/*
 * imx-ssi.c  --  ALSA Soc Audio Layer
 *
 * Copyright 2009 Sascha Hauer <s.hauer@pengutronix.de>
 *
 * This code is based on code copyrighted by Freescale,
 * Liam Girdwood, Javier Martin and probably others.
 *
 *  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;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 *
 * The i.MX SSI core has some nasty limitations in AC97 mode. While most
 * sane processor vendors have a FIFO per AC97 slot, the i.MX has only
 * one FIFO which combines all valid receive slots. We cannot even select
 * which slots we want to receive. The WM9712 with which this driver
 * was developed with always sends GPIO status data in slot 12 which
 * we receive in our (PCM-) data stream. The only chance we have is to
 * manually skip this data in the FIQ handler. With sampling rates different
 * from 48000Hz not every frame has valid receive data, so the ratio
 * between pcm data and GPIO status data changes. Our FIQ handler is not
 * able to handle this, hence this driver only works with 48000Hz sampling
 * rate.
 * Reading and writing AC97 registers is another challenge. The core
 * provides us status bits when the read register is updated with *another*
 * value. When we read the same register two times (and the register still
 * contains the same value) these status bits are not set. We work
 * around this by not polling these bits but only wait a fixed delay.
 *
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>

#include <sound/core.h>
#include <sound/initval.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <linux/platform_data/asoc-imx-ssi.h>

#include "imx-ssi.h"

#define SSI_SACNT_DEFAULT (SSI_SACNT_AC97EN | SSI_SACNT_FV)

/*
 * SSI Network Mode or TDM slots configuration.
 * Should only be called when port is inactive (i.e. SSIEN = 0).
 */
static int imx_ssi_set_dai_tdm_slot(struct snd_soc_dai *cpu_dai,
        unsigned int tx_mask, unsigned int rx_mask, int slots, int slot_width)
{
        struct imx_ssi *ssi = snd_soc_dai_get_drvdata(cpu_dai);
        u32 sccr;

        sccr = readl(ssi->base + SSI_STCCR);
        sccr &= ~SSI_STCCR_DC_MASK;
        sccr |= SSI_STCCR_DC(slots - 1);
        writel(sccr, ssi->base + SSI_STCCR);

        sccr = readl(ssi->base + SSI_SRCCR);
        sccr &= ~SSI_STCCR_DC_MASK;
        sccr |= SSI_STCCR_DC(slots - 1);
        writel(sccr, ssi->base + SSI_SRCCR);

        writel(tx_mask, ssi->base + SSI_STMSK);
        writel(rx_mask, ssi->base + SSI_SRMSK);

        return 0;
}

/*
 * SSI DAI format configuration.
 * Should only be called when port is inactive (i.e. SSIEN = 0).
 */
static int imx_ssi_set_dai_fmt(struct snd_soc_dai *cpu_dai, unsigned int fmt)
{
        struct imx_ssi *ssi = snd_soc_dai_get_drvdata(cpu_dai);
        u32 strcr = 0, scr;

        scr = readl(ssi->base + SSI_SCR) & ~(SSI_SCR_SYN | SSI_SCR_NET);

        /* DAI mode */
        switch (fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
        case SND_SOC_DAIFMT_I2S:
                /* data on rising edge of bclk, frame low 1clk before data */
                strcr |= SSI_STCR_TFSI | SSI_STCR_TEFS | SSI_STCR_TXBIT0;
                scr |= SSI_SCR_NET;
                if (ssi->flags & IMX_SSI_USE_I2S_SLAVE) {
                        scr &= ~SSI_I2S_MODE_MASK;
                        scr |= SSI_SCR_I2S_MODE_SLAVE;
                }
                break;
        case SND_SOC_DAIFMT_LEFT_J:
                /* data on rising edge of bclk, frame high with data */
                strcr |= SSI_STCR_TXBIT0;
                break;
        case SND_SOC_DAIFMT_DSP_B:
                /* data on rising edge of bclk, frame high with data */
                strcr |= SSI_STCR_TFSL | SSI_STCR_TXBIT0;
                break;
        case SND_SOC_DAIFMT_DSP_A:
                /* data on rising edge of bclk, frame high 1clk before data */
                strcr |= SSI_STCR_TFSL | SSI_STCR_TXBIT0 | SSI_STCR_TEFS;
                break;
        }

