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mpc5200_dma.c

/*
 * 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 <linux/slab.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->runtime->dma_addr + (s->period_next * s->period_bytes);
      bcom_submit_next_buffer(s->bcom_task, NULL);

      /* Update for next period */
      s->period_next = (s->period_next + 1) % s->runtime->periods;
}

/* Bestcomm DMA irq handler */
static irqreturn_t psc_dma_bcom_irq(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 = (s->period_current+1) % s->runtime->periods;
            s->period_count++;

            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 = to_psc_dma_stream(substream, psc_dma);
      struct mpc52xx_psc __iomem *regs = psc_dma->psc_regs;
      u16 imr;
      unsigned long flags;
      int i;

      switch (cmd) {
      case SNDRV_PCM_TRIGGER_START:
            dev_dbg(psc_dma->dev, "START: stream=%i fbits=%u ps=%u #p=%u\n",
                  substream->pstr->stream, runtime->frame_bits,
                  (int)runtime->period_size, runtime->periods);
            s->period_bytes = frames_to_bytes(runtime,
                                      runtime->period_size);
            s->period_next = 0;
            s->period_current = 0;
            s->active = 1;
            s->period_count = 0;
            s->runtime = runtime;

            /* 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);
            else
                  bcom_gen_bd_tx_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);

            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:
            dev_dbg(psc_dma->dev, "STOP: stream=%i periods_count=%i\n",
                  substream->pstr->stream, s->period_count);
            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, "unhandled trigger: stream=%i cmd=%i\n",
                  substream->pstr->stream, cmd);
            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 * s->period_bytes;

      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, IRQF_SHARED,
                    "psc-dma-capture", &psc_dma->capture);
      rc |= request_irq(psc_dma->playback.irq, &psc_dma_bcom_irq, 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");

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