/*
 *  Copyright (C) 2013, Analog Devices Inc.
 *      Author: Lars-Peter Clausen <lars@metafoo.de>
 *
 *  This program is free software; you can redistribute it and/or modify it
 *  under  the terms of the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the License, or (at your
 *  option) any later version.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  675 Mass Ave, Cambridge, MA 02139, USA.
 *
 */
#include <linux/module.h>
#include <linux/init.h>
#include <linux/dmaengine.h>
#include <linux/slab.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>
#include <linux/dma-mapping.h>
#include <linux/of.h>

#include <sound/dmaengine_pcm.h>

/*
 * The platforms dmaengine driver does not support reporting the amount of
 * bytes that are still left to transfer.
 */
#define SND_DMAENGINE_PCM_FLAG_NO_RESIDUE BIT(31)

struct dmaengine_pcm {
        struct dma_chan *chan[SNDRV_PCM_STREAM_LAST + 1];
        const struct snd_dmaengine_pcm_config *config;
        struct snd_soc_platform platform;
        unsigned int flags;
};

static struct dmaengine_pcm *soc_platform_to_pcm(struct snd_soc_platform *p)
{
        return container_of(p, struct dmaengine_pcm, platform);
}

static struct device *dmaengine_dma_dev(struct dmaengine_pcm *pcm,
        struct snd_pcm_substream *substream)
{
        if (!pcm->chan[substream->stream])
                return NULL;

        return pcm->chan[substream->stream]->device->dev;
}

/**
 * snd_dmaengine_pcm_prepare_slave_config() - Generic prepare_slave_config callback
 * @substream: PCM substream
 * @params: hw_params
 * @slave_config: DMA slave config to prepare
 *
 * This function can be used as a generic prepare_slave_config callback for
 * platforms which make use of the snd_dmaengine_dai_dma_data struct for their
 * DAI DMA data. Internally the function will first call
 * snd_hwparams_to_dma_slave_config to fill in the slave config based on the
 * hw_params, followed by snd_dmaengine_set_config_from_dai_data to fill in the
 * remaining fields based on the DAI DMA data.
 */
int snd_dmaengine_pcm_prepare_slave_config(struct snd_pcm_substream *substream,
        struct snd_pcm_hw_params *params, struct dma_slave_config *slave_config)
{
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct snd_dmaengine_dai_dma_data *dma_data;
        int ret;

        dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);

        ret = snd_hwparams_to_dma_slave_config(substream, params, slave_config);
        if (ret)
                return ret;

        snd_dmaengine_pcm_set_config_from_dai_data(substream, dma_data,
                slave_config);

        return 0;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_prepare_slave_config);

static int dmaengine_pcm_hw_params(struct snd_pcm_substream *substream,
        struct snd_pcm_hw_params *params)
{
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
        struct dma_chan *chan = snd_dmaengine_pcm_get_chan(substream);
        int (*prepare_slave_config)(struct snd_pcm_substream *substream,
                        struct snd_pcm_hw_params *params,
                        struct dma_slave_config *slave_config);
        struct dma_slave_config slave_config;
        int ret;

        memset(&slave_config, 0, sizeof(slave_config));

        if (!pcm->config)
                prepare_slave_config = snd_dmaengine_pcm_prepare_slave_config;
        else
                prepare_slave_config = pcm->config->prepare_slave_config;

        if (prepare_slave_config) {
                ret = prepare_slave_config(substream, params, &slave_config);
                if (ret)
                        return ret;

                ret = dmaengine_slave_config(chan, &slave_config);
                if (ret)
                        return ret;
        }

        return snd_pcm_lib_malloc_pages(substream, params_buffer_bytes(params));
}

static int dmaengine_pcm_set_runtime_hwparams(struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
        struct device *dma_dev = dmaengine_dma_dev(pcm, substream);
        struct dma_chan *chan = pcm->chan[substream->stream];
        struct snd_dmaengine_dai_dma_data *dma_data;
        struct dma_slave_caps dma_caps;
        struct snd_pcm_hardware hw;
        u32 addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
                          BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
                          BIT(DMA_SLAVE_BUSWIDTH_4_BYTES);
        int i, ret;

