// SPDX-License-Identifier: GPL-2.0
//
// Renesas R-Car SSIU/SSI support
//
// Copyright (C) 2013 Renesas Solutions Corp.
// Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
//
// Based on fsi.c
// Kuninori Morimoto <morimoto.kuninori@renesas.com>

/*
 * you can enable below define if you don't need
 * SSI interrupt status debug message when debugging
 * see rsnd_dbg_irq_status()
 *
 * #define RSND_DEBUG_NO_IRQ_STATUS 1
 */

#include <sound/simple_card_utils.h>
#include <linux/delay.h>
#include "rsnd.h"
#define RSND_SSI_NAME_SIZE 16

/*
 * SSICR
 */
#define FORCE           (1 << 31)       /* Fixed */
#define DMEN            (1 << 28)       /* DMA Enable */
#define UIEN            (1 << 27)       /* Underflow Interrupt Enable */
#define OIEN            (1 << 26)       /* Overflow Interrupt Enable */
#define IIEN            (1 << 25)       /* Idle Mode Interrupt Enable */
#define DIEN            (1 << 24)       /* Data Interrupt Enable */
#define CHNL_4          (1 << 22)       /* Channels */
#define CHNL_6          (2 << 22)       /* Channels */
#define CHNL_8          (3 << 22)       /* Channels */
#define DWL_MASK        (7 << 19)       /* Data Word Length mask */
#define DWL_8           (0 << 19)       /* Data Word Length */
#define DWL_16          (1 << 19)       /* Data Word Length */
#define DWL_18          (2 << 19)       /* Data Word Length */
#define DWL_20          (3 << 19)       /* Data Word Length */
#define DWL_22          (4 << 19)       /* Data Word Length */
#define DWL_24          (5 << 19)       /* Data Word Length */
#define DWL_32          (6 << 19)       /* Data Word Length */

#define SWL_32          (3 << 16)       /* R/W System Word Length */
#define SCKD            (1 << 15)       /* Serial Bit Clock Direction */
#define SWSD            (1 << 14)       /* Serial WS Direction */
#define SCKP            (1 << 13)       /* Serial Bit Clock Polarity */
#define SWSP            (1 << 12)       /* Serial WS Polarity */
#define SDTA            (1 << 10)       /* Serial Data Alignment */
#define PDTA            (1 <<  9)       /* Parallel Data Alignment */
#define DEL             (1 <<  8)       /* Serial Data Delay */
#define CKDV(v)         (v <<  4)       /* Serial Clock Division Ratio */
#define TRMD            (1 <<  1)       /* Transmit/Receive Mode Select */
#define EN              (1 <<  0)       /* SSI Module Enable */

/*
 * SSISR
 */
#define UIRQ            (1 << 27)       /* Underflow Error Interrupt Status */
#define OIRQ            (1 << 26)       /* Overflow Error Interrupt Status */
#define IIRQ            (1 << 25)       /* Idle Mode Interrupt Status */
#define DIRQ            (1 << 24)       /* Data Interrupt Status Flag */

/*
 * SSIWSR
 */
#define CONT            (1 << 8)        /* WS Continue Function */
#define WS_MODE         (1 << 0)        /* WS Mode */

#define SSI_NAME "ssi"

struct rsnd_ssi {
        struct rsnd_mod mod;
        struct rsnd_mod *dma;

        u32 flags;
        u32 cr_own;
        u32 cr_clk;
        u32 cr_mode;
        u32 cr_en;
        u32 wsr;
        int chan;
        int rate;
        int irq;
        unsigned int usrcnt;

        /* for PIO */
        int byte_pos;
        int byte_per_period;
        int next_period_byte;
};

/* flags */
#define RSND_SSI_CLK_PIN_SHARE          (1 << 0)
#define RSND_SSI_NO_BUSIF               (1 << 1) /* SSI+DMA without BUSIF */
#define RSND_SSI_HDMI0                  (1 << 2) /* for HDMI0 */
#define RSND_SSI_HDMI1                  (1 << 3) /* for HDMI1 */
#define RSND_SSI_PROBED                 (1 << 4)

#define for_each_rsnd_ssi(pos, priv, i)                                 \
        for (i = 0;                                                     \
             (i < rsnd_ssi_nr(priv)) &&                                 \
                ((pos) = ((struct rsnd_ssi *)(priv)->ssi + i));         \
             i++)

