drivers/dma/imx-dma.c

/*
 * drivers/dma/imx-dma.c
 *
 * This file contains a driver for the Freescale i.MX DMA engine
 * found on i.MX1/21/27
 *
 * Copyright 2010 Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>
 * Copyright 2012 Javier Martin, Vista Silicon <javier.martin@vista-silicon.com>
 *
 * The code contained herein is licensed under the GNU General Public
 * License. You may obtain a copy of the GNU General Public License
 * Version 2 or later at the following locations:
 *
 * http://www.opensource.org/licenses/gpl-license.html
 * http://www.gnu.org/copyleft/gpl.html
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/types.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/slab.h>
#include <linux/platform_device.h>
#include <linux/dmaengine.h>

#include <asm/irq.h>
#include <mach/dma-v1.h>
#include <mach/hardware.h>

#define IMXDMA_MAX_CHAN_DESCRIPTORS	16

enum  imxdma_prep_type {
	IMXDMA_DESC_MEMCPY,
	IMXDMA_DESC_INTERLEAVED,
	IMXDMA_DESC_SLAVE_SG,
	IMXDMA_DESC_CYCLIC,
};

struct imxdma_desc {
	struct list_head		node;
	struct dma_async_tx_descriptor	desc;
	enum dma_status			status;
	dma_addr_t			src;
	dma_addr_t			dest;
	size_t				len;
	unsigned int			dmamode;
	enum imxdma_prep_type		type;
	/* For memcpy and interleaved */
	unsigned int			config_port;
	unsigned int			config_mem;
	/* For interleaved transfers */
	unsigned int			x;
	unsigned int			y;
	unsigned int			w;
	/* For slave sg and cyclic */
	struct scatterlist		*sg;
	unsigned int			sgcount;
};

struct imxdma_channel {
	struct imxdma_engine		*imxdma;
	unsigned int			channel;
	unsigned int			imxdma_channel;

	struct tasklet_struct		dma_tasklet;
	struct list_head		ld_free;
	struct list_head		ld_queue;
	struct list_head		ld_active;
	int				descs_allocated;
	enum dma_slave_buswidth		word_size;
	dma_addr_t			per_address;
	u32				watermark_level;
	struct dma_chan			chan;
	spinlock_t			lock;
	dma_cookie_t			last_completed;
	int				dma_request;
	struct scatterlist		*sg_list;
};

#define MAX_DMA_CHANNELS 8

struct imxdma_engine {
	struct device			*dev;
	struct device_dma_parameters	dma_parms;
	struct dma_device		dma_device;
	struct imxdma_channel		channel[MAX_DMA_CHANNELS];
};

static struct imxdma_channel *to_imxdma_chan(struct dma_chan *chan)
{
	return container_of(chan, struct imxdma_channel, chan);
}

static inline bool imxdma_chan_is_doing_cyclic(struct imxdma_channel *imxdmac)
{
	struct imxdma_desc *desc;

	if (!list_empty(&imxdmac->ld_active)) {
		desc = list_first_entry(&imxdmac->ld_active, struct imxdma_desc,
					node);
		if (desc->type == IMXDMA_DESC_CYCLIC)
			return true;
	}
	return false;
}

static void imxdma_irq_handler(int channel, void *data)
{
	struct imxdma_channel *imxdmac = data;

	tasklet_schedule(&imxdmac->dma_tasklet);
}

static void imxdma_err_handler(int channel, void *data, int error)
{
	struct imxdma_channel *imxdmac = data;

	tasklet_schedule(&imxdmac->dma_tasklet);
}

static void imxdma_progression(int channel, void *data,
		struct scatterlist *sg)
{
	struct imxdma_channel *imxdmac = data;

	tasklet_schedule(&imxdmac->dma_tasklet);
}

static int imxdma_xfer_desc(struct imxdma_desc *d)
{
	struct imxdma_channel *imxdmac = to_imxdma_chan(d->desc.chan);
	int ret;

