imx-pcm-fiq.c

// SPDX-License-Identifier: GPL-2.0+
// imx-pcm-fiq.c  --  ALSA Soc Audio Layer
//
// Copyright 2009 Sascha Hauer <[email protected]>
//
// This code is based on code copyrighted by Freescale,
// Liam Girdwood, Javier Martin and probably others.

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

#include <asm/fiq.h>

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

#include "imx-ssi.h"
#include "imx-pcm.h"

struct imx_pcm_runtime_data {
	unsigned int period;
	int periods;
	unsigned long offset;
	struct hrtimer hrt;
	int poll_time_ns;
	struct snd_pcm_substream *substream;
	atomic_t playing;
	atomic_t capturing;
};

static enum hrtimer_restart snd_hrtimer_callback(struct hrtimer *hrt)
{
	struct imx_pcm_runtime_data *iprtd =
		container_of(hrt, struct imx_pcm_runtime_data, hrt);
	struct snd_pcm_substream *substream = iprtd->substream;
	struct pt_regs regs;

	if (!atomic_read(&iprtd->playing) && !atomic_read(&iprtd->capturing))
		return HRTIMER_NORESTART;

	get_fiq_regs(&regs);

	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
		iprtd->offset = regs.ARM_r8 & 0xffff;
	else
		iprtd->offset = regs.ARM_r9 & 0xffff;

	snd_pcm_period_elapsed(substream);

	hrtimer_forward_now(hrt, ns_to_ktime(iprtd->poll_time_ns));

	return HRTIMER_RESTART;
}

static struct fiq_handler fh = {
	.name		= DRV_NAME,
};

static int snd_imx_pcm_hw_params(struct snd_soc_component *component,
				 struct snd_pcm_substream *substream,
				 struct snd_pcm_hw_params *params)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	iprtd->periods = params_periods(params);
	iprtd->period = params_period_bytes(params);
	iprtd->offset = 0;
	iprtd->poll_time_ns = 1000000000 / params_rate(params) *
				params_period_size(params);

	return 0;
}

static int snd_imx_pcm_prepare(struct snd_soc_component *component,
			       struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;
	struct pt_regs regs;

	get_fiq_regs(&regs);
	if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
		regs.ARM_r8 = (iprtd->period * iprtd->periods - 1) << 16;
	else
		regs.ARM_r9 = (iprtd->period * iprtd->periods - 1) << 16;

	set_fiq_regs(&regs);

	return 0;
}

static int imx_pcm_fiq;

static int snd_imx_pcm_trigger(struct snd_soc_component *component,
			       struct snd_pcm_substream *substream, int cmd)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	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)
			atomic_set(&iprtd->playing, 1);
		else
			atomic_set(&iprtd->capturing, 1);
		hrtimer_start(&iprtd->hrt, ns_to_ktime(iprtd->poll_time_ns),
		      HRTIMER_MODE_REL);
		enable_fiq(imx_pcm_fiq);
		break;

	case SNDRV_PCM_TRIGGER_STOP:
	case SNDRV_PCM_TRIGGER_SUSPEND:
	case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
		if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
			atomic_set(&iprtd->playing, 0);
		else
			atomic_set(&iprtd->capturing, 0);
		if (!atomic_read(&iprtd->playing) &&
				!atomic_read(&iprtd->capturing))
			disable_fiq(imx_pcm_fiq);
		break;

	default:
		return -EINVAL;
	}

	return 0;
}

static snd_pcm_uframes_t
snd_imx_pcm_pointer(struct snd_soc_component *component,
		    struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	return bytes_to_frames(substream->runtime, iprtd->offset);
}

static const struct snd_pcm_hardware snd_imx_hardware = {
	.info = SNDRV_PCM_INFO_INTERLEAVED |
		SNDRV_PCM_INFO_BLOCK_TRANSFER |
		SNDRV_PCM_INFO_MMAP |
		SNDRV_PCM_INFO_MMAP_VALID |
		SNDRV_PCM_INFO_PAUSE |
		SNDRV_PCM_INFO_RESUME,
	.formats = SNDRV_PCM_FMTBIT_S16_LE,
	.buffer_bytes_max = IMX_SSI_DMABUF_SIZE,
	.period_bytes_min = 128,
	.period_bytes_max = 16 * 1024,
	.periods_min = 4,
	.periods_max = 255,
	.fifo_size = 0,
};

static int snd_imx_open(struct snd_soc_component *component,
			struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd;
	int ret;

