/*
 *   intel_hdmi_audio.c - Intel HDMI audio driver
 *
 *  Copyright (C) 2016 Intel Corp
 *  Authors:    Sailaja Bandarupalli <sailaja.bandarupalli@intel.com>
 *              Ramesh Babu K V <ramesh.babu@intel.com>
 *              Vaibhav Agarwal <vaibhav.agarwal@intel.com>
 *              Jerome Anand <jerome.anand@intel.com>
 *  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; version 2 of the License.
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  General Public License for more details.
 *
 * ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 * ALSA driver for Intel HDMI audio
 */

#include <linux/types.h>
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/pm_runtime.h>
#include <linux/dma-mapping.h>
#include <linux/delay.h>
#include <asm/cacheflush.h>
#include <sound/core.h>
#include <sound/asoundef.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/initval.h>
#include <sound/control.h>
#include <sound/jack.h>
#include <drm/drm_edid.h>
#include <drm/intel_lpe_audio.h>
#include "intel_hdmi_audio.h"

/*standard module options for ALSA. This module supports only one card*/
static int hdmi_card_index = SNDRV_DEFAULT_IDX1;
static char *hdmi_card_id = SNDRV_DEFAULT_STR1;

module_param_named(index, hdmi_card_index, int, 0444);
MODULE_PARM_DESC(index,
                "Index value for INTEL Intel HDMI Audio controller.");
module_param_named(id, hdmi_card_id, charp, 0444);
MODULE_PARM_DESC(id,
                "ID string for INTEL Intel HDMI Audio controller.");

/*
 * ELD SA bits in the CEA Speaker Allocation data block
 */
static const int eld_speaker_allocation_bits[] = {
        [0] = FL | FR,
        [1] = LFE,
        [2] = FC,
        [3] = RL | RR,
        [4] = RC,
        [5] = FLC | FRC,
        [6] = RLC | RRC,
        /* the following are not defined in ELD yet */
        [7] = 0,
};

/*
 * This is an ordered list!
 *
 * The preceding ones have better chances to be selected by
 * hdmi_channel_allocation().
 */
static struct cea_channel_speaker_allocation channel_allocations[] = {
/*                        channel:   7     6    5    4    3     2    1    0  */
{ .ca_index = 0x00,  .speakers = {   0,    0,   0,   0,   0,    0,  FR,  FL } },
                                /* 2.1 */
{ .ca_index = 0x01,  .speakers = {   0,    0,   0,   0,   0,  LFE,  FR,  FL } },
                                /* Dolby Surround */
{ .ca_index = 0x02,  .speakers = {   0,    0,   0,   0,  FC,    0,  FR,  FL } },
                                /* surround40 */
{ .ca_index = 0x08,  .speakers = {   0,    0,  RR,  RL,   0,    0,  FR,  FL } },
                                /* surround41 */
{ .ca_index = 0x09,  .speakers = {   0,    0,  RR,  RL,   0,  LFE,  FR,  FL } },
                                /* surround50 */
{ .ca_index = 0x0a,  .speakers = {   0,    0,  RR,  RL,  FC,    0,  FR,  FL } },
                                /* surround51 */
{ .ca_index = 0x0b,  .speakers = {   0,    0,  RR,  RL,  FC,  LFE,  FR,  FL } },
                                /* 6.1 */
{ .ca_index = 0x0f,  .speakers = {   0,   RC,  RR,  RL,  FC,  LFE,  FR,  FL } },
                                /* surround71 */
{ .ca_index = 0x13,  .speakers = { RRC,  RLC,  RR,  RL,  FC,  LFE,  FR,  FL } },

{ .ca_index = 0x03,  .speakers = {   0,    0,   0,   0,  FC,  LFE,  FR,  FL } },
{ .ca_index = 0x04,  .speakers = {   0,    0,   0,  RC,   0,    0,  FR,  FL } },
{ .ca_index = 0x05,  .speakers = {   0,    0,   0,  RC,   0,  LFE,  FR,  FL } },
{ .ca_index = 0x06,  .speakers = {   0,    0,   0,  RC,  FC,    0,  FR,  FL } },
{ .ca_index = 0x07,  .speakers = {   0,    0,   0,  RC,  FC,  LFE,  FR,  FL } },
{ .ca_index = 0x0c,  .speakers = {   0,   RC,  RR,  RL,   0,    0,  FR,  FL } },
{ .ca_index = 0x0d,  .speakers = {   0,   RC,  RR,  RL,   0,  LFE,  FR,  FL } },
{ .ca_index = 0x0e,  .speakers = {   0,   RC,  RR,  RL,  FC,    0,  FR,  FL } },
{ .ca_index = 0x10,  .speakers = { RRC,  RLC,  RR,  RL,   0,    0,  FR,  FL } },
{ .ca_index = 0x11,  .speakers = { RRC,  RLC,  RR,  RL,   0,  LFE,  FR,  FL } },
{ .ca_index = 0x12,  .speakers = { RRC,  RLC,  RR,  RL,  FC,    0,  FR,  FL } },
{ .ca_index = 0x14,  .speakers = { FRC,  FLC,   0,   0,   0,    0,  FR,  FL } },
{ .ca_index = 0x15,  .speakers = { FRC,  FLC,   0,   0,   0,  LFE,  FR,  FL } },
{ .ca_index = 0x16,  .speakers = { FRC,  FLC,   0,   0,  FC,    0,  FR,  FL } },
{ .ca_index = 0x17,  .speakers = { FRC,  FLC,   0,   0,  FC,  LFE,  FR,  FL } },
{ .ca_index = 0x18,  .speakers = { FRC,  FLC,   0,  RC,   0,    0,  FR,  FL } },
{ .ca_index = 0x19,  .speakers = { FRC,  FLC,   0,  RC,   0,  LFE,  FR,  FL } },
{ .ca_index = 0x1a,  .speakers = { FRC,  FLC,   0,  RC,  FC,    0,  FR,  FL } },
{ .ca_index = 0x1b,  .speakers = { FRC,  FLC,   0,  RC,  FC,  LFE,  FR,  FL } },
{ .ca_index = 0x1c,  .speakers = { FRC,  FLC,  RR,  RL,   0,    0,  FR,  FL } },
{ .ca_index = 0x1d,  .speakers = { FRC,  FLC,  RR,  RL,   0,  LFE,  FR,  FL } },
{ .ca_index = 0x1e,  .speakers = { FRC,  FLC,  RR,  RL,  FC,    0,  FR,  FL } },
{ .ca_index = 0x1f,  .speakers = { FRC,  FLC,  RR,  RL,  FC,  LFE,  FR,  FL } },
};

static const struct channel_map_table map_tables[] = {
        { SNDRV_CHMAP_FL,       0x00,   FL },
        { SNDRV_CHMAP_FR,       0x01,   FR },
        { SNDRV_CHMAP_RL,       0x04,   RL },
        { SNDRV_CHMAP_RR,       0x05,   RR },
        { SNDRV_CHMAP_LFE,      0x02,   LFE },
        { SNDRV_CHMAP_FC,       0x03,   FC },
        { SNDRV_CHMAP_RLC,      0x06,   RLC },
        { SNDRV_CHMAP_RRC,      0x07,   RRC },
        {} /* terminator */
};

/* hardware capability structure */
static const struct snd_pcm_hardware had_pcm_hardware = {
        .info = (SNDRV_PCM_INFO_INTERLEAVED |
                SNDRV_PCM_INFO_MMAP |
                SNDRV_PCM_INFO_MMAP_VALID |
                SNDRV_PCM_INFO_NO_PERIOD_WAKEUP),
        .formats = (SNDRV_PCM_FMTBIT_S16_LE |
                    SNDRV_PCM_FMTBIT_S24_LE |
                    SNDRV_PCM_FMTBIT_S32_LE),
        .rates = SNDRV_PCM_RATE_32000 |
                SNDRV_PCM_RATE_44100 |
                SNDRV_PCM_RATE_48000 |
                SNDRV_PCM_RATE_88200 |
                SNDRV_PCM_RATE_96000 |
                SNDRV_PCM_RATE_176400 |
                SNDRV_PCM_RATE_192000,
        .rate_min = HAD_MIN_RATE,
        .rate_max = HAD_MAX_RATE,
        .channels_min = HAD_MIN_CHANNEL,
        .channels_max = HAD_MAX_CHANNEL,
        .buffer_bytes_max = HAD_MAX_BUFFER,
        .period_bytes_min = HAD_MIN_PERIOD_BYTES,
        .period_bytes_max = HAD_MAX_PERIOD_BYTES,
        .periods_min = HAD_MIN_PERIODS,
        .periods_max = HAD_MAX_PERIODS,
        .fifo_size = HAD_FIFO_SIZE,
};

