/*
 * rt5514-spi.c  --  RT5514 SPI driver
 *
 * Copyright 2015 Realtek Semiconductor Corp.
 * Author: Oder Chiou <oder_chiou@realtek.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#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/gpio.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 <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include <sound/soc-dapm.h>
#include <sound/initval.h>
#include <sound/tlv.h>

#include "rt5514-spi.h"

static struct spi_device *rt5514_spi;

struct rt5514_dsp {
        struct device *dev;
        struct delayed_work copy_work;
        struct mutex dma_lock;
        struct snd_pcm_substream *substream;
        unsigned int buf_base, buf_limit, buf_rp;
        size_t buf_size, get_size, dma_offset;
};

static const struct snd_pcm_hardware rt5514_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       = 0x20000 / 8,
        .periods_min            = 8,
        .periods_max            = 8,
        .channels_min           = 1,
        .channels_max           = 1,
        .buffer_bytes_max       = 0x20000,
};

static struct snd_soc_dai_driver rt5514_spi_dai = {
        .name = "rt5514-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,
        },
};

static void rt5514_spi_copy_work(struct work_struct *work)
{
        struct rt5514_dsp *rt5514_dsp =
                container_of(work, struct rt5514_dsp, copy_work.work);
        struct snd_pcm_runtime *runtime;
        size_t period_bytes, truncated_bytes = 0;
        unsigned int cur_wp, remain_data;
        u8 buf[8];

        mutex_lock(&rt5514_dsp->dma_lock);
        if (!rt5514_dsp->substream) {
                dev_err(rt5514_dsp->dev, "No pcm substream\n");
                goto done;
        }

        runtime = rt5514_dsp->substream->runtime;
        period_bytes = snd_pcm_lib_period_bytes(rt5514_dsp->substream);

        if (rt5514_dsp->get_size >= rt5514_dsp->buf_size) {
                rt5514_spi_burst_read(RT5514_BUFFER_VOICE_WP, (u8 *)&buf,
                        sizeof(buf));
                cur_wp = buf[0] | buf[1] << 8 | buf[2] << 16 |
                                        buf[3] << 24;

                if (cur_wp >= rt5514_dsp->buf_rp)
                        remain_data = (cur_wp - rt5514_dsp->buf_rp);
                else
                        remain_data =
                                (rt5514_dsp->buf_limit - rt5514_dsp->buf_rp) +
                                (cur_wp - rt5514_dsp->buf_base);

                if (remain_data < period_bytes) {
                        schedule_delayed_work(&rt5514_dsp->copy_work, 5);
                        goto done;
                }
        }

        if (rt5514_dsp->buf_rp + period_bytes <= rt5514_dsp->buf_limit) {
                rt5514_spi_burst_read(rt5514_dsp->buf_rp,
                        runtime->dma_area + rt5514_dsp->dma_offset,
                        period_bytes);

                if (rt5514_dsp->buf_rp + period_bytes == rt5514_dsp->buf_limit)
                        rt5514_dsp->buf_rp = rt5514_dsp->buf_base;
                else
                        rt5514_dsp->buf_rp += period_bytes;
        } else {
                truncated_bytes = rt5514_dsp->buf_limit - rt5514_dsp->buf_rp;
                rt5514_spi_burst_read(rt5514_dsp->buf_rp,
                        runtime->dma_area + rt5514_dsp->dma_offset,
                        truncated_bytes);

                rt5514_spi_burst_read(rt5514_dsp->buf_base,
                        runtime->dma_area + rt5514_dsp->dma_offset +
                        truncated_bytes, period_bytes - truncated_bytes);

                rt5514_dsp->buf_rp = rt5514_dsp->buf_base + period_bytes -
                        truncated_bytes;
        }

        rt5514_dsp->get_size += period_bytes;
        rt5514_dsp->dma_offset += period_bytes;
        if (rt5514_dsp->dma_offset >= runtime->dma_bytes)
                rt5514_dsp->dma_offset = 0;

        snd_pcm_period_elapsed(rt5514_dsp->substream);

        schedule_delayed_work(&rt5514_dsp->copy_work, 5);

done:
        mutex_unlock(&rt5514_dsp->dma_lock);
}

static void rt5514_schedule_copy(struct rt5514_dsp *rt5514_dsp)
{
        u8 buf[8];

        rt5514_dsp->get_size = 0;