#define rsnd_ssi_get(priv, id) ((struct rsnd_ssi *)(priv->ssi) + id)
#define rsnd_ssi_nr(priv) ((priv)->ssi_nr)
#define rsnd_mod_to_ssi(_mod) container_of((_mod), struct rsnd_ssi, mod)
#define rsnd_ssi_is_parent(ssi, io) ((ssi) == rsnd_io_to_mod_ssip(io))
#define rsnd_ssi_is_multi_slave(mod, io) \
        (rsnd_ssi_multi_slaves(io) & (1 << rsnd_mod_id(mod)))
#define rsnd_ssi_is_run_mods(mod, io) \
        (rsnd_ssi_run_mods(io) & (1 << rsnd_mod_id(mod)))
#define rsnd_ssi_can_output_clk(mod) (!__rsnd_ssi_is_pin_sharing(mod))

int rsnd_ssi_hdmi_port(struct rsnd_dai_stream *io)
{
        struct rsnd_mod *mod = rsnd_io_to_mod_ssi(io);
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);

        if (rsnd_flags_has(ssi, RSND_SSI_HDMI0))
                return RSND_SSI_HDMI_PORT0;

        if (rsnd_flags_has(ssi, RSND_SSI_HDMI1))
                return RSND_SSI_HDMI_PORT1;

        return 0;
}

int rsnd_ssi_use_busif(struct rsnd_dai_stream *io)
{
        struct rsnd_mod *mod = rsnd_io_to_mod_ssi(io);
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
        int use_busif = 0;

        if (!rsnd_ssi_is_dma_mode(mod))
                return 0;

        if (!(rsnd_flags_has(ssi, RSND_SSI_NO_BUSIF)))
                use_busif = 1;
        if (rsnd_io_to_mod_src(io))
                use_busif = 1;

        return use_busif;
}

static void rsnd_ssi_status_clear(struct rsnd_mod *mod)
{
        rsnd_mod_write(mod, SSISR, 0);
}

static u32 rsnd_ssi_status_get(struct rsnd_mod *mod)
{
        return rsnd_mod_read(mod, SSISR);
}

static void rsnd_ssi_status_check(struct rsnd_mod *mod,
                                  u32 bit)
{
        struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
        struct device *dev = rsnd_priv_to_dev(priv);
        u32 status;
        int i;

        for (i = 0; i < 1024; i++) {
                status = rsnd_ssi_status_get(mod);
                if (status & bit)
                        return;

                udelay(5);
        }

        dev_warn(dev, "%s[%d] status check failed\n",
                 rsnd_mod_name(mod), rsnd_mod_id(mod));
}

static u32 rsnd_ssi_multi_slaves(struct rsnd_dai_stream *io)
{
        struct rsnd_mod *mod;
        enum rsnd_mod_type types[] = {
                RSND_MOD_SSIM1,
                RSND_MOD_SSIM2,
                RSND_MOD_SSIM3,
        };
        int i, mask;

        mask = 0;
        for (i = 0; i < ARRAY_SIZE(types); i++) {
                mod = rsnd_io_to_mod(io, types[i]);
                if (!mod)
                        continue;

                mask |= 1 << rsnd_mod_id(mod);
        }

        return mask;
}

static u32 rsnd_ssi_run_mods(struct rsnd_dai_stream *io)
{
        struct rsnd_mod *ssi_mod = rsnd_io_to_mod_ssi(io);
        struct rsnd_mod *ssi_parent_mod = rsnd_io_to_mod_ssip(io);
        u32 mods;

        mods = rsnd_ssi_multi_slaves_runtime(io) |
                1 << rsnd_mod_id(ssi_mod);

        if (ssi_parent_mod)
                mods |= 1 << rsnd_mod_id(ssi_parent_mod);

        return mods;
}

u32 rsnd_ssi_multi_slaves_runtime(struct rsnd_dai_stream *io)
{
        if (rsnd_runtime_is_ssi_multi(io))
                return rsnd_ssi_multi_slaves(io);

        return 0;
}

unsigned int rsnd_ssi_clk_query(struct rsnd_priv *priv,
                       int param1, int param2, int *idx)
{
        int ssi_clk_mul_table[] = {
                1, 2, 4, 8, 16, 6, 12,
        };
        int j, ret;
        unsigned int main_rate;

        for (j = 0; j < ARRAY_SIZE(ssi_clk_mul_table); j++) {

                /*
                 * It will set SSIWSR.CONT here, but SSICR.CKDV = 000
                 * with it is not allowed. (SSIWSR.WS_MODE with
                 * SSICR.CKDV = 000 is not allowed either).
                 * Skip it. See SSICR.CKDV
                 */
                if (j == 0)
                        continue;