/* Get the active PCM substream;
 * Call had_substream_put() for unreferecing.
 * Don't call this inside had_spinlock, as it takes by itself
 */
static struct snd_pcm_substream *
had_substream_get(struct snd_intelhad *intelhaddata)
{
        struct snd_pcm_substream *substream;
        unsigned long flags;

        spin_lock_irqsave(&intelhaddata->had_spinlock, flags);
        substream = intelhaddata->stream_info.substream;
        if (substream)
                intelhaddata->stream_info.substream_refcount++;
        spin_unlock_irqrestore(&intelhaddata->had_spinlock, flags);
        return substream;
}

/* Unref the active PCM substream;
 * Don't call this inside had_spinlock, as it takes by itself
 */
static void had_substream_put(struct snd_intelhad *intelhaddata)
{
        unsigned long flags;

        spin_lock_irqsave(&intelhaddata->had_spinlock, flags);
        intelhaddata->stream_info.substream_refcount--;
        spin_unlock_irqrestore(&intelhaddata->had_spinlock, flags);
}

/* Register access functions */
static u32 had_read_register_raw(struct snd_intelhad *ctx, u32 reg)
{
        return ioread32(ctx->mmio_start + ctx->had_config_offset + reg);
}

static void had_write_register_raw(struct snd_intelhad *ctx, u32 reg, u32 val)
{
        iowrite32(val, ctx->mmio_start + ctx->had_config_offset + reg);
}

static void had_read_register(struct snd_intelhad *ctx, u32 reg, u32 *val)
{
        if (!ctx->connected)
                *val = 0;
        else
                *val = had_read_register_raw(ctx, reg);
}

static void had_write_register(struct snd_intelhad *ctx, u32 reg, u32 val)
{
        if (ctx->connected)
                had_write_register_raw(ctx, reg, val);
}

/*
 * enable / disable audio configuration
 *
 * The normal read/modify should not directly be used on VLV2 for
 * updating AUD_CONFIG register.
 * This is because:
 * Bit6 of AUD_CONFIG register is writeonly due to a silicon bug on VLV2
 * HDMI IP. As a result a read-modify of AUD_CONFIG regiter will always
 * clear bit6. AUD_CONFIG[6:4] represents the "channels" field of the
 * register. This field should be 1xy binary for configuration with 6 or
 * more channels. Read-modify of AUD_CONFIG (Eg. for enabling audio)
 * causes the "channels" field to be updated as 0xy binary resulting in
 * bad audio. The fix is to always write the AUD_CONFIG[6:4] with
 * appropriate value when doing read-modify of AUD_CONFIG register.
 */
static void had_enable_audio(struct snd_intelhad *intelhaddata,
                             bool enable)
{
        /* update the cached value */
        intelhaddata->aud_config.regx.aud_en = enable;
        had_write_register(intelhaddata, AUD_CONFIG,
                           intelhaddata->aud_config.regval);
}

/* forcibly ACKs to both BUFFER_DONE and BUFFER_UNDERRUN interrupts */
static void had_ack_irqs(struct snd_intelhad *ctx)
{
        u32 status_reg;

        if (!ctx->connected)
                return;
        had_read_register(ctx, AUD_HDMI_STATUS, &status_reg);
        status_reg |= HDMI_AUDIO_BUFFER_DONE | HDMI_AUDIO_UNDERRUN;
        had_write_register(ctx, AUD_HDMI_STATUS, status_reg);
        had_read_register(ctx, AUD_HDMI_STATUS, &status_reg);
}

/* Reset buffer pointers */
static void had_reset_audio(struct snd_intelhad *intelhaddata)
{
        had_write_register(intelhaddata, AUD_HDMI_STATUS,
                           AUD_HDMI_STATUSG_MASK_FUNCRST);
        had_write_register(intelhaddata, AUD_HDMI_STATUS, 0);
}

/*
 * initialize audio channel status registers
 * This function is called in the prepare callback
 */
static int had_prog_status_reg(struct snd_pcm_substream *substream,
                        struct snd_intelhad *intelhaddata)
{
        union aud_cfg cfg_val = {.regval = 0};
        union aud_ch_status_0 ch_stat0 = {.regval = 0};
        union aud_ch_status_1 ch_stat1 = {.regval = 0};

        ch_stat0.regx.lpcm_id = (intelhaddata->aes_bits &
                                          IEC958_AES0_NONAUDIO) >> 1;
        ch_stat0.regx.clk_acc = (intelhaddata->aes_bits &
                                          IEC958_AES3_CON_CLOCK) >> 4;
        cfg_val.regx.val_bit = ch_stat0.regx.lpcm_id;

        switch (substream->runtime->rate) {
        case AUD_SAMPLE_RATE_32:
                ch_stat0.regx.samp_freq = CH_STATUS_MAP_32KHZ;
                break;

        case AUD_SAMPLE_RATE_44_1:
                ch_stat0.regx.samp_freq = CH_STATUS_MAP_44KHZ;
                break;
        case AUD_SAMPLE_RATE_48:
                ch_stat0.regx.samp_freq = CH_STATUS_MAP_48KHZ;
                break;
        case AUD_SAMPLE_RATE_88_2:
                ch_stat0.regx.samp_freq = CH_STATUS_MAP_88KHZ;
                break;
        case AUD_SAMPLE_RATE_96:
                ch_stat0.regx.samp_freq = CH_STATUS_MAP_96KHZ;
                break;
        case AUD_SAMPLE_RATE_176_4:
                ch_stat0.regx.samp_freq = CH_STATUS_MAP_176KHZ;
                break;
        case AUD_SAMPLE_RATE_192:
                ch_stat0.regx.samp_freq = CH_STATUS_MAP_192KHZ;
                break;

        default:
                /* control should never come here */
                return -EINVAL;
        }

        had_write_register(intelhaddata,
                           AUD_CH_STATUS_0, ch_stat0.regval);

        switch (substream->runtime->format) {
        case SNDRV_PCM_FORMAT_S16_LE:
                ch_stat1.regx.max_wrd_len = MAX_SMPL_WIDTH_20;
                ch_stat1.regx.wrd_len = SMPL_WIDTH_16BITS;
                break;
        case SNDRV_PCM_FORMAT_S24_LE:
        case SNDRV_PCM_FORMAT_S32_LE:
                ch_stat1.regx.max_wrd_len = MAX_SMPL_WIDTH_24;
                ch_stat1.regx.wrd_len = SMPL_WIDTH_24BITS;
                break;
        default:
                return -EINVAL;
        }

        had_write_register(intelhaddata,
                           AUD_CH_STATUS_1, ch_stat1.regval);
        return 0;
}

/*
 * function to initialize audio
 * registers and buffer confgiuration registers
 * This function is called in the prepare callback
 */
static int had_init_audio_ctrl(struct snd_pcm_substream *substream,
                               struct snd_intelhad *intelhaddata)
{
        union aud_cfg cfg_val = {.regval = 0};
        union aud_buf_config buf_cfg = {.regval = 0};
        u8 channels;

        had_prog_status_reg(substream, intelhaddata);

        buf_cfg.regx.audio_fifo_watermark = FIFO_THRESHOLD;
        buf_cfg.regx.dma_fifo_watermark = DMA_FIFO_THRESHOLD;
        buf_cfg.regx.aud_delay = 0;
        had_write_register(intelhaddata, AUD_BUF_CONFIG, buf_cfg.regval);

        channels = substream->runtime->channels;
        cfg_val.regx.num_ch = channels - 2;
        if (channels <= 2)
                cfg_val.regx.layout = LAYOUT0;
        else
                cfg_val.regx.layout = LAYOUT1;

        if (substream->runtime->format == SNDRV_PCM_FORMAT_S16_LE)
                cfg_val.regx.packet_mode = 1;

        if (substream->runtime->format == SNDRV_PCM_FORMAT_S32_LE)
                cfg_val.regx.left_align = 1;

        cfg_val.regx.val_bit = 1;

        /* fix up the DP bits */
        if (intelhaddata->dp_output) {
                cfg_val.regx.dp_modei = 1;
                cfg_val.regx.set = 1;
        }

        had_write_register(intelhaddata, AUD_CONFIG, cfg_val.regval);
        intelhaddata->aud_config = cfg_val;
        return 0;
}

