root/sound/soc/bcm/bcm63xx-pcm-whistler.c
// SPDX-License-Identifier: GPL-2.0-or-later
// linux/sound/bcm/bcm63xx-pcm-whistler.c
// BCM63xx whistler pcm interface
// Copyright (c) 2020 Broadcom Corporation
// Author: Kevin-Ke Li <kevin-ke.li@broadcom.com>

#include <linux/dma-mapping.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <sound/pcm_params.h>
#include <linux/regmap.h>
#include <linux/of_device.h>
#include <sound/soc.h>
#include "bcm63xx-i2s.h"


struct i2s_dma_desc {
        unsigned char *dma_area;
        dma_addr_t dma_addr;
        unsigned int dma_len;
};

struct bcm63xx_runtime_data {
        int dma_len;
        dma_addr_t dma_addr;
        dma_addr_t dma_addr_next;
};

static const struct snd_pcm_hardware bcm63xx_pcm_hardware = {
        .info = SNDRV_PCM_INFO_MMAP |
                SNDRV_PCM_INFO_MMAP_VALID |
                SNDRV_PCM_INFO_INTERLEAVED |
                SNDRV_PCM_INFO_PAUSE |
                SNDRV_PCM_INFO_RESUME,
        .formats = SNDRV_PCM_FMTBIT_S32_LE, /* support S32 only */
        .period_bytes_max = 8192 - 32,
        .periods_min = 1,
        .periods_max = PAGE_SIZE/sizeof(struct i2s_dma_desc),
        .buffer_bytes_max = 128 * 1024,
        .fifo_size = 32,
};

static int bcm63xx_pcm_hw_params(struct snd_soc_component *component,
                                 struct snd_pcm_substream *substream,
                                 struct snd_pcm_hw_params *params)
{
        struct i2s_dma_desc *dma_desc;
        struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);

        dma_desc = kzalloc_obj(*dma_desc, GFP_NOWAIT);
        if (!dma_desc)
                return -ENOMEM;

        snd_soc_dai_set_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream, dma_desc);

        return 0;
}

static int bcm63xx_pcm_hw_free(struct snd_soc_component *component,
                        struct snd_pcm_substream *substream)
{
        struct i2s_dma_desc     *dma_desc;
        struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);

        dma_desc = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);
        kfree(dma_desc);

        return 0;
}

static int bcm63xx_pcm_trigger(struct snd_soc_component *component,
                               struct snd_pcm_substream *substream, int cmd)
{
        int ret = 0;
        struct snd_soc_pcm_runtime *rtd;
        struct bcm_i2s_priv *i2s_priv;
        struct regmap   *regmap_i2s;

        rtd = snd_soc_substream_to_rtd(substream);
        i2s_priv = dev_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0)->dev);
        regmap_i2s = i2s_priv->regmap_i2s;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                switch (cmd) {
                case SNDRV_PCM_TRIGGER_START:
                        regmap_update_bits(regmap_i2s,
                                           I2S_TX_IRQ_EN,
                                           I2S_TX_DESC_OFF_INTR_EN,
                                           I2S_TX_DESC_OFF_INTR_EN);
                        regmap_update_bits(regmap_i2s,
                                           I2S_TX_CFG,
                                           I2S_TX_ENABLE_MASK,
                                           I2S_TX_ENABLE);
                        break;
                case SNDRV_PCM_TRIGGER_STOP:
                case SNDRV_PCM_TRIGGER_SUSPEND:
                case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                        regmap_write(regmap_i2s,
                                     I2S_TX_IRQ_EN,
                                     0);
                        regmap_update_bits(regmap_i2s,
                                           I2S_TX_CFG,
                                           I2S_TX_ENABLE_MASK,
                                           0);
                        break;
                default:
                        ret = -EINVAL;
                }
        } else {
                switch (cmd) {
                case SNDRV_PCM_TRIGGER_START:
                        regmap_update_bits(regmap_i2s,
                                           I2S_RX_IRQ_EN,
                                           I2S_RX_DESC_OFF_INTR_EN_MSK,
                                           I2S_RX_DESC_OFF_INTR_EN);
                        regmap_update_bits(regmap_i2s,
                                           I2S_RX_CFG,
                                           I2S_RX_ENABLE_MASK,
                                           I2S_RX_ENABLE);
                        break;
                case SNDRV_PCM_TRIGGER_STOP:
                case SNDRV_PCM_TRIGGER_SUSPEND:
                case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
                        regmap_update_bits(regmap_i2s,
                                           I2S_RX_IRQ_EN,
                                           I2S_RX_DESC_OFF_INTR_EN_MSK,
                                           0);
                        regmap_update_bits(regmap_i2s,
                                           I2S_RX_CFG,
                                           I2S_RX_ENABLE_MASK,
                                           0);
                        break;
                default:
                        ret = -EINVAL;
                }
        }
        return ret;
}