        /**
         * The address area x1800XXXX is the register address, and it cannot
         * support spi burst read perfectly. So we use the spi burst read
         * individually to make sure the data correctly.
         */
        rt5514_spi_burst_read(RT5514_BUFFER_VOICE_BASE, (u8 *)&buf,
                sizeof(buf));
        rt5514_dsp->buf_base = buf[0] | buf[1] << 8 | buf[2] << 16 |
                                buf[3] << 24;

        rt5514_spi_burst_read(RT5514_BUFFER_VOICE_LIMIT, (u8 *)&buf,
                sizeof(buf));
        rt5514_dsp->buf_limit = buf[0] | buf[1] << 8 | buf[2] << 16 |
                                buf[3] << 24;

        rt5514_spi_burst_read(RT5514_BUFFER_VOICE_WP, (u8 *)&buf,
                sizeof(buf));
        rt5514_dsp->buf_rp = buf[0] | buf[1] << 8 | buf[2] << 16 |
                                buf[3] << 24;

        if (rt5514_dsp->buf_rp % 8)
                rt5514_dsp->buf_rp = (rt5514_dsp->buf_rp / 8) * 8;

        rt5514_dsp->buf_size = rt5514_dsp->buf_limit - rt5514_dsp->buf_base;

        if (rt5514_dsp->buf_base && rt5514_dsp->buf_limit &&
                rt5514_dsp->buf_rp && rt5514_dsp->buf_size)
                schedule_delayed_work(&rt5514_dsp->copy_work, 0);
}

static irqreturn_t rt5514_spi_irq(int irq, void *data)
{
        struct rt5514_dsp *rt5514_dsp = data;

        rt5514_schedule_copy(rt5514_dsp);

        return IRQ_HANDLED;
}

/* PCM for streaming audio from the DSP buffer */
static int rt5514_spi_pcm_open(struct snd_pcm_substream *substream)
{
        snd_soc_set_runtime_hwparams(substream, &rt5514_spi_pcm_hardware);

        return 0;
}

static int rt5514_spi_hw_params(struct snd_pcm_substream *substream,
                               struct snd_pcm_hw_params *hw_params)
{
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct rt5514_dsp *rt5514_dsp =
                        snd_soc_platform_get_drvdata(rtd->platform);
        int ret;
        u8 buf[8];

        mutex_lock(&rt5514_dsp->dma_lock);
        ret = snd_pcm_lib_alloc_vmalloc_buffer(substream,
                        params_buffer_bytes(hw_params));
        rt5514_dsp->substream = substream;
        rt5514_dsp->dma_offset = 0;

        /* Read IRQ status and schedule copy accordingly. */
        rt5514_spi_burst_read(RT5514_IRQ_CTRL, (u8 *)&buf, sizeof(buf));
        if (buf[0] & RT5514_IRQ_STATUS_BIT)
                rt5514_schedule_copy(rt5514_dsp);

        mutex_unlock(&rt5514_dsp->dma_lock);

        return ret;
}

static int rt5514_spi_hw_free(struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct rt5514_dsp *rt5514_dsp =
                        snd_soc_platform_get_drvdata(rtd->platform);

        mutex_lock(&rt5514_dsp->dma_lock);
        rt5514_dsp->substream = NULL;
        mutex_unlock(&rt5514_dsp->dma_lock);

        cancel_delayed_work_sync(&rt5514_dsp->copy_work);

        return snd_pcm_lib_free_vmalloc_buffer(substream);
}

static snd_pcm_uframes_t rt5514_spi_pcm_pointer(
                struct snd_pcm_substream *substream)
{
        struct snd_pcm_runtime *runtime = substream->runtime;
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct rt5514_dsp *rt5514_dsp =
                snd_soc_platform_get_drvdata(rtd->platform);

