root/sound/soc/fsl/imx-pcm-fiq.c
// SPDX-License-Identifier: GPL-2.0+
// imx-pcm-fiq.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.

#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_obj(*iprtd);
        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");