        /* DAI clock inversion */
        switch (fmt & SND_SOC_DAIFMT_INV_MASK) {
        case SND_SOC_DAIFMT_IB_IF:
                strcr |= SSI_STCR_TFSI;
                strcr &= ~SSI_STCR_TSCKP;
                break;
        case SND_SOC_DAIFMT_IB_NF:
                strcr &= ~(SSI_STCR_TSCKP | SSI_STCR_TFSI);
                break;
        case SND_SOC_DAIFMT_NB_IF:
                strcr |= SSI_STCR_TFSI | SSI_STCR_TSCKP;
                break;
        case SND_SOC_DAIFMT_NB_NF:
                strcr &= ~SSI_STCR_TFSI;
                strcr |= SSI_STCR_TSCKP;
                break;
        }

        /* DAI clock master masks */
        switch (fmt & SND_SOC_DAIFMT_MASTER_MASK) {
        case SND_SOC_DAIFMT_CBM_CFM:
                break;
        default:
                /* Master mode not implemented, needs handling of clocks. */
                return -EINVAL;
        }

        strcr |= SSI_STCR_TFEN0;

        if (ssi->flags & IMX_SSI_NET)
                scr |= SSI_SCR_NET;
        if (ssi->flags & IMX_SSI_SYN)
                scr |= SSI_SCR_SYN;

        writel(strcr, ssi->base + SSI_STCR);
        writel(strcr, ssi->base + SSI_SRCR);
        writel(scr, ssi->base + SSI_SCR);

        return 0;
}

/*
 * SSI system clock configuration.
 * Should only be called when port is inactive (i.e. SSIEN = 0).
 */
static int imx_ssi_set_dai_sysclk(struct snd_soc_dai *cpu_dai,
                                  int clk_id, unsigned int freq, int dir)
{
        struct imx_ssi *ssi = snd_soc_dai_get_drvdata(cpu_dai);
        u32 scr;

        scr = readl(ssi->base + SSI_SCR);

        switch (clk_id) {
        case IMX_SSP_SYS_CLK:
                if (dir == SND_SOC_CLOCK_OUT)
                        scr |= SSI_SCR_SYS_CLK_EN;
                else
                        scr &= ~SSI_SCR_SYS_CLK_EN;
                break;
        default:
                return -EINVAL;
        }

        writel(scr, ssi->base + SSI_SCR);

        return 0;
}

/*
 * SSI Clock dividers
 * Should only be called when port is inactive (i.e. SSIEN = 0).
 */
static int imx_ssi_set_dai_clkdiv(struct snd_soc_dai *cpu_dai,
                                  int div_id, int div)
{
        struct imx_ssi *ssi = snd_soc_dai_get_drvdata(cpu_dai);
        u32 stccr, srccr;

        stccr = readl(ssi->base + SSI_STCCR);
        srccr = readl(ssi->base + SSI_SRCCR);

        switch (div_id) {
        case IMX_SSI_TX_DIV_2:
                stccr &= ~SSI_STCCR_DIV2;
                stccr |= div;
                break;
        case IMX_SSI_TX_DIV_PSR:
                stccr &= ~SSI_STCCR_PSR;
                stccr |= div;
                break;
        case IMX_SSI_TX_DIV_PM:
                stccr &= ~0xff;
                stccr |= SSI_STCCR_PM(div);
                break;
        case IMX_SSI_RX_DIV_2:
                stccr &= ~SSI_STCCR_DIV2;
                stccr |= div;
                break;
        case IMX_SSI_RX_DIV_PSR:
                stccr &= ~SSI_STCCR_PSR;
                stccr |= div;
                break;
        case IMX_SSI_RX_DIV_PM:
                stccr &= ~0xff;
                stccr |= SSI_STCCR_PM(div);
                break;
        default:
                return -EINVAL;
        }

        writel(stccr, ssi->base + SSI_STCCR);
        writel(srccr, ssi->base + SSI_SRCCR);

        return 0;
}

/*
 * Should only be called when port is inactive (i.e. SSIEN = 0),
 * although can be called multiple times by upper layers.
 */
static int imx_ssi_hw_params(struct snd_pcm_substream *substream,
                             struct snd_pcm_hw_params *params,
                             struct snd_soc_dai *cpu_dai)
{
        struct imx_ssi *ssi = snd_soc_dai_get_drvdata(cpu_dai);
        u32 reg, sccr;

        /* Tx/Rx config */
        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                reg = SSI_STCCR;
        else
                reg = SSI_SRCCR;

        if (ssi->flags & IMX_SSI_SYN)
                reg = SSI_STCCR;

        sccr = readl(ssi->base + reg) & ~SSI_STCCR_WL_MASK;