	/* Configure and enable */
	switch (d->type) {
	case IMXDMA_DESC_MEMCPY:
		ret = imx_dma_config_channel(imxdmac->imxdma_channel,
					  d->config_port, d->config_mem, 0, 0);
		if (ret < 0)
			return ret;
		ret = imx_dma_setup_single(imxdmac->imxdma_channel, d->src,
					   d->len, d->dest, d->dmamode);
		if (ret < 0)
			return ret;
		break;
	case IMXDMA_DESC_CYCLIC:
		ret = imx_dma_setup_progression_handler(imxdmac->imxdma_channel,
							imxdma_progression);
		if (ret < 0)
			return ret;
		/*
		 * We fall through here since cyclic transfer is the same as
		 * slave_sg adding a progression handler and a specific sg
		 * configuration which is done in 'imxdma_prep_dma_cyclic'.
		 */
	case IMXDMA_DESC_SLAVE_SG:
		if (d->dmamode == DMA_MODE_READ)
			ret = imx_dma_setup_sg(imxdmac->imxdma_channel, d->sg,
				       d->sgcount, d->len, d->src, d->dmamode);
		else
			ret = imx_dma_setup_sg(imxdmac->imxdma_channel, d->sg,
				      d->sgcount, d->len, d->dest, d->dmamode);
		if (ret < 0)
			return ret;
		break;
	default:
		return -EINVAL;
	}
	imx_dma_enable(imxdmac->imxdma_channel);
	return 0;
}

static void imxdma_tasklet(unsigned long data)
{
	struct imxdma_channel *imxdmac = (void *)data;
	struct imxdma_engine *imxdma = imxdmac->imxdma;
	struct imxdma_desc *desc;

	spin_lock(&imxdmac->lock);

	if (list_empty(&imxdmac->ld_active)) {
		/* Someone might have called terminate all */
		goto out;
	}
	desc = list_first_entry(&imxdmac->ld_active, struct imxdma_desc, node);

	if (desc->desc.callback)
		desc->desc.callback(desc->desc.callback_param);

	imxdmac->last_completed = desc->desc.cookie;

	/* If we are dealing with a cyclic descriptor keep it on ld_active */
	if (imxdma_chan_is_doing_cyclic(imxdmac))
		goto out;

	list_move_tail(imxdmac->ld_active.next, &imxdmac->ld_free);

	if (!list_empty(&imxdmac->ld_queue)) {
		desc = list_first_entry(&imxdmac->ld_queue, struct imxdma_desc,
					node);
		list_move_tail(imxdmac->ld_queue.next, &imxdmac->ld_active);
		if (imxdma_xfer_desc(desc) < 0)
			dev_warn(imxdma->dev, "%s: channel: %d couldn't xfer desc\n",
				 __func__, imxdmac->channel);
	}
out:
	spin_unlock(&imxdmac->lock);
}

static int imxdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
		unsigned long arg)
{
	struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
	struct dma_slave_config *dmaengine_cfg = (void *)arg;
	int ret;
	unsigned long flags;
	unsigned int mode = 0;

	switch (cmd) {
	case DMA_TERMINATE_ALL:
		imx_dma_disable(imxdmac->imxdma_channel);

		spin_lock_irqsave(&imxdmac->lock, flags);
		list_splice_tail_init(&imxdmac->ld_active, &imxdmac->ld_free);
		list_splice_tail_init(&imxdmac->ld_queue, &imxdmac->ld_free);
		spin_unlock_irqrestore(&imxdmac->lock, flags);
		return 0;
	case DMA_SLAVE_CONFIG:
		if (dmaengine_cfg->direction == DMA_DEV_TO_MEM) {
			imxdmac->per_address = dmaengine_cfg->src_addr;
			imxdmac->watermark_level = dmaengine_cfg->src_maxburst;
			imxdmac->word_size = dmaengine_cfg->src_addr_width;
		} else {
			imxdmac->per_address = dmaengine_cfg->dst_addr;
			imxdmac->watermark_level = dmaengine_cfg->dst_maxburst;
			imxdmac->word_size = dmaengine_cfg->dst_addr_width;
		}

		switch (imxdmac->word_size) {
		case DMA_SLAVE_BUSWIDTH_1_BYTE:
			mode = IMX_DMA_MEMSIZE_8;
			break;
		case DMA_SLAVE_BUSWIDTH_2_BYTES:
			mode = IMX_DMA_MEMSIZE_16;
			break;
		default:
		case DMA_SLAVE_BUSWIDTH_4_BYTES:
			mode = IMX_DMA_MEMSIZE_32;
			break;
		}
		ret = imx_dma_config_channel(imxdmac->imxdma_channel,
				mode | IMX_DMA_TYPE_FIFO,
				IMX_DMA_MEMSIZE_32 | IMX_DMA_TYPE_LINEAR,
				imxdmac->dma_request, 1);