        if (pcm->config && pcm->config->pcm_hardware)
                return snd_soc_set_runtime_hwparams(substream,
                                pcm->config->pcm_hardware);

        dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);

        memset(&hw, 0, sizeof(hw));
        hw.info = SNDRV_PCM_INFO_MMAP | SNDRV_PCM_INFO_MMAP_VALID |
                        SNDRV_PCM_INFO_INTERLEAVED;
        hw.periods_min = 2;
        hw.periods_max = UINT_MAX;
        hw.period_bytes_min = 256;
        hw.period_bytes_max = dma_get_max_seg_size(dma_dev);
        hw.buffer_bytes_max = SIZE_MAX;
        hw.fifo_size = dma_data->fifo_size;

        if (pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
                hw.info |= SNDRV_PCM_INFO_BATCH;

        ret = dma_get_slave_caps(chan, &dma_caps);
        if (ret == 0) {
                if (dma_caps.cmd_pause)
                        hw.info |= SNDRV_PCM_INFO_PAUSE | SNDRV_PCM_INFO_RESUME;
                if (dma_caps.residue_granularity <= DMA_RESIDUE_GRANULARITY_SEGMENT)
                        hw.info |= SNDRV_PCM_INFO_BATCH;

                if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK)
                        addr_widths = dma_caps.dst_addr_widths;
                else
                        addr_widths = dma_caps.src_addr_widths;
        }

        /*
         * If SND_DMAENGINE_PCM_DAI_FLAG_PACK is set keep
         * hw.formats set to 0, meaning no restrictions are in place.
         * In this case it's the responsibility of the DAI driver to
         * provide the supported format information.
         */
        if (!(dma_data->flags & SND_DMAENGINE_PCM_DAI_FLAG_PACK))
                /*
                 * Prepare formats mask for valid/allowed sample types. If the
                 * dma does not have support for the given physical word size,
                 * it needs to be masked out so user space can not use the
                 * format which produces corrupted audio.
                 * In case the dma driver does not implement the slave_caps the
                 * default assumption is that it supports 1, 2 and 4 bytes
                 * widths.
                 */
                for (i = 0; i <= SNDRV_PCM_FORMAT_LAST; i++) {
                        int bits = snd_pcm_format_physical_width(i);

                        /*
                         * Enable only samples with DMA supported physical
                         * widths
                         */
                        switch (bits) {
                        case 8:
                        case 16:
                        case 24:
                        case 32:
                        case 64:
                                if (addr_widths & (1 << (bits / 8)))
                                        hw.formats |= (1LL << i);
                                break;
                        default:
                                /* Unsupported types */
                                break;
                        }
                }

        return snd_soc_set_runtime_hwparams(substream, &hw);
}

static int dmaengine_pcm_open(struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
        struct dma_chan *chan = pcm->chan[substream->stream];
        int ret;

        ret = dmaengine_pcm_set_runtime_hwparams(substream);
        if (ret)
                return ret;

        return snd_dmaengine_pcm_open(substream, chan);
}

static struct dma_chan *dmaengine_pcm_compat_request_channel(
        struct snd_soc_pcm_runtime *rtd,
        struct snd_pcm_substream *substream)
{
        struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
        struct snd_dmaengine_dai_dma_data *dma_data;
        dma_filter_fn fn = NULL;

        dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);

        if ((pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX) && pcm->chan[0])
                return pcm->chan[0];

        if (pcm->config && pcm->config->compat_request_channel)
                return pcm->config->compat_request_channel(rtd, substream);

        if (pcm->config)
                fn = pcm->config->compat_filter_fn;

        return snd_dmaengine_pcm_request_channel(fn, dma_data->filter_data);
}

static bool dmaengine_pcm_can_report_residue(struct device *dev,
        struct dma_chan *chan)
{
        struct dma_slave_caps dma_caps;
        int ret;

