// SPDX-License-Identifier: GPL-2.0-only
/*
 * rt5677-spi.c  --  RT5677 ALSA SoC audio codec driver
 *
 * Copyright 2013 Realtek Semiconductor Corp.
 * Author: Oder Chiou <oder_chiou@realtek.com>
 */

#include <linux/module.h>
#include <linux/input.h>
#include <linux/spi/spi.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/uaccess.h>
#include <linux/regulator/consumer.h>
#include <linux/pm_qos.h>
#include <linux/sysfs.h>
#include <linux/clk.h>
#include <linux/firmware.h>
#include <linux/acpi.h>

#include <sound/soc.h>

#include "rt5677.h"
#include "rt5677-spi.h"

#define DRV_NAME "rt5677spi"

#define RT5677_SPI_BURST_LEN    240
#define RT5677_SPI_HEADER       5
#define RT5677_SPI_FREQ         6000000

/* The AddressPhase and DataPhase of SPI commands are MSB first on the wire.
 * DataPhase word size of 16-bit commands is 2 bytes.
 * DataPhase word size of 32-bit commands is 4 bytes.
 * DataPhase word size of burst commands is 8 bytes.
 * The DSP CPU is little-endian.
 */
#define RT5677_SPI_WRITE_BURST  0x5
#define RT5677_SPI_READ_BURST   0x4
#define RT5677_SPI_WRITE_32     0x3
#define RT5677_SPI_READ_32      0x2
#define RT5677_SPI_WRITE_16     0x1
#define RT5677_SPI_READ_16      0x0

#define RT5677_BUF_BYTES_TOTAL          0x20000
#define RT5677_MIC_BUF_ADDR             0x60030000
#define RT5677_MODEL_ADDR               0x5FFC9800
#define RT5677_MIC_BUF_BYTES            ((u32)(RT5677_BUF_BYTES_TOTAL - \
                                        sizeof(u32)))
#define RT5677_MIC_BUF_FIRST_READ_SIZE  0x10000

static struct spi_device *g_spi;
static DEFINE_MUTEX(spi_mutex);

struct rt5677_dsp {
        struct device *dev;
        struct delayed_work copy_work;
        struct mutex dma_lock;
        struct snd_pcm_substream *substream;
        size_t dma_offset;      /* zero-based offset into runtime->dma_area */
        size_t avail_bytes;     /* number of new bytes since last period */
        u32 mic_read_offset;    /* zero-based offset into DSP's mic buffer */
        bool new_hotword;       /* a new hotword is fired */
};

static const struct snd_pcm_hardware rt5677_spi_pcm_hardware = {
        .info                   = SNDRV_PCM_INFO_MMAP |
                                  SNDRV_PCM_INFO_MMAP_VALID |
                                  SNDRV_PCM_INFO_INTERLEAVED,
        .formats                = SNDRV_PCM_FMTBIT_S16_LE,
        .period_bytes_min       = PAGE_SIZE,
        .period_bytes_max       = RT5677_BUF_BYTES_TOTAL / 8,
        .periods_min            = 8,
        .periods_max            = 8,
        .channels_min           = 1,
        .channels_max           = 1,
        .buffer_bytes_max       = RT5677_BUF_BYTES_TOTAL,
};

static struct snd_soc_dai_driver rt5677_spi_dai = {
        /* The DAI name "rt5677-dsp-cpu-dai" is not used. The actual DAI name
         * registered with ASoC is the name of the device "spi-RT5677AA:00",
         * because we only have one DAI. See snd_soc_register_dais().
         */
        .name = "rt5677-dsp-cpu-dai",
        .id = 0,
        .capture = {
                .stream_name = "DSP Capture",
                .channels_min = 1,
                .channels_max = 1,
                .rates = SNDRV_PCM_RATE_16000,
                .formats = SNDRV_PCM_FMTBIT_S16_LE,
        },
};

