// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2015 VanguardiaSur - www.vanguardiasur.com.ar
 *
 * Based on the audio support from the tw6869 driver:
 * Copyright 2015 www.starterkit.ru <info@starterkit.ru>
 *
 * Based on:
 * Driver for Intersil|Techwell TW6869 based DVR cards
 * (c) 2011-12 liran <jli11@intersil.com> [Intersil|Techwell China]
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kmod.h>
#include <linux/mutex.h>
#include <linux/pci.h>
#include <linux/delay.h>

#include <sound/core.h>
#include <sound/initval.h>
#include <sound/pcm.h>
#include <sound/control.h>
#include "tw686x.h"
#include "tw686x-regs.h"

#define AUDIO_CHANNEL_OFFSET 8

void tw686x_audio_irq(struct tw686x_dev *dev, unsigned long requests,
                      unsigned int pb_status)
{
        unsigned long flags;
        unsigned int ch, pb;

        for_each_set_bit(ch, &requests, max_channels(dev)) {
                struct tw686x_audio_channel *ac = &dev->audio_channels[ch];
                struct tw686x_audio_buf *done = NULL;
                struct tw686x_audio_buf *next = NULL;
                struct tw686x_dma_desc *desc;

                pb = !!(pb_status & BIT(AUDIO_CHANNEL_OFFSET + ch));

                spin_lock_irqsave(&ac->lock, flags);

                /* Sanity check */
                if (!ac->ss || !ac->curr_bufs[0] || !ac->curr_bufs[1]) {
                        spin_unlock_irqrestore(&ac->lock, flags);
                        continue;
                }

                if (!list_empty(&ac->buf_list)) {
                        next = list_first_entry(&ac->buf_list,
                                        struct tw686x_audio_buf, list);
                        list_move_tail(&next->list, &ac->buf_list);
                        done = ac->curr_bufs[!pb];
                        ac->curr_bufs[pb] = next;
                }
                spin_unlock_irqrestore(&ac->lock, flags);

                if (!done)
                        continue;
                /*
                 * Checking for a non-nil dma_desc[pb]->virt buffer is
                 * the same as checking for memcpy DMA mode.
                 */
                desc = &ac->dma_descs[pb];
                if (desc->virt) {
                        memcpy(done->virt, desc->virt,
                               dev->period_size);
                } else {
                        u32 reg = pb ? ADMA_B_ADDR[ch] : ADMA_P_ADDR[ch];
                        reg_write(dev, reg, next->dma);
                }
                ac->ptr = done->dma - ac->buf[0].dma;
                snd_pcm_period_elapsed(ac->ss);
        }
}

/*
 * Audio parameters are global and shared among all
 * capture channels. The driver prevents changes to
 * the parameters if any audio channel is capturing.
 */
static const struct snd_pcm_hardware tw686x_capture_hw = {
        .info                   = (SNDRV_PCM_INFO_MMAP |
                                   SNDRV_PCM_INFO_INTERLEAVED |
                                   SNDRV_PCM_INFO_BLOCK_TRANSFER |
                                   SNDRV_PCM_INFO_MMAP_VALID),
        .formats                = SNDRV_PCM_FMTBIT_S16_LE,
        .rates                  = SNDRV_PCM_RATE_8000_48000,
        .rate_min               = 8000,
        .rate_max               = 48000,
        .channels_min           = 1,
        .channels_max           = 1,
        .buffer_bytes_max       = TW686X_AUDIO_PAGE_MAX * AUDIO_DMA_SIZE_MAX,
        .period_bytes_min       = AUDIO_DMA_SIZE_MIN,
        .period_bytes_max       = AUDIO_DMA_SIZE_MAX,
        .periods_min            = TW686X_AUDIO_PERIODS_MIN,
        .periods_max            = TW686X_AUDIO_PERIODS_MAX,
};