                /*
                 * this driver is assuming that
                 * system word is 32bit x chan
                 * see rsnd_ssi_init()
                 */
                main_rate = 32 * param1 * param2 * ssi_clk_mul_table[j];

                ret = rsnd_adg_clk_query(priv, main_rate);
                if (ret < 0)
                        continue;

                if (idx)
                        *idx = j;

                return main_rate;
        }

        return 0;
}

static int rsnd_ssi_master_clk_start(struct rsnd_mod *mod,
                                     struct rsnd_dai_stream *io)
{
        struct rsnd_priv *priv = rsnd_io_to_priv(io);
        struct device *dev = rsnd_priv_to_dev(priv);
        struct rsnd_dai *rdai = rsnd_io_to_rdai(io);
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
        int chan = rsnd_runtime_channel_for_ssi(io);
        int idx, ret;
        unsigned int main_rate;
        unsigned int rate = rsnd_io_is_play(io) ?
                rsnd_src_get_out_rate(priv, io) :
                rsnd_src_get_in_rate(priv, io);

        if (!rsnd_rdai_is_clk_master(rdai))
                return 0;

        if (!rsnd_ssi_can_output_clk(mod))
                return 0;

        if (rsnd_ssi_is_multi_slave(mod, io))
                return 0;

        if (ssi->rate) {
                if (ssi->rate != rate) {
                        dev_err(dev, "SSI parent/child should use same rate\n");
                        return -EINVAL;
                }

                return 0;
        }

        main_rate = rsnd_ssi_clk_query(priv, rate, chan, &idx);
        if (!main_rate) {
                dev_err(dev, "unsupported clock rate\n");
                return -EIO;
        }

        ret = rsnd_adg_ssi_clk_try_start(mod, main_rate);
        if (ret < 0)
                return ret;

        /*
         * SSI clock will be output contiguously
         * by below settings.
         * This means, rsnd_ssi_master_clk_start()
         * and rsnd_ssi_register_setup() are necessary
         * for SSI parent
         *
         * SSICR  : FORCE, SCKD, SWSD
         * SSIWSR : CONT
         */
        ssi->cr_clk = FORCE | SWL_32 | SCKD | SWSD | CKDV(idx);
        ssi->wsr = CONT;
        ssi->rate = rate;

        dev_dbg(dev, "%s[%d] outputs %u Hz\n",
                rsnd_mod_name(mod),
                rsnd_mod_id(mod), rate);

        return 0;
}

static void rsnd_ssi_master_clk_stop(struct rsnd_mod *mod,
                                     struct rsnd_dai_stream *io)
{
        struct rsnd_dai *rdai = rsnd_io_to_rdai(io);
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);

        if (!rsnd_rdai_is_clk_master(rdai))
                return;

        if (!rsnd_ssi_can_output_clk(mod))
                return;

        if (ssi->usrcnt > 1)
                return;

        ssi->cr_clk     = 0;
        ssi->rate       = 0;

        rsnd_adg_ssi_clk_stop(mod);
}

static void rsnd_ssi_config_init(struct rsnd_mod *mod,
                                struct rsnd_dai_stream *io)
{
        struct rsnd_dai *rdai = rsnd_io_to_rdai(io);
        struct snd_pcm_runtime *runtime = rsnd_io_to_runtime(io);
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
        u32 cr_own      = ssi->cr_own;
        u32 cr_mode     = ssi->cr_mode;
        u32 wsr         = ssi->wsr;
        int is_tdm;

        is_tdm = rsnd_runtime_is_ssi_tdm(io);

        /*
         * always use 32bit system word.
         * see also rsnd_ssi_master_clk_enable()
         */
        cr_own |= FORCE | SWL_32;

        if (rdai->bit_clk_inv)
                cr_own |= SCKP;
        if (rdai->frm_clk_inv ^ is_tdm)
                cr_own |= SWSP;
        if (rdai->data_alignment)
                cr_own |= SDTA;
        if (rdai->sys_delay)
                cr_own |= DEL;

        /*
         * We shouldn't exchange SWSP after running.
         * This means, parent needs to care it.
         */
        if (rsnd_ssi_is_parent(mod, io))
                goto init_end;

        if (rsnd_io_is_play(io))
                cr_own |= TRMD;

        cr_own &= ~DWL_MASK;
        switch (snd_pcm_format_width(runtime->format)) {
        case 16:
                cr_own |= DWL_16;
                break;
        case 24:
                cr_own |= DWL_24;
                break;
        }

        if (rsnd_ssi_is_dma_mode(mod)) {
                cr_mode = UIEN | OIEN | /* over/under run */
                          DMEN;         /* DMA : enable DMA */
        } else {
                cr_mode = DIEN;         /* PIO : enable Data interrupt */
        }

        /*
         * TDM Extend Mode
         * see
         *      rsnd_ssiu_init_gen2()
         */
        wsr = ssi->wsr;
        if (is_tdm) {
                wsr     |= WS_MODE;
                cr_own  |= CHNL_8;
        }
init_end:
        ssi->cr_own     = cr_own;
        ssi->cr_mode    = cr_mode;
        ssi->wsr        = wsr;
}

static void rsnd_ssi_register_setup(struct rsnd_mod *mod)
{
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);

        rsnd_mod_write(mod, SSIWSR,     ssi->wsr);
        rsnd_mod_write(mod, SSICR,      ssi->cr_own     |
                                        ssi->cr_clk     |
                                        ssi->cr_mode    |
                                        ssi->cr_en);
}

