/*
 * siu_pcm.c - ALSA driver for Renesas SH7343, SH7722 SIU peripheral.
 *
 * Copyright (C) 2009-2010 Guennadi Liakhovetski <g.liakhovetski@gmx.de>
 * Copyright (C) 2006 Carlos Munoz <carlos@kenati.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * 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/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/platform_device.h>

#include <sound/control.h>
#include <sound/core.h>
#include <sound/pcm.h>
#include <sound/pcm_params.h>
#include <sound/soc.h>

#include <asm/siu.h>

#include "siu.h"

#define GET_MAX_PERIODS(buf_bytes, period_bytes) \
                                ((buf_bytes) / (period_bytes))
#define PERIOD_OFFSET(buf_addr, period_num, period_bytes) \
                                ((buf_addr) + ((period_num) * (period_bytes)))

#define RWF_STM_RD              0x01            /* Read in progress */
#define RWF_STM_WT              0x02            /* Write in progress */

struct siu_port *siu_ports[SIU_PORT_NUM];

/* transfersize is number of u32 dma transfers per period */
static int siu_pcm_stmwrite_stop(struct siu_port *port_info)
{
        struct siu_info *info = siu_i2s_data;
        u32 __iomem *base = info->reg;
        struct siu_stream *siu_stream = &port_info->playback;
        u32 stfifo;

        if (!siu_stream->rw_flg)
                return -EPERM;

        /* output FIFO disable */
        stfifo = siu_read32(base + SIU_STFIFO);
        siu_write32(base + SIU_STFIFO, stfifo & ~0x0c180c18);
        pr_debug("%s: STFIFO %x -> %x\n", __func__,
                 stfifo, stfifo & ~0x0c180c18);

        /* during stmwrite clear */
        siu_stream->rw_flg = 0;

        return 0;
}

static int siu_pcm_stmwrite_start(struct siu_port *port_info)
{
        struct siu_stream *siu_stream = &port_info->playback;

        if (siu_stream->rw_flg)
                return -EPERM;

        /* Current period in buffer */
        port_info->playback.cur_period = 0;

        /* during stmwrite flag set */
        siu_stream->rw_flg = RWF_STM_WT;

        /* DMA transfer start */
        tasklet_schedule(&siu_stream->tasklet);

        return 0;
}

static void siu_dma_tx_complete(void *arg)
{
        struct siu_stream *siu_stream = arg;

        if (!siu_stream->rw_flg)
                return;

        /* Update completed period count */
        if (++siu_stream->cur_period >=
            GET_MAX_PERIODS(siu_stream->buf_bytes,
                            siu_stream->period_bytes))
                siu_stream->cur_period = 0;

        pr_debug("%s: done period #%d (%u/%u bytes), cookie %d\n",
                __func__, siu_stream->cur_period,
                siu_stream->cur_period * siu_stream->period_bytes,
                siu_stream->buf_bytes, siu_stream->cookie);

        tasklet_schedule(&siu_stream->tasklet);

        /* Notify alsa: a period is done */
        snd_pcm_period_elapsed(siu_stream->substream);
}

static int siu_pcm_wr_set(struct siu_port *port_info,
                          dma_addr_t buff, u32 size)
{
        struct siu_info *info = siu_i2s_data;
        u32 __iomem *base = info->reg;
        struct siu_stream *siu_stream = &port_info->playback;
        struct snd_pcm_substream *substream = siu_stream->substream;
        struct device *dev = substream->pcm->card->dev;
        struct dma_async_tx_descriptor *desc;
        dma_cookie_t cookie;
        struct scatterlist sg;
        u32 stfifo;

        sg_init_table(&sg, 1);
        sg_set_page(&sg, pfn_to_page(PFN_DOWN(buff)),
                    size, offset_in_page(buff));
        sg_dma_len(&sg) = size;
        sg_dma_address(&sg) = buff;

        desc = dmaengine_prep_slave_sg(siu_stream->chan,
                &sg, 1, DMA_MEM_TO_DEV, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!desc) {
                dev_err(dev, "Failed to allocate a dma descriptor\n");
                return -ENOMEM;
        }

        desc->callback = siu_dma_tx_complete;
        desc->callback_param = siu_stream;
        cookie = desc->tx_submit(desc);
        if (cookie < 0) {
                dev_err(dev, "Failed to submit a dma transfer\n");
                return cookie;
        }

        siu_stream->tx_desc = desc;
        siu_stream->cookie = cookie;

        dma_async_issue_pending(siu_stream->chan);

