/*
 * Freescale MPC5200 PSC DMA
 * ALSA SoC Platform driver
 *
 * Copyright (C) 2008 Secret Lab Technologies Ltd.
 * Copyright (C) 2009 Jon Smirl, Digispeaker
 */

#include <linux/module.h>
#include <linux/of_device.h>

#include <sound/soc.h>

#include <sysdev/bestcomm/bestcomm.h>
#include <sysdev/bestcomm/gen_bd.h>
#include <asm/mpc52xx_psc.h>

#include "mpc5200_dma.h"

/*
 * Interrupt handlers
 */
static irqreturn_t psc_dma_status_irq(int irq, void *_psc_dma)
{
        struct psc_dma *psc_dma = _psc_dma;
        struct mpc52xx_psc __iomem *regs = psc_dma->psc_regs;
        u16 isr;

        isr = in_be16(&regs->mpc52xx_psc_isr);

        /* Playback underrun error */
        if (psc_dma->playback.active && (isr & MPC52xx_PSC_IMR_TXEMP))
                psc_dma->stats.underrun_count++;

        /* Capture overrun error */
        if (psc_dma->capture.active && (isr & MPC52xx_PSC_IMR_ORERR))
                psc_dma->stats.overrun_count++;

        out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);

        return IRQ_HANDLED;
}

/**
 * psc_dma_bcom_enqueue_next_buffer - Enqueue another audio buffer
 * @s: pointer to stream private data structure
 *
 * Enqueues another audio period buffer into the bestcomm queue.
 *
 * Note: The routine must only be called when there is space available in
 * the queue.  Otherwise the enqueue will fail and the audio ring buffer
 * will get out of sync
 */
static void psc_dma_bcom_enqueue_next_buffer(struct psc_dma_stream *s)
{
        struct bcom_bd *bd;

        /* Prepare and enqueue the next buffer descriptor */
        bd = bcom_prepare_next_buffer(s->bcom_task);
        bd->status = s->period_bytes;
        bd->data[0] = s->period_next_pt;
        bcom_submit_next_buffer(s->bcom_task, NULL);

        /* Update for next period */
        s->period_next_pt += s->period_bytes;
        if (s->period_next_pt >= s->period_end)
                s->period_next_pt = s->period_start;
}

static void psc_dma_bcom_enqueue_tx(struct psc_dma_stream *s)
{
        if (s->appl_ptr > s->runtime->control->appl_ptr) {
                /*
                 * In this case s->runtime->control->appl_ptr has wrapped around.
                 * Play the data to the end of the boundary, then wrap our own
                 * appl_ptr back around.
                 */
                while (s->appl_ptr < s->runtime->boundary) {
                        if (bcom_queue_full(s->bcom_task))
                                return;

                        s->appl_ptr += s->period_size;

                        psc_dma_bcom_enqueue_next_buffer(s);
                }
                s->appl_ptr -= s->runtime->boundary;
        }

        while (s->appl_ptr < s->runtime->control->appl_ptr) {

                if (bcom_queue_full(s->bcom_task))
                        return;

                s->appl_ptr += s->period_size;

                psc_dma_bcom_enqueue_next_buffer(s);
        }
}

/* Bestcomm DMA irq handler */
static irqreturn_t psc_dma_bcom_irq_tx(int irq, void *_psc_dma_stream)
{
        struct psc_dma_stream *s = _psc_dma_stream;

        spin_lock(&s->psc_dma->lock);
        /* For each finished period, dequeue the completed period buffer
         * and enqueue a new one in it's place. */
        while (bcom_buffer_done(s->bcom_task)) {
                bcom_retrieve_buffer(s->bcom_task, NULL, NULL);

                s->period_current_pt += s->period_bytes;
                if (s->period_current_pt >= s->period_end)
                        s->period_current_pt = s->period_start;
        }
        psc_dma_bcom_enqueue_tx(s);
        spin_unlock(&s->psc_dma->lock);