/*
 *      SSI mod common functions
 */
static int rsnd_ssi_init(struct rsnd_mod *mod,
                         struct rsnd_dai_stream *io,
                         struct rsnd_priv *priv)
{
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);

        if (!rsnd_ssi_is_run_mods(mod, io))
                return 0;

        ssi->usrcnt++;

        rsnd_mod_power_on(mod);

        rsnd_ssi_config_init(mod, io);

        rsnd_ssi_register_setup(mod);

        /* clear error status */
        rsnd_ssi_status_clear(mod);

        return 0;
}

static int rsnd_ssi_quit(struct rsnd_mod *mod,
                         struct rsnd_dai_stream *io,
                         struct rsnd_priv *priv)
{
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
        struct device *dev = rsnd_priv_to_dev(priv);

        if (!rsnd_ssi_is_run_mods(mod, io))
                return 0;

        if (!ssi->usrcnt) {
                dev_err(dev, "%s[%d] usrcnt error\n",
                        rsnd_mod_name(mod), rsnd_mod_id(mod));
                return -EIO;
        }

        rsnd_ssi_master_clk_stop(mod, io);

        rsnd_mod_power_off(mod);

        ssi->usrcnt--;

        if (!ssi->usrcnt) {
                ssi->cr_own     = 0;
                ssi->cr_mode    = 0;
                ssi->wsr        = 0;
        }

        return 0;
}

static int rsnd_ssi_hw_params(struct rsnd_mod *mod,
                              struct rsnd_dai_stream *io,
                              struct snd_pcm_substream *substream,
                              struct snd_pcm_hw_params *params)
{
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
        int chan = params_channels(params);

        /*
         * snd_pcm_ops::hw_params will be called *before*
         * snd_soc_dai_ops::trigger. Thus, ssi->usrcnt is 0
         * in 1st call.
         */
        if (ssi->usrcnt) {
                /*
                 * Already working.
                 * It will happen if SSI has parent/child connection.
                 * it is error if child <-> parent SSI uses
                 * different channels.
                 */
                if (ssi->chan != chan)
                        return -EIO;
        }

        ssi->chan = chan;

        return 0;
}

static int rsnd_ssi_start(struct rsnd_mod *mod,
                          struct rsnd_dai_stream *io,
                          struct rsnd_priv *priv)
{
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);

        if (!rsnd_ssi_is_run_mods(mod, io))
                return 0;

        /*
         * EN will be set via SSIU :: SSI_CONTROL
         * if Multi channel mode
         */
        if (rsnd_ssi_multi_slaves_runtime(io))
                return 0;

        /*
         * EN is for data output.
         * SSI parent EN is not needed.
         */
        if (rsnd_ssi_is_parent(mod, io))
                return 0;

        ssi->cr_en = EN;

        rsnd_mod_write(mod, SSICR,      ssi->cr_own     |
                                        ssi->cr_clk     |
                                        ssi->cr_mode    |
                                        ssi->cr_en);

        return 0;
}

static int rsnd_ssi_stop(struct rsnd_mod *mod,
                         struct rsnd_dai_stream *io,
                         struct rsnd_priv *priv)
{
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
        u32 cr;

        if (!rsnd_ssi_is_run_mods(mod, io))
                return 0;

        if (rsnd_ssi_is_parent(mod, io))
                return 0;

        cr  =   ssi->cr_own     |
                ssi->cr_clk;

        /*
         * disable all IRQ,
         * Playback: Wait all data was sent
         * Capture:  It might not receave data. Do nothing
         */
        if (rsnd_io_is_play(io)) {
                rsnd_mod_write(mod, SSICR, cr | EN);
                rsnd_ssi_status_check(mod, DIRQ);
        }

        /*
         * disable SSI,
         * and, wait idle state
         */
        rsnd_mod_write(mod, SSICR, cr); /* disabled all */
        rsnd_ssi_status_check(mod, IIRQ);

        ssi->cr_en = 0;

        return 0;
}

static int rsnd_ssi_irq(struct rsnd_mod *mod,
                        struct rsnd_dai_stream *io,
                        struct rsnd_priv *priv,
                        int enable)
{
        u32 val = 0;

        if (rsnd_is_gen1(priv))
                return 0;

        if (rsnd_ssi_is_parent(mod, io))
                return 0;

        if (!rsnd_ssi_is_run_mods(mod, io))
                return 0;

        if (enable)
                val = rsnd_ssi_is_dma_mode(mod) ? 0x0e000000 : 0x0f000000;

        rsnd_mod_write(mod, SSI_INT_ENABLE, val);

        return 0;
}

static bool rsnd_ssi_pio_interrupt(struct rsnd_mod *mod,
                                   struct rsnd_dai_stream *io);
static void __rsnd_ssi_interrupt(struct rsnd_mod *mod,
                                 struct rsnd_dai_stream *io)
{
        struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
        struct device *dev = rsnd_priv_to_dev(priv);
        int is_dma = rsnd_ssi_is_dma_mode(mod);
        u32 status;
        bool elapsed = false;
        bool stop = false;

        spin_lock(&priv->lock);