/* PCM for streaming audio from the DSP buffer */
static int rt5677_spi_pcm_open(
                struct snd_soc_component *component,
                struct snd_pcm_substream *substream)
{
        snd_soc_set_runtime_hwparams(substream, &rt5677_spi_pcm_hardware);
        return 0;
}

static int rt5677_spi_pcm_close(
                struct snd_soc_component *component,
                struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
        struct snd_soc_component *codec_component =
                        snd_soc_rtdcom_lookup(rtd, "rt5677");
        struct rt5677_priv *rt5677 =
                        snd_soc_component_get_drvdata(codec_component);
        struct rt5677_dsp *rt5677_dsp =
                        snd_soc_component_get_drvdata(component);

        cancel_delayed_work_sync(&rt5677_dsp->copy_work);
        rt5677->set_dsp_vad(codec_component, false);
        return 0;
}

static int rt5677_spi_hw_params(
                struct snd_soc_component *component,
                struct snd_pcm_substream *substream,
                struct snd_pcm_hw_params *hw_params)
{
        struct rt5677_dsp *rt5677_dsp =
                        snd_soc_component_get_drvdata(component);

        mutex_lock(&rt5677_dsp->dma_lock);
        rt5677_dsp->substream = substream;
        mutex_unlock(&rt5677_dsp->dma_lock);

        return 0;
}

static int rt5677_spi_hw_free(
                struct snd_soc_component *component,
                struct snd_pcm_substream *substream)
{
        struct rt5677_dsp *rt5677_dsp =
                        snd_soc_component_get_drvdata(component);

        mutex_lock(&rt5677_dsp->dma_lock);
        rt5677_dsp->substream = NULL;
        mutex_unlock(&rt5677_dsp->dma_lock);

        return 0;
}

static int rt5677_spi_prepare(
                struct snd_soc_component *component,
                struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = asoc_substream_to_rtd(substream);
        struct snd_soc_component *rt5677_component =
                        snd_soc_rtdcom_lookup(rtd, "rt5677");
        struct rt5677_priv *rt5677 =
                        snd_soc_component_get_drvdata(rt5677_component);
        struct rt5677_dsp *rt5677_dsp =
                        snd_soc_component_get_drvdata(component);

        rt5677->set_dsp_vad(rt5677_component, true);
        rt5677_dsp->dma_offset = 0;
        rt5677_dsp->avail_bytes = 0;
        return 0;
}

static snd_pcm_uframes_t rt5677_spi_pcm_pointer(
                struct snd_soc_component *component,
                struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct rt5677_dsp *rt5677_dsp =
                        snd_soc_component_get_drvdata(component);

        return bytes_to_frames(runtime, rt5677_dsp->dma_offset);
}

static int rt5677_spi_mic_write_offset(u32 *mic_write_offset)
{
        int ret;
        /* Grab the first 4 bytes that hold the write pointer on the
         * dsp, and check to make sure that it points somewhere inside the
         * buffer.
         */
        ret = rt5677_spi_read(RT5677_MIC_BUF_ADDR, mic_write_offset,
                        sizeof(u32));
        if (ret)
                return ret;
        /* Adjust the offset so that it's zero-based */
        *mic_write_offset = *mic_write_offset - sizeof(u32);
        return *mic_write_offset < RT5677_MIC_BUF_BYTES ? 0 : -EFAULT;
}

/*
 * Copy one contiguous block of audio samples from the DSP mic buffer to the
 * dma_area of the pcm runtime. The receiving buffer may wrap around.
 * @begin: start offset of the block to copy, in bytes.
 * @end:   offset of the first byte after the block to copy, must be greater
 *         than or equal to begin.
 *
 * Return: Zero if successful, or a negative error code on failure.
 */
static int rt5677_spi_copy_block(struct rt5677_dsp *rt5677_dsp,
                u32 begin, u32 end)
{
        struct snd_pcm_runtime *runtime = rt5677_dsp->substream->runtime;
        size_t bytes_per_frame = frames_to_bytes(runtime, 1);
        size_t first_chunk_len, second_chunk_len;
        int ret;

        if (begin > end || runtime->dma_bytes < 2 * bytes_per_frame) {
                dev_err(rt5677_dsp->dev,
                        "Invalid copy from (%u, %u), dma_area size %zu\n",
                        begin, end, runtime->dma_bytes);
                return -EINVAL;
        }