        /* If the stream is active, then also inform the PCM middle layer
         * of the period finished event. */
        if (s->active)
                snd_pcm_period_elapsed(s->stream);

        return IRQ_HANDLED;
}

static irqreturn_t psc_dma_bcom_irq_rx(int irq, void *_psc_dma_stream)
{
        struct psc_dma_stream *s = _psc_dma_stream;

        spin_lock(&s->psc_dma->lock);
        /* For each finished period, dequeue the completed period buffer
         * and enqueue a new one in it's place. */
        while (bcom_buffer_done(s->bcom_task)) {
                bcom_retrieve_buffer(s->bcom_task, NULL, NULL);

                s->period_current_pt += s->period_bytes;
                if (s->period_current_pt >= s->period_end)
                        s->period_current_pt = s->period_start;

                psc_dma_bcom_enqueue_next_buffer(s);
        }
        spin_unlock(&s->psc_dma->lock);

        /* If the stream is active, then also inform the PCM middle layer
         * of the period finished event. */
        if (s->active)
                snd_pcm_period_elapsed(s->stream);

        return IRQ_HANDLED;
}

static int psc_dma_hw_free(struct snd_pcm_substream *substream)
{
        snd_pcm_set_runtime_buffer(substream, NULL);
        return 0;
}

/**
 * psc_dma_trigger: start and stop the DMA transfer.
 *
 * This function is called by ALSA to start, stop, pause, and resume the DMA
 * transfer of data.
 */
static int psc_dma_trigger(struct snd_pcm_substream *substream, int cmd)
{
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct psc_dma *psc_dma = rtd->dai->cpu_dai->private_data;
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct psc_dma_stream *s;
        struct mpc52xx_psc __iomem *regs = psc_dma->psc_regs;
        u16 imr;
        unsigned long flags;
        int i;

        if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
                s = &psc_dma->capture;
        else
                s = &psc_dma->playback;

        dev_dbg(psc_dma->dev, "psc_dma_trigger(substream=%p, cmd=%i)"
                " stream_id=%i\n",
                substream, cmd, substream->pstr->stream);

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
                s->period_bytes = frames_to_bytes(runtime,
                                                  runtime->period_size);
                s->period_start = virt_to_phys(runtime->dma_area);
                s->period_end = s->period_start +
                                (s->period_bytes * runtime->periods);
                s->period_next_pt = s->period_start;
                s->period_current_pt = s->period_start;
                s->period_size = runtime->period_size;
                s->active = 1;

                /* track appl_ptr so that we have a better chance of detecting
                 * end of stream and not over running it.
                 */
                s->runtime = runtime;
                s->appl_ptr = s->runtime->control->appl_ptr -
                                (runtime->period_size * runtime->periods);

                /* Fill up the bestcomm bd queue and enable DMA.
                 * This will begin filling the PSC's fifo.
                 */
                spin_lock_irqsave(&psc_dma->lock, flags);

                if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE) {
                        bcom_gen_bd_rx_reset(s->bcom_task);
                        for (i = 0; i < runtime->periods; i++)
                                if (!bcom_queue_full(s->bcom_task))
                                        psc_dma_bcom_enqueue_next_buffer(s);
                } else {
                        bcom_gen_bd_tx_reset(s->bcom_task);
                        psc_dma_bcom_enqueue_tx(s);
                }

                bcom_enable(s->bcom_task);
                spin_unlock_irqrestore(&psc_dma->lock, flags);

                out_8(&regs->command, MPC52xx_PSC_RST_ERR_STAT);

                break;

        case SNDRV_PCM_TRIGGER_STOP:
                s->active = 0;

                spin_lock_irqsave(&psc_dma->lock, flags);
                bcom_disable(s->bcom_task);
                if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
                        bcom_gen_bd_rx_reset(s->bcom_task);
                else
                        bcom_gen_bd_tx_reset(s->bcom_task);
                spin_unlock_irqrestore(&psc_dma->lock, flags);

                break;

        default:
                dev_dbg(psc_dma->dev, "invalid command\n");
                return -EINVAL;
        }