        /* ignore all cases if not working */
        if (!rsnd_io_is_working(io))
                goto rsnd_ssi_interrupt_out;

        status = rsnd_ssi_status_get(mod);

        /* PIO only */
        if (!is_dma && (status & DIRQ))
                elapsed = rsnd_ssi_pio_interrupt(mod, io);

        /* DMA only */
        if (is_dma && (status & (UIRQ | OIRQ))) {
                rsnd_dbg_irq_status(dev, "%s[%d] err status : 0x%08x\n",
                        rsnd_mod_name(mod), rsnd_mod_id(mod), status);

                stop = true;
        }

        rsnd_ssi_status_clear(mod);
rsnd_ssi_interrupt_out:
        spin_unlock(&priv->lock);

        if (elapsed)
                rsnd_dai_period_elapsed(io);

        if (stop)
                snd_pcm_stop_xrun(io->substream);

}

static irqreturn_t rsnd_ssi_interrupt(int irq, void *data)
{
        struct rsnd_mod *mod = data;

        rsnd_mod_interrupt(mod, __rsnd_ssi_interrupt);

        return IRQ_HANDLED;
}

/*
 *              SSI PIO
 */
static void rsnd_ssi_parent_attach(struct rsnd_mod *mod,
                                   struct rsnd_dai_stream *io)
{
        struct rsnd_dai *rdai = rsnd_io_to_rdai(io);
        struct rsnd_priv *priv = rsnd_mod_to_priv(mod);

        if (!__rsnd_ssi_is_pin_sharing(mod))
                return;

        if (!rsnd_rdai_is_clk_master(rdai))
                return;

        switch (rsnd_mod_id(mod)) {
        case 1:
        case 2:
                rsnd_dai_connect(rsnd_ssi_mod_get(priv, 0), io, RSND_MOD_SSIP);
                break;
        case 4:
                rsnd_dai_connect(rsnd_ssi_mod_get(priv, 3), io, RSND_MOD_SSIP);
                break;
        case 8:
                rsnd_dai_connect(rsnd_ssi_mod_get(priv, 7), io, RSND_MOD_SSIP);
                break;
        }
}

static int rsnd_ssi_pcm_new(struct rsnd_mod *mod,
                            struct rsnd_dai_stream *io,
                            struct snd_soc_pcm_runtime *rtd)
{
        /*
         * rsnd_rdai_is_clk_master() will be enabled after set_fmt,
         * and, pcm_new will be called after it.
         * This function reuse pcm_new at this point.
         */
        rsnd_ssi_parent_attach(mod, io);

        return 0;
}

static int rsnd_ssi_common_probe(struct rsnd_mod *mod,
                                 struct rsnd_dai_stream *io,
                                 struct rsnd_priv *priv)
{
        struct device *dev = rsnd_priv_to_dev(priv);
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
        int ret;

        /*
         * SSIP/SSIU/IRQ are not needed on
         * SSI Multi slaves
         */
        if (rsnd_ssi_is_multi_slave(mod, io))
                return 0;

        /*
         * It can't judge ssi parent at this point
         * see rsnd_ssi_pcm_new()
         */

        ret = rsnd_ssiu_attach(io, mod);
        if (ret < 0)
                return ret;

        /*
         * SSI might be called again as PIO fallback
         * It is easy to manual handling for IRQ request/free
         *
         * OTOH, this function might be called many times if platform is
         * using MIX. It needs xxx_attach() many times on xxx_probe().
         * Because of it, we can't control .probe/.remove calling count by
         * mod->status.
         * But it don't need to call request_irq() many times.
         * Let's control it by RSND_SSI_PROBED flag.
         */
        if (!rsnd_flags_has(ssi, RSND_SSI_PROBED)) {
                ret = request_irq(ssi->irq,
                                  rsnd_ssi_interrupt,
                                  IRQF_SHARED,
                                  dev_name(dev), mod);

                rsnd_flags_set(ssi, RSND_SSI_PROBED);
        }

        return ret;
}

static int rsnd_ssi_common_remove(struct rsnd_mod *mod,
                                  struct rsnd_dai_stream *io,
                                  struct rsnd_priv *priv)
{
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
        struct rsnd_mod *pure_ssi_mod = rsnd_io_to_mod_ssi(io);

        /* Do nothing if non SSI (= SSI parent, multi SSI) mod */
        if (pure_ssi_mod != mod)
                return 0;