        ret = dma_get_slave_caps(chan, &dma_caps);
        if (ret != 0) {
                dev_warn(dev, "Failed to get DMA channel capabilities, falling back to period counting: %d\n",
                         ret);
                return false;
        }

        if (dma_caps.residue_granularity == DMA_RESIDUE_GRANULARITY_DESCRIPTOR)
                return false;

        return true;
}

static int dmaengine_pcm_new(struct snd_soc_pcm_runtime *rtd)
{
        struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);
        const struct snd_dmaengine_pcm_config *config = pcm->config;
        struct device *dev = rtd->platform->dev;
        struct snd_dmaengine_dai_dma_data *dma_data;
        struct snd_pcm_substream *substream;
        size_t prealloc_buffer_size;
        size_t max_buffer_size;
        unsigned int i;
        int ret;

        if (config && config->prealloc_buffer_size) {
                prealloc_buffer_size = config->prealloc_buffer_size;
                max_buffer_size = config->pcm_hardware->buffer_bytes_max;
        } else {
                prealloc_buffer_size = 512 * 1024;
                max_buffer_size = SIZE_MAX;
        }


        for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE; i++) {
                substream = rtd->pcm->streams[i].substream;
                if (!substream)
                        continue;

                dma_data = snd_soc_dai_get_dma_data(rtd->cpu_dai, substream);

                if (!pcm->chan[i] &&
                    (pcm->flags & SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME))
                        pcm->chan[i] = dma_request_slave_channel(dev,
                                dma_data->chan_name);

                if (!pcm->chan[i] && (pcm->flags & SND_DMAENGINE_PCM_FLAG_COMPAT)) {
                        pcm->chan[i] = dmaengine_pcm_compat_request_channel(rtd,
                                substream);
                }

                if (!pcm->chan[i]) {
                        dev_err(rtd->platform->dev,
                                "Missing dma channel for stream: %d\n", i);
                        return -EINVAL;
                }

                ret = snd_pcm_lib_preallocate_pages(substream,
                                SNDRV_DMA_TYPE_DEV_IRAM,
                                dmaengine_dma_dev(pcm, substream),
                                prealloc_buffer_size,
                                max_buffer_size);
                if (ret)
                        return ret;

                if (!dmaengine_pcm_can_report_residue(dev, pcm->chan[i]))
                        pcm->flags |= SND_DMAENGINE_PCM_FLAG_NO_RESIDUE;
        }

        return 0;
}

static snd_pcm_uframes_t dmaengine_pcm_pointer(
        struct snd_pcm_substream *substream)
{
        struct snd_soc_pcm_runtime *rtd = substream->private_data;
        struct dmaengine_pcm *pcm = soc_platform_to_pcm(rtd->platform);

        if (pcm->flags & SND_DMAENGINE_PCM_FLAG_NO_RESIDUE)
                return snd_dmaengine_pcm_pointer_no_residue(substream);
        else
                return snd_dmaengine_pcm_pointer(substream);
}

static const struct snd_pcm_ops dmaengine_pcm_ops = {
        .open           = dmaengine_pcm_open,
        .close          = snd_dmaengine_pcm_close,
        .ioctl          = snd_pcm_lib_ioctl,
        .hw_params      = dmaengine_pcm_hw_params,
        .hw_free        = snd_pcm_lib_free_pages,
        .trigger        = snd_dmaengine_pcm_trigger,
        .pointer        = dmaengine_pcm_pointer,
};

static const struct snd_soc_platform_driver dmaengine_pcm_platform = {
        .component_driver = {
                .probe_order = SND_SOC_COMP_ORDER_LATE,
        },
        .ops            = &dmaengine_pcm_ops,
        .pcm_new        = dmaengine_pcm_new,
};