/*
 * Compute derived values in channel_allocations[].
 */
static void init_channel_allocations(void)
{
        int i, j;
        struct cea_channel_speaker_allocation *p;

        for (i = 0; i < ARRAY_SIZE(channel_allocations); i++) {
                p = channel_allocations + i;
                p->channels = 0;
                p->spk_mask = 0;
                for (j = 0; j < ARRAY_SIZE(p->speakers); j++)
                        if (p->speakers[j]) {
                                p->channels++;
                                p->spk_mask |= p->speakers[j];
                        }
        }
}

/*
 * The transformation takes two steps:
 *
 *      eld->spk_alloc => (eld_speaker_allocation_bits[]) => spk_mask
 *            spk_mask => (channel_allocations[])         => ai->CA
 *
 * TODO: it could select the wrong CA from multiple candidates.
 */
static int had_channel_allocation(struct snd_intelhad *intelhaddata,
                                  int channels)
{
        int i;
        int ca = 0;
        int spk_mask = 0;

        /*
         * CA defaults to 0 for basic stereo audio
         */
        if (channels <= 2)
                return 0;

        /*
         * expand ELD's speaker allocation mask
         *
         * ELD tells the speaker mask in a compact(paired) form,
         * expand ELD's notions to match the ones used by Audio InfoFrame.
         */

        for (i = 0; i < ARRAY_SIZE(eld_speaker_allocation_bits); i++) {
                if (intelhaddata->eld[DRM_ELD_SPEAKER] & (1 << i))
                        spk_mask |= eld_speaker_allocation_bits[i];
        }

        /* search for the first working match in the CA table */
        for (i = 0; i < ARRAY_SIZE(channel_allocations); i++) {
                if (channels == channel_allocations[i].channels &&
                (spk_mask & channel_allocations[i].spk_mask) ==
                                channel_allocations[i].spk_mask) {
                        ca = channel_allocations[i].ca_index;
                        break;
                }
        }

        dev_dbg(intelhaddata->dev, "select CA 0x%x for %d\n", ca, channels);

        return ca;
}

/* from speaker bit mask to ALSA API channel position */
static int spk_to_chmap(int spk)
{
        const struct channel_map_table *t = map_tables;

        for (; t->map; t++) {
                if (t->spk_mask == spk)
                        return t->map;
        }
        return 0;
}

static void had_build_channel_allocation_map(struct snd_intelhad *intelhaddata)
{
        int i, c;
        int spk_mask = 0;
        struct snd_pcm_chmap_elem *chmap;
        u8 eld_high, eld_high_mask = 0xF0;
        u8 high_msb;

        kfree(intelhaddata->chmap->chmap);
        intelhaddata->chmap->chmap = NULL;

        chmap = kzalloc(sizeof(*chmap), GFP_KERNEL);
        if (!chmap)
                return;

        dev_dbg(intelhaddata->dev, "eld speaker = %x\n",
                intelhaddata->eld[DRM_ELD_SPEAKER]);

        /* WA: Fix the max channel supported to 8 */

        /*
         * Sink may support more than 8 channels, if eld_high has more than
         * one bit set. SOC supports max 8 channels.
         * Refer eld_speaker_allocation_bits, for sink speaker allocation
         */

        /* if 0x2F < eld < 0x4F fall back to 0x2f, else fall back to 0x4F */
        eld_high = intelhaddata->eld[DRM_ELD_SPEAKER] & eld_high_mask;
        if ((eld_high & (eld_high-1)) && (eld_high > 0x1F)) {
                /* eld_high & (eld_high-1): if more than 1 bit set */
                /* 0x1F: 7 channels */
                for (i = 1; i < 4; i++) {
                        high_msb = eld_high & (0x80 >> i);
                        if (high_msb) {
                                intelhaddata->eld[DRM_ELD_SPEAKER] &=
                                        high_msb | 0xF;
                                break;
                        }
                }
        }

        for (i = 0; i < ARRAY_SIZE(eld_speaker_allocation_bits); i++) {
                if (intelhaddata->eld[DRM_ELD_SPEAKER] & (1 << i))
                        spk_mask |= eld_speaker_allocation_bits[i];
        }

        for (i = 0; i < ARRAY_SIZE(channel_allocations); i++) {
                if (spk_mask == channel_allocations[i].spk_mask) {
                        for (c = 0; c < channel_allocations[i].channels; c++) {
                                chmap->map[c] = spk_to_chmap(
                                        channel_allocations[i].speakers[
                                                (MAX_SPEAKERS - 1) - c]);
                        }
                        chmap->channels = channel_allocations[i].channels;
                        intelhaddata->chmap->chmap = chmap;
                        break;
                }
        }
        if (i >= ARRAY_SIZE(channel_allocations))
                kfree(chmap);
}

/*
 * ALSA API channel-map control callbacks
 */
static int had_chmap_ctl_info(struct snd_kcontrol *kcontrol,
                                struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_INTEGER;
        uinfo->count = HAD_MAX_CHANNEL;
        uinfo->value.integer.min = 0;
        uinfo->value.integer.max = SNDRV_CHMAP_LAST;
        return 0;
}

static int had_chmap_ctl_get(struct snd_kcontrol *kcontrol,
                                struct snd_ctl_elem_value *ucontrol)
{
        struct snd_pcm_chmap *info = snd_kcontrol_chip(kcontrol);
        struct snd_intelhad *intelhaddata = info->private_data;
        int i;
        const struct snd_pcm_chmap_elem *chmap;

        memset(ucontrol->value.integer.value, 0,
               sizeof(long) * HAD_MAX_CHANNEL);
        mutex_lock(&intelhaddata->mutex);
        if (!intelhaddata->chmap->chmap) {
                mutex_unlock(&intelhaddata->mutex);
                return 0;
        }

        chmap = intelhaddata->chmap->chmap;
        for (i = 0; i < chmap->channels; i++)
                ucontrol->value.integer.value[i] = chmap->map[i];
        mutex_unlock(&intelhaddata->mutex);

        return 0;
}

static int had_register_chmap_ctls(struct snd_intelhad *intelhaddata,
                                                struct snd_pcm *pcm)
{
        int err;

        err = snd_pcm_add_chmap_ctls(pcm, SNDRV_PCM_STREAM_PLAYBACK,
                        NULL, 0, (unsigned long)intelhaddata,
                        &intelhaddata->chmap);
        if (err < 0)
                return err;

        intelhaddata->chmap->private_data = intelhaddata;
        intelhaddata->chmap->kctl->info = had_chmap_ctl_info;
        intelhaddata->chmap->kctl->get = had_chmap_ctl_get;
        intelhaddata->chmap->chmap = NULL;
        return 0;
}

/*
 * Initialize Data Island Packets registers
 * This function is called in the prepare callback
 */
static void had_prog_dip(struct snd_pcm_substream *substream,
                         struct snd_intelhad *intelhaddata)
{
        int i;
        union aud_ctrl_st ctrl_state = {.regval = 0};
        union aud_info_frame2 frame2 = {.regval = 0};
        union aud_info_frame3 frame3 = {.regval = 0};
        u8 checksum = 0;
        u32 info_frame;
        int channels;
        int ca;

        channels = substream->runtime->channels;

        had_write_register(intelhaddata, AUD_CNTL_ST, ctrl_state.regval);

        ca = had_channel_allocation(intelhaddata, channels);
        if (intelhaddata->dp_output) {
                info_frame = DP_INFO_FRAME_WORD1;
                frame2.regval = (substream->runtime->channels - 1) | (ca << 24);
        } else {
                info_frame = HDMI_INFO_FRAME_WORD1;
                frame2.regx.chnl_cnt = substream->runtime->channels - 1;
                frame3.regx.chnl_alloc = ca;

                /* Calculte the byte wide checksum for all valid DIP words */
                for (i = 0; i < BYTES_PER_WORD; i++)
                        checksum += (info_frame >> (i * 8)) & 0xff;
                for (i = 0; i < BYTES_PER_WORD; i++)
                        checksum += (frame2.regval >> (i * 8)) & 0xff;
                for (i = 0; i < BYTES_PER_WORD; i++)
                        checksum += (frame3.regval >> (i * 8)) & 0xff;

                frame2.regx.chksum = -(checksum);
        }

        had_write_register(intelhaddata, AUD_HDMIW_INFOFR, info_frame);
        had_write_register(intelhaddata, AUD_HDMIW_INFOFR, frame2.regval);
        had_write_register(intelhaddata, AUD_HDMIW_INFOFR, frame3.regval);