        return bytes_to_frames(runtime, rt5514_dsp->dma_offset);
}

static const struct snd_pcm_ops rt5514_spi_pcm_ops = {
        .open           = rt5514_spi_pcm_open,
        .hw_params      = rt5514_spi_hw_params,
        .hw_free        = rt5514_spi_hw_free,
        .pointer        = rt5514_spi_pcm_pointer,
        .mmap           = snd_pcm_lib_mmap_vmalloc,
        .page           = snd_pcm_lib_get_vmalloc_page,
};

static int rt5514_spi_pcm_probe(struct snd_soc_platform *platform)
{
        struct rt5514_dsp *rt5514_dsp;
        int ret;

        rt5514_dsp = devm_kzalloc(platform->dev, sizeof(*rt5514_dsp),
                        GFP_KERNEL);

        rt5514_dsp->dev = &rt5514_spi->dev;
        mutex_init(&rt5514_dsp->dma_lock);
        INIT_DELAYED_WORK(&rt5514_dsp->copy_work, rt5514_spi_copy_work);
        snd_soc_platform_set_drvdata(platform, rt5514_dsp);

        if (rt5514_spi->irq) {
                ret = devm_request_threaded_irq(&rt5514_spi->dev,
                        rt5514_spi->irq, NULL, rt5514_spi_irq,
                        IRQF_TRIGGER_RISING | IRQF_ONESHOT, "rt5514-spi",
                        rt5514_dsp);
                if (ret)
                        dev_err(&rt5514_spi->dev,
                                "%s Failed to reguest IRQ: %d\n", __func__,
                                ret);
        }

        return 0;
}

static const struct snd_soc_platform_driver rt5514_spi_platform = {
        .probe = rt5514_spi_pcm_probe,
        .ops = &rt5514_spi_pcm_ops,
};

static const struct snd_soc_component_driver rt5514_spi_dai_component = {
        .name           = "rt5514-spi-dai",
};

/**
 * rt5514_spi_burst_read - Read data from SPI by rt5514 address.
 * @addr: Start address.
 * @rxbuf: Data Buffer for reading.
 * @len: Data length, it must be a multiple of 8.
 *
 *
 * Returns true for success.
 */
int rt5514_spi_burst_read(unsigned int addr, u8 *rxbuf, size_t len)
{
        u8 spi_cmd = RT5514_SPI_CMD_BURST_READ;
        int status;
        u8 write_buf[8];
        unsigned int i, end, offset = 0;

        struct spi_message message;
        struct spi_transfer x[3];

        while (offset < len) {
                if (offset + RT5514_SPI_BUF_LEN <= len)
                        end = RT5514_SPI_BUF_LEN;
                else
                        end = len % RT5514_SPI_BUF_LEN;

                write_buf[0] = spi_cmd;
                write_buf[1] = ((addr + offset) & 0xff000000) >> 24;
                write_buf[2] = ((addr + offset) & 0x00ff0000) >> 16;
                write_buf[3] = ((addr + offset) & 0x0000ff00) >> 8;
                write_buf[4] = ((addr + offset) & 0x000000ff) >> 0;

                spi_message_init(&message);
                memset(x, 0, sizeof(x));

                x[0].len = 5;
                x[0].tx_buf = write_buf;
                spi_message_add_tail(&x[0], &message);

                x[1].len = 4;
                x[1].tx_buf = write_buf;
                spi_message_add_tail(&x[1], &message);

                x[2].len = end;
                x[2].rx_buf = rxbuf + offset;
                spi_message_add_tail(&x[2], &message);

                status = spi_sync(rt5514_spi, &message);

                if (status)
                        return false;

                offset += RT5514_SPI_BUF_LEN;
        }

        for (i = 0; i < len; i += 8) {
                write_buf[0] = rxbuf[i + 0];
                write_buf[1] = rxbuf[i + 1];
                write_buf[2] = rxbuf[i + 2];
                write_buf[3] = rxbuf[i + 3];
                write_buf[4] = rxbuf[i + 4];
                write_buf[5] = rxbuf[i + 5];
                write_buf[6] = rxbuf[i + 6];
                write_buf[7] = rxbuf[i + 7];