		if (ret)
			return ret;

		imx_dma_config_burstlen(imxdmac->imxdma_channel,
				imxdmac->watermark_level * imxdmac->word_size);

		return 0;
	default:
		return -ENOSYS;
	}

	return -EINVAL;
}

static enum dma_status imxdma_tx_status(struct dma_chan *chan,
					    dma_cookie_t cookie,
					    struct dma_tx_state *txstate)
{
	struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
	dma_cookie_t last_used;
	enum dma_status ret;
	unsigned long flags;

	spin_lock_irqsave(&imxdmac->lock, flags);
	last_used = chan->cookie;

	ret = dma_async_is_complete(cookie, imxdmac->last_completed, last_used);
	dma_set_tx_state(txstate, imxdmac->last_completed, last_used, 0);
	spin_unlock_irqrestore(&imxdmac->lock, flags);

	return ret;
}

static dma_cookie_t imxdma_assign_cookie(struct imxdma_channel *imxdma)
{
	dma_cookie_t cookie = imxdma->chan.cookie;

	if (++cookie < 0)
		cookie = 1;

	imxdma->chan.cookie = cookie;

	return cookie;
}

static dma_cookie_t imxdma_tx_submit(struct dma_async_tx_descriptor *tx)
{
	struct imxdma_channel *imxdmac = to_imxdma_chan(tx->chan);
	dma_cookie_t cookie;
	unsigned long flags;

	spin_lock_irqsave(&imxdmac->lock, flags);

	list_move_tail(imxdmac->ld_free.next, &imxdmac->ld_queue);
	cookie = imxdma_assign_cookie(imxdmac);
	tx->cookie = cookie;

	spin_unlock_irqrestore(&imxdmac->lock, flags);

	return cookie;
}

static int imxdma_alloc_chan_resources(struct dma_chan *chan)
{
	struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
	struct imx_dma_data *data = chan->private;

	if (data != NULL)
		imxdmac->dma_request = data->dma_request;

	while (imxdmac->descs_allocated < IMXDMA_MAX_CHAN_DESCRIPTORS) {
		struct imxdma_desc *desc;

		desc = kzalloc(sizeof(*desc), GFP_KERNEL);
		if (!desc)
			break;
		__memzero(&desc->desc, sizeof(struct dma_async_tx_descriptor));
		dma_async_tx_descriptor_init(&desc->desc, chan);
		desc->desc.tx_submit = imxdma_tx_submit;
		/* txd.flags will be overwritten in prep funcs */
		desc->desc.flags = DMA_CTRL_ACK;
		desc->status = DMA_SUCCESS;

		list_add_tail(&desc->node, &imxdmac->ld_free);
		imxdmac->descs_allocated++;
	}

	if (!imxdmac->descs_allocated)
		return -ENOMEM;

	return imxdmac->descs_allocated;
}

static void imxdma_free_chan_resources(struct dma_chan *chan)
{
	struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
	struct imxdma_desc *desc, *_desc;
	unsigned long flags;

	spin_lock_irqsave(&imxdmac->lock, flags);

	imx_dma_disable(imxdmac->imxdma_channel);
	list_splice_tail_init(&imxdmac->ld_active, &imxdmac->ld_free);
	list_splice_tail_init(&imxdmac->ld_queue, &imxdmac->ld_free);

	spin_unlock_irqrestore(&imxdmac->lock, flags);

	list_for_each_entry_safe(desc, _desc, &imxdmac->ld_free, node) {
		kfree(desc);
		imxdmac->descs_allocated--;
	}
	INIT_LIST_HEAD(&imxdmac->ld_free);

	if (imxdmac->sg_list) {
		kfree(imxdmac->sg_list);
		imxdmac->sg_list = NULL;
	}
}