        /* PIO will request IRQ again */
        if (rsnd_flags_has(ssi, RSND_SSI_PROBED)) {
                free_irq(ssi->irq, mod);

                rsnd_flags_del(ssi, RSND_SSI_PROBED);
        }

        return 0;
}

/*
 *      SSI PIO functions
 */
static bool rsnd_ssi_pio_interrupt(struct rsnd_mod *mod,
                                   struct rsnd_dai_stream *io)
{
        struct snd_pcm_runtime *runtime = rsnd_io_to_runtime(io);
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
        u32 *buf = (u32 *)(runtime->dma_area + ssi->byte_pos);
        int shift = 0;
        int byte_pos;
        bool elapsed = false;

        if (snd_pcm_format_width(runtime->format) == 24)
                shift = 8;

        /*
         * 8/16/32 data can be assesse to TDR/RDR register
         * directly as 32bit data
         * see rsnd_ssi_init()
         */
        if (rsnd_io_is_play(io))
                rsnd_mod_write(mod, SSITDR, (*buf) << shift);
        else
                *buf = (rsnd_mod_read(mod, SSIRDR) >> shift);

        byte_pos = ssi->byte_pos + sizeof(*buf);

        if (byte_pos >= ssi->next_period_byte) {
                int period_pos = byte_pos / ssi->byte_per_period;

                if (period_pos >= runtime->periods) {
                        byte_pos = 0;
                        period_pos = 0;
                }

                ssi->next_period_byte = (period_pos + 1) * ssi->byte_per_period;

                elapsed = true;
        }

        WRITE_ONCE(ssi->byte_pos, byte_pos);

        return elapsed;
}

static int rsnd_ssi_pio_init(struct rsnd_mod *mod,
                             struct rsnd_dai_stream *io,
                             struct rsnd_priv *priv)
{
        struct snd_pcm_runtime *runtime = rsnd_io_to_runtime(io);
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);

        if (!rsnd_ssi_is_parent(mod, io)) {
                ssi->byte_pos           = 0;
                ssi->byte_per_period    = runtime->period_size *
                                          runtime->channels *
                                          samples_to_bytes(runtime, 1);
                ssi->next_period_byte   = ssi->byte_per_period;
        }

        return rsnd_ssi_init(mod, io, priv);
}

static int rsnd_ssi_pio_pointer(struct rsnd_mod *mod,
                            struct rsnd_dai_stream *io,
                            snd_pcm_uframes_t *pointer)
{
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
        struct snd_pcm_runtime *runtime = rsnd_io_to_runtime(io);

        *pointer = bytes_to_frames(runtime, READ_ONCE(ssi->byte_pos));

        return 0;
}

static int rsnd_ssi_prepare(struct rsnd_mod *mod,
                            struct rsnd_dai_stream *io,
                            struct rsnd_priv *priv)
{
        return rsnd_ssi_master_clk_start(mod, io);
}

static struct rsnd_mod_ops rsnd_ssi_pio_ops = {
        .name   = SSI_NAME,
        .probe  = rsnd_ssi_common_probe,
        .remove = rsnd_ssi_common_remove,
        .init   = rsnd_ssi_pio_init,
        .quit   = rsnd_ssi_quit,
        .start  = rsnd_ssi_start,
        .stop   = rsnd_ssi_stop,
        .irq    = rsnd_ssi_irq,
        .pointer = rsnd_ssi_pio_pointer,
        .pcm_new = rsnd_ssi_pcm_new,
        .hw_params = rsnd_ssi_hw_params,
        .prepare = rsnd_ssi_prepare,
};

static int rsnd_ssi_dma_probe(struct rsnd_mod *mod,
                              struct rsnd_dai_stream *io,
                              struct rsnd_priv *priv)
{
        struct rsnd_ssi *ssi = rsnd_mod_to_ssi(mod);
        int ret;

        /*
         * SSIP/SSIU/IRQ/DMA are not needed on
         * SSI Multi slaves
         */
        if (rsnd_ssi_is_multi_slave(mod, io))
                return 0;

        ret = rsnd_ssi_common_probe(mod, io, priv);
        if (ret)
                return ret;

        /* SSI probe might be called many times in MUX multi path */
        ret = rsnd_dma_attach(io, mod, &ssi->dma);

        return ret;
}

static int rsnd_ssi_fallback(struct rsnd_mod *mod,
                             struct rsnd_dai_stream *io,
                             struct rsnd_priv *priv)
{
        struct device *dev = rsnd_priv_to_dev(priv);

