates and
 * more than two channels at the same time.
 *
 * Return: Zero if successful, or a negative error code on failure.
 */
int snd_ac97_pcm_double_rate_rules(struct snd_pcm_runtime *runtime)
{
        int err;

        err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_RATE,
                                  double_rate_hw_constraint_rate, NULL,
                                  SNDRV_PCM_HW_PARAM_CHANNELS, -1);
        if (err < 0)
                return err;
        err = snd_pcm_hw_rule_add(runtime, 0, SNDRV_PCM_HW_PARAM_CHANNELS,
                                  double_rate_hw_constraint_channels, NULL,
                                  SNDRV_PCM_HW_PARAM_RATE, -1);
        return err;
}

EXPORT_SYMBOL(snd_ac97_pcm_double_rate_rules);