        /* only output FIFO enable */
        stfifo = siu_read32(base + SIU_STFIFO);
        siu_write32(base + SIU_STFIFO, stfifo | (port_info->stfifo & 0x0c180c18));
        dev_dbg(dev, "%s: STFIFO %x -> %x\n", __func__,
                stfifo, stfifo | (port_info->stfifo & 0x0c180c18));

        return 0;
}

static int siu_pcm_rd_set(struct siu_port *port_info,
                          dma_addr_t buff, size_t size)
{
        struct siu_info *info = siu_i2s_data;
        u32 __iomem *base = info->reg;
        struct siu_stream *siu_stream = &port_info->capture;
        struct snd_pcm_substream *substream = siu_stream->substream;
        struct device *dev = substream->pcm->card->dev;
        struct dma_async_tx_descriptor *desc;
        dma_cookie_t cookie;
        struct scatterlist sg;
        u32 stfifo;

        dev_dbg(dev, "%s: %u@%llx\n", __func__, size, (unsigned long long)buff);

        sg_init_table(&sg, 1);
        sg_set_page(&sg, pfn_to_page(PFN_DOWN(buff)),
                    size, offset_in_page(buff));
        sg_dma_len(&sg) = size;
        sg_dma_address(&sg) = buff;

        desc = dmaengine_prep_slave_sg(siu_stream->chan,
                &sg, 1, DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
        if (!desc) {
                dev_err(dev, "Failed to allocate dma descriptor\n");
                return -ENOMEM;
        }

        desc->callback = siu_dma_tx_complete;
        desc->callback_param = siu_stream;
        cookie = desc->tx_submit(desc);
        if (cookie < 0) {
                dev_err(dev, "Failed to submit dma descriptor\n");
                return cookie;
        }

        siu_stream->tx_desc = desc;
        siu_stream->cookie = cookie;

        dma_async_issue_pending(siu_stream->chan);

        /* only input FIFO enable */
        stfifo = siu_read32(base + SIU_STFIFO);
        siu_write32(base + SIU_STFIFO, siu_read32(base + SIU_STFIFO) |
                    (port_info->stfifo & 0x13071307));
        dev_dbg(dev, "%s: STFIFO %x -> %x\n", __func__,
                stfifo, stfifo | (port_info->stfifo & 0x13071307));

        return 0;
}

static void siu_io_tasklet(unsigned long data)
{
        struct siu_stream *siu_stream = (struct siu_stream *)data;
        struct snd_pcm_substream *substream = siu_stream->substream;
        struct device *dev = substream->pcm->card->dev;
        struct snd_pcm_runtime *rt = substream->runtime;
        struct siu_port *port_info = siu_port_info(substream);

        dev_dbg(dev, "%s: flags %x\n", __func__, siu_stream->rw_flg);

        if (!siu_stream->rw_flg) {
                dev_dbg(dev, "%s: stream inactive\n", __func__);
                return;
        }

        if (substream->stream == SNDRV_PCM_STREAM_CAPTURE) {
                dma_addr_t buff;
                size_t count;
                u8 *virt;

                buff = (dma_addr_t)PERIOD_OFFSET(rt->dma_addr,
                                                siu_stream->cur_period,
                                                siu_stream->period_bytes);
                virt = PERIOD_OFFSET(rt->dma_area,
                                     siu_stream->cur_period,
                                     siu_stream->period_bytes);
                count = siu_stream->period_bytes;

                /* DMA transfer start */
                siu_pcm_rd_set(port_info, buff, count);
        } else {
                siu_pcm_wr_set(port_info,
                               (dma_addr_t)PERIOD_OFFSET(rt->dma_addr,
                                                siu_stream->cur_period,
                                                siu_stream->period_bytes),
                               siu_stream->period_bytes);
        }
}