        /* Update interrupt enable settings */
        imr = 0;
        if (psc_dma->playback.active)
                imr |= MPC52xx_PSC_IMR_TXEMP;
        if (psc_dma->capture.active)
                imr |= MPC52xx_PSC_IMR_ORERR;
        out_be16(&regs->isr_imr.imr, psc_dma->imr | imr);

        return 0;
}


/* ---------------------------------------------------------------------
 * The PSC DMA 'ASoC platform' driver
 *
 * Can be referenced by an 'ASoC machine' driver
 * This driver only deals with the audio bus; it doesn't have any
 * interaction with the attached codec
 */

static const struct snd_pcm_hardware psc_dma_hardware = {
        .info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
                SNDRV_PCM_INFO_INTERLEAVED | SNDRV_PCM_INFO_BLOCK_TRANSFER |
                SNDRV_PCM_INFO_BATCH,
        .formats = SNDRV_PCM_FMTBIT_S8 | SNDRV_PCM_FMTBIT_S16_BE |
                SNDRV_PCM_FMTBIT_S24_BE | SNDRV_PCM_FMTBIT_S32_BE,
        .rate_min = 8000,
        .rate_max = 48000,
        .channels_min = 1,
        .channels_max = 2,
        .period_bytes_max       = 1024 * 1024,
        .period_bytes_min       = 32,
        .periods_min            = 2,
        .periods_max            = 256,
        .buffer_bytes_max       = 2 * 1024 * 1024,
        .fifo_size              = 512,
};

static int psc_dma_open(struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct psc_dma *psc_dma = rtd->dai->cpu_dai->private_data;
        struct psc_dma_stream *s;
        int rc;

        dev_dbg(psc_dma->dev, "psc_dma_open(substream=%p)\n", substream);

        if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
                s = &psc_dma->capture;
        else
                s = &psc_dma->playback;

        snd_soc_set_runtime_hwparams(substream, &psc_dma_hardware);

        rc = snd_pcm_hw_constraint_integer(runtime,
                SNDRV_PCM_HW_PARAM_PERIODS);
        if (rc < 0) {
                dev_err(substream->pcm->card->dev, "invalid buffer size\n");
                return rc;
        }

        s->stream = substream;
        return 0;
}

static int psc_dma_close(struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct psc_dma *psc_dma = rtd->dai->cpu_dai->private_data;
        struct psc_dma_stream *s;

        dev_dbg(psc_dma->dev, "psc_dma_close(substream=%p)\n", substream);

        if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
                s = &psc_dma->capture;
        else
                s = &psc_dma->playback;

        if (!psc_dma->playback.active &&
            !psc_dma->capture.active) {

                /* Disable all interrupts and reset the PSC */
                out_be16(&psc_dma->psc_regs->isr_imr.imr, psc_dma->imr);
                out_8(&psc_dma->psc_regs->command, 4 << 4); /* reset error */
        }
        s->stream = NULL;
        return 0;
}

static snd_pcm_uframes_t
psc_dma_pointer(struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct psc_dma *psc_dma = rtd->dai->cpu_dai->private_data;
        struct psc_dma_stream *s;
        dma_addr_t count;

        if (substream->pstr->stream == SNDRV_PCM_STREAM_CAPTURE)
                s = &psc_dma->capture;
        else
                s = &psc_dma->playback;

        count = s->period_current_pt - s->period_start;

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

static int
psc_dma_hw_params(struct snd_pcm_substream *substream,
                         struct snd_pcm_hw_params *params)
{
        snd_pcm_set_runtime_buffer(substream, &substream->dma_buffer);

        return 0;
}

static struct snd_pcm_ops psc_dma_ops = {
        .open           = psc_dma_open,
        .close          = psc_dma_close,
        .hw_free        = psc_dma_hw_free,
        .ioctl          = snd_pcm_lib_ioctl,
        .pointer        = psc_dma_pointer,
        .trigger        = psc_dma_trigger,
        .hw_params      = psc_dma_hw_params,
};

static u64 psc_dma_dmamask = 0xffffffff;
static int psc_dma_new(struct snd_card *card, struct snd_soc_dai *dai,
                           struct snd_pcm *pcm)
{
        struct snd_soc_pcm_runtime *rtd = pcm->private_data;
        struct psc_dma *psc_dma = rtd->dai->cpu_dai->private_data;
        size_t size = psc_dma_hardware.buffer_bytes_max;
        int rc = 0;