        /* program remaining DIP words with zero */
        for (i = 0; i < HAD_MAX_DIP_WORDS-VALID_DIP_WORDS; i++)
                had_write_register(intelhaddata, AUD_HDMIW_INFOFR, 0x0);

        ctrl_state.regx.dip_freq = 1;
        ctrl_state.regx.dip_en_sta = 1;
        had_write_register(intelhaddata, AUD_CNTL_ST, ctrl_state.regval);
}

static int had_calculate_maud_value(u32 aud_samp_freq, u32 link_rate)
{
        u32 maud_val;

        /* Select maud according to DP 1.2 spec */
        if (link_rate == DP_2_7_GHZ) {
                switch (aud_samp_freq) {
                case AUD_SAMPLE_RATE_32:
                        maud_val = AUD_SAMPLE_RATE_32_DP_2_7_MAUD_VAL;
                        break;

                case AUD_SAMPLE_RATE_44_1:
                        maud_val = AUD_SAMPLE_RATE_44_1_DP_2_7_MAUD_VAL;
                        break;

                case AUD_SAMPLE_RATE_48:
                        maud_val = AUD_SAMPLE_RATE_48_DP_2_7_MAUD_VAL;
                        break;

                case AUD_SAMPLE_RATE_88_2:
                        maud_val = AUD_SAMPLE_RATE_88_2_DP_2_7_MAUD_VAL;
                        break;

                case AUD_SAMPLE_RATE_96:
                        maud_val = AUD_SAMPLE_RATE_96_DP_2_7_MAUD_VAL;
                        break;

                case AUD_SAMPLE_RATE_176_4:
                        maud_val = AUD_SAMPLE_RATE_176_4_DP_2_7_MAUD_VAL;
                        break;

                case HAD_MAX_RATE:
                        maud_val = HAD_MAX_RATE_DP_2_7_MAUD_VAL;
                        break;

                default:
                        maud_val = -EINVAL;
                        break;
                }
        } else if (link_rate == DP_1_62_GHZ) {
                switch (aud_samp_freq) {
                case AUD_SAMPLE_RATE_32:
                        maud_val = AUD_SAMPLE_RATE_32_DP_1_62_MAUD_VAL;
                        break;

                case AUD_SAMPLE_RATE_44_1:
                        maud_val = AUD_SAMPLE_RATE_44_1_DP_1_62_MAUD_VAL;
                        break;

                case AUD_SAMPLE_RATE_48:
                        maud_val = AUD_SAMPLE_RATE_48_DP_1_62_MAUD_VAL;
                        break;

                case AUD_SAMPLE_RATE_88_2:
                        maud_val = AUD_SAMPLE_RATE_88_2_DP_1_62_MAUD_VAL;
                        break;

                case AUD_SAMPLE_RATE_96:
                        maud_val = AUD_SAMPLE_RATE_96_DP_1_62_MAUD_VAL;
                        break;

                case AUD_SAMPLE_RATE_176_4:
                        maud_val = AUD_SAMPLE_RATE_176_4_DP_1_62_MAUD_VAL;
                        break;

                case HAD_MAX_RATE:
                        maud_val = HAD_MAX_RATE_DP_1_62_MAUD_VAL;
                        break;

                default:
                        maud_val = -EINVAL;
                        break;
                }
        } else
                maud_val = -EINVAL;

        return maud_val;
}

/*
 * Program HDMI audio CTS value
 *
 * @aud_samp_freq: sampling frequency of audio data
 * @tmds: sampling frequency of the display data
 * @link_rate: DP link rate
 * @n_param: N value, depends on aud_samp_freq
 * @intelhaddata: substream private data
 *
 * Program CTS register based on the audio and display sampling frequency
 */
static void had_prog_cts(u32 aud_samp_freq, u32 tmds, u32 link_rate,
                         u32 n_param, struct snd_intelhad *intelhaddata)
{
        u32 cts_val;
        u64 dividend, divisor;

        if (intelhaddata->dp_output) {
                /* Substitute cts_val with Maud according to DP 1.2 spec*/
                cts_val = had_calculate_maud_value(aud_samp_freq, link_rate);
        } else {
                /* Calculate CTS according to HDMI 1.3a spec*/
                dividend = (u64)tmds * n_param*1000;
                divisor = 128 * aud_samp_freq;
                cts_val = div64_u64(dividend, divisor);
        }
        dev_dbg(intelhaddata->dev, "TMDS value=%d, N value=%d, CTS Value=%d\n",
                 tmds, n_param, cts_val);
        had_write_register(intelhaddata, AUD_HDMI_CTS, (BIT(24) | cts_val));
}

static int had_calculate_n_value(u32 aud_samp_freq)
{
        int n_val;

        /* Select N according to HDMI 1.3a spec*/
        switch (aud_samp_freq) {
        case AUD_SAMPLE_RATE_32:
                n_val = 4096;
                break;

        case AUD_SAMPLE_RATE_44_1:
                n_val = 6272;
                break;

        case AUD_SAMPLE_RATE_48:
                n_val = 6144;
                break;

        case AUD_SAMPLE_RATE_88_2:
                n_val = 12544;
                break;

        case AUD_SAMPLE_RATE_96:
                n_val = 12288;
                break;

        case AUD_SAMPLE_RATE_176_4:
                n_val = 25088;
                break;

        case HAD_MAX_RATE:
                n_val = 24576;
                break;

        default:
                n_val = -EINVAL;
                break;
        }
        return n_val;
}

/*
 * Program HDMI audio N value
 *
 * @aud_samp_freq: sampling frequency of audio data
 * @n_param: N value, depends on aud_samp_freq
 * @intelhaddata: substream private data
 *
 * This function is called in the prepare callback.
 * It programs based on the audio and display sampling frequency
 */
static int had_prog_n(u32 aud_samp_freq, u32 *n_param,
                      struct snd_intelhad *intelhaddata)
{
        int n_val;

        if (intelhaddata->dp_output) {
                /*
                 * According to DP specs, Maud and Naud values hold
                 * a relationship, which is stated as:
                 * Maud/Naud = 512 * fs / f_LS_Clk
                 * where, fs is the sampling frequency of the audio stream
                 * and Naud is 32768 for Async clock.
                 */

                n_val = DP_NAUD_VAL;
        } else
                n_val = had_calculate_n_value(aud_samp_freq);

        if (n_val < 0)
                return n_val;

        had_write_register(intelhaddata, AUD_N_ENABLE, (BIT(24) | n_val));
        *n_param = n_val;
        return 0;
}

/*
 * PCM ring buffer handling
 *
 * The hardware provides a ring buffer with the fixed 4 buffer descriptors
 * (BDs).  The driver maps these 4 BDs onto the PCM ring buffer.  The mapping
 * moves at each period elapsed.  The below illustrates how it works:
 *
 * At time=0
 *  PCM | 0 | 1 | 2 | 3 | 4 | 5 | .... |n-1|
 *  BD  | 0 | 1 | 2 | 3 |
 *
 * At time=1 (period elapsed)
 *  PCM | 0 | 1 | 2 | 3 | 4 | 5 | .... |n-1|
 *  BD      | 1 | 2 | 3 | 0 |
 *
 * At time=2 (second period elapsed)
 *  PCM | 0 | 1 | 2 | 3 | 4 | 5 | .... |n-1|
 *  BD          | 2 | 3 | 0 | 1 |
 *
 * The bd_head field points to the index of the BD to be read.  It's also the
 * position to be filled at next.  The pcm_head and the pcm_filled fields
 * point to the indices of the current position and of the next position to
 * be filled, respectively.  For PCM buffer there are both _head and _filled
 * because they may be difference when nperiods > 4.  For example, in the
 * example above at t=1, bd_head=1 and pcm_head=1 while pcm_filled=5:
 *
 * pcm_head (=1) --v               v-- pcm_filled (=5)
 *       PCM | 0 | 1 | 2 | 3 | 4 | 5 | .... |n-1|
 *       BD      | 1 | 2 | 3 | 0 |
 *  bd_head (=1) --^               ^-- next to fill (= bd_head)
 *
 * For nperiods < 4, the remaining BDs out of 4 are marked as invalid, so that
 * the hardware skips those BDs in the loop.
 *
 * An exceptional setup is the case with nperiods=1.  Since we have to update
 * BDs after finishing one BD processing, we'd need at least two BDs, where
 * both BDs point to the same content, the same address, the same size of the
 * whole PCM buffer.
 */

#define AUD_BUF_ADDR(x)         (AUD_BUF_A_ADDR + (x) * HAD_REG_WIDTH)
#define AUD_BUF_LEN(x)          (AUD_BUF_A_LENGTH + (x) * HAD_REG_WIDTH)