static int tw686x_pcm_open(struct snd_pcm_substream *ss)
{
        struct tw686x_dev *dev = snd_pcm_substream_chip(ss);
        struct tw686x_audio_channel *ac = &dev->audio_channels[ss->number];
        struct snd_pcm_runtime *rt = ss->runtime;
        int err;

        ac->ss = ss;
        rt->hw = tw686x_capture_hw;

        err = snd_pcm_hw_constraint_integer(rt, SNDRV_PCM_HW_PARAM_PERIODS);
        if (err < 0)
                return err;

        return 0;
}

static int tw686x_pcm_close(struct snd_pcm_substream *ss)
{
        struct tw686x_dev *dev = snd_pcm_substream_chip(ss);
        struct tw686x_audio_channel *ac = &dev->audio_channels[ss->number];

        ac->ss = NULL;
        return 0;
}

static int tw686x_pcm_prepare(struct snd_pcm_substream *ss)
{
        struct tw686x_dev *dev = snd_pcm_substream_chip(ss);
        struct tw686x_audio_channel *ac = &dev->audio_channels[ss->number];
        struct snd_pcm_runtime *rt = ss->runtime;
        unsigned int period_size = snd_pcm_lib_period_bytes(ss);
        struct tw686x_audio_buf *p_buf, *b_buf;
        unsigned long flags;
        int i;

        spin_lock_irqsave(&dev->lock, flags);
        /*
         * Given the audio parameters are global (i.e. shared across
         * DMA channels), we need to check new params are allowed.
         */
        if (((dev->audio_rate != rt->rate) ||
             (dev->period_size != period_size)) && dev->audio_enabled)
                goto err_audio_busy;

        tw686x_disable_channel(dev, AUDIO_CHANNEL_OFFSET + ac->ch);
        spin_unlock_irqrestore(&dev->lock, flags);

        if (dev->audio_rate != rt->rate) {
                u32 reg;

                dev->audio_rate = rt->rate;
                reg = ((125000000 / rt->rate) << 16) +
                       ((125000000 % rt->rate) << 16) / rt->rate;

                reg_write(dev, AUDIO_CONTROL2, reg);
        }

        if (dev->period_size != period_size) {
                u32 reg;

                dev->period_size = period_size;
                reg = reg_read(dev, AUDIO_CONTROL1);
                reg &= ~(AUDIO_DMA_SIZE_MASK << AUDIO_DMA_SIZE_SHIFT);
                reg |= period_size << AUDIO_DMA_SIZE_SHIFT;

                reg_write(dev, AUDIO_CONTROL1, reg);
        }

        if (rt->periods < TW686X_AUDIO_PERIODS_MIN ||
            rt->periods > TW686X_AUDIO_PERIODS_MAX)
                return -EINVAL;

        spin_lock_irqsave(&ac->lock, flags);
        INIT_LIST_HEAD(&ac->buf_list);

        for (i = 0; i < rt->periods; i++) {
                ac->buf[i].dma = rt->dma_addr + period_size * i;
                ac->buf[i].virt = rt->dma_area + period_size * i;
                INIT_LIST_HEAD(&ac->buf[i].list);
                list_add_tail(&ac->buf[i].list, &ac->buf_list);
        }

        p_buf = list_first_entry(&ac->buf_list, struct tw686x_audio_buf, list);
        list_move_tail(&p_buf->list, &ac->buf_list);

        b_buf = list_first_entry(&ac->buf_list, struct tw686x_audio_buf, list);
        list_move_tail(&b_buf->list, &ac->buf_list);

        ac->curr_bufs[0] = p_buf;
        ac->curr_bufs[1] = b_buf;
        ac->ptr = 0;

        if (dev->dma_mode != TW686X_DMA_MODE_MEMCPY) {
                reg_write(dev, ADMA_P_ADDR[ac->ch], p_buf->dma);
                reg_write(dev, ADMA_B_ADDR[ac->ch], b_buf->dma);
        }

        spin_unlock_irqrestore(&ac->lock, flags);

        return 0;

err_audio_busy:
        spin_unlock_irqrestore(&dev->lock, flags);
        return -EBUSY;
}

static int tw686x_pcm_trigger(struct snd_pcm_substream *ss, int cmd)
{
        struct tw686x_dev *dev = snd_pcm_substream_chip(ss);
        struct tw686x_audio_channel *ac = &dev->audio_channels[ss->number];
        unsigned long flags;
        int err = 0;