static struct dma_async_tx_descriptor *imxdma_prep_slave_sg(
		struct dma_chan *chan, struct scatterlist *sgl,
		unsigned int sg_len, enum dma_transfer_direction direction,
		unsigned long flags)
{
	struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
	struct scatterlist *sg;
	int i, dma_length = 0;
	struct imxdma_desc *desc;

	if (list_empty(&imxdmac->ld_free) ||
	    imxdma_chan_is_doing_cyclic(imxdmac))
		return NULL;

	desc = list_first_entry(&imxdmac->ld_free, struct imxdma_desc, node);

	for_each_sg(sgl, sg, sg_len, i) {
		dma_length += sg->length;
	}

	switch (imxdmac->word_size) {
	case DMA_SLAVE_BUSWIDTH_4_BYTES:
		if (sgl->length & 3 || sgl->dma_address & 3)
			return NULL;
		break;
	case DMA_SLAVE_BUSWIDTH_2_BYTES:
		if (sgl->length & 1 || sgl->dma_address & 1)
			return NULL;
		break;
	case DMA_SLAVE_BUSWIDTH_1_BYTE:
		break;
	default:
		return NULL;
	}

	desc->type = IMXDMA_DESC_SLAVE_SG;
	desc->sg = sgl;
	desc->sgcount = sg_len;
	desc->len = dma_length;
	if (direction == DMA_DEV_TO_MEM) {
		desc->dmamode = DMA_MODE_READ;
		desc->src = imxdmac->per_address;
	} else {
		desc->dmamode = DMA_MODE_WRITE;
		desc->dest = imxdmac->per_address;
	}
	desc->desc.callback = NULL;
	desc->desc.callback_param = NULL;

	return &desc->desc;
}

static struct dma_async_tx_descriptor *imxdma_prep_dma_cyclic(
		struct dma_chan *chan, dma_addr_t dma_addr, size_t buf_len,
		size_t period_len, enum dma_transfer_direction direction)
{
	struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
	struct imxdma_engine *imxdma = imxdmac->imxdma;
	struct imxdma_desc *desc;
	int i;
	unsigned int periods = buf_len / period_len;

	dev_dbg(imxdma->dev, "%s channel: %d buf_len=%d period_len=%d\n",
			__func__, imxdmac->channel, buf_len, period_len);

	if (list_empty(&imxdmac->ld_free) ||
	    imxdma_chan_is_doing_cyclic(imxdmac))
		return NULL;

	desc = list_first_entry(&imxdmac->ld_free, struct imxdma_desc, node);

	if (imxdmac->sg_list)
		kfree(imxdmac->sg_list);

	imxdmac->sg_list = kcalloc(periods + 1,
			sizeof(struct scatterlist), GFP_KERNEL);
	if (!imxdmac->sg_list)
		return NULL;

	sg_init_table(imxdmac->sg_list, periods);

	for (i = 0; i < periods; i++) {
		imxdmac->sg_list[i].page_link = 0;
		imxdmac->sg_list[i].offset = 0;
		imxdmac->sg_list[i].dma_address = dma_addr;
		imxdmac->sg_list[i].length = period_len;
		dma_addr += period_len;
	}

	/* close the loop */
	imxdmac->sg_list[periods].offset = 0;
	imxdmac->sg_list[periods].length = 0;
	imxdmac->sg_list[periods].page_link =
		((unsigned long)imxdmac->sg_list | 0x01) & ~0x02;

	desc->type = IMXDMA_DESC_CYCLIC;
	desc->sg = imxdmac->sg_list;
	desc->sgcount = periods;
	desc->len = IMX_DMA_LENGTH_LOOP;
	if (direction == DMA_DEV_TO_MEM) {
		desc->dmamode = DMA_MODE_READ;
		desc->src = imxdmac->per_address;
	} else {
		desc->dmamode = DMA_MODE_WRITE;
		desc->dest = imxdmac->per_address;
	}
	desc->desc.callback = NULL;
	desc->desc.callback_param = NULL;

	return &desc->desc;
}

static struct dma_async_tx_descriptor *imxdma_prep_dma_memcpy(
	struct dma_chan *chan, dma_addr_t dest,
	dma_addr_t src, size_t len, unsigned long flags)
{
	struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
	struct imxdma_engine *imxdma = imxdmac->imxdma;
	struct imxdma_desc *desc;