static const char * const dmaengine_pcm_dma_channel_names[] = {
        [SNDRV_PCM_STREAM_PLAYBACK] = "tx",
        [SNDRV_PCM_STREAM_CAPTURE] = "rx",
};

static int dmaengine_pcm_request_chan_of(struct dmaengine_pcm *pcm,
        struct device *dev, const struct snd_dmaengine_pcm_config *config)
{
        unsigned int i;
        const char *name;
        struct dma_chan *chan;

        if ((pcm->flags & (SND_DMAENGINE_PCM_FLAG_NO_DT |
                           SND_DMAENGINE_PCM_FLAG_CUSTOM_CHANNEL_NAME)) ||
            !dev->of_node)
                return 0;

        if (config && config->dma_dev) {
                /*
                 * If this warning is seen, it probably means that your Linux
                 * device structure does not match your HW device structure.
                 * It would be best to refactor the Linux device structure to
                 * correctly match the HW structure.
                 */
                dev_warn(dev, "DMA channels sourced from device %s",
                         dev_name(config->dma_dev));
                dev = config->dma_dev;
        }

        for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE;
             i++) {
                if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
                        name = "rx-tx";
                else
                        name = dmaengine_pcm_dma_channel_names[i];
                if (config && config->chan_names[i])
                        name = config->chan_names[i];
                chan = dma_request_slave_channel_reason(dev, name);
                if (IS_ERR(chan)) {
                        if (PTR_ERR(chan) == -EPROBE_DEFER)
                                return -EPROBE_DEFER;
                        pcm->chan[i] = NULL;
                } else {
                        pcm->chan[i] = chan;
                }
                if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
                        break;
        }

        if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
                pcm->chan[1] = pcm->chan[0];

        return 0;
}

static void dmaengine_pcm_release_chan(struct dmaengine_pcm *pcm)
{
        unsigned int i;

        for (i = SNDRV_PCM_STREAM_PLAYBACK; i <= SNDRV_PCM_STREAM_CAPTURE;
             i++) {
                if (!pcm->chan[i])
                        continue;
                dma_release_channel(pcm->chan[i]);
                if (pcm->flags & SND_DMAENGINE_PCM_FLAG_HALF_DUPLEX)
                        break;
        }
}

/**
 * snd_dmaengine_pcm_register - Register a dmaengine based PCM device
 * @dev: The parent device for the PCM device
 * @config: Platform specific PCM configuration
 * @flags: Platform specific quirks
 */
int snd_dmaengine_pcm_register(struct device *dev,
        const struct snd_dmaengine_pcm_config *config, unsigned int flags)
{
        struct dmaengine_pcm *pcm;
        int ret;

        pcm = kzalloc(sizeof(*pcm), GFP_KERNEL);
        if (!pcm)
                return -ENOMEM;

        pcm->config = config;
        pcm->flags = flags;

        ret = dmaengine_pcm_request_chan_of(pcm, dev, config);
        if (ret)
                goto err_free_dma;

        ret = snd_soc_add_platform(dev, &pcm->platform,
                &dmaengine_pcm_platform);
        if (ret)
                goto err_free_dma;

        return 0;

err_free_dma:
        dmaengine_pcm_release_chan(pcm);
        kfree(pcm);
        return ret;
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_register);

/**
 * snd_dmaengine_pcm_unregister - Removes a dmaengine based PCM device
 * @dev: Parent device the PCM was register with
 *
 * Removes a dmaengine based PCM device previously registered with
 * snd_dmaengine_pcm_register.
 */
void snd_dmaengine_pcm_unregister(struct device *dev)
{
        struct snd_soc_platform *platform;
        struct dmaengine_pcm *pcm;

        platform = snd_soc_lookup_platform(dev);
        if (!platform)
                return;

        pcm = soc_platform_to_pcm(platform);

        snd_soc_remove_platform(platform);
        dmaengine_pcm_release_chan(pcm);
        kfree(pcm);
}
EXPORT_SYMBOL_GPL(snd_dmaengine_pcm_unregister);

MODULE_LICENSE("GPL");