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
                if (ac->curr_bufs[0] && ac->curr_bufs[1]) {
                        spin_lock_irqsave(&dev->lock, flags);
                        dev->audio_enabled = 1;
                        tw686x_enable_channel(dev,
                                AUDIO_CHANNEL_OFFSET + ac->ch);
                        spin_unlock_irqrestore(&dev->lock, flags);

                        mod_timer(&dev->dma_delay_timer,
                                  jiffies + msecs_to_jiffies(100));
                } else {
                        err = -EIO;
                }
                break;
        case SNDRV_PCM_TRIGGER_STOP:
                spin_lock_irqsave(&dev->lock, flags);
                dev->audio_enabled = 0;
                tw686x_disable_channel(dev, AUDIO_CHANNEL_OFFSET + ac->ch);
                spin_unlock_irqrestore(&dev->lock, flags);

                spin_lock_irqsave(&ac->lock, flags);
                ac->curr_bufs[0] = NULL;
                ac->curr_bufs[1] = NULL;
                spin_unlock_irqrestore(&ac->lock, flags);
                break;
        default:
                err = -EINVAL;
        }
        return err;
}

static snd_pcm_uframes_t tw686x_pcm_pointer(struct snd_pcm_substream *ss)
{
        struct tw686x_dev *dev = snd_pcm_substream_chip(ss);
        struct tw686x_audio_channel *ac = &dev->audio_channels[ss->number];

        return bytes_to_frames(ss->runtime, ac->ptr);
}

static const struct snd_pcm_ops tw686x_pcm_ops = {
        .open = tw686x_pcm_open,
        .close = tw686x_pcm_close,
        .prepare = tw686x_pcm_prepare,
        .trigger = tw686x_pcm_trigger,
        .pointer = tw686x_pcm_pointer,
};

static int tw686x_snd_pcm_init(struct tw686x_dev *dev)
{
        struct snd_card *card = dev->snd_card;
        struct snd_pcm *pcm;
        struct snd_pcm_substream *ss;
        unsigned int i;
        int err;

        err = snd_pcm_new(card, card->driver, 0, 0, max_channels(dev), &pcm);
        if (err < 0)
                return err;

        snd_pcm_set_ops(pcm, SNDRV_PCM_STREAM_CAPTURE, &tw686x_pcm_ops);
        snd_pcm_chip(pcm) = dev;
        pcm->info_flags = 0;
        strscpy(pcm->name, "tw686x PCM", sizeof(pcm->name));

        for (i = 0, ss = pcm->streams[SNDRV_PCM_STREAM_CAPTURE].substream;
             ss; ss = ss->next, i++)
                snprintf(ss->name, sizeof(ss->name), "vch%u audio", i);

        snd_pcm_set_managed_buffer_all(pcm,
                                SNDRV_DMA_TYPE_DEV,
                                &dev->pci_dev->dev,
                                TW686X_AUDIO_PAGE_MAX * AUDIO_DMA_SIZE_MAX,
                                TW686X_AUDIO_PAGE_MAX * AUDIO_DMA_SIZE_MAX);
        return 0;
}

static void tw686x_audio_dma_free(struct tw686x_dev *dev,
                                  struct tw686x_audio_channel *ac)
{
        int pb;

        for (pb = 0; pb < 2; pb++) {
                if (!ac->dma_descs[pb].virt)
                        continue;
                dma_free_coherent(&dev->pci_dev->dev, ac->dma_descs[pb].size,
                                  ac->dma_descs[pb].virt,
                                  ac->dma_descs[pb].phys);
                ac->dma_descs[pb].virt = NULL;
        }
}

static int tw686x_audio_dma_alloc(struct tw686x_dev *dev,
                                  struct tw686x_audio_channel *ac)
{
        int pb;