/* Set up a buffer descriptor at the "filled" position */
static void had_prog_bd(struct snd_pcm_substream *substream,
                        struct snd_intelhad *intelhaddata)
{
        int idx = intelhaddata->bd_head;
        int ofs = intelhaddata->pcmbuf_filled * intelhaddata->period_bytes;
        u32 addr = substream->runtime->dma_addr + ofs;

        addr |= AUD_BUF_VALID;
        if (!substream->runtime->no_period_wakeup)
                addr |= AUD_BUF_INTR_EN;
        had_write_register(intelhaddata, AUD_BUF_ADDR(idx), addr);
        had_write_register(intelhaddata, AUD_BUF_LEN(idx),
                           intelhaddata->period_bytes);

        /* advance the indices to the next */
        intelhaddata->bd_head++;
        intelhaddata->bd_head %= intelhaddata->num_bds;
        intelhaddata->pcmbuf_filled++;
        intelhaddata->pcmbuf_filled %= substream->runtime->periods;
}

/* invalidate a buffer descriptor with the given index */
static void had_invalidate_bd(struct snd_intelhad *intelhaddata,
                              int idx)
{
        had_write_register(intelhaddata, AUD_BUF_ADDR(idx), 0);
        had_write_register(intelhaddata, AUD_BUF_LEN(idx), 0);
}

/* Initial programming of ring buffer */
static void had_init_ringbuf(struct snd_pcm_substream *substream,
                             struct snd_intelhad *intelhaddata)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        int i, num_periods;

        num_periods = runtime->periods;
        intelhaddata->num_bds = min(num_periods, HAD_NUM_OF_RING_BUFS);
        /* set the minimum 2 BDs for num_periods=1 */
        intelhaddata->num_bds = max(intelhaddata->num_bds, 2U);
        intelhaddata->period_bytes =
                frames_to_bytes(runtime, runtime->period_size);
        WARN_ON(intelhaddata->period_bytes & 0x3f);

        intelhaddata->bd_head = 0;
        intelhaddata->pcmbuf_head = 0;
        intelhaddata->pcmbuf_filled = 0;

        for (i = 0; i < HAD_NUM_OF_RING_BUFS; i++) {
                if (i < intelhaddata->num_bds)
                        had_prog_bd(substream, intelhaddata);
                else /* invalidate the rest */
                        had_invalidate_bd(intelhaddata, i);
        }

        intelhaddata->bd_head = 0; /* reset at head again before starting */
}

/* process a bd, advance to the next */
static void had_advance_ringbuf(struct snd_pcm_substream *substream,
                                struct snd_intelhad *intelhaddata)
{
        int num_periods = substream->runtime->periods;

        /* reprogram the next buffer */
        had_prog_bd(substream, intelhaddata);

        /* proceed to next */
        intelhaddata->pcmbuf_head++;
        intelhaddata->pcmbuf_head %= num_periods;
}

/* process the current BD(s);
 * returns the current PCM buffer byte position, or -EPIPE for underrun.
 */
static int had_process_ringbuf(struct snd_pcm_substream *substream,
                               struct snd_intelhad *intelhaddata)
{
        int len, processed;
        unsigned long flags;

        processed = 0;
        spin_lock_irqsave(&intelhaddata->had_spinlock, flags);
        for (;;) {
                /* get the remaining bytes on the buffer */
                had_read_register(intelhaddata,
                                  AUD_BUF_LEN(intelhaddata->bd_head),
                                  &len);
                if (len < 0 || len > intelhaddata->period_bytes) {
                        dev_dbg(intelhaddata->dev, "Invalid buf length %d\n",
                                len);
                        len = -EPIPE;
                        goto out;
                }

                if (len > 0) /* OK, this is the current buffer */
                        break;

                /* len=0 => already empty, check the next buffer */
                if (++processed >= intelhaddata->num_bds) {
                        len = -EPIPE; /* all empty? - report underrun */
                        goto out;
                }
                had_advance_ringbuf(substream, intelhaddata);
        }

        len = intelhaddata->period_bytes - len;
        len += intelhaddata->period_bytes * intelhaddata->pcmbuf_head;
 out:
        spin_unlock_irqrestore(&intelhaddata->had_spinlock, flags);
        return len;
}

/* called from irq handler */
static void had_process_buffer_done(struct snd_intelhad *intelhaddata)
{
        struct snd_pcm_substream *substream;

        substream = had_substream_get(intelhaddata);
        if (!substream)
                return; /* no stream? - bail out */

        if (!intelhaddata->connected) {
                snd_pcm_stop_xrun(substream);
                goto out; /* disconnected? - bail out */
        }

        /* process or stop the stream */
        if (had_process_ringbuf(substream, intelhaddata) < 0)
                snd_pcm_stop_xrun(substream);
        else
                snd_pcm_period_elapsed(substream);

 out:
        had_substream_put(intelhaddata);
}

/*
 * The interrupt status 'sticky' bits might not be cleared by
 * setting '1' to that bit once...
 */
static void wait_clear_underrun_bit(struct snd_intelhad *intelhaddata)
{
        int i;
        u32 val;

        for (i = 0; i < 100; i++) {
                /* clear bit30, 31 AUD_HDMI_STATUS */
                had_read_register(intelhaddata, AUD_HDMI_STATUS, &val);
                if (!(val & AUD_HDMI_STATUS_MASK_UNDERRUN))
                        return;
                udelay(100);
                cond_resched();
                had_write_register(intelhaddata, AUD_HDMI_STATUS, val);
        }
        dev_err(intelhaddata->dev, "Unable to clear UNDERRUN bits\n");
}

/* Perform some reset procedure but only when need_reset is set;
 * this is called from prepare or hw_free callbacks once after trigger STOP
 * or underrun has been processed in order to settle down the h/w state.
 */
static void had_do_reset(struct snd_intelhad *intelhaddata)
{
        if (!intelhaddata->need_reset || !intelhaddata->connected)
                return;

        /* Reset buffer pointers */
        had_reset_audio(intelhaddata);
        wait_clear_underrun_bit(intelhaddata);
        intelhaddata->need_reset = false;
}

/* called from irq handler */
static void had_process_buffer_underrun(struct snd_intelhad *intelhaddata)
{
        struct snd_pcm_substream *substream;

        /* Report UNDERRUN error to above layers */
        substream = had_substream_get(intelhaddata);
        if (substream) {
                snd_pcm_stop_xrun(substream);
                had_substream_put(intelhaddata);
        }
        intelhaddata->need_reset = true;
}

/*
 * ALSA PCM open callback
 */
static int had_pcm_open(struct snd_pcm_substream *substream)
{
        struct snd_intelhad *intelhaddata;
        struct snd_pcm_runtime *runtime;
        int retval;

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

        pm_runtime_get_sync(intelhaddata->dev);

        /* set the runtime hw parameter with local snd_pcm_hardware struct */
        runtime->hw = had_pcm_hardware;

        retval = snd_pcm_hw_constraint_integer(runtime,
                         SNDRV_PCM_HW_PARAM_PERIODS);
        if (retval < 0)
                goto error;

        /* Make sure, that the period size is always aligned
         * 64byte boundary
         */
        retval = snd_pcm_hw_constraint_step(substream->runtime, 0,
                        SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 64);
        if (retval < 0)
                goto error;

        retval = snd_pcm_hw_constraint_msbits(runtime, 0, 32, 24);
        if (retval < 0)
                goto error;

        /* expose PCM substream */
        spin_lock_irq(&intelhaddata->had_spinlock);
        intelhaddata->stream_info.substream = substream;
        intelhaddata->stream_info.substream_refcount++;
        spin_unlock_irq(&intelhaddata->had_spinlock);

        return retval;
 error:
        pm_runtime_mark_last_busy(intelhaddata->dev);
        pm_runtime_put_autosuspend(intelhaddata->dev);
        return retval;
}

/*
 * ALSA PCM close callback
 */
static int had_pcm_close(struct snd_pcm_substream *substream)
{
        struct snd_intelhad *intelhaddata;

        intelhaddata = snd_pcm_substream_chip(substream);

        /* unreference and sync with the pending PCM accesses */
        spin_lock_irq(&intelhaddata->had_spinlock);
        intelhaddata->stream_info.substream = NULL;
        intelhaddata->stream_info.substream_refcount--;
        while (intelhaddata->stream_info.substream_refcount > 0) {
                spin_unlock_irq(&intelhaddata->had_spinlock);
                cpu_relax();
                spin_lock_irq(&intelhaddata->had_spinlock);
        }
        spin_unlock_irq(&intelhaddata->had_spinlock);

        pm_runtime_mark_last_busy(intelhaddata->dev);
        pm_runtime_put_autosuspend(intelhaddata->dev);
        return 0;
}