static int bcm63xx_pcm_prepare(struct snd_soc_component *component,
                        struct snd_pcm_substream *substream)
{
        struct i2s_dma_desc     *dma_desc;
        struct regmap           *regmap_i2s;
        struct bcm_i2s_priv     *i2s_priv;
        struct snd_soc_pcm_runtime *rtd = snd_soc_substream_to_rtd(substream);
        struct snd_pcm_runtime *runtime = substream->runtime;
        uint32_t regaddr_desclen, regaddr_descaddr;

        dma_desc = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);
        dma_desc->dma_len  = snd_pcm_lib_period_bytes(substream);
        dma_desc->dma_addr = runtime->dma_addr;
        dma_desc->dma_area = runtime->dma_area;

        if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                regaddr_desclen = I2S_TX_DESC_IFF_LEN;
                regaddr_descaddr = I2S_TX_DESC_IFF_ADDR;
        } else {
                regaddr_desclen = I2S_RX_DESC_IFF_LEN;
                regaddr_descaddr = I2S_RX_DESC_IFF_ADDR;
        }

        i2s_priv = dev_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0)->dev);
        regmap_i2s = i2s_priv->regmap_i2s;

        regmap_write(regmap_i2s, regaddr_desclen, dma_desc->dma_len);
        regmap_write(regmap_i2s, regaddr_descaddr, dma_desc->dma_addr);

        return 0;
}

static snd_pcm_uframes_t
bcm63xx_pcm_pointer(struct snd_soc_component *component,
                struct snd_pcm_substream *substream)
{
        snd_pcm_uframes_t x;
        struct bcm63xx_runtime_data *prtd = substream->runtime->private_data;

        if (!prtd->dma_addr_next)
                prtd->dma_addr_next = substream->runtime->dma_addr;

        x = bytes_to_frames(substream->runtime,
                prtd->dma_addr_next - substream->runtime->dma_addr);

        return x == substream->runtime->buffer_size ? 0 : x;
}

static int bcm63xx_pcm_open(struct snd_soc_component *component,
                        struct snd_pcm_substream *substream)
{
        int ret = 0;
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct bcm63xx_runtime_data *prtd;

        runtime->hw = bcm63xx_pcm_hardware;
        ret = snd_pcm_hw_constraint_step(runtime, 0,
                                         SNDRV_PCM_HW_PARAM_PERIOD_BYTES, 32);
        if (ret)
                goto out;

        ret = snd_pcm_hw_constraint_step(runtime, 0,
                                         SNDRV_PCM_HW_PARAM_BUFFER_BYTES, 32);
        if (ret)
                goto out;

        ret = snd_pcm_hw_constraint_integer(runtime,
                                            SNDRV_PCM_HW_PARAM_PERIODS);
        if (ret < 0)
                goto out;

        ret = -ENOMEM;
        prtd = kzalloc_obj(*prtd);
        if (!prtd)
                goto out;

        runtime->private_data = prtd;
        return 0;
out:
        return ret;
}

static int bcm63xx_pcm_close(struct snd_soc_component *component,
                        struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct bcm63xx_runtime_data *prtd = runtime->private_data;