        /*
         * fallback to PIO
         *
         * SSI .probe might be called again.
         * see
         *      rsnd_rdai_continuance_probe()
         */
        mod->ops = &rsnd_ssi_pio_ops;

        dev_info(dev, "%s[%d] fallback to PIO mode\n",
                 rsnd_mod_name(mod), rsnd_mod_id(mod));

        return 0;
}

static struct dma_chan *rsnd_ssi_dma_req(struct rsnd_dai_stream *io,
                                         struct rsnd_mod *mod)
{
        struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
        int is_play = rsnd_io_is_play(io);
        char *name;

        if (rsnd_ssi_use_busif(io))
                name = is_play ? "rxu" : "txu";
        else
                name = is_play ? "rx" : "tx";

        return rsnd_dma_request_channel(rsnd_ssi_of_node(priv),
                                        mod, name);
}

static struct rsnd_mod_ops rsnd_ssi_dma_ops = {
        .name   = SSI_NAME,
        .dma_req = rsnd_ssi_dma_req,
        .probe  = rsnd_ssi_dma_probe,
        .remove = rsnd_ssi_common_remove,
        .init   = rsnd_ssi_init,
        .quit   = rsnd_ssi_quit,
        .start  = rsnd_ssi_start,
        .stop   = rsnd_ssi_stop,
        .irq    = rsnd_ssi_irq,
        .pcm_new = rsnd_ssi_pcm_new,
        .fallback = rsnd_ssi_fallback,
        .hw_params = rsnd_ssi_hw_params,
        .prepare = rsnd_ssi_prepare,
};

int rsnd_ssi_is_dma_mode(struct rsnd_mod *mod)
{
        return mod->ops == &rsnd_ssi_dma_ops;
}


/*
 *              ssi mod function
 */
static void rsnd_ssi_connect(struct rsnd_mod *mod,
                             struct rsnd_dai_stream *io)
{
        struct rsnd_dai *rdai = rsnd_io_to_rdai(io);
        enum rsnd_mod_type types[] = {
                RSND_MOD_SSI,
                RSND_MOD_SSIM1,
                RSND_MOD_SSIM2,
                RSND_MOD_SSIM3,
        };
        enum rsnd_mod_type type;
        int i;

        /* try SSI -> SSIM1 -> SSIM2 -> SSIM3 */
        for (i = 0; i < ARRAY_SIZE(types); i++) {
                type = types[i];
                if (!rsnd_io_to_mod(io, type)) {
                        rsnd_dai_connect(mod, io, type);
                        rsnd_rdai_channels_set(rdai, (i + 1) * 2);
                        rsnd_rdai_ssi_lane_set(rdai, (i + 1));
                        return;
                }
        }
}

void rsnd_parse_connect_ssi(struct rsnd_dai *rdai,
                            struct device_node *playback,
                            struct device_node *capture)
{
        struct rsnd_priv *priv = rsnd_rdai_to_priv(rdai);
        struct device_node *node;
        struct device_node *np;
        struct rsnd_mod *mod;
        int i;

        node = rsnd_ssi_of_node(priv);
        if (!node)
                return;

        i = 0;
        for_each_child_of_node(node, np) {
                mod = rsnd_ssi_mod_get(priv, i);
                if (np == playback)

                        rsnd_ssi_connect(mod, &rdai->playback);
                if (np == capture)
                        rsnd_ssi_connect(mod, &rdai->capture);
                i++;
        }

        of_node_put(node);
}

static void __rsnd_ssi_parse_hdmi_connection(struct rsnd_priv *priv,
                                             struct rsnd_dai_stream *io,
                                             struct device_node *remote_ep)
{
        struct device *dev = rsnd_priv_to_dev(priv);
        struct rsnd_mod *mod = rsnd_io_to_mod_ssi(io);
        struct rsnd_ssi *ssi;
        struct device_node *remote_node = of_graph_get_port_parent(remote_ep);

        /* support Gen3 only */
        if (!rsnd_is_gen3(priv))
                return;

        if (!mod)
                return;

        ssi  = rsnd_mod_to_ssi(mod);

        /* HDMI0 */
        if (strstr(remote_node->full_name, "hdmi@fead0000")) {
                rsnd_flags_set(ssi, RSND_SSI_HDMI0);
                dev_dbg(dev, "%s[%d] connected to HDMI0\n",
                         rsnd_mod_name(mod), rsnd_mod_id(mod));
        }

        /* HDMI1 */
        if (strstr(remote_node->full_name, "hdmi@feae0000")) {
                rsnd_flags_set(ssi, RSND_SSI_HDMI1);
                dev_dbg(dev, "%s[%d] connected to HDMI1\n",
                        rsnd_mod_name(mod), rsnd_mod_id(mod));
        }
}

void rsnd_ssi_parse_hdmi_connection(struct rsnd_priv *priv,
                                    struct device_node *endpoint,
                                    int dai_i)
{
        struct rsnd_dai *rdai = rsnd_rdai_get(priv, dai_i);
        struct device_node *remote_ep;

        remote_ep = of_graph_get_remote_endpoint(endpoint);
        if (!remote_ep)
                return;