        /* The block to copy is empty */
        if (begin == end)
                return 0;

        /* If the incoming chunk is too big for the receiving buffer, only the
         * last "receiving buffer size - one frame" bytes are copied.
         */
        if (end - begin > runtime->dma_bytes - bytes_per_frame)
                begin = end - (runtime->dma_bytes - bytes_per_frame);

        /* May need to split to two chunks, calculate the size of each */
        first_chunk_len = end - begin;
        second_chunk_len = 0;
        if (rt5677_dsp->dma_offset + first_chunk_len > runtime->dma_bytes) {
                /* Receiving buffer wrapped around */
                second_chunk_len = first_chunk_len;
                first_chunk_len = runtime->dma_bytes - rt5677_dsp->dma_offset;
                second_chunk_len -= first_chunk_len;
        }

        /* Copy first chunk */
        ret = rt5677_spi_read(RT5677_MIC_BUF_ADDR + sizeof(u32) + begin,
                        runtime->dma_area + rt5677_dsp->dma_offset,
                        first_chunk_len);
        if (ret)
                return ret;
        rt5677_dsp->dma_offset += first_chunk_len;
        if (rt5677_dsp->dma_offset == runtime->dma_bytes)
                rt5677_dsp->dma_offset = 0;

        /* Copy second chunk */
        if (second_chunk_len) {
                ret = rt5677_spi_read(RT5677_MIC_BUF_ADDR + sizeof(u32) +
                                begin + first_chunk_len, runtime->dma_area,
                                second_chunk_len);
                if (!ret)
                        rt5677_dsp->dma_offset = second_chunk_len;
        }
        return ret;
}

/*
 * Copy a given amount of audio samples from the DSP mic buffer starting at
 * mic_read_offset, to the dma_area of the pcm runtime. The source buffer may
 * wrap around. mic_read_offset is updated after successful copy.
 * @amount: amount of samples to copy, in bytes.
 *
 * Return: Zero if successful, or a negative error code on failure.
 */
static int rt5677_spi_copy(struct rt5677_dsp *rt5677_dsp, u32 amount)
{
        int ret = 0;
        u32 target;

        if (amount == 0)
                return ret;

        target = rt5677_dsp->mic_read_offset + amount;
        /* Copy the first chunk in DSP's mic buffer */
        ret |= rt5677_spi_copy_block(rt5677_dsp, rt5677_dsp->mic_read_offset,
                        min(target, RT5677_MIC_BUF_BYTES));

        if (target >= RT5677_MIC_BUF_BYTES) {
                /* Wrap around, copy the second chunk */
                target -= RT5677_MIC_BUF_BYTES;
                ret |= rt5677_spi_copy_block(rt5677_dsp, 0, target);
        }

        if (!ret)
                rt5677_dsp->mic_read_offset = target;
        return ret;
}

/*
 * A delayed work that streams audio samples from the DSP mic buffer to the
 * dma_area of the pcm runtime via SPI.
 */
static void rt5677_spi_copy_work(struct work_struct *work)
{
        struct rt5677_dsp *rt5677_dsp =
                container_of(work, struct rt5677_dsp, copy_work.work);
        struct snd_pcm_runtime *runtime;
        u32 mic_write_offset;
        size_t new_bytes, copy_bytes, period_bytes;
        unsigned int delay;
        int ret = 0;

        /* Ensure runtime->dma_area buffer does not go away while copying. */
        mutex_lock(&rt5677_dsp->dma_lock);
        if (!rt5677_dsp->substream) {
                dev_err(rt5677_dsp->dev, "No pcm substream\n");
                goto done;
        }

        runtime = rt5677_dsp->substream->runtime;

        if (rt5677_spi_mic_write_offset(&mic_write_offset)) {
                dev_err(rt5677_dsp->dev, "No mic_write_offset\n");
                goto done;
        }

