text: /*
   * SH7760 ("camelot") DMABRG audio DMA unit support
   *
   * Copyright (C) 2007 Manuel Lauss <mano@roarinelk.homelinux.net>
   *  licensed under the terms outlined in the file COPYING at the root
   *  of the linux kernel sources.
   *
   * The SH7760 DMABRG provides 4 dma channels (2x rec, 2x play), which
   * trigger an interrupt when one half of the programmed transfer size
   * has been xmitted.
   *
   * FIXME: little-endian only for now
   */
  
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/platform_device.h>
  #include <linux/dma-mapping.h>
  #include <sound/driver.h>
  #include <sound/core.h>
  #include <sound/pcm.h>
  #include <sound/pcm_params.h>
  #include <sound/soc.h>
  #include <asm/dmabrg.h>
  
  
  /* registers and bits */
  #define BRGATXSAR	0x00
  #define BRGARXDAR	0x04
  #define BRGATXTCR	0x08
  #define BRGARXTCR	0x0C
  #define BRGACR		0x10
  #define BRGATXTCNT	0x14
  #define BRGARXTCNT	0x18
  
  #define ACR_RAR		(1 << 18)
  #define ACR_RDS		(1 << 17)
  #define ACR_RDE		(1 << 16)
  #define ACR_TAR		(1 << 2)
  #define ACR_TDS		(1 << 1)
  #define ACR_TDE		(1 << 0)
  
  /* receiver/transmitter data alignment */
  #define ACR_RAM_NONE	(0 << 24)
  #define ACR_RAM_4BYTE	(1 << 24)
  #define ACR_RAM_2WORD	(2 << 24)
  #define ACR_TAM_NONE	(0 << 8)
  #define ACR_TAM_4BYTE	(1 << 8)
  #define ACR_TAM_2WORD	(2 << 8)
  
  
  struct camelot_pcm {
  	unsigned long mmio;  /* DMABRG audio channel control reg MMIO */
  	unsigned int txid;    /* ID of first DMABRG IRQ for this unit */
  
  	struct snd_pcm_substream *tx_ss;
  	unsigned long tx_period_size;
  	unsigned int  tx_period;
  
  	struct snd_pcm_substream *rx_ss;
  	unsigned long rx_period_size;
  	unsigned int  rx_period;
  
  } cam_pcm_data[2] = {
  	{
  		.mmio	=	0xFE3C0040,
  		.txid	=	DMABRGIRQ_A0TXF,
  	},
  	{
  		.mmio	=	0xFE3C0060,
  		.txid	=	DMABRGIRQ_A1TXF,
  	},
  };
  
  #define BRGREG(x)	(*(unsigned long *)(cam->mmio + (x)))
  
  /*
   * set a minimum of 16kb per period, to avoid interrupt-"storm" and
   * resulting skipping. In general, the bigger the minimum size, the
   * better for overall system performance. (The SH7760 is a puny CPU
   * with a slow SDRAM interface and poor internal bus bandwidth,
   * *especially* when the LCDC is active).  The minimum for the DMAC
   * is 8 bytes; 16kbytes are enough to get skip-free playback of a
   * 44kHz/16bit/stereo MP3 on a lightly loaded system, and maintain
   * reasonable responsiveness in MPlayer.
   */
  #define DMABRG_PERIOD_MIN		16 * 1024
  #define DMABRG_PERIOD_MAX		0x03fffffc
  #define DMABRG_PREALLOC_BUFFER		32 * 1024
  #define DMABRG_PREALLOC_BUFFER_MAX	32 * 1024
  
  /* support everything the SSI supports */
  #define DMABRG_RATES	\
  	SNDRV_PCM_RATE_8000_192000
  
  #define DMABRG_FMTS	\
  	(SNDRV_PCM_FMTBIT_S8      | SNDRV_PCM_FMTBIT_U8      |	\
  	 SNDRV_PCM_FMTBIT_S16_LE  | SNDRV_PCM_FMTBIT_U16_LE  |	\
  	 SNDRV_PCM_FMTBIT_S20_3LE | SNDRV_PCM_FMTBIT_U20_3LE |	\
  	 SNDRV_PCM_FMTBIT_S24_3LE | SNDRV_PCM_FMTBIT_U24_3LE |	\
  	 SNDRV_PCM_FMTBIT_S32_LE  | SNDRV_PCM_FMTBIT_U32_LE)
  