        dev_dbg(rtd->socdev->dev, "psc_dma_new(card=%p, dai=%p, pcm=%p)\n",
                card, dai, pcm);

        if (!card->dev->dma_mask)
                card->dev->dma_mask = &psc_dma_dmamask;
        if (!card->dev->coherent_dma_mask)
                card->dev->coherent_dma_mask = 0xffffffff;

        if (pcm->streams[0].substream) {
                rc = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->card->dev,
                                size, &pcm->streams[0].substream->dma_buffer);
                if (rc)
                        goto playback_alloc_err;
        }

        if (pcm->streams[1].substream) {
                rc = snd_dma_alloc_pages(SNDRV_DMA_TYPE_DEV, pcm->card->dev,
                                size, &pcm->streams[1].substream->dma_buffer);
                if (rc)
                        goto capture_alloc_err;
        }

        if (rtd->socdev->card->codec->ac97)
                rtd->socdev->card->codec->ac97->private_data = psc_dma;

        return 0;

 capture_alloc_err:
        if (pcm->streams[0].substream)
                snd_dma_free_pages(&pcm->streams[0].substream->dma_buffer);

 playback_alloc_err:
        dev_err(card->dev, "Cannot allocate buffer(s)\n");

        return -ENOMEM;
}

static void psc_dma_free(struct snd_pcm *pcm)
{
        struct snd_soc_pcm_runtime *rtd = pcm->private_data;
        struct snd_pcm_substream *substream;
        int stream;

        dev_dbg(rtd->socdev->dev, "psc_dma_free(pcm=%p)\n", pcm);

        for (stream = 0; stream < 2; stream++) {
                substream = pcm->streams[stream].substream;
                if (substream) {
                        snd_dma_free_pages(&substream->dma_buffer);
                        substream->dma_buffer.area = NULL;
                        substream->dma_buffer.addr = 0;
                }
        }
}

struct snd_soc_platform mpc5200_audio_dma_platform = {
        .name           = "mpc5200-psc-audio",
        .pcm_ops        = &psc_dma_ops,
        .pcm_new        = &psc_dma_new,
        .pcm_free       = &psc_dma_free,
};
EXPORT_SYMBOL_GPL(mpc5200_audio_dma_platform);

int mpc5200_audio_dma_create(struct of_device *op)
{
        phys_addr_t fifo;
        struct psc_dma *psc_dma;
        struct resource res;
        int size, irq, rc;
        const __be32 *prop;
        void __iomem *regs;
        int ret;

        /* Fetch the registers and IRQ of the PSC */
        irq = irq_of_parse_and_map(op->node, 0);
        if (of_address_to_resource(op->node, 0, &res)) {
                dev_err(&op->dev, "Missing reg property\n");
                return -ENODEV;
        }
        regs = ioremap(res.start, 1 + res.end - res.start);
        if (!regs) {
                dev_err(&op->dev, "Could not map registers\n");
                return -ENODEV;
        }

        /* Allocate and initialize the driver private data */
        psc_dma = kzalloc(sizeof *psc_dma, GFP_KERNEL);
        if (!psc_dma) {
                ret = -ENOMEM;
                goto out_unmap;
        }

        /* Get the PSC ID */
        prop = of_get_property(op->node, "cell-index", &size);
        if (!prop || size < sizeof *prop) {
                ret = -ENODEV;
                goto out_free;
        }

        spin_lock_init(&psc_dma->lock);
        mutex_init(&psc_dma->mutex);
        psc_dma->id = be32_to_cpu(*prop);
        psc_dma->irq = irq;
        psc_dma->psc_regs = regs;
        psc_dma->fifo_regs = regs + sizeof *psc_dma->psc_regs;
        psc_dma->dev = &op->dev;
        psc_dma->playback.psc_dma = psc_dma;
        psc_dma->capture.psc_dma = psc_dma;
        snprintf(psc_dma->name, sizeof psc_dma->name, "PSC%u", psc_dma->id);