/* Capture */
static int siu_pcm_stmread_start(struct siu_port *port_info)
{
        struct siu_stream *siu_stream = &port_info->capture;

        if (siu_stream->xfer_cnt > 0x1000000)
                return -EINVAL;
        if (siu_stream->rw_flg)
                return -EPERM;

        /* Current period in buffer */
        siu_stream->cur_period = 0;

        /* during stmread flag set */
        siu_stream->rw_flg = RWF_STM_RD;

        tasklet_schedule(&siu_stream->tasklet);

        return 0;
}

static int siu_pcm_stmread_stop(struct siu_port *port_info)
{
        struct siu_info *info = siu_i2s_data;
        u32 __iomem *base = info->reg;
        struct siu_stream *siu_stream = &port_info->capture;
        struct device *dev = siu_stream->substream->pcm->card->dev;
        u32 stfifo;

        if (!siu_stream->rw_flg)
                return -EPERM;

        /* input FIFO disable */
        stfifo = siu_read32(base + SIU_STFIFO);
        siu_write32(base + SIU_STFIFO, stfifo & ~0x13071307);
        dev_dbg(dev, "%s: STFIFO %x -> %x\n", __func__,
                stfifo, stfifo & ~0x13071307);

        /* during stmread flag clear */
        siu_stream->rw_flg = 0;

        return 0;
}

static int siu_pcm_hw_params(struct snd_pcm_substream *ss,
                             struct snd_pcm_hw_params *hw_params)
{
        struct siu_info *info = siu_i2s_data;
        struct device *dev = ss->pcm->card->dev;
        int ret;

        dev_dbg(dev, "%s: port=%d\n", __func__, info->port_id);

        ret = snd_pcm_lib_malloc_pages(ss, params_buffer_bytes(hw_params));
        if (ret < 0)
                dev_err(dev, "snd_pcm_lib_malloc_pages() failed\n");

        return ret;
}

static int siu_pcm_hw_free(struct snd_pcm_substream *ss)
{
        struct siu_info *info = siu_i2s_data;
        struct siu_port *port_info = siu_port_info(ss);
        struct device *dev = ss->pcm->card->dev;
        struct siu_stream *siu_stream;

        if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
                siu_stream = &port_info->playback;
        else
                siu_stream = &port_info->capture;

        dev_dbg(dev, "%s: port=%d\n", __func__, info->port_id);

        return snd_pcm_lib_free_pages(ss);
}

static bool filter(struct dma_chan *chan, void *slave)
{
        struct sh_dmae_slave *param = slave;

        pr_debug("%s: slave ID %d\n", __func__, param->shdma_slave.slave_id);

        chan->private = &param->shdma_slave;
        return true;
}

static int siu_pcm_open(struct snd_pcm_substream *ss)
{
        /* Playback / Capture */
        struct snd_soc_pcm_runtime *rtd = ss->private_data;
        struct siu_platform *pdata = rtd->platform->dev->platform_data;
        struct siu_info *info = siu_i2s_data;
        struct siu_port *port_info = siu_port_info(ss);
        struct siu_stream *siu_stream;
        u32 port = info->port_id;
        struct device *dev = ss->pcm->card->dev;
        dma_cap_mask_t mask;
        struct sh_dmae_slave *param;

        dma_cap_zero(mask);
        dma_cap_set(DMA_SLAVE, mask);

        dev_dbg(dev, "%s, port=%d@%p\n", __func__, port, port_info);

        if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK) {
                siu_stream = &port_info->playback;
                param = &siu_stream->param;
                param->shdma_slave.slave_id = port ? pdata->dma_slave_tx_b :
                        pdata->dma_slave_tx_a;
        } else {
                siu_stream = &port_info->capture;
                param = &siu_stream->param;
                param->shdma_slave.slave_id = port ? pdata->dma_slave_rx_b :
                        pdata->dma_slave_rx_a;
        }