/*
 * ALSA PCM hw_params callback
 */
static int had_pcm_hw_params(struct snd_pcm_substream *substream,
                             struct snd_pcm_hw_params *hw_params)
{
        struct snd_intelhad *intelhaddata;
        unsigned long addr;
        int pages, buf_size, retval;

        intelhaddata = snd_pcm_substream_chip(substream);
        buf_size = params_buffer_bytes(hw_params);
        retval = snd_pcm_lib_malloc_pages(substream, buf_size);
        if (retval < 0)
                return retval;
        dev_dbg(intelhaddata->dev, "%s:allocated memory = %d\n",
                __func__, buf_size);
        /* mark the pages as uncached region */
        addr = (unsigned long) substream->runtime->dma_area;
        pages = (substream->runtime->dma_bytes + PAGE_SIZE - 1) / PAGE_SIZE;
        retval = set_memory_uc(addr, pages);
        if (retval) {
                dev_err(intelhaddata->dev, "set_memory_uc failed.Error:%d\n",
                        retval);
                return retval;
        }
        memset(substream->runtime->dma_area, 0, buf_size);

        return retval;
}

/*
 * ALSA PCM hw_free callback
 */
static int had_pcm_hw_free(struct snd_pcm_substream *substream)
{
        struct snd_intelhad *intelhaddata;
        unsigned long addr;
        u32 pages;

        intelhaddata = snd_pcm_substream_chip(substream);
        had_do_reset(intelhaddata);

        /* mark back the pages as cached/writeback region before the free */
        if (substream->runtime->dma_area != NULL) {
                addr = (unsigned long) substream->runtime->dma_area;
                pages = (substream->runtime->dma_bytes + PAGE_SIZE - 1) /
                                                                PAGE_SIZE;
                set_memory_wb(addr, pages);
                return snd_pcm_lib_free_pages(substream);
        }
        return 0;
}

/*
 * ALSA PCM trigger callback
 */
static int had_pcm_trigger(struct snd_pcm_substream *substream, int cmd)
{
        int retval = 0;
        struct snd_intelhad *intelhaddata;

        intelhaddata = snd_pcm_substream_chip(substream);

        spin_lock(&intelhaddata->had_spinlock);
        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
        case SNDRV_PCM_TRIGGER_RESUME:
                /* Enable Audio */
                had_ack_irqs(intelhaddata); /* FIXME: do we need this? */
                had_enable_audio(intelhaddata, true);
                break;

        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                /* Disable Audio */
                had_enable_audio(intelhaddata, false);
                intelhaddata->need_reset = true;
                break;

        default:
                retval = -EINVAL;
        }
        spin_unlock(&intelhaddata->had_spinlock);
        return retval;
}

/*
 * ALSA PCM prepare callback
 */
static int had_pcm_prepare(struct snd_pcm_substream *substream)
{
        int retval;
        u32 disp_samp_freq, n_param;
        u32 link_rate = 0;
        struct snd_intelhad *intelhaddata;
        struct snd_pcm_runtime *runtime;

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

        dev_dbg(intelhaddata->dev, "period_size=%d\n",
                (int)frames_to_bytes(runtime, runtime->period_size));
        dev_dbg(intelhaddata->dev, "periods=%d\n", runtime->periods);
        dev_dbg(intelhaddata->dev, "buffer_size=%d\n",
                (int)snd_pcm_lib_buffer_bytes(substream));
        dev_dbg(intelhaddata->dev, "rate=%d\n", runtime->rate);
        dev_dbg(intelhaddata->dev, "channels=%d\n", runtime->channels);

        had_do_reset(intelhaddata);

        /* Get N value in KHz */
        disp_samp_freq = intelhaddata->tmds_clock_speed;

        retval = had_prog_n(substream->runtime->rate, &n_param, intelhaddata);
        if (retval) {
                dev_err(intelhaddata->dev,
                        "programming N value failed %#x\n", retval);
                goto prep_end;
        }

        if (intelhaddata->dp_output)
                link_rate = intelhaddata->link_rate;

        had_prog_cts(substream->runtime->rate, disp_samp_freq, link_rate,
                     n_param, intelhaddata);

        had_prog_dip(substream, intelhaddata);

        retval = had_init_audio_ctrl(substream, intelhaddata);

        /* Prog buffer address */
        had_init_ringbuf(substream, intelhaddata);

        /*
         * Program channel mapping in following order:
         * FL, FR, C, LFE, RL, RR
         */

        had_write_register(intelhaddata, AUD_BUF_CH_SWAP, SWAP_LFE_CENTER);

prep_end:
        return retval;
}

/*
 * ALSA PCM pointer callback
 */
static snd_pcm_uframes_t had_pcm_pointer(struct snd_pcm_substream *substream)
{
        struct snd_intelhad *intelhaddata;
        int len;

        intelhaddata = snd_pcm_substream_chip(substream);

        if (!intelhaddata->connected)
                return SNDRV_PCM_POS_XRUN;

        len = had_process_ringbuf(substream, intelhaddata);
        if (len < 0)
                return SNDRV_PCM_POS_XRUN;
        len = bytes_to_frames(substream->runtime, len);
        /* wrapping may happen when periods=1 */
        len %= substream->runtime->buffer_size;
        return len;
}

/*
 * ALSA PCM mmap callback
 */
static int had_pcm_mmap(struct snd_pcm_substream *substream,
                        struct vm_area_struct *vma)
{
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
        return remap_pfn_range(vma, vma->vm_start,
                        substream->dma_buffer.addr >> PAGE_SHIFT,
                        vma->vm_end - vma->vm_start, vma->vm_page_prot);
}

/*
 * ALSA PCM ops
 */
static const struct snd_pcm_ops had_pcm_ops = {
        .open =         had_pcm_open,
        .close =        had_pcm_close,
        .ioctl =        snd_pcm_lib_ioctl,
        .hw_params =    had_pcm_hw_params,
        .hw_free =      had_pcm_hw_free,
        .prepare =      had_pcm_prepare,
        .trigger =      had_pcm_trigger,
        .pointer =      had_pcm_pointer,
        .mmap =         had_pcm_mmap,
};

/* process mode change of the running stream; called in mutex */
static int had_process_mode_change(struct snd_intelhad *intelhaddata)
{
        struct snd_pcm_substream *substream;
        int retval = 0;
        u32 disp_samp_freq, n_param;
        u32 link_rate = 0;

        substream = had_substream_get(intelhaddata);
        if (!substream)
                return 0;

        /* Disable Audio */
        had_enable_audio(intelhaddata, false);

        /* Update CTS value */
        disp_samp_freq = intelhaddata->tmds_clock_speed;

        retval = had_prog_n(substream->runtime->rate, &n_param, intelhaddata);
        if (retval) {
                dev_err(intelhaddata->dev,
                        "programming N value failed %#x\n", retval);
                goto out;
        }

        if (intelhaddata->dp_output)
                link_rate = intelhaddata->link_rate;

        had_prog_cts(substream->runtime->rate, disp_samp_freq, link_rate,
                     n_param, intelhaddata);

        /* Enable Audio */
        had_enable_audio(intelhaddata, true);

out:
        had_substream_put(intelhaddata);
        return retval;
}

/* process hot plug, called from wq with mutex locked */
static void had_process_hot_plug(struct snd_intelhad *intelhaddata)
{
        struct snd_pcm_substream *substream;

        spin_lock_irq(&intelhaddata->had_spinlock);
        if (intelhaddata->connected) {
                dev_dbg(intelhaddata->dev, "Device already connected\n");
                spin_unlock_irq(&intelhaddata->had_spinlock);
                return;
        }

        intelhaddata->connected = true;
        dev_dbg(intelhaddata->dev,
                "%s @ %d:DEBUG PLUG/UNPLUG : HAD_DRV_CONNECTED\n",
                        __func__, __LINE__);
        spin_unlock_irq(&intelhaddata->had_spinlock);

        had_build_channel_allocation_map(intelhaddata);

        /* Report to above ALSA layer */
        substream = had_substream_get(intelhaddata);
        if (substream) {
                snd_pcm_stop_xrun(substream);
                had_substream_put(intelhaddata);
        }

        snd_jack_report(intelhaddata->jack, SND_JACK_AVOUT);
}

/* process hot unplug, called from wq with mutex locked */
static void had_process_hot_unplug(struct snd_intelhad *intelhaddata)
{
        struct snd_pcm_substream *substream;

        spin_lock_irq(&intelhaddata->had_spinlock);
        if (!intelhaddata->connected) {
                dev_dbg(intelhaddata->dev, "Device already disconnected\n");
                spin_unlock_irq(&intelhaddata->had_spinlock);
                return;