        __rsnd_ssi_parse_hdmi_connection(priv, &rdai->playback, remote_ep);
        __rsnd_ssi_parse_hdmi_connection(priv, &rdai->capture,  remote_ep);
}

struct rsnd_mod *rsnd_ssi_mod_get(struct rsnd_priv *priv, int id)
{
        if (WARN_ON(id < 0 || id >= rsnd_ssi_nr(priv)))
                id = 0;

        return rsnd_mod_get(rsnd_ssi_get(priv, id));
}

int __rsnd_ssi_is_pin_sharing(struct rsnd_mod *mod)
{
        if (!mod)
                return 0;

        return !!(rsnd_flags_has(rsnd_mod_to_ssi(mod), RSND_SSI_CLK_PIN_SHARE));
}

static u32 *rsnd_ssi_get_status(struct rsnd_dai_stream *io,
                                struct rsnd_mod *mod,
                                enum rsnd_mod_type type)
{
        /*
         * SSIP (= SSI parent) needs to be special, otherwise,
         * 2nd SSI might doesn't start. see also rsnd_mod_call()
         *
         * We can't include parent SSI status on SSI, because we don't know
         * how many SSI requests parent SSI. Thus, it is localed on "io" now.
         * ex) trouble case
         *      Playback: SSI0
         *      Capture : SSI1 (needs SSI0)
         *
         * 1) start Capture  -> SSI0/SSI1 are started.
         * 2) start Playback -> SSI0 doesn't work, because it is already
         *                      marked as "started" on 1)
         *
         * OTOH, using each mod's status is good for MUX case.
         * It doesn't need to start in 2nd start
         * ex)
         *      IO-0: SRC0 -> CTU1 -+-> MUX -> DVC -> SSIU -> SSI0
         *                          |
         *      IO-1: SRC1 -> CTU2 -+
         *
         * 1) start IO-0 ->     start SSI0
         * 2) start IO-1 ->     SSI0 doesn't need to start, because it is
         *                      already started on 1)
         */
        if (type == RSND_MOD_SSIP)
                return &io->parent_ssi_status;

        return rsnd_mod_get_status(io, mod, type);
}

int rsnd_ssi_probe(struct rsnd_priv *priv)
{
        struct device_node *node;
        struct device_node *np;
        struct device *dev = rsnd_priv_to_dev(priv);
        struct rsnd_mod_ops *ops;
        struct clk *clk;
        struct rsnd_ssi *ssi;
        char name[RSND_SSI_NAME_SIZE];
        int i, nr, ret;

        node = rsnd_ssi_of_node(priv);
        if (!node)
                return -EINVAL;

        nr = of_get_child_count(node);
        if (!nr) {
                ret = -EINVAL;
                goto rsnd_ssi_probe_done;
        }

        ssi     = devm_kcalloc(dev, nr, sizeof(*ssi), GFP_KERNEL);
        if (!ssi) {
                ret = -ENOMEM;
                goto rsnd_ssi_probe_done;
        }

        priv->ssi       = ssi;
        priv->ssi_nr    = nr;

        i = 0;
        for_each_child_of_node(node, np) {
                if (!of_device_is_available(np))
                        goto skip;

                ssi = rsnd_ssi_get(priv, i);

                snprintf(name, RSND_SSI_NAME_SIZE, "%s.%d",
                         SSI_NAME, i);

                clk = devm_clk_get(dev, name);
                if (IS_ERR(clk)) {
                        ret = PTR_ERR(clk);
                        of_node_put(np);
                        goto rsnd_ssi_probe_done;
                }

                if (of_get_property(np, "shared-pin", NULL))
                        rsnd_flags_set(ssi, RSND_SSI_CLK_PIN_SHARE);

                if (of_get_property(np, "no-busif", NULL))
                        rsnd_flags_set(ssi, RSND_SSI_NO_BUSIF);

                ssi->irq = irq_of_parse_and_map(np, 0);
                if (!ssi->irq) {
                        ret = -EINVAL;
                        of_node_put(np);
                        goto rsnd_ssi_probe_done;
                }

                if (of_property_read_bool(np, "pio-transfer"))
                        ops = &rsnd_ssi_pio_ops;
                else
                        ops = &rsnd_ssi_dma_ops;

                ret = rsnd_mod_init(priv, rsnd_mod_get(ssi), ops, clk,
                                    rsnd_ssi_get_status, RSND_MOD_SSI, i);
                if (ret) {
                        of_node_put(np);
                        goto rsnd_ssi_probe_done;
                }
skip:
                i++;
        }

        ret = 0;

rsnd_ssi_probe_done:
        of_node_put(node);

        return ret;
}

void rsnd_ssi_remove(struct rsnd_priv *priv)
{
        struct rsnd_ssi *ssi;
        int i;

        for_each_rsnd_ssi(ssi, priv, i) {
                rsnd_mod_quit(rsnd_mod_get(ssi));
        }
}