        /* DAI data (word) size */
        switch (params_format(params)) {
        case SNDRV_PCM_FORMAT_S16_LE:
                sccr |= SSI_SRCCR_WL(16);
                break;
        case SNDRV_PCM_FORMAT_S20_3LE:
                sccr |= SSI_SRCCR_WL(20);
                break;
        case SNDRV_PCM_FORMAT_S24_LE:
                sccr |= SSI_SRCCR_WL(24);
                break;
        }

        writel(sccr, ssi->base + reg);

        return 0;
}

static int imx_ssi_trigger(struct snd_pcm_substream *substream, int cmd,
                struct snd_soc_dai *dai)
{
        struct imx_ssi *ssi = snd_soc_dai_get_drvdata(dai);
        unsigned int sier_bits, sier;
        unsigned int scr;

        scr = readl(ssi->base + SSI_SCR);
        sier = readl(ssi->base + SSI_SIER);

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                if (ssi->flags & IMX_SSI_DMA)
                        sier_bits = SSI_SIER_TDMAE;
                else
                        sier_bits = SSI_SIER_TIE | SSI_SIER_TFE0_EN;
        } else {
                if (ssi->flags & IMX_SSI_DMA)
                        sier_bits = SSI_SIER_RDMAE;
                else
                        sier_bits = SSI_SIER_RIE | SSI_SIER_RFF0_EN;
        }

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
        case SNDRV_PCM_TRIGGER_RESUME:
        case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                        scr |= SSI_SCR_TE;
                else
                        scr |= SSI_SCR_RE;
                sier |= sier_bits;

                if (++ssi->enabled == 1)
                        scr |= SSI_SCR_SSIEN;

                break;

        case SNDRV_PCM_TRIGGER_STOP:
        case SNDRV_PCM_TRIGGER_SUSPEND:
        case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                        scr &= ~SSI_SCR_TE;
                else
                        scr &= ~SSI_SCR_RE;
                sier &= ~sier_bits;

                if (--ssi->enabled == 0)
                        scr &= ~SSI_SCR_SSIEN;

                break;
        default:
                return -EINVAL;
        }

        if (!(ssi->flags & IMX_SSI_USE_AC97))
                /* rx/tx are always enabled to access ac97 registers */
                writel(scr, ssi->base + SSI_SCR);

        writel(sier, ssi->base + SSI_SIER);

        return 0;
}

static const struct snd_soc_dai_ops imx_ssi_pcm_dai_ops = {
        .hw_params      = imx_ssi_hw_params,
        .set_fmt        = imx_ssi_set_dai_fmt,
        .set_clkdiv     = imx_ssi_set_dai_clkdiv,
        .set_sysclk     = imx_ssi_set_dai_sysclk,
        .set_tdm_slot   = imx_ssi_set_dai_tdm_slot,
        .trigger        = imx_ssi_trigger,
};

static int imx_ssi_dai_probe(struct snd_soc_dai *dai)
{
        struct imx_ssi *ssi = dev_get_drvdata(dai->dev);
        uint32_t val;

        snd_soc_dai_set_drvdata(dai, ssi);

        val = SSI_SFCSR_TFWM0(ssi->dma_params_tx.maxburst) |
                SSI_SFCSR_RFWM0(ssi->dma_params_rx.maxburst);
        writel(val, ssi->base + SSI_SFCSR);

        /* Tx/Rx config */
        dai->playback_dma_data = &ssi->dma_params_tx;
        dai->capture_dma_data = &ssi->dma_params_rx;

        return 0;
}

static struct snd_soc_dai_driver imx_ssi_dai = {
        .probe = imx_ssi_dai_probe,
        .playback = {
                .channels_min = 1,
                .channels_max = 2,
                .rates = SNDRV_PCM_RATE_8000_96000,
                .formats = SNDRV_PCM_FMTBIT_S16_LE,
        },
        .capture = {
                .channels_min = 1,
                .channels_max = 2,
                .rates = SNDRV_PCM_RATE_8000_96000,
                .formats = SNDRV_PCM_FMTBIT_S16_LE,
        },
        .ops = &imx_ssi_pcm_dai_ops,
};

static struct snd_soc_dai_driver imx_ac97_dai = {
        .probe = imx_ssi_dai_probe,
        .ac97_control = 1,
        .playback = {
                .stream_name = "AC97 Playback",
                .channels_min = 2,
                .channels_max = 2,
                .rates = SNDRV_PCM_RATE_8000_48000,
                .formats = SNDRV_PCM_FMTBIT_S16_LE,
        },
        .capture = {
                .stream_name = "AC97 Capture",
                .channels_min = 2,
                .channels_max = 2,
                .rates = SNDRV_PCM_RATE_48000,
                .formats = SNDRV_PCM_FMTBIT_S16_LE,
        },
        .ops = &imx_ssi_pcm_dai_ops,
};