	iprtd = kzalloc(sizeof(*iprtd), GFP_KERNEL);
	if (iprtd == NULL)
		return -ENOMEM;
	runtime->private_data = iprtd;

	iprtd->substream = substream;

	atomic_set(&iprtd->playing, 0);
	atomic_set(&iprtd->capturing, 0);
	hrtimer_setup(&iprtd->hrt, snd_hrtimer_callback, CLOCK_MONOTONIC, HRTIMER_MODE_REL);

	ret = snd_pcm_hw_constraint_integer(substream->runtime,
			SNDRV_PCM_HW_PARAM_PERIODS);
	if (ret < 0) {
		kfree(iprtd);
		return ret;
	}

	snd_soc_set_runtime_hwparams(substream, &snd_imx_hardware);
	return 0;
}

static int snd_imx_close(struct snd_soc_component *component,
			 struct snd_pcm_substream *substream)
{
	struct snd_pcm_runtime *runtime = substream->runtime;
	struct imx_pcm_runtime_data *iprtd = runtime->private_data;

	hrtimer_cancel(&iprtd->hrt);

	kfree(iprtd);

	return 0;
}

static int imx_pcm_new(struct snd_soc_pcm_runtime *rtd)
{
	struct snd_card *card = rtd->card->snd_card;
	struct snd_pcm *pcm = rtd->pcm;
	int ret;

	ret = dma_coerce_mask_and_coherent(card->dev, DMA_BIT_MASK(32));
	if (ret)
		return ret;

	return snd_pcm_set_fixed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV_WC,
					    pcm->card->dev,
					    IMX_SSI_DMABUF_SIZE);
}

static int ssi_irq;

static int snd_imx_pcm_new(struct snd_soc_component *component,
			   struct snd_soc_pcm_runtime *rtd)
{
	struct snd_pcm *pcm = rtd->pcm;
	struct snd_pcm_substream *substream;
	int ret;

	ret = imx_pcm_new(rtd);
	if (ret)
		return ret;

	substream = pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
	if (substream) {
		struct snd_dma_buffer *buf = &substream->dma_buffer;

		imx_ssi_fiq_tx_buffer = (unsigned long)buf->area;
	}

	substream = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
	if (substream) {
		struct snd_dma_buffer *buf = &substream->dma_buffer;

		imx_ssi_fiq_rx_buffer = (unsigned long)buf->area;
	}

	set_fiq_handler(&imx_ssi_fiq_start,
		&imx_ssi_fiq_end - &imx_ssi_fiq_start);

	return 0;
}

static void snd_imx_pcm_free(struct snd_soc_component *component,
			     struct snd_pcm *pcm)
{
	mxc_set_irq_fiq(ssi_irq, 0);
	release_fiq(&fh);
}

static const struct snd_soc_component_driver imx_soc_component_fiq = {
	.open		= snd_imx_open,
	.close		= snd_imx_close,
	.hw_params	= snd_imx_pcm_hw_params,
	.prepare	= snd_imx_pcm_prepare,
	.trigger	= snd_imx_pcm_trigger,
	.pointer	= snd_imx_pcm_pointer,
	.pcm_construct	= snd_imx_pcm_new,
	.pcm_destruct	= snd_imx_pcm_free,
};

int imx_pcm_fiq_init(struct platform_device *pdev,
		struct imx_pcm_fiq_params *params)
{
	int ret;

	ret = claim_fiq(&fh);
	if (ret) {
		dev_err(&pdev->dev, "failed to claim fiq: %d", ret);
		return ret;
	}

	mxc_set_irq_fiq(params->irq, 1);
	ssi_irq = params->irq;

	imx_pcm_fiq = params->irq;

	imx_ssi_fiq_base = (unsigned long)params->base;

	params->dma_params_tx->maxburst = 4;
	params->dma_params_rx->maxburst = 6;

	ret = devm_snd_soc_register_component(&pdev->dev, &imx_soc_component_fiq,
					      NULL, 0);
	if (ret)
		goto failed_register;

	return 0;

failed_register:
	mxc_set_irq_fiq(ssi_irq, 0);
	release_fiq(&fh);

	return ret;
}
EXPORT_SYMBOL_GPL(imx_pcm_fiq_init);

void imx_pcm_fiq_exit(struct platform_device *pdev)
{
}
EXPORT_SYMBOL_GPL(imx_pcm_fiq_exit);

MODULE_DESCRIPTION("Freescale i.MX PCM FIQ handler");
MODULE_LICENSE("GPL");