        /* Get DMA channel */
        siu_stream->chan = dma_request_channel(mask, filter, param);
        if (!siu_stream->chan) {
                dev_err(dev, "DMA channel allocation failed!\n");
                return -EBUSY;
        }

        siu_stream->substream = ss;

        return 0;
}

static int siu_pcm_close(struct snd_pcm_substream *ss)
{
        struct siu_info *info = siu_i2s_data;
        struct device *dev = ss->pcm->card->dev;
        struct siu_port *port_info = siu_port_info(ss);
        struct siu_stream *siu_stream;

        dev_dbg(dev, "%s: port=%d\n", __func__, info->port_id);

        if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
                siu_stream = &port_info->playback;
        else
                siu_stream = &port_info->capture;

        dma_release_channel(siu_stream->chan);
        siu_stream->chan = NULL;

        siu_stream->substream = NULL;

        return 0;
}

static int siu_pcm_prepare(struct snd_pcm_substream *ss)
{
        struct siu_info *info = siu_i2s_data;
        struct siu_port *port_info = siu_port_info(ss);
        struct device *dev = ss->pcm->card->dev;
        struct snd_pcm_runtime  *rt = ss->runtime;
        struct siu_stream *siu_stream;
        snd_pcm_sframes_t xfer_cnt;

        if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
                siu_stream = &port_info->playback;
        else
                siu_stream = &port_info->capture;

        rt = siu_stream->substream->runtime;

        siu_stream->buf_bytes = snd_pcm_lib_buffer_bytes(ss);
        siu_stream->period_bytes = snd_pcm_lib_period_bytes(ss);

        dev_dbg(dev, "%s: port=%d, %d channels, period=%u bytes\n", __func__,
                info->port_id, rt->channels, siu_stream->period_bytes);

        /* We only support buffers that are multiples of the period */
        if (siu_stream->buf_bytes % siu_stream->period_bytes) {
                dev_err(dev, "%s() - buffer=%d not multiple of period=%d\n",
                       __func__, siu_stream->buf_bytes,
                       siu_stream->period_bytes);
                return -EINVAL;
        }

        xfer_cnt = bytes_to_frames(rt, siu_stream->period_bytes);
        if (!xfer_cnt || xfer_cnt > 0x1000000)
                return -EINVAL;

        siu_stream->format = rt->format;
        siu_stream->xfer_cnt = xfer_cnt;

        dev_dbg(dev, "port=%d buf=%lx buf_bytes=%d period_bytes=%d "
                "format=%d channels=%d xfer_cnt=%d\n", info->port_id,
                (unsigned long)rt->dma_addr, siu_stream->buf_bytes,
                siu_stream->period_bytes,
                siu_stream->format, rt->channels, (int)xfer_cnt);

        return 0;
}

static int siu_pcm_trigger(struct snd_pcm_substream *ss, int cmd)
{
        struct siu_info *info = siu_i2s_data;
        struct device *dev = ss->pcm->card->dev;
        struct siu_port *port_info = siu_port_info(ss);
        int ret;

        dev_dbg(dev, "%s: port=%d@%p, cmd=%d\n", __func__,
                info->port_id, port_info, cmd);

        switch (cmd) {
        case SNDRV_PCM_TRIGGER_START:
                if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
                        ret = siu_pcm_stmwrite_start(port_info);
                else
                        ret = siu_pcm_stmread_start(port_info);

                if (ret < 0)
                        dev_warn(dev, "%s: start failed on port=%d\n",
                                 __func__, info->port_id);

                break;
        case SNDRV_PCM_TRIGGER_STOP:
                if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
                        siu_pcm_stmwrite_stop(port_info);
                else
                        siu_pcm_stmread_stop(port_info);
                ret = 0;

                break;
        default:
                dev_err(dev, "%s() unsupported cmd=%d\n", __func__, cmd);
                ret = -EINVAL;
        }

        return ret;
}

/*
 * So far only resolution of one period is supported, subject to extending the
 * dmangine API
 */
static snd_pcm_uframes_t siu_pcm_pointer_dma(struct snd_pcm_substream *ss)
{
        struct device *dev = ss->pcm->card->dev;
        struct siu_info *info = siu_i2s_data;
        u32 __iomem *base = info->reg;
        struct siu_port *port_info = siu_port_info(ss);
        struct snd_pcm_runtime *rt = ss->runtime;
        size_t ptr;
        struct siu_stream *siu_stream;

        if (ss->stream == SNDRV_PCM_STREAM_PLAYBACK)
                siu_stream = &port_info->playback;
        else
                siu_stream = &port_info->capture;