static const struct snd_soc_component_driver imx_component = {
        .name           = DRV_NAME,
};

static void setup_channel_to_ac97(struct imx_ssi *imx_ssi)
{
        void __iomem *base = imx_ssi->base;

        writel(0x0, base + SSI_SCR);
        writel(0x0, base + SSI_STCR);
        writel(0x0, base + SSI_SRCR);

        writel(SSI_SCR_SYN | SSI_SCR_NET, base + SSI_SCR);

        writel(SSI_SFCSR_RFWM0(8) |
                SSI_SFCSR_TFWM0(8) |
                SSI_SFCSR_RFWM1(8) |
                SSI_SFCSR_TFWM1(8), base + SSI_SFCSR);

        writel(SSI_STCCR_WL(16) | SSI_STCCR_DC(12), base + SSI_STCCR);
        writel(SSI_STCCR_WL(16) | SSI_STCCR_DC(12), base + SSI_SRCCR);

        writel(SSI_SCR_SYN | SSI_SCR_NET | SSI_SCR_SSIEN, base + SSI_SCR);
        writel(SSI_SOR_WAIT(3), base + SSI_SOR);

        writel(SSI_SCR_SYN | SSI_SCR_NET | SSI_SCR_SSIEN |
                        SSI_SCR_TE | SSI_SCR_RE,
                        base + SSI_SCR);

        writel(SSI_SACNT_DEFAULT, base + SSI_SACNT);
        writel(0xff, base + SSI_SACCDIS);
        writel(0x300, base + SSI_SACCEN);
}

static struct imx_ssi *ac97_ssi;

static void imx_ssi_ac97_write(struct snd_ac97 *ac97, unsigned short reg,
                unsigned short val)
{
        struct imx_ssi *imx_ssi = ac97_ssi;
        void __iomem *base = imx_ssi->base;
        unsigned int lreg;
        unsigned int lval;

        if (reg > 0x7f)
                return;

        pr_debug("%s: 0x%02x 0x%04x\n", __func__, reg, val);

        lreg = reg <<  12;
        writel(lreg, base + SSI_SACADD);

        lval = val << 4;
        writel(lval , base + SSI_SACDAT);

        writel(SSI_SACNT_DEFAULT | SSI_SACNT_WR, base + SSI_SACNT);
        udelay(100);
}

static unsigned short imx_ssi_ac97_read(struct snd_ac97 *ac97,
                unsigned short reg)
{
        struct imx_ssi *imx_ssi = ac97_ssi;
        void __iomem *base = imx_ssi->base;

        unsigned short val = -1;
        unsigned int lreg;

        lreg = (reg & 0x7f) <<  12 ;
        writel(lreg, base + SSI_SACADD);
        writel(SSI_SACNT_DEFAULT | SSI_SACNT_RD, base + SSI_SACNT);

        udelay(100);

        val = (readl(base + SSI_SACDAT) >> 4) & 0xffff;

        pr_debug("%s: 0x%02x 0x%04x\n", __func__, reg, val);

        return val;
}

static void imx_ssi_ac97_reset(struct snd_ac97 *ac97)
{
        struct imx_ssi *imx_ssi = ac97_ssi;

        if (imx_ssi->ac97_reset)
                imx_ssi->ac97_reset(ac97);
        /* First read sometimes fails, do a dummy read */
        imx_ssi_ac97_read(ac97, 0);
}

static void imx_ssi_ac97_warm_reset(struct snd_ac97 *ac97)
{
        struct imx_ssi *imx_ssi = ac97_ssi;

        if (imx_ssi->ac97_warm_reset)
                imx_ssi->ac97_warm_reset(ac97);