        kfree(prtd);
        return 0;
}

static irqreturn_t i2s_dma_isr(int irq, void *bcm_i2s_priv)
{
        unsigned int availdepth, ifflevel, offlevel, int_status, val_1, val_2;
        struct bcm63xx_runtime_data *prtd;
        struct snd_pcm_substream *substream;
        struct snd_pcm_runtime *runtime;
        struct regmap *regmap_i2s;
        struct i2s_dma_desc *dma_desc;
        struct snd_soc_pcm_runtime *rtd;
        struct bcm_i2s_priv *i2s_priv;

        i2s_priv = (struct bcm_i2s_priv *)bcm_i2s_priv;
        regmap_i2s = i2s_priv->regmap_i2s;

        /* rx */
        regmap_read(regmap_i2s, I2S_RX_IRQ_CTL, &int_status);

        if (int_status & I2S_RX_DESC_OFF_INTR_EN_MSK) {
                substream = i2s_priv->capture_substream;
                runtime = substream->runtime;
                rtd = snd_soc_substream_to_rtd(substream);
                prtd = runtime->private_data;
                dma_desc = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);

                offlevel = (int_status & I2S_RX_DESC_OFF_LEVEL_MASK) >>
                           I2S_RX_DESC_OFF_LEVEL_SHIFT;
                bool val_read = false;
                while (offlevel) {
                        regmap_read(regmap_i2s, I2S_RX_DESC_OFF_ADDR, &val_1);
                        regmap_read(regmap_i2s, I2S_RX_DESC_OFF_LEN, &val_2);
                        val_read = true;
                        offlevel--;
                }
                if (val_read)
                        prtd->dma_addr_next = val_1 + val_2;

                ifflevel = (int_status & I2S_RX_DESC_IFF_LEVEL_MASK) >>
                           I2S_RX_DESC_IFF_LEVEL_SHIFT;

                availdepth = I2S_DESC_FIFO_DEPTH - ifflevel;
                while (availdepth) {
                        dma_desc->dma_addr +=
                                        snd_pcm_lib_period_bytes(substream);
                        dma_desc->dma_area +=
                                        snd_pcm_lib_period_bytes(substream);
                        if (dma_desc->dma_addr - runtime->dma_addr >=
                                                runtime->dma_bytes) {
                                dma_desc->dma_addr = runtime->dma_addr;
                                dma_desc->dma_area = runtime->dma_area;
                        }

                        prtd->dma_addr = dma_desc->dma_addr;
                        regmap_write(regmap_i2s, I2S_RX_DESC_IFF_LEN,
                                     snd_pcm_lib_period_bytes(substream));
                        regmap_write(regmap_i2s, I2S_RX_DESC_IFF_ADDR,
                                     dma_desc->dma_addr);
                        availdepth--;
                }

                snd_pcm_period_elapsed(substream);

                /* Clear interrupt by writing 0 */
                regmap_update_bits(regmap_i2s, I2S_RX_IRQ_CTL,
                                   I2S_RX_INTR_MASK, 0);
        }

        /* tx */
        regmap_read(regmap_i2s, I2S_TX_IRQ_CTL, &int_status);

        if (int_status & I2S_TX_DESC_OFF_INTR_EN_MSK) {
                substream = i2s_priv->play_substream;
                runtime = substream->runtime;
                rtd = snd_soc_substream_to_rtd(substream);
                prtd = runtime->private_data;
                dma_desc = snd_soc_dai_get_dma_data(snd_soc_rtd_to_cpu(rtd, 0), substream);

                offlevel = (int_status & I2S_TX_DESC_OFF_LEVEL_MASK) >>
                           I2S_TX_DESC_OFF_LEVEL_SHIFT;
                while (offlevel) {
                        regmap_read(regmap_i2s, I2S_TX_DESC_OFF_ADDR, &val_1);
                        regmap_read(regmap_i2s, I2S_TX_DESC_OFF_LEN,  &val_2);
                        prtd->dma_addr_next = val_1 + val_2;
                        offlevel--;
                }