  static struct snd_pcm_hardware camelot_pcm_hardware = {
  	.info = (SNDRV_PCM_INFO_MMAP |
  		SNDRV_PCM_INFO_INTERLEAVED |
  		SNDRV_PCM_INFO_BLOCK_TRANSFER |
  		SNDRV_PCM_INFO_MMAP_VALID),
  	.formats =	DMABRG_FMTS,
  	.rates =	DMABRG_RATES,
  	.rate_min =		8000,
  	.rate_max =		192000,
  	.channels_min =		2,
  	.channels_max =		8,		/* max of the SSI */
  	.buffer_bytes_max =	DMABRG_PERIOD_MAX,
  	.period_bytes_min =	DMABRG_PERIOD_MIN,
  	.period_bytes_max =	DMABRG_PERIOD_MAX / 2,
  	.periods_min =		2,
  	.periods_max =		2,
  	.fifo_size =		128,
  };
  
  static void camelot_txdma(void *data)
  {
  	struct camelot_pcm *cam = data;
  	cam->tx_period ^= 1;
  	snd_pcm_period_elapsed(cam->tx_ss);
  }
  
  static void camelot_rxdma(void *data)
  {
  	struct camelot_pcm *cam = data;
  	cam->rx_period ^= 1;
  	snd_pcm_period_elapsed(cam->rx_ss);
  }
  
  static int camelot_pcm_open(struct snd_pcm_substream *substream)
  {
  	struct snd_soc_pcm_runtime *rtd = substream->private_data;
  	struct camelot_pcm *cam = &cam_pcm_data[rtd->dai->cpu_dai->id];
  	int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
  	int ret, dmairq;
  
  	snd_soc_set_runtime_hwparams(substream, &camelot_pcm_hardware);
  
  	/* DMABRG buffer half/full events */
  	dmairq = (recv) ? cam->txid + 2 : cam->txid;
  	if (recv) {
  		cam->rx_ss = substream;
  		ret = dmabrg_request_irq(dmairq, camelot_rxdma, cam);
  		if (unlikely(ret)) {
  			pr_debug("audio unit %d irqs already taken!\n",
  			     rtd->dai->cpu_dai->id);
  			return -EBUSY;
  		}
  		(void)dmabrg_request_irq(dmairq + 1,camelot_rxdma, cam);
  	} else {
  		cam->tx_ss = substream;
  		ret = dmabrg_request_irq(dmairq, camelot_txdma, cam);
  		if (unlikely(ret)) {
  			pr_debug("audio unit %d irqs already taken!\n",
  			     rtd->dai->cpu_dai->id);
  			return -EBUSY;
  		}
  		(void)dmabrg_request_irq(dmairq + 1, camelot_txdma, cam);
  	}
  	return 0;
  }
  
  static int camelot_pcm_close(struct snd_pcm_substream *substream)
  {
  	struct snd_soc_pcm_runtime *rtd = substream->private_data;
  	struct camelot_pcm *cam = &cam_pcm_data[rtd->dai->cpu_dai->id];
  	int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
  	int dmairq;
  
  	dmairq = (recv) ? cam->txid + 2 : cam->txid;
  
  	if (recv)
  		cam->rx_ss = NULL;
  	else
  		cam->tx_ss = NULL;
  
  	dmabrg_free_irq(dmairq + 1);
  	dmabrg_free_irq(dmairq);
  
  	return 0;
  }
  
  static int camelot_hw_params(struct snd_pcm_substream *substream,
  			     struct snd_pcm_hw_params *hw_params)
  {
  	struct snd_soc_pcm_runtime *rtd = substream->private_data;
  	struct camelot_pcm *cam = &cam_pcm_data[rtd->dai->cpu_dai->id];
  	int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
  	int ret;
  
  	ret = snd_pcm_lib_malloc_pages(substream,
  				       params_buffer_bytes(hw_params));
  	if (ret < 0)
  		return ret;
  
  	if (recv) {
  		cam->rx_period_size = params_period_bytes(hw_params);
  		cam->rx_period = 0;
  	} else {
  		cam->tx_period_size = params_period_bytes(hw_params);
  		cam->tx_period = 0;
  	}
  	return 0;
  }
  
  static int camelot_hw_free(struct snd_pcm_substream *substream)
  {
  	return snd_pcm_lib_free_pages(substream);
  }
  
  static int camelot_prepare(struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct snd_soc_pcm_runtime *rtd = substream->private_data;
  	struct camelot_pcm *cam = &cam_pcm_data[rtd->dai->cpu_dai->id];
  
  	pr_debug("PCM data: addr 0x%08ulx len %d\n",
  		 (u32)runtime->dma_addr, runtime->dma_bytes);
   