        /* If this is the first time that we've asked for streaming data after
         * a hotword is fired, we should start reading from the previous 2
         * seconds of audio from wherever the mic_write_offset is currently.
         */
        if (rt5677_dsp->new_hotword) {
                rt5677_dsp->new_hotword = false;
                /* See if buffer wraparound happens */
                if (mic_write_offset < RT5677_MIC_BUF_FIRST_READ_SIZE)
                        rt5677_dsp->mic_read_offset = RT5677_MIC_BUF_BYTES -
                                        (RT5677_MIC_BUF_FIRST_READ_SIZE -
                                        mic_write_offset);
                else
                        rt5677_dsp->mic_read_offset = mic_write_offset -
                                        RT5677_MIC_BUF_FIRST_READ_SIZE;
        }

        /* Calculate the amount of new samples in bytes */
        if (rt5677_dsp->mic_read_offset <= mic_write_offset)
                new_bytes = mic_write_offset - rt5677_dsp->mic_read_offset;
        else
                new_bytes = RT5677_MIC_BUF_BYTES + mic_write_offset
                                - rt5677_dsp->mic_read_offset;

        /* Copy all new samples from DSP mic buffer, one period at a time */
        period_bytes = snd_pcm_lib_period_bytes(rt5677_dsp->substream);
        while (new_bytes) {
                copy_bytes = min(new_bytes, period_bytes
                                - rt5677_dsp->avail_bytes);
                ret = rt5677_spi_copy(rt5677_dsp, copy_bytes);
                if (ret) {
                        dev_err(rt5677_dsp->dev, "Copy failed %d\n", ret);
                        goto done;
                }
                rt5677_dsp->avail_bytes += copy_bytes;
                if (rt5677_dsp->avail_bytes >= period_bytes) {
                        snd_pcm_period_elapsed(rt5677_dsp->substream);
                        rt5677_dsp->avail_bytes = 0;
                }
                new_bytes -= copy_bytes;
        }

        delay = bytes_to_frames(runtime, period_bytes) / (runtime->rate / 1000);
        schedule_delayed_work(&rt5677_dsp->copy_work, msecs_to_jiffies(delay));
done:
        mutex_unlock(&rt5677_dsp->dma_lock);
}

static int rt5677_spi_pcm_new(struct snd_soc_component *component,
                              struct snd_soc_pcm_runtime *rtd)
{
        snd_pcm_set_managed_buffer_all(rtd->pcm, SNDRV_DMA_TYPE_VMALLOC,
                                       NULL, 0, 0);
        return 0;
}

static int rt5677_spi_pcm_probe(struct snd_soc_component *component)
{
        struct rt5677_dsp *rt5677_dsp;

        rt5677_dsp = devm_kzalloc(component->dev, sizeof(*rt5677_dsp),
                        GFP_KERNEL);
        if (!rt5677_dsp)
                return -ENOMEM;
        rt5677_dsp->dev = &g_spi->dev;
        mutex_init(&rt5677_dsp->dma_lock);
        INIT_DELAYED_WORK(&rt5677_dsp->copy_work, rt5677_spi_copy_work);

        snd_soc_component_set_drvdata(component, rt5677_dsp);
        return 0;
}

static const struct snd_soc_component_driver rt5677_spi_dai_component = {
        .name           = DRV_NAME,
        .probe          = rt5677_spi_pcm_probe,
        .open           = rt5677_spi_pcm_open,
        .close          = rt5677_spi_pcm_close,
        .hw_params      = rt5677_spi_hw_params,
        .hw_free        = rt5677_spi_hw_free,
        .prepare        = rt5677_spi_prepare,
        .pointer        = rt5677_spi_pcm_pointer,
        .pcm_construct  = rt5677_spi_pcm_new,
};

