/*
 * Renesas SUDMAC support
 *
 * Copyright (C) 2013 Renesas Solutions Corp.
 *
 * based on drivers/dma/sh/shdma.c:
 * Copyright (C) 2011-2012 Guennadi Liakhovetski <g.liakhovetski@gmx.de>
 * Copyright (C) 2009 Nobuhiro Iwamatsu <iwamatsu.nobuhiro@renesas.com>
 * Copyright (C) 2009 Renesas Solutions, Inc. All rights reserved.
 * Copyright (C) 2007 Freescale Semiconductor, Inc. All rights reserved.
 *
 * This is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/dmaengine.h>
#include <linux/platform_device.h>
#include <linux/sudmac.h>

struct sudmac_chan {
	struct shdma_chan shdma_chan;
	void __iomem *base;
	char dev_id[16];	/* unique name per DMAC of channel */

	u32 offset;		/* for CFG, BA, BBC, CA, CBC, DEN */
	u32 cfg;
	u32 dint_end_bit;
};

struct sudmac_device {
	struct shdma_dev shdma_dev;
	struct sudmac_pdata *pdata;
	void __iomem *chan_reg;
};

struct sudmac_regs {
	u32 base_addr;
	u32 base_byte_count;
};

struct sudmac_desc {
	struct sudmac_regs hw;
	struct shdma_desc shdma_desc;
};

#define to_chan(schan) container_of(schan, struct sudmac_chan, shdma_chan)
#define to_desc(sdesc) container_of(sdesc, struct sudmac_desc, shdma_desc)
#define to_sdev(sc) container_of(sc->shdma_chan.dma_chan.device, \
				 struct sudmac_device, shdma_dev.dma_dev)

/* SUDMAC register */
#define SUDMAC_CH0CFG		0x00
#define SUDMAC_CH0BA		0x10
#define SUDMAC_CH0BBC		0x18
#define SUDMAC_CH0CA		0x20
#define SUDMAC_CH0CBC		0x28
#define SUDMAC_CH0DEN		0x30
#define SUDMAC_DSTSCLR		0x38
#define SUDMAC_DBUFCTRL		0x3C
#define SUDMAC_DINTCTRL		0x40
#define SUDMAC_DINTSTS		0x44
#define SUDMAC_DINTSTSCLR	0x48
#define SUDMAC_CH0SHCTRL	0x50

/* Definitions for the sudmac_channel.config */
#define SUDMAC_SENDBUFM	0x1000 /* b12: Transmit Buffer Mode */
#define SUDMAC_RCVENDM	0x0100 /* b8: Receive Data Transfer End Mode */
#define SUDMAC_LBA_WAIT	0x0030 /* b5-4: Local Bus Access Wait */

/* Definitions for the sudmac_channel.dint_end_bit */
#define SUDMAC_CH1ENDE	0x0002 /* b1: Ch1 DMA Transfer End Int Enable */
#define SUDMAC_CH0ENDE	0x0001 /* b0: Ch0 DMA Transfer End Int Enable */

#define SUDMAC_DRV_NAME "sudmac"

static void sudmac_writel(struct sudmac_chan *sc, u32 data, u32 reg)
{
	iowrite32(data, sc->base + reg);
}

static u32 sudmac_readl(struct sudmac_chan *sc, u32 reg)
{
	return ioread32(sc->base + reg);
}

static bool sudmac_is_busy(struct sudmac_chan *sc)
{
	u32 den = sudmac_readl(sc, SUDMAC_CH0DEN + sc->offset);

	if (den)
		return true; /* working */

	return false; /* waiting */
}

static void sudmac_set_reg(struct sudmac_chan *sc, struct sudmac_regs *hw,
			   struct shdma_desc *sdesc)
{
	sudmac_writel(sc, sc->cfg, SUDMAC_CH0CFG + sc->offset);
	sudmac_writel(sc, hw->base_addr, SUDMAC_CH0BA + sc->offset);
	sudmac_writel(sc, hw->base_byte_count, SUDMAC_CH0BBC + sc->offset);
}

static void sudmac_start(struct sudmac_chan *sc)
{
	u32 dintctrl = sudmac_readl(sc, SUDMAC_DINTCTRL);

	sudmac_writel(sc, dintctrl | sc->dint_end_bit, SUDMAC_DINTCTRL);
	sudmac_writel(sc, 1, SUDMAC_CH0DEN + sc->offset);
}

static void sudmac_start_xfer(struct shdma_chan *schan,
			      struct shdma_desc *sdesc)
{
	struct sudmac_chan *sc = to_chan(schan);
	struct sudmac_desc *sd = to_desc(sdesc);

	sudmac_set_reg(sc, &sd->hw, sdesc);
	sudmac_start(sc);
}

static bool sudmac_channel_busy(struct shdma_chan *schan)
{
	struct sudmac_chan *sc = to_chan(schan);