                rxbuf[i + 0] = write_buf[7];
                rxbuf[i + 1] = write_buf[6];
                rxbuf[i + 2] = write_buf[5];
                rxbuf[i + 3] = write_buf[4];
                rxbuf[i + 4] = write_buf[3];
                rxbuf[i + 5] = write_buf[2];
                rxbuf[i + 6] = write_buf[1];
                rxbuf[i + 7] = write_buf[0];
        }

        return true;
}

/**
 * rt5514_spi_burst_write - Write data to SPI by rt5514 address.
 * @addr: Start address.
 * @txbuf: Data Buffer for writng.
 * @len: Data length, it must be a multiple of 8.
 *
 *
 * Returns true for success.
 */
int rt5514_spi_burst_write(u32 addr, const u8 *txbuf, size_t len)
{
        u8 spi_cmd = RT5514_SPI_CMD_BURST_WRITE;
        u8 *write_buf;
        unsigned int i, end, offset = 0;

        write_buf = kmalloc(RT5514_SPI_BUF_LEN + 6, GFP_KERNEL);

        if (write_buf == NULL)
                return -ENOMEM;

        while (offset < len) {
                if (offset + RT5514_SPI_BUF_LEN <= len)
                        end = RT5514_SPI_BUF_LEN;
                else
                        end = len % RT5514_SPI_BUF_LEN;

                write_buf[0] = spi_cmd;
                write_buf[1] = ((addr + offset) & 0xff000000) >> 24;
                write_buf[2] = ((addr + offset) & 0x00ff0000) >> 16;
                write_buf[3] = ((addr + offset) & 0x0000ff00) >> 8;
                write_buf[4] = ((addr + offset) & 0x000000ff) >> 0;

                for (i = 0; i < end; i += 8) {
                        write_buf[i + 12] = txbuf[offset + i + 0];
                        write_buf[i + 11] = txbuf[offset + i + 1];
                        write_buf[i + 10] = txbuf[offset + i + 2];
                        write_buf[i +  9] = txbuf[offset + i + 3];
                        write_buf[i +  8] = txbuf[offset + i + 4];
                        write_buf[i +  7] = txbuf[offset + i + 5];
                        write_buf[i +  6] = txbuf[offset + i + 6];
                        write_buf[i +  5] = txbuf[offset + i + 7];
                }

                write_buf[end + 5] = spi_cmd;

                spi_write(rt5514_spi, write_buf, end + 6);

                offset += RT5514_SPI_BUF_LEN;
        }

        kfree(write_buf);

        return 0;
}
EXPORT_SYMBOL_GPL(rt5514_spi_burst_write);

static int rt5514_spi_probe(struct spi_device *spi)
{
        int ret;

        rt5514_spi = spi;

        ret = devm_snd_soc_register_platform(&spi->dev, &rt5514_spi_platform);
        if (ret < 0) {
                dev_err(&spi->dev, "Failed to register platform.\n");
                return ret;
        }

        ret = devm_snd_soc_register_component(&spi->dev,
                                              &rt5514_spi_dai_component,
                                              &rt5514_spi_dai, 1);
        if (ret < 0) {
                dev_err(&spi->dev, "Failed to register component.\n");
                return ret;
        }

        return 0;
}

static const struct of_device_id rt5514_of_match[] = {
        { .compatible = "realtek,rt5514", },
        {},
};
MODULE_DEVICE_TABLE(of, rt5514_of_match);

static struct spi_driver rt5514_spi_driver = {
        .driver = {
                .name = "rt5514",
                .of_match_table = of_match_ptr(rt5514_of_match),
        },
        .probe = rt5514_spi_probe,
};
module_spi_driver(rt5514_spi_driver);

MODULE_DESCRIPTION("RT5514 SPI driver");
MODULE_AUTHOR("Oder Chiou <oder_chiou@realtek.com>");
MODULE_LICENSE("GPL v2");