/* Select a suitable transfer command for the next transfer to ensure
 * the transfer address is always naturally aligned while minimizing
 * the total number of transfers required.
 *
 * 3 transfer commands are available:
 * RT5677_SPI_READ/WRITE_16:    Transfer 2 bytes
 * RT5677_SPI_READ/WRITE_32:    Transfer 4 bytes
 * RT5677_SPI_READ/WRITE_BURST: Transfer any multiples of 8 bytes
 *
 * Note:
 * 16 Bit writes and reads are restricted to the address range
 * 0x18020000 ~ 0x18021000
 *
 * For example, reading 256 bytes at 0x60030004 uses the following commands:
 * 0x60030004 RT5677_SPI_READ_32        4 bytes
 * 0x60030008 RT5677_SPI_READ_BURST     240 bytes
 * 0x600300F8 RT5677_SPI_READ_BURST     8 bytes
 * 0x60030100 RT5677_SPI_READ_32        4 bytes
 *
 * Input:
 * @read: true for read commands; false for write commands
 * @align: alignment of the next transfer address
 * @remain: number of bytes remaining to transfer
 *
 * Output:
 * @len: number of bytes to transfer with the selected command
 * Returns the selected command
 */
static u8 rt5677_spi_select_cmd(bool read, u32 align, u32 remain, u32 *len)
{
        u8 cmd;

        if (align == 4 || remain <= 4) {
                cmd = RT5677_SPI_READ_32;
                *len = 4;
        } else {
                cmd = RT5677_SPI_READ_BURST;
                *len = (((remain - 1) >> 3) + 1) << 3;
                *len = min_t(u32, *len, RT5677_SPI_BURST_LEN);
        }
        return read ? cmd : cmd + 1;
}

/* Copy dstlen bytes from src to dst, while reversing byte order for each word.
 * If srclen < dstlen, zeros are padded.
 */
static void rt5677_spi_reverse(u8 *dst, u32 dstlen, const u8 *src, u32 srclen)
{
        u32 w, i, si;
        u32 word_size = min_t(u32, dstlen, 8);

        for (w = 0; w < dstlen; w += word_size) {
                for (i = 0; i < word_size && i + w < dstlen; i++) {
                        si = w + word_size - i - 1;
                        dst[w + i] = si < srclen ? src[si] : 0;
                }
        }
}

/* Read DSP address space using SPI. addr and len have to be 4-byte aligned. */
int rt5677_spi_read(u32 addr, void *rxbuf, size_t len)
{
        u32 offset;
        int status = 0;
        struct spi_transfer t[2];
        struct spi_message m;
        /* +4 bytes is for the DummyPhase following the AddressPhase */
        u8 header[RT5677_SPI_HEADER + 4];
        u8 body[RT5677_SPI_BURST_LEN];
        u8 spi_cmd;
        u8 *cb = rxbuf;

        if (!g_spi)
                return -ENODEV;

        if ((addr & 3) || (len & 3)) {
                dev_err(&g_spi->dev, "Bad read align 0x%x(%zu)\n", addr, len);
                return -EACCES;
        }

        memset(t, 0, sizeof(t));
        t[0].tx_buf = header;
        t[0].len = sizeof(header);
        t[0].speed_hz = RT5677_SPI_FREQ;
        t[1].rx_buf = body;
        t[1].speed_hz = RT5677_SPI_FREQ;
        spi_message_init_with_transfers(&m, t, ARRAY_SIZE(t));

        for (offset = 0; offset < len; offset += t[1].len) {
                spi_cmd = rt5677_spi_select_cmd(true, (addr + offset) & 7,
                                len - offset, &t[1].len);

                /* Construct SPI message header */
                header[0] = spi_cmd;
                header[1] = ((addr + offset) & 0xff000000) >> 24;
                header[2] = ((addr + offset) & 0x00ff0000) >> 16;
                header[3] = ((addr + offset) & 0x0000ff00) >> 8;
                header[4] = ((addr + offset) & 0x000000ff) >> 0;

                mutex_lock(&spi_mutex);
                status |= spi_sync(g_spi, &m);
                mutex_unlock(&spi_mutex);


                /* Copy data back to caller buffer */
                rt5677_spi_reverse(cb + offset, len - offset, body, t[1].len);
        }
        return status;
}
EXPORT_SYMBOL_GPL(rt5677_spi_read);