        /* First read sometimes fails, do a dummy read */
        imx_ssi_ac97_read(ac97, 0);
}

static struct snd_ac97_bus_ops imx_ssi_ac97_ops = {
        .read           = imx_ssi_ac97_read,
        .write          = imx_ssi_ac97_write,
        .reset          = imx_ssi_ac97_reset,
        .warm_reset     = imx_ssi_ac97_warm_reset
};

static int imx_ssi_probe(struct platform_device *pdev)
{
        struct resource *res;
        struct imx_ssi *ssi;
        struct imx_ssi_platform_data *pdata = pdev->dev.platform_data;
        int ret = 0;
        struct snd_soc_dai_driver *dai;

        ssi = devm_kzalloc(&pdev->dev, sizeof(*ssi), GFP_KERNEL);
        if (!ssi)
                return -ENOMEM;
        dev_set_drvdata(&pdev->dev, ssi);

        if (pdata) {
                ssi->ac97_reset = pdata->ac97_reset;
                ssi->ac97_warm_reset = pdata->ac97_warm_reset;
                ssi->flags = pdata->flags;
        }

        ssi->irq = platform_get_irq(pdev, 0);

        ssi->clk = devm_clk_get(&pdev->dev, NULL);
        if (IS_ERR(ssi->clk)) {
                ret = PTR_ERR(ssi->clk);
                dev_err(&pdev->dev, "Cannot get the clock: %d\n",
                        ret);
                goto failed_clk;
        }
        clk_prepare_enable(ssi->clk);

        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        ssi->base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(ssi->base)) {
                ret = PTR_ERR(ssi->base);
                goto failed_register;
        }

        if (ssi->flags & IMX_SSI_USE_AC97) {
                if (ac97_ssi) {
                        dev_err(&pdev->dev, "AC'97 SSI already registered\n");
                        ret = -EBUSY;
                        goto failed_register;
                }
                ac97_ssi = ssi;
                setup_channel_to_ac97(ssi);
                dai = &imx_ac97_dai;
        } else
                dai = &imx_ssi_dai;

        writel(0x0, ssi->base + SSI_SIER);

        ssi->dma_params_rx.addr = res->start + SSI_SRX0;
        ssi->dma_params_tx.addr = res->start + SSI_STX0;

        ssi->dma_params_tx.maxburst = 6;
        ssi->dma_params_rx.maxburst = 4;

        ssi->dma_params_tx.filter_data = &ssi->filter_data_tx;
        ssi->dma_params_rx.filter_data = &ssi->filter_data_rx;

        res = platform_get_resource_byname(pdev, IORESOURCE_DMA, "tx0");
        if (res) {
                imx_pcm_dma_params_init_data(&ssi->filter_data_tx, res->start,
                        false);
        }

        res = platform_get_resource_byname(pdev, IORESOURCE_DMA, "rx0");
        if (res) {
                imx_pcm_dma_params_init_data(&ssi->filter_data_rx, res->start,
                        false);
        }

        platform_set_drvdata(pdev, ssi);

        ret = snd_soc_set_ac97_ops(&imx_ssi_ac97_ops);
        if (ret != 0) {
                dev_err(&pdev->dev, "Failed to set AC'97 ops: %d\n", ret);
                goto failed_register;
        }

        ret = snd_soc_register_component(&pdev->dev, &imx_component,
                                         dai, 1);
        if (ret) {
                dev_err(&pdev->dev, "register DAI failed\n");
                goto failed_register;
        }

        ret = imx_pcm_fiq_init(pdev);
        if (ret)
                goto failed_pcm_fiq;

        ret = imx_pcm_dma_init(pdev);
        if (ret)
                goto failed_pcm_dma;

        return 0;

failed_pcm_dma:
        imx_pcm_fiq_exit(pdev);
failed_pcm_fiq:
        snd_soc_unregister_component(&pdev->dev);
failed_register:
        release_mem_region(res->start, resource_size(res));
        clk_disable_unprepare(ssi->clk);
failed_clk:
        snd_soc_set_ac97_ops(NULL);

        return ret;
}

static int imx_ssi_remove(struct platform_device *pdev)
{
        struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        struct imx_ssi *ssi = platform_get_drvdata(pdev);

        imx_pcm_dma_exit(pdev);
        imx_pcm_fiq_exit(pdev);

        snd_soc_unregister_component(&pdev->dev);

        if (ssi->flags & IMX_SSI_USE_AC97)
                ac97_ssi = NULL;

        release_mem_region(res->start, resource_size(res));
        clk_disable_unprepare(ssi->clk);
        snd_soc_set_ac97_ops(NULL);

        return 0;
}

static struct platform_driver imx_ssi_driver = {
        .probe = imx_ssi_probe,
        .remove = imx_ssi_remove,

        .driver = {
                .name = "imx-ssi",
                .owner = THIS_MODULE,
        },
};

module_platform_driver(imx_ssi_driver);

/* Module information */
MODULE_AUTHOR("Sascha Hauer, <s.hauer@pengutronix.de>");
MODULE_DESCRIPTION("i.MX I2S/ac97 SoC Interface");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:imx-ssi");