	return sudmac_is_busy(sc);
}

static void sudmac_setup_xfer(struct shdma_chan *schan, int slave_id)
{
}

static const struct sudmac_slave_config *sudmac_find_slave(
	struct sudmac_chan *sc, int slave_id)
{
	struct sudmac_device *sdev = to_sdev(sc);
	struct sudmac_pdata *pdata = sdev->pdata;
	const struct sudmac_slave_config *cfg;
	int i;

	for (i = 0, cfg = pdata->slave; i < pdata->slave_num; i++, cfg++)
		if (cfg->slave_id == slave_id)
			return cfg;

	return NULL;
}

static int sudmac_set_slave(struct shdma_chan *schan, int slave_id,
			    dma_addr_t slave_addr, bool try)
{
	struct sudmac_chan *sc = to_chan(schan);
	const struct sudmac_slave_config *cfg = sudmac_find_slave(sc, slave_id);

	if (!cfg)
		return -ENODEV;

	return 0;
}

static inline void sudmac_dma_halt(struct sudmac_chan *sc)
{
	u32 dintctrl = sudmac_readl(sc, SUDMAC_DINTCTRL);

	sudmac_writel(sc, 0, SUDMAC_CH0DEN + sc->offset);
	sudmac_writel(sc, dintctrl & ~sc->dint_end_bit, SUDMAC_DINTCTRL);
	sudmac_writel(sc, sc->dint_end_bit, SUDMAC_DINTSTSCLR);
}

static int sudmac_desc_setup(struct shdma_chan *schan,
			     struct shdma_desc *sdesc,
			     dma_addr_t src, dma_addr_t dst, size_t *len)
{
	struct sudmac_chan *sc = to_chan(schan);
	struct sudmac_desc *sd = to_desc(sdesc);

	dev_dbg(sc->shdma_chan.dev, "%s: src=%x, dst=%x, len=%d\n",
		__func__, src, dst, *len);

	if (*len > schan->max_xfer_len)
		*len = schan->max_xfer_len;

	if (dst)
		sd->hw.base_addr = dst;
	else if (src)
		sd->hw.base_addr = src;
	sd->hw.base_byte_count = *len;

	return 0;
}

static void sudmac_halt(struct shdma_chan *schan)
{
	struct sudmac_chan *sc = to_chan(schan);

	sudmac_dma_halt(sc);
}

static bool sudmac_chan_irq(struct shdma_chan *schan, int irq)
{
	struct sudmac_chan *sc = to_chan(schan);
	u32 dintsts = sudmac_readl(sc, SUDMAC_DINTSTS);

	if (!(dintsts & sc->dint_end_bit))
		return false;

	/* DMA stop */
	sudmac_dma_halt(sc);

	return true;
}

static size_t sudmac_get_partial(struct shdma_chan *schan,
				 struct shdma_desc *sdesc)
{
	struct sudmac_chan *sc = to_chan(schan);
	struct sudmac_desc *sd = to_desc(sdesc);
	u32 current_byte_count = sudmac_readl(sc, SUDMAC_CH0CBC + sc->offset);

	return sd->hw.base_byte_count - current_byte_count;
}

static bool sudmac_desc_completed(struct shdma_chan *schan,
				  struct shdma_desc *sdesc)
{
	struct sudmac_chan *sc = to_chan(schan);
	struct sudmac_desc *sd = to_desc(sdesc);
	u32 current_addr = sudmac_readl(sc, SUDMAC_CH0CA + sc->offset);

	return sd->hw.base_addr + sd->hw.base_byte_count == current_addr;
}

static int sudmac_chan_probe(struct sudmac_device *su_dev, int id, int irq,
			     unsigned long flags)
{
	struct shdma_dev *sdev = &su_dev->shdma_dev;
	struct platform_device *pdev = to_platform_device(sdev->dma_dev.dev);
	struct sudmac_chan *sc;
	struct shdma_chan *schan;
	int err;

	sc = devm_kzalloc(&pdev->dev, sizeof(struct sudmac_chan), GFP_KERNEL);
	if (!sc) {
		dev_err(sdev->dma_dev.dev,
			"No free memory for allocating dma channels!\n");
		return -ENOMEM;
	}

	schan = &sc->shdma_chan;
	schan->max_xfer_len = 64 * 1024 * 1024 - 1;

	shdma_chan_probe(sdev, schan, id);

	sc->base = su_dev->chan_reg;

	/* get platform_data */
	sc->offset = su_dev->pdata->channel->offset;
	if (su_dev->pdata->channel->config & SUDMAC_TX_BUFFER_MODE)
		sc->cfg |= SUDMAC_SENDBUFM;
	if (su_dev->pdata->channel->config & SUDMAC_RX_END_MODE)
		sc->cfg |= SUDMAC_RCVENDM;
	sc->cfg |= (su_dev->pdata->channel->wait << 4) & SUDMAC_LBA_WAIT;

	if (su_dev->pdata->channel->dint_end_bit & SUDMAC_DMA_BIT_CH0)
		sc->dint_end_bit |= SUDMAC_CH0ENDE;
	if (su_dev->pdata->channel->dint_end_bit & SUDMAC_DMA_BIT_CH1)
		sc->dint_end_bit |= SUDMAC_CH1ENDE;