        }

        /* Disable Audio */
        had_enable_audio(intelhaddata, false);

        intelhaddata->connected = false;
        dev_dbg(intelhaddata->dev,
                "%s @ %d:DEBUG PLUG/UNPLUG : HAD_DRV_DISCONNECTED\n",
                        __func__, __LINE__);
        spin_unlock_irq(&intelhaddata->had_spinlock);

        kfree(intelhaddata->chmap->chmap);
        intelhaddata->chmap->chmap = NULL;

        /* Report to above ALSA layer */
        substream = had_substream_get(intelhaddata);
        if (substream) {
                snd_pcm_stop_xrun(substream);
                had_substream_put(intelhaddata);
        }

        snd_jack_report(intelhaddata->jack, 0);
}

/*
 * ALSA iec958 and ELD controls
 */

static int had_iec958_info(struct snd_kcontrol *kcontrol,
                                struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_IEC958;
        uinfo->count = 1;
        return 0;
}

static int had_iec958_get(struct snd_kcontrol *kcontrol,
                                struct snd_ctl_elem_value *ucontrol)
{
        struct snd_intelhad *intelhaddata = snd_kcontrol_chip(kcontrol);

        mutex_lock(&intelhaddata->mutex);
        ucontrol->value.iec958.status[0] = (intelhaddata->aes_bits >> 0) & 0xff;
        ucontrol->value.iec958.status[1] = (intelhaddata->aes_bits >> 8) & 0xff;
        ucontrol->value.iec958.status[2] =
                                        (intelhaddata->aes_bits >> 16) & 0xff;
        ucontrol->value.iec958.status[3] =
                                        (intelhaddata->aes_bits >> 24) & 0xff;
        mutex_unlock(&intelhaddata->mutex);
        return 0;
}

static int had_iec958_mask_get(struct snd_kcontrol *kcontrol,
                                struct snd_ctl_elem_value *ucontrol)
{
        ucontrol->value.iec958.status[0] = 0xff;
        ucontrol->value.iec958.status[1] = 0xff;
        ucontrol->value.iec958.status[2] = 0xff;
        ucontrol->value.iec958.status[3] = 0xff;
        return 0;
}

static int had_iec958_put(struct snd_kcontrol *kcontrol,
                                struct snd_ctl_elem_value *ucontrol)
{
        unsigned int val;
        struct snd_intelhad *intelhaddata = snd_kcontrol_chip(kcontrol);
        int changed = 0;

        val = (ucontrol->value.iec958.status[0] << 0) |
                (ucontrol->value.iec958.status[1] << 8) |
                (ucontrol->value.iec958.status[2] << 16) |
                (ucontrol->value.iec958.status[3] << 24);
        mutex_lock(&intelhaddata->mutex);
        if (intelhaddata->aes_bits != val) {
                intelhaddata->aes_bits = val;
                changed = 1;
        }
        mutex_unlock(&intelhaddata->mutex);
        return changed;
}

static int had_ctl_eld_info(struct snd_kcontrol *kcontrol,
                            struct snd_ctl_elem_info *uinfo)
{
        uinfo->type = SNDRV_CTL_ELEM_TYPE_BYTES;
        uinfo->count = HDMI_MAX_ELD_BYTES;
        return 0;
}

static int had_ctl_eld_get(struct snd_kcontrol *kcontrol,
                           struct snd_ctl_elem_value *ucontrol)
{
        struct snd_intelhad *intelhaddata = snd_kcontrol_chip(kcontrol);

        mutex_lock(&intelhaddata->mutex);
        memcpy(ucontrol->value.bytes.data, intelhaddata->eld,
               HDMI_MAX_ELD_BYTES);
        mutex_unlock(&intelhaddata->mutex);
        return 0;
}

static const struct snd_kcontrol_new had_controls[] = {
        {
                .access = SNDRV_CTL_ELEM_ACCESS_READ,
                .iface = SNDRV_CTL_ELEM_IFACE_PCM,
                .name = SNDRV_CTL_NAME_IEC958("", PLAYBACK, MASK),
                .info = had_iec958_info, /* shared */
                .get = had_iec958_mask_get,
        },
        {
                .iface = SNDRV_CTL_ELEM_IFACE_PCM,
                .name = SNDRV_CTL_NAME_IEC958("", PLAYBACK, DEFAULT),
                .info = had_iec958_info,
                .get = had_iec958_get,
                .put = had_iec958_put,
        },
        {
                .access = (SNDRV_CTL_ELEM_ACCESS_READ |
                           SNDRV_CTL_ELEM_ACCESS_VOLATILE),
                .iface = SNDRV_CTL_ELEM_IFACE_PCM,
                .name = "ELD",
                .info = had_ctl_eld_info,
                .get = had_ctl_eld_get,
        },
};

/*
 * audio interrupt handler
 */
static irqreturn_t display_pipe_interrupt_handler(int irq, void *dev_id)
{
        struct snd_intelhad *ctx = dev_id;
        u32 audio_stat;

        /* use raw register access to ack IRQs even while disconnected */
        audio_stat = had_read_register_raw(ctx, AUD_HDMI_STATUS);

        if (audio_stat & HDMI_AUDIO_UNDERRUN) {
                had_write_register_raw(ctx, AUD_HDMI_STATUS,
                                       HDMI_AUDIO_UNDERRUN);
                had_process_buffer_underrun(ctx);
        }

        if (audio_stat & HDMI_AUDIO_BUFFER_DONE) {
                had_write_register_raw(ctx, AUD_HDMI_STATUS,
                                       HDMI_AUDIO_BUFFER_DONE);
                had_process_buffer_done(ctx);
        }

        return IRQ_HANDLED;
}

/*
 * monitor plug/unplug notification from i915; just kick off the work
 */
static void notify_audio_lpe(struct platform_device *pdev)
{
        struct snd_intelhad *ctx = platform_get_drvdata(pdev);

        schedule_work(&ctx->hdmi_audio_wq);
}

/* the work to handle monitor hot plug/unplug */
static void had_audio_wq(struct work_struct *work)
{
        struct snd_intelhad *ctx =
                container_of(work, struct snd_intelhad, hdmi_audio_wq);
        struct intel_hdmi_lpe_audio_pdata *pdata = ctx->dev->platform_data;

        pm_runtime_get_sync(ctx->dev);
        mutex_lock(&ctx->mutex);
        if (!pdata->hdmi_connected) {
                dev_dbg(ctx->dev, "%s: Event: HAD_NOTIFY_HOT_UNPLUG\n",
                        __func__);
                memset(ctx->eld, 0, sizeof(ctx->eld)); /* clear the old ELD */
                had_process_hot_unplug(ctx);
        } else {
                struct intel_hdmi_lpe_audio_eld *eld = &pdata->eld;

                dev_dbg(ctx->dev, "%s: HAD_NOTIFY_ELD : port = %d, tmds = %d\n",
                        __func__, eld->port_id, pdata->tmds_clock_speed);

                switch (eld->pipe_id) {
                case 0:
                        ctx->had_config_offset = AUDIO_HDMI_CONFIG_A;
                        break;
                case 1:
                        ctx->had_config_offset = AUDIO_HDMI_CONFIG_B;
                        break;
                case 2:
                        ctx->had_config_offset = AUDIO_HDMI_CONFIG_C;
                        break;
                default:
                        dev_dbg(ctx->dev, "Invalid pipe %d\n",
                                eld->pipe_id);
                        break;
                }

                memcpy(ctx->eld, eld->eld_data, sizeof(ctx->eld));

                ctx->dp_output = pdata->dp_output;
                ctx->tmds_clock_speed = pdata->tmds_clock_speed;
                ctx->link_rate = pdata->link_rate;

                had_process_hot_plug(ctx);

                /* Process mode change if stream is active */
                had_process_mode_change(ctx);
        }
        mutex_unlock(&ctx->mutex);
        pm_runtime_mark_last_busy(ctx->dev);
        pm_runtime_put_autosuspend(ctx->dev);
}

/*
 * Jack interface
 */
static int had_create_jack(struct snd_intelhad *ctx)
{
        int err;

        err = snd_jack_new(ctx->card, "HDMI/DP", SND_JACK_AVOUT, &ctx->jack,
                           true, false);
        if (err < 0)
                return err;
        ctx->jack->private_data = ctx;
        return 0;
}