        /* Find the address of the fifo data registers and setup the
         * DMA tasks */
        fifo = res.start + offsetof(struct mpc52xx_psc, buffer.buffer_32);
        psc_dma->capture.bcom_task =
                bcom_psc_gen_bd_rx_init(psc_dma->id, 10, fifo, 512);
        psc_dma->playback.bcom_task =
                bcom_psc_gen_bd_tx_init(psc_dma->id, 10, fifo);
        if (!psc_dma->capture.bcom_task ||
            !psc_dma->playback.bcom_task) {
                dev_err(&op->dev, "Could not allocate bestcomm tasks\n");
                ret = -ENODEV;
                goto out_free;
        }

        /* Disable all interrupts and reset the PSC */
        out_be16(&psc_dma->psc_regs->isr_imr.imr, psc_dma->imr);
         /* reset receiver */
        out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_RST_RX);
         /* reset transmitter */
        out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_RST_TX);
         /* reset error */
        out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_RST_ERR_STAT);
         /* reset mode */
        out_8(&psc_dma->psc_regs->command, MPC52xx_PSC_SEL_MODE_REG_1);

        /* Set up mode register;
         * First write: RxRdy (FIFO Alarm) generates rx FIFO irq
         * Second write: register Normal mode for non loopback
         */
        out_8(&psc_dma->psc_regs->mode, 0);
        out_8(&psc_dma->psc_regs->mode, 0);

        /* Set the TX and RX fifo alarm thresholds */
        out_be16(&psc_dma->fifo_regs->rfalarm, 0x100);
        out_8(&psc_dma->fifo_regs->rfcntl, 0x4);
        out_be16(&psc_dma->fifo_regs->tfalarm, 0x100);
        out_8(&psc_dma->fifo_regs->tfcntl, 0x7);

        /* Lookup the IRQ numbers */
        psc_dma->playback.irq =
                bcom_get_task_irq(psc_dma->playback.bcom_task);
        psc_dma->capture.irq =
                bcom_get_task_irq(psc_dma->capture.bcom_task);

        rc = request_irq(psc_dma->irq, &psc_dma_status_irq, IRQF_SHARED,
                         "psc-dma-status", psc_dma);
        rc |= request_irq(psc_dma->capture.irq,
                          &psc_dma_bcom_irq_rx, IRQF_SHARED,
                          "psc-dma-capture", &psc_dma->capture);
        rc |= request_irq(psc_dma->playback.irq,
                          &psc_dma_bcom_irq_tx, IRQF_SHARED,
                          "psc-dma-playback", &psc_dma->playback);
        if (rc) {
                ret = -ENODEV;
                goto out_irq;
        }

        /* Save what we've done so it can be found again later */
        dev_set_drvdata(&op->dev, psc_dma);

        /* Tell the ASoC OF helpers about it */
        return snd_soc_register_platform(&mpc5200_audio_dma_platform);
out_irq:
        free_irq(psc_dma->irq, psc_dma);
        free_irq(psc_dma->capture.irq, &psc_dma->capture);
        free_irq(psc_dma->playback.irq, &psc_dma->playback);
out_free:
        kfree(psc_dma);
out_unmap:
        iounmap(regs);
        return ret;
}
EXPORT_SYMBOL_GPL(mpc5200_audio_dma_create);

int mpc5200_audio_dma_destroy(struct of_device *op)
{
        struct psc_dma *psc_dma = dev_get_drvdata(&op->dev);

        dev_dbg(&op->dev, "mpc5200_audio_dma_destroy()\n");

        snd_soc_unregister_platform(&mpc5200_audio_dma_platform);

        bcom_gen_bd_rx_release(psc_dma->capture.bcom_task);
        bcom_gen_bd_tx_release(psc_dma->playback.bcom_task);

        /* Release irqs */
        free_irq(psc_dma->irq, psc_dma);
        free_irq(psc_dma->capture.irq, &psc_dma->capture);
        free_irq(psc_dma->playback.irq, &psc_dma->playback);

        iounmap(psc_dma->psc_regs);
        kfree(psc_dma);
        dev_set_drvdata(&op->dev, NULL);

        return 0;
}
EXPORT_SYMBOL_GPL(mpc5200_audio_dma_destroy);

MODULE_AUTHOR("Grant Likely <grant.likely@secretlab.ca>");
MODULE_DESCRIPTION("Freescale MPC5200 PSC in DMA mode ASoC Driver");
MODULE_LICENSE("GPL");