	/* set up channel irq */
	if (pdev->id >= 0)
		snprintf(sc->dev_id, sizeof(sc->dev_id), "sudmac%d.%d",
			 pdev->id, id);
	else
		snprintf(sc->dev_id, sizeof(sc->dev_id), "sudmac%d", id);

	err = shdma_request_irq(schan, irq, flags, sc->dev_id);
	if (err) {
		dev_err(sdev->dma_dev.dev,
			"DMA channel %d request_irq failed %d\n", id, err);
		goto err_no_irq;
	}

	return 0;

err_no_irq:
	/* remove from dmaengine device node */
	shdma_chan_remove(schan);
	return err;
}

static void sudmac_chan_remove(struct sudmac_device *su_dev)
{
	struct dma_device *dma_dev = &su_dev->shdma_dev.dma_dev;
	struct shdma_chan *schan;
	int i;

	shdma_for_each_chan(schan, &su_dev->shdma_dev, i) {
		BUG_ON(!schan);

		shdma_chan_remove(schan);
	}
	dma_dev->chancnt = 0;
}

static dma_addr_t sudmac_slave_addr(struct shdma_chan *schan)
{
	/* SUDMAC doesn't need the address */
	return 0;
}

static struct shdma_desc *sudmac_embedded_desc(void *buf, int i)
{
	return &((struct sudmac_desc *)buf)[i].shdma_desc;
}

static const struct shdma_ops sudmac_shdma_ops = {
	.desc_completed = sudmac_desc_completed,
	.halt_channel = sudmac_halt,
	.channel_busy = sudmac_channel_busy,
	.slave_addr = sudmac_slave_addr,
	.desc_setup = sudmac_desc_setup,
	.set_slave = sudmac_set_slave,
	.setup_xfer = sudmac_setup_xfer,
	.start_xfer = sudmac_start_xfer,
	.embedded_desc = sudmac_embedded_desc,
	.chan_irq = sudmac_chan_irq,
	.get_partial = sudmac_get_partial,
};

static int sudmac_probe(struct platform_device *pdev)
{
	struct sudmac_pdata *pdata = dev_get_platdata(&pdev->dev);
	int err, i;
	struct sudmac_device *su_dev;
	struct dma_device *dma_dev;
	struct resource *chan, *irq_res;

	/* get platform data */
	if (!pdata)
		return -ENODEV;

	irq_res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
	if (!irq_res)
		return -ENODEV;

	err = -ENOMEM;
	su_dev = devm_kzalloc(&pdev->dev, sizeof(struct sudmac_device),
			      GFP_KERNEL);
	if (!su_dev) {
		dev_err(&pdev->dev, "Not enough memory\n");
		return err;
	}

	dma_dev = &su_dev->shdma_dev.dma_dev;

	chan = platform_get_resource(pdev, IORESOURCE_MEM, 0);
	su_dev->chan_reg = devm_ioremap_resource(&pdev->dev, chan);
	if (IS_ERR(su_dev->chan_reg))
		return PTR_ERR(su_dev->chan_reg);

	dma_cap_set(DMA_SLAVE, dma_dev->cap_mask);

	su_dev->shdma_dev.ops = &sudmac_shdma_ops;
	su_dev->shdma_dev.desc_size = sizeof(struct sudmac_desc);
	err = shdma_init(&pdev->dev, &su_dev->shdma_dev, pdata->channel_num);
	if (err < 0)
		return err;

	/* platform data */
	su_dev->pdata = dev_get_platdata(&pdev->dev);

	platform_set_drvdata(pdev, su_dev);

	/* Create DMA Channel */
	for (i = 0; i < pdata->channel_num; i++) {
		err = sudmac_chan_probe(su_dev, i, irq_res->start, IRQF_SHARED);
		if (err)
			goto chan_probe_err;
	}

	err = dma_async_device_register(&su_dev->shdma_dev.dma_dev);
	if (err < 0)
		goto chan_probe_err;

	return err;

chan_probe_err:
	sudmac_chan_remove(su_dev);

	shdma_cleanup(&su_dev->shdma_dev);

	return err;
}

static int sudmac_remove(struct platform_device *pdev)
{
	struct sudmac_device *su_dev = platform_get_drvdata(pdev);
	struct dma_device *dma_dev = &su_dev->shdma_dev.dma_dev;

	dma_async_device_unregister(dma_dev);
	sudmac_chan_remove(su_dev);
	shdma_cleanup(&su_dev->shdma_dev);

	return 0;
}

static struct platform_driver sudmac_driver = {
	.driver		= {
		.owner	= THIS_MODULE,
		.name	= SUDMAC_DRV_NAME,
	},
	.probe		= sudmac_probe,
	.remove		= sudmac_remove,
};
module_platform_driver(sudmac_driver);

MODULE_AUTHOR("Yoshihiro Shimoda");
MODULE_DESCRIPTION("Renesas SUDMAC driver");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("platform:" SUDMAC_DRV_NAME);