/* Write DSP address space using SPI. addr has to be 4-byte aligned.
 * If len is not 4-byte aligned, then extra zeros are written at the end
 * as padding.
 */
int rt5677_spi_write(u32 addr, const void *txbuf, size_t len)
{
        u32 offset;
        int status = 0;
        struct spi_transfer t;
        struct spi_message m;
        /* +1 byte is for the DummyPhase following the DataPhase */
        u8 buf[RT5677_SPI_HEADER + RT5677_SPI_BURST_LEN + 1];
        u8 *body = buf + RT5677_SPI_HEADER;
        u8 spi_cmd;
        const u8 *cb = txbuf;

        if (!g_spi)
                return -ENODEV;

        if (addr & 3) {
                dev_err(&g_spi->dev, "Bad write align 0x%x(%zu)\n", addr, len);
                return -EACCES;
        }

        memset(&t, 0, sizeof(t));
        t.tx_buf = buf;
        t.speed_hz = RT5677_SPI_FREQ;
        spi_message_init_with_transfers(&m, &t, 1);

        for (offset = 0; offset < len;) {
                spi_cmd = rt5677_spi_select_cmd(false, (addr + offset) & 7,
                                len - offset, &t.len);

                /* Construct SPI message header */
                buf[0] = spi_cmd;
                buf[1] = ((addr + offset) & 0xff000000) >> 24;
                buf[2] = ((addr + offset) & 0x00ff0000) >> 16;
                buf[3] = ((addr + offset) & 0x0000ff00) >> 8;
                buf[4] = ((addr + offset) & 0x000000ff) >> 0;

                /* Fetch data from caller buffer */
                rt5677_spi_reverse(body, t.len, cb + offset, len - offset);
                offset += t.len;
                t.len += RT5677_SPI_HEADER + 1;

                mutex_lock(&spi_mutex);
                status |= spi_sync(g_spi, &m);
                mutex_unlock(&spi_mutex);
        }
        return status;
}
EXPORT_SYMBOL_GPL(rt5677_spi_write);

int rt5677_spi_write_firmware(u32 addr, const struct firmware *fw)
{
        return rt5677_spi_write(addr, fw->data, fw->size);
}
EXPORT_SYMBOL_GPL(rt5677_spi_write_firmware);

void rt5677_spi_hotword_detected(void)
{
        struct rt5677_dsp *rt5677_dsp;

        if (!g_spi)
                return;

        rt5677_dsp = dev_get_drvdata(&g_spi->dev);
        if (!rt5677_dsp) {
                dev_err(&g_spi->dev, "Can't get rt5677_dsp\n");
                return;
        }

        mutex_lock(&rt5677_dsp->dma_lock);
        dev_info(rt5677_dsp->dev, "Hotword detected\n");
        rt5677_dsp->new_hotword = true;
        mutex_unlock(&rt5677_dsp->dma_lock);

        schedule_delayed_work(&rt5677_dsp->copy_work, 0);
}
EXPORT_SYMBOL_GPL(rt5677_spi_hotword_detected);

static int rt5677_spi_probe(struct spi_device *spi)
{
        int ret;

        g_spi = spi;

        ret = devm_snd_soc_register_component(&spi->dev,
                                              &rt5677_spi_dai_component,
                                              &rt5677_spi_dai, 1);
        if (ret < 0)
                dev_err(&spi->dev, "Failed to register component.\n");

        return ret;
}

#ifdef CONFIG_ACPI
static const struct acpi_device_id rt5677_spi_acpi_id[] = {
        { "RT5677AA", 0 },
        { }
};
MODULE_DEVICE_TABLE(acpi, rt5677_spi_acpi_id);
#endif

static struct spi_driver rt5677_spi_driver = {
        .driver = {
                .name = DRV_NAME,
                .acpi_match_table = ACPI_PTR(rt5677_spi_acpi_id),
        },
        .probe = rt5677_spi_probe,
};
module_spi_driver(rt5677_spi_driver);

MODULE_DESCRIPTION("ASoC RT5677 SPI driver");
MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
MODULE_LICENSE("GPL v2");