                ifflevel = (int_status & I2S_TX_DESC_IFF_LEVEL_MASK) >>
                        I2S_TX_DESC_IFF_LEVEL_SHIFT;
                availdepth = I2S_DESC_FIFO_DEPTH - ifflevel;

                while (availdepth) {
                        dma_desc->dma_addr +=
                                        snd_pcm_lib_period_bytes(substream);
                        dma_desc->dma_area +=
                                        snd_pcm_lib_period_bytes(substream);

                        if (dma_desc->dma_addr - runtime->dma_addr >=
                                                        runtime->dma_bytes) {
                                dma_desc->dma_addr = runtime->dma_addr;
                                dma_desc->dma_area = runtime->dma_area;
                        }

                        prtd->dma_addr = dma_desc->dma_addr;
                        regmap_write(regmap_i2s, I2S_TX_DESC_IFF_LEN,
                                snd_pcm_lib_period_bytes(substream));
                        regmap_write(regmap_i2s, I2S_TX_DESC_IFF_ADDR,
                                        dma_desc->dma_addr);
                        availdepth--;
                }

                snd_pcm_period_elapsed(substream);

                /* Clear interrupt by writing 0 */
                regmap_update_bits(regmap_i2s, I2S_TX_IRQ_CTL,
                                   I2S_TX_INTR_MASK, 0);
        }

        return IRQ_HANDLED;
}

static int bcm63xx_soc_pcm_new(struct snd_soc_component *component,
                struct snd_soc_pcm_runtime *rtd)
{
        struct snd_pcm *pcm = rtd->pcm;
        struct bcm_i2s_priv *i2s_priv;
        int ret;

        i2s_priv = dev_get_drvdata(snd_soc_rtd_to_cpu(rtd, 0)->dev);

        ret = of_dma_configure(pcm->card->dev, pcm->card->dev->of_node, 1);
        if (ret)
                return ret;

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

        if (pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream)
                i2s_priv->play_substream =
                        pcm->streams[SNDRV_PCM_STREAM_PLAYBACK].substream;
        if (pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream)
                i2s_priv->capture_substream =
                        pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;

        return snd_pcm_set_fixed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV_WC,
                                            pcm->card->dev,
                                            bcm63xx_pcm_hardware.buffer_bytes_max);
}

static const struct snd_soc_component_driver bcm63xx_soc_platform = {
        .open = bcm63xx_pcm_open,
        .close = bcm63xx_pcm_close,
        .hw_params = bcm63xx_pcm_hw_params,
        .hw_free = bcm63xx_pcm_hw_free,
        .prepare = bcm63xx_pcm_prepare,
        .trigger = bcm63xx_pcm_trigger,
        .pointer = bcm63xx_pcm_pointer,
        .pcm_construct = bcm63xx_soc_pcm_new,
};

int bcm63xx_soc_platform_probe(struct platform_device *pdev,
                               struct bcm_i2s_priv *i2s_priv)
{
        int ret;

        ret = platform_get_irq(pdev, 0);
        if (ret < 0)
                return ret;

        ret = devm_request_irq(&pdev->dev, ret, i2s_dma_isr,
                               irq_get_trigger_type(ret), "i2s_dma", (void *)i2s_priv);
        if (ret) {
                dev_err(&pdev->dev,
                        "i2s_init: failed to request interrupt.ret=%d\n", ret);
                return ret;
        }

        return devm_snd_soc_register_component(&pdev->dev,
                                        &bcm63xx_soc_platform, NULL, 0);
}

int bcm63xx_soc_platform_remove(struct platform_device *pdev)
{
        return 0;
}

MODULE_AUTHOR("Kevin,Li <kevin-ke.li@broadcom.com>");
MODULE_DESCRIPTION("Broadcom DSL XPON ASOC PCM Interface");
MODULE_LICENSE("GPL v2");