        /*
         * In the memcpy DMA mode we allocate a coherent buffer
         * and use it for the DMA capture. Otherwise, DMA
         * acts on the ALSA buffers as received in pcm_prepare.
         */
        if (dev->dma_mode != TW686X_DMA_MODE_MEMCPY)
                return 0;

        for (pb = 0; pb < 2; pb++) {
                u32 reg = pb ? ADMA_B_ADDR[ac->ch] : ADMA_P_ADDR[ac->ch];
                void *virt;

                virt = dma_alloc_coherent(&dev->pci_dev->dev,
                                          AUDIO_DMA_SIZE_MAX,
                                          &ac->dma_descs[pb].phys, GFP_KERNEL);
                if (!virt) {
                        dev_err(&dev->pci_dev->dev,
                                "dma%d: unable to allocate audio DMA %s-buffer\n",
                                ac->ch, pb ? "B" : "P");
                        return -ENOMEM;
                }
                ac->dma_descs[pb].virt = virt;
                ac->dma_descs[pb].size = AUDIO_DMA_SIZE_MAX;
                reg_write(dev, reg, ac->dma_descs[pb].phys);
        }
        return 0;
}

void tw686x_audio_free(struct tw686x_dev *dev)
{
        unsigned long flags;
        u32 dma_ch_mask;
        u32 dma_cmd;

        spin_lock_irqsave(&dev->lock, flags);
        dma_cmd = reg_read(dev, DMA_CMD);
        dma_ch_mask = reg_read(dev, DMA_CHANNEL_ENABLE);
        reg_write(dev, DMA_CMD, dma_cmd & ~0xff00);
        reg_write(dev, DMA_CHANNEL_ENABLE, dma_ch_mask & ~0xff00);
        spin_unlock_irqrestore(&dev->lock, flags);

        if (!dev->snd_card)
                return;
        snd_card_free(dev->snd_card);
        dev->snd_card = NULL;
}

int tw686x_audio_init(struct tw686x_dev *dev)
{
        struct pci_dev *pci_dev = dev->pci_dev;
        struct snd_card *card;
        int err, ch;

        /* Enable external audio */
        reg_write(dev, AUDIO_CONTROL1, BIT(0));

        err = snd_card_new(&pci_dev->dev, SNDRV_DEFAULT_IDX1,
                           SNDRV_DEFAULT_STR1,
                           THIS_MODULE, 0, &card);
        if (err < 0)
                return err;

        dev->snd_card = card;
        strscpy(card->driver, "tw686x", sizeof(card->driver));
        strscpy(card->shortname, "tw686x", sizeof(card->shortname));
        strscpy(card->longname, pci_name(pci_dev), sizeof(card->longname));
        snd_card_set_dev(card, &pci_dev->dev);

        for (ch = 0; ch < max_channels(dev); ch++) {
                struct tw686x_audio_channel *ac;

                ac = &dev->audio_channels[ch];
                spin_lock_init(&ac->lock);
                ac->dev = dev;
                ac->ch = ch;

                err = tw686x_audio_dma_alloc(dev, ac);
                if (err < 0)
                        goto err_cleanup;
        }

        err = tw686x_snd_pcm_init(dev);
        if (err < 0)
                goto err_cleanup;

        err = snd_card_register(card);
        if (!err)
                return 0;

err_cleanup:
        for (ch = 0; ch < max_channels(dev); ch++) {
                if (!dev->audio_channels[ch].dev)
                        continue;
                tw686x_audio_dma_free(dev, &dev->audio_channels[ch]);
        }
        snd_card_free(card);
        dev->snd_card = NULL;
        return err;
}