        /*
         * ptr is the offset into the buffer where the dma is currently at. We
         * check if the dma buffer has just wrapped.
         */
        ptr = PERIOD_OFFSET(rt->dma_addr,
                            siu_stream->cur_period,
                            siu_stream->period_bytes) - rt->dma_addr;

        dev_dbg(dev,
                "%s: port=%d, events %x, FSTS %x, xferred %u/%u, cookie %d\n",
                __func__, info->port_id, siu_read32(base + SIU_EVNTC),
                siu_read32(base + SIU_SBFSTS), ptr, siu_stream->buf_bytes,
                siu_stream->cookie);

        if (ptr >= siu_stream->buf_bytes)
                ptr = 0;

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

static int siu_pcm_new(struct snd_soc_pcm_runtime *rtd)
{
        /* card->dev == socdev->dev, see snd_soc_new_pcms() */
        struct snd_card *card = rtd->card->snd_card;
        struct snd_pcm *pcm = rtd->pcm;
        struct siu_info *info = siu_i2s_data;
        struct platform_device *pdev = to_platform_device(card->dev);
        int ret;
        int i;

        /* pdev->id selects between SIUA and SIUB */
        if (pdev->id < 0 || pdev->id >= SIU_PORT_NUM)
                return -EINVAL;

        info->port_id = pdev->id;

        /*
         * While the siu has 2 ports, only one port can be on at a time (only 1
         * SPB). So far all the boards using the siu had only one of the ports
         * wired to a codec. To simplify things, we only register one port with
         * alsa. In case both ports are needed, it should be changed here
         */
        for (i = pdev->id; i < pdev->id + 1; i++) {
                struct siu_port **port_info = &siu_ports[i];

                ret = siu_init_port(i, port_info, card);
                if (ret < 0)
                        return ret;

                ret = snd_pcm_lib_preallocate_pages_for_all(pcm,
                                SNDRV_DMA_TYPE_DEV, NULL,
                                SIU_BUFFER_BYTES_MAX, SIU_BUFFER_BYTES_MAX);
                if (ret < 0) {
                        dev_err(card->dev,
                               "snd_pcm_lib_preallocate_pages_for_all() err=%d",
                                ret);
                        goto fail;
                }

                (*port_info)->pcm = pcm;

                /* IO tasklets */
                tasklet_init(&(*port_info)->playback.tasklet, siu_io_tasklet,
                             (unsigned long)&(*port_info)->playback);
                tasklet_init(&(*port_info)->capture.tasklet, siu_io_tasklet,
                             (unsigned long)&(*port_info)->capture);
        }

        dev_info(card->dev, "SuperH SIU driver initialized.\n");
        return 0;

fail:
        siu_free_port(siu_ports[pdev->id]);
        dev_err(card->dev, "SIU: failed to initialize.\n");
        return ret;
}

static void siu_pcm_free(struct snd_pcm *pcm)
{
        struct platform_device *pdev = to_platform_device(pcm->card->dev);
        struct siu_port *port_info = siu_ports[pdev->id];

        tasklet_kill(&port_info->capture.tasklet);
        tasklet_kill(&port_info->playback.tasklet);

        siu_free_port(port_info);
        snd_pcm_lib_preallocate_free_for_all(pcm);

        dev_dbg(pcm->card->dev, "%s\n", __func__);
}

static struct snd_pcm_ops siu_pcm_ops = {
        .open           = siu_pcm_open,
        .close          = siu_pcm_close,
        .ioctl          = snd_pcm_lib_ioctl,
        .hw_params      = siu_pcm_hw_params,
        .hw_free        = siu_pcm_hw_free,
        .prepare        = siu_pcm_prepare,
        .trigger        = siu_pcm_trigger,
        .pointer        = siu_pcm_pointer_dma,
};

struct snd_soc_platform_driver siu_platform = {
        .ops                    = &siu_pcm_ops,
        .pcm_new        = siu_pcm_new,
        .pcm_free       = siu_pcm_free,
};
EXPORT_SYMBOL_GPL(siu_platform);