  	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
  		BRGREG(BRGATXSAR) = (unsigned long)runtime->dma_area;
  		BRGREG(BRGATXTCR) = runtime->dma_bytes;
  	} else {
  		BRGREG(BRGARXDAR) = (unsigned long)runtime->dma_area;
  		BRGREG(BRGARXTCR) = runtime->dma_bytes;
  	}
  
  	return 0;
  }
  
  static inline void dmabrg_play_dma_start(struct camelot_pcm *cam)
  {
  	unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
  	/* start DMABRG engine: XFER start, auto-addr-reload */
  	BRGREG(BRGACR) = acr | ACR_TDE | ACR_TAR | ACR_TAM_2WORD;
  }
  
  static inline void dmabrg_play_dma_stop(struct camelot_pcm *cam)
  {
  	unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
  	/* forcibly terminate data transmission */
  	BRGREG(BRGACR) = acr | ACR_TDS;
  }
  
  static inline void dmabrg_rec_dma_start(struct camelot_pcm *cam)
  {
  	unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
  	/* start DMABRG engine: recv start, auto-reload */
  	BRGREG(BRGACR) = acr | ACR_RDE | ACR_RAR | ACR_RAM_2WORD;
  }
  
  static inline void dmabrg_rec_dma_stop(struct camelot_pcm *cam)
  {
  	unsigned long acr = BRGREG(BRGACR) & ~(ACR_TDS | ACR_RDS);
  	/* forcibly terminate data receiver */
  	BRGREG(BRGACR) = acr | ACR_RDS;
  }
  
  static int camelot_trigger(struct snd_pcm_substream *substream, int cmd)
  {
  	struct snd_soc_pcm_runtime *rtd = substream->private_data;
  	struct camelot_pcm *cam = &cam_pcm_data[rtd->dai->cpu_dai->id];
  	int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
  
  	switch (cmd) {
  	case SNDRV_PCM_TRIGGER_START:
  		if (recv)
  			dmabrg_rec_dma_start(cam);
  		else
  			dmabrg_play_dma_start(cam);
  		break;
  	case SNDRV_PCM_TRIGGER_STOP:
  		if (recv)
  			dmabrg_rec_dma_stop(cam);
  		else
  			dmabrg_play_dma_stop(cam);
  		break;
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static snd_pcm_uframes_t camelot_pos(struct snd_pcm_substream *substream)
  {
  	struct snd_pcm_runtime *runtime = substream->runtime;
  	struct snd_soc_pcm_runtime *rtd = substream->private_data;
  	struct camelot_pcm *cam = &cam_pcm_data[rtd->dai->cpu_dai->id];
  	int recv = substream->stream == SNDRV_PCM_STREAM_PLAYBACK ? 0:1;
  	unsigned long pos;
  
  	/* cannot use the DMABRG pointer register: under load, by the
  	 * time ALSA comes around to read the register, it is already
  	 * far ahead (or worse, already done with the fragment) of the
  	 * position at the time the IRQ was triggered, which results in
  	 * fast-playback sound in my test application (ScummVM)
  	 */
  	if (recv)
  		pos = cam->rx_period ? cam->rx_period_size : 0;
  	else
  		pos = cam->tx_period ? cam->tx_period_size : 0;
  
  	return bytes_to_frames(runtime, pos);
  }
  
  static struct snd_pcm_ops camelot_pcm_ops = {
  	.open		= camelot_pcm_open,
  	.close		= camelot_pcm_close,
  	.ioctl		= snd_pcm_lib_ioctl,
  	.hw_params	= camelot_hw_params,
  	.hw_free	= camelot_hw_free,
  	.prepare	= camelot_prepare,
  	.trigger	= camelot_trigger,
  	.pointer	= camelot_pos,
  };
  
  static void camelot_pcm_free(struct snd_pcm *pcm)
  {
  	snd_pcm_lib_preallocate_free_for_all(pcm);
  }
  
  static int camelot_pcm_new(struct snd_card *card,
  			   struct snd_soc_codec_dai *dai,
  			   struct snd_pcm *pcm)
  {
  	/* dont use SNDRV_DMA_TYPE_DEV, since it will oops the SH kernel
  	 * in MMAP mode (i.e. aplay -M)
  	 */
  	snd_pcm_lib_preallocate_pages_for_all(pcm,
  		SNDRV_DMA_TYPE_CONTINUOUS,
  		snd_dma_continuous_data(GFP_KERNEL),
  		DMABRG_PREALLOC_BUFFER,	DMABRG_PREALLOC_BUFFER_MAX);
  
  	return 0;
  }
  
  struct snd_soc_platform sh7760_soc_platform = {
  	.name		= "sh7760-pcm",
  	.pcm_ops 	= &camelot_pcm_ops,
  	.pcm_new	= camelot_pcm_new,
  	.pcm_free	= camelot_pcm_free,
  };
  EXPORT_SYMBOL_GPL(sh7760_soc_platform);
  
  MODULE_LICENSE("GPL");
  MODULE_DESCRIPTION("SH7760 Audio DMA (DMABRG) driver");
  MODULE_AUTHOR("Manuel Lauss <mano@roarinelk.homelinux.net>");
  