/*
 * Renesas R-Car Audio DMAC support
 *
 * Copyright (C) 2015 Renesas Electronics Corp.
 * Copyright (c) 2015 Kuninori Morimoto <kuninori.morimoto.gx@renesas.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 "rsnd.h"

static void rsnd_dma_complete(void *data)
{
	struct rsnd_dma *dma = (struct rsnd_dma *)data;
	struct rsnd_mod *mod = rsnd_dma_to_mod(dma);
	struct rsnd_dai_stream *io = rsnd_mod_to_io(mod);

	/*
	 * Renesas sound Gen1 needs 1 DMAC,
	 * Gen2 needs 2 DMAC.
	 * In Gen2 case, it are Audio-DMAC, and Audio-DMAC-peri-peri.
	 * But, Audio-DMAC-peri-peri doesn't have interrupt,
	 * and this driver is assuming that here.
	 *
	 * If Audio-DMAC-peri-peri has interrpt,
	 * rsnd_dai_pointer_update() will be called twice,
	 * ant it will breaks io->byte_pos
	 */

	rsnd_dai_pointer_update(io, io->byte_per_period);
}

#define DMA_NAME_SIZE 16
#define MOD_MAX 4 /* MEM/SSI/SRC/DVC */
static int _rsnd_dma_of_name(char *dma_name, struct rsnd_mod *mod)
{
	if (mod)
		return snprintf(dma_name, DMA_NAME_SIZE / 2, "%s%d",
				rsnd_mod_dma_name(mod), rsnd_mod_id(mod));
	else
		return snprintf(dma_name, DMA_NAME_SIZE / 2, "mem");

}

static void rsnd_dma_of_name(struct rsnd_mod *mod_from,
			     struct rsnd_mod *mod_to,
			     char *dma_name)
{
	int index = 0;

	index = _rsnd_dma_of_name(dma_name + index, mod_from);
	*(dma_name + index++) = '_';
	index = _rsnd_dma_of_name(dma_name + index, mod_to);
}

void rsnd_dma_stop(struct rsnd_dma *dma)
{
	dmaengine_terminate_all(dma->chan);
}

void rsnd_dma_start(struct rsnd_dma *dma)
{
	struct rsnd_mod *mod = rsnd_dma_to_mod(dma);
	struct rsnd_priv *priv = rsnd_mod_to_priv(mod);
	struct rsnd_dai_stream *io = rsnd_mod_to_io(mod);
	struct snd_pcm_substream *substream = io->substream;
	struct device *dev = rsnd_priv_to_dev(priv);
	struct dma_async_tx_descriptor *desc;

	desc = dmaengine_prep_dma_cyclic(dma->chan,
					 (dma->addr) ? dma->addr :
					 substream->runtime->dma_addr,
					 snd_pcm_lib_buffer_bytes(substream),
					 snd_pcm_lib_period_bytes(substream),
					 dma->dir,
					 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);

	if (!desc) {
		dev_err(dev, "dmaengine_prep_slave_sg() fail\n");
		return;
	}

	desc->callback		= rsnd_dma_complete;
	desc->callback_param	= dma;

	if (dmaengine_submit(desc) < 0) {
		dev_err(dev, "dmaengine_submit() fail\n");
		return;
	}

	dma_async_issue_pending(dma->chan);
}

static void rsnd_dma_of_path(struct rsnd_dma *dma,
			     int is_play,
			     struct rsnd_mod **mod_from,
			     struct rsnd_mod **mod_to);

int rsnd_dma_init(struct rsnd_priv *priv, struct rsnd_dma *dma, int id)
{
	struct device *dev = rsnd_priv_to_dev(priv);
	struct dma_slave_config cfg = {};
	struct rsnd_mod *mod = rsnd_dma_to_mod(dma);
	struct rsnd_mod *mod_from;
	struct rsnd_mod *mod_to;
	struct rsnd_dai_stream *io = rsnd_mod_to_io(mod);
	int is_play = rsnd_io_is_play(io);
	char dma_name[DMA_NAME_SIZE];
	dma_cap_mask_t mask;
	int ret;

	if (dma->chan) {
		dev_err(dev, "it already has dma channel\n");
		return -EIO;
	}

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

	rsnd_dma_of_path(dma, is_play, &mod_from, &mod_to);
	rsnd_dma_of_name(mod_from, mod_to, dma_name);

	cfg.direction	= is_play ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;
	cfg.src_addr	= rsnd_gen_dma_addr(priv, mod_from, is_play, 1);
	cfg.dst_addr	= rsnd_gen_dma_addr(priv, mod_to,   is_play, 0);
	cfg.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
	cfg.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;

	dev_dbg(dev, "dma : %s %pad -> %pad\n",
		dma_name, &cfg.src_addr, &cfg.dst_addr);

	dma->chan = dma_request_slave_channel_compat(mask, shdma_chan_filter,
						     (void *)id, dev,
						     dma_name);
	if (!dma->chan) {
		dev_err(dev, "can't get dma channel\n");
		goto rsnd_dma_channel_err;
	}

	ret = dmaengine_slave_config(dma->chan, &cfg);
	if (ret < 0)
		goto rsnd_dma_init_err;

	dma->addr = is_play ? cfg.src_addr : cfg.dst_addr;
	dma->dir = is_play ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM;

	return 0;

rsnd_dma_init_err:
	rsnd_dma_quit(dma);
rsnd_dma_channel_err:

	/*
	 * DMA failed. try to PIO mode
	 * see
	 *	rsnd_ssi_fallback()
	 *	rsnd_rdai_continuance_probe()
	 */
	return -EAGAIN;
}

void rsnd_dma_quit(struct rsnd_dma *dma)
{
	if (dma->chan)
		dma_release_channel(dma->chan);

	dma->chan = NULL;
}

static void rsnd_dma_of_path(struct rsnd_dma *dma,
			     int is_play,
			     struct rsnd_mod **mod_from,
			     struct rsnd_mod **mod_to)
{
	struct rsnd_mod *this = rsnd_dma_to_mod(dma);
	struct rsnd_dai_stream *io = rsnd_mod_to_io(this);
	struct rsnd_mod *ssi = rsnd_io_to_mod_ssi(io);
	struct rsnd_mod *src = rsnd_io_to_mod_src(io);
	struct rsnd_mod *dvc = rsnd_io_to_mod_dvc(io);
	struct rsnd_mod *mod[MOD_MAX];
	int i, index;


	for (i = 0; i < MOD_MAX; i++)
		mod[i] = NULL;

	/*
	 * in play case...
	 *
	 * src -> dst
	 *
	 * mem -> SSI
	 * mem -> SRC -> SSI
	 * mem -> SRC -> DVC -> SSI
	 */
	mod[0] = NULL; /* for "mem" */
	index = 1;
	for (i = 1; i < MOD_MAX; i++) {
		if (!src) {
			mod[i] = ssi;
		} else if (!dvc) {
			mod[i] = src;
			src = NULL;
		} else {
			if ((!is_play) && (this == src))
				this = dvc;

			mod[i] = (is_play) ? src : dvc;
			i++;
			mod[i] = (is_play) ? dvc : src;
			src = NULL;
			dvc = NULL;
		}

		if (mod[i] == this)
			index = i;

		if (mod[i] == ssi)
			break;
	}

	if (is_play) {
		*mod_from = mod[index - 1];
		*mod_to   = mod[index];
	} else {
		*mod_from = mod[index];
		*mod_to   = mod[index - 1];
	}
}