/*
 * PM callbacks
 */

static int hdmi_lpe_audio_runtime_suspend(struct device *dev)
{
        struct snd_intelhad *ctx = dev_get_drvdata(dev);
        struct snd_pcm_substream *substream;

        substream = had_substream_get(ctx);
        if (substream) {
                snd_pcm_suspend(substream);
                had_substream_put(ctx);
        }

        return 0;
}

static int __maybe_unused hdmi_lpe_audio_suspend(struct device *dev)
{
        struct snd_intelhad *ctx = dev_get_drvdata(dev);
        int err;

        err = hdmi_lpe_audio_runtime_suspend(dev);
        if (!err)
                snd_power_change_state(ctx->card, SNDRV_CTL_POWER_D3hot);
        return err;
}

static int hdmi_lpe_audio_runtime_resume(struct device *dev)
{
        pm_runtime_mark_last_busy(dev);
        return 0;
}

static int __maybe_unused hdmi_lpe_audio_resume(struct device *dev)
{
        struct snd_intelhad *ctx = dev_get_drvdata(dev);

        hdmi_lpe_audio_runtime_resume(dev);
        snd_power_change_state(ctx->card, SNDRV_CTL_POWER_D0);
        return 0;
}

/* release resources */
static void hdmi_lpe_audio_free(struct snd_card *card)
{
        struct snd_intelhad *ctx = card->private_data;

        cancel_work_sync(&ctx->hdmi_audio_wq);

        if (ctx->mmio_start)
                iounmap(ctx->mmio_start);
        if (ctx->irq >= 0)
                free_irq(ctx->irq, ctx);
}

/*
 * hdmi_lpe_audio_probe - start bridge with i915
 *
 * This function is called when the i915 driver creates the
 * hdmi-lpe-audio platform device.
 */
static int hdmi_lpe_audio_probe(struct platform_device *pdev)
{
        struct snd_card *card;
        struct snd_intelhad *ctx;
        struct snd_pcm *pcm;
        struct intel_hdmi_lpe_audio_pdata *pdata;
        int irq;
        struct resource *res_mmio;
        int i, ret;

        pdata = pdev->dev.platform_data;
        if (!pdata) {
                dev_err(&pdev->dev, "%s: quit: pdata not allocated by i915!!\n", __func__);
                return -EINVAL;
        }

        /* get resources */
        irq = platform_get_irq(pdev, 0);
        if (irq < 0) {
                dev_err(&pdev->dev, "Could not get irq resource\n");
                return -ENODEV;
        }

        res_mmio = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        if (!res_mmio) {
                dev_err(&pdev->dev, "Could not get IO_MEM resources\n");
                return -ENXIO;
        }

        /* create a card instance with ALSA framework */
        ret = snd_card_new(&pdev->dev, hdmi_card_index, hdmi_card_id,
                           THIS_MODULE, sizeof(*ctx), &card);
        if (ret)
                return ret;

        ctx = card->private_data;
        spin_lock_init(&ctx->had_spinlock);
        mutex_init(&ctx->mutex);
        ctx->connected = false;
        ctx->dev = &pdev->dev;
        ctx->card = card;
        ctx->aes_bits = SNDRV_PCM_DEFAULT_CON_SPDIF;
        strcpy(card->driver, INTEL_HAD);
        strcpy(card->shortname, "Intel HDMI/DP LPE Audio");
        strcpy(card->longname, "Intel HDMI/DP LPE Audio");

        ctx->irq = -1;
        ctx->tmds_clock_speed = DIS_SAMPLE_RATE_148_5;
        INIT_WORK(&ctx->hdmi_audio_wq, had_audio_wq);

        card->private_free = hdmi_lpe_audio_free;

        /* assume pipe A as default */
        ctx->had_config_offset = AUDIO_HDMI_CONFIG_A;

        platform_set_drvdata(pdev, ctx);

        dev_dbg(&pdev->dev, "%s: mmio_start = 0x%x, mmio_end = 0x%x\n",
                __func__, (unsigned int)res_mmio->start,
                (unsigned int)res_mmio->end);

        ctx->mmio_start = ioremap_nocache(res_mmio->start,
                                          (size_t)(resource_size(res_mmio)));
        if (!ctx->mmio_start) {
                dev_err(&pdev->dev, "Could not get ioremap\n");
                ret = -EACCES;
                goto err;
        }

        /* setup interrupt handler */
        ret = request_irq(irq, display_pipe_interrupt_handler, 0,
                          pdev->name, ctx);
        if (ret < 0) {
                dev_err(&pdev->dev, "request_irq failed\n");
                goto err;
        }

        ctx->irq = irq;

        ret = snd_pcm_new(card, INTEL_HAD, PCM_INDEX, MAX_PB_STREAMS,
                          MAX_CAP_STREAMS, &pcm);
        if (ret)
                goto err;

        /* setup private data which can be retrieved when required */
        pcm->private_data = ctx;
        pcm->info_flags = 0;
        strncpy(pcm->name, card->shortname, strlen(card->shortname));
        /* setup the ops for playabck */
        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_PLAYBACK, &had_pcm_ops);

        /* only 32bit addressable */
        dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));
        dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));

        /* allocate dma pages;
         * try to allocate 600k buffer as default which is large enough
         */
        snd_pcm_lib_preallocate_pages_for_all(pcm,
                        SNDRV_DMA_TYPE_DEV, NULL,
                        HAD_DEFAULT_BUFFER, HAD_MAX_BUFFER);

        /* create controls */
        for (i = 0; i < ARRAY_SIZE(had_controls); i++) {
                ret = snd_ctl_add(card, snd_ctl_new1(&had_controls[i], ctx));
                if (ret < 0)
                        goto err;
        }

        init_channel_allocations();

        /* Register channel map controls */
        ret = had_register_chmap_ctls(ctx, pcm);
        if (ret < 0)
                goto err;

        ret = had_create_jack(ctx);
        if (ret < 0)
                goto err;

        ret = snd_card_register(card);
        if (ret)
                goto err;

        spin_lock_irq(&pdata->lpe_audio_slock);
        pdata->notify_audio_lpe = notify_audio_lpe;
        pdata->notify_pending = false;
        spin_unlock_irq(&pdata->lpe_audio_slock);

        /* runtime PM isn't enabled as default, since it won't save much on
         * BYT/CHT devices; user who want the runtime PM should adjust the
         * power/ontrol and power/autosuspend_delay_ms sysfs entries instead
         */
        pm_runtime_use_autosuspend(&pdev->dev);
        pm_runtime_mark_last_busy(&pdev->dev);
        pm_runtime_set_active(&pdev->dev);

        dev_dbg(&pdev->dev, "%s: handle pending notification\n", __func__);
        schedule_work(&ctx->hdmi_audio_wq);

        return 0;

err:
        snd_card_free(card);
        return ret;
}

/*
 * hdmi_lpe_audio_remove - stop bridge with i915
 *
 * This function is called when the platform device is destroyed.
 */
static int hdmi_lpe_audio_remove(struct platform_device *pdev)
{
        struct snd_intelhad *ctx = platform_get_drvdata(pdev);

        snd_card_free(ctx->card);
        return 0;
}

static const struct dev_pm_ops hdmi_lpe_audio_pm = {
        SET_SYSTEM_SLEEP_PM_OPS(hdmi_lpe_audio_suspend, hdmi_lpe_audio_resume)
        SET_RUNTIME_PM_OPS(hdmi_lpe_audio_runtime_suspend,
                           hdmi_lpe_audio_runtime_resume, NULL)
};

static struct platform_driver hdmi_lpe_audio_driver = {
        .driver         = {
                .name  = "hdmi-lpe-audio",
                .pm = &hdmi_lpe_audio_pm,
        },
        .probe          = hdmi_lpe_audio_probe,
        .remove         = hdmi_lpe_audio_remove,
};

module_platform_driver(hdmi_lpe_audio_driver);
MODULE_ALIAS("platform:hdmi_lpe_audio");

MODULE_AUTHOR("Sailaja Bandarupalli <sailaja.bandarupalli@intel.com>");
MODULE_AUTHOR("Ramesh Babu K V <ramesh.babu@intel.com>");
MODULE_AUTHOR("Vaibhav Agarwal <vaibhav.agarwal@intel.com>");
MODULE_AUTHOR("Jerome Anand <jerome.anand@intel.com>");
MODULE_DESCRIPTION("Intel HDMI Audio driver");
MODULE_LICENSE("GPL v2");
MODULE_SUPPORTED_DEVICE("{Intel,Intel_HAD}");