	dev_dbg(imxdma->dev, "%s channel: %d src=0x%x dst=0x%x len=%d\n",
			__func__, imxdmac->channel, src, dest, len);

	if (list_empty(&imxdmac->ld_free) ||
	    imxdma_chan_is_doing_cyclic(imxdmac))
		return NULL;

	desc = list_first_entry(&imxdmac->ld_free, struct imxdma_desc, node);

	desc->type = IMXDMA_DESC_MEMCPY;
	desc->src = src;
	desc->dest = dest;
	desc->len = len;
	desc->dmamode = DMA_MODE_WRITE;
	desc->config_port = IMX_DMA_MEMSIZE_32 | IMX_DMA_TYPE_LINEAR;
	desc->config_mem = IMX_DMA_MEMSIZE_32 | IMX_DMA_TYPE_LINEAR;
	desc->desc.callback = NULL;
	desc->desc.callback_param = NULL;

	return &desc->desc;
}

static void imxdma_issue_pending(struct dma_chan *chan)
{
	struct imxdma_channel *imxdmac = to_imxdma_chan(chan);
	struct imxdma_engine *imxdma = imxdmac->imxdma;
	struct imxdma_desc *desc;
	unsigned long flags;

	spin_lock_irqsave(&imxdmac->lock, flags);
	if (list_empty(&imxdmac->ld_active) &&
	    !list_empty(&imxdmac->ld_queue)) {
		desc = list_first_entry(&imxdmac->ld_queue,
					struct imxdma_desc, node);

		if (imxdma_xfer_desc(desc) < 0) {
			dev_warn(imxdma->dev,
				 "%s: channel: %d couldn't issue DMA xfer\n",
				 __func__, imxdmac->channel);
		} else {
			list_move_tail(imxdmac->ld_queue.next,
				       &imxdmac->ld_active);
		}
	}
	spin_unlock_irqrestore(&imxdmac->lock, flags);
}

static int __init imxdma_probe(struct platform_device *pdev)
{
	struct imxdma_engine *imxdma;
	int ret, i;

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

	INIT_LIST_HEAD(&imxdma->dma_device.channels);

	dma_cap_set(DMA_SLAVE, imxdma->dma_device.cap_mask);
	dma_cap_set(DMA_CYCLIC, imxdma->dma_device.cap_mask);
	dma_cap_set(DMA_MEMCPY, imxdma->dma_device.cap_mask);

	/* Initialize channel parameters */
	for (i = 0; i < MAX_DMA_CHANNELS; i++) {
		struct imxdma_channel *imxdmac = &imxdma->channel[i];

		imxdmac->imxdma_channel = imx_dma_request_by_prio("dmaengine",
				DMA_PRIO_MEDIUM);
		if ((int)imxdmac->channel < 0) {
			ret = -ENODEV;
			goto err_init;
		}

		imx_dma_setup_handlers(imxdmac->imxdma_channel,
		       imxdma_irq_handler, imxdma_err_handler, imxdmac);

		imxdmac->imxdma = imxdma;
		spin_lock_init(&imxdmac->lock);

		INIT_LIST_HEAD(&imxdmac->ld_queue);
		INIT_LIST_HEAD(&imxdmac->ld_free);
		INIT_LIST_HEAD(&imxdmac->ld_active);

		tasklet_init(&imxdmac->dma_tasklet, imxdma_tasklet,
			     (unsigned long)imxdmac);
		imxdmac->chan.device = &imxdma->dma_device;
		imxdmac->channel = i;

		/* Add the channel to the DMAC list */
		list_add_tail(&imxdmac->chan.device_node,
			      &imxdma->dma_device.channels);
	}

	imxdma->dev = &pdev->dev;
	imxdma->dma_device.dev = &pdev->dev;

	imxdma->dma_device.device_alloc_chan_resources = imxdma_alloc_chan_resources;
	imxdma->dma_device.device_free_chan_resources = imxdma_free_chan_resources;
	imxdma->dma_device.device_tx_status = imxdma_tx_status;
	imxdma->dma_device.device_prep_slave_sg = imxdma_prep_slave_sg;
	imxdma->dma_device.device_prep_dma_cyclic = imxdma_prep_dma_cyclic;
	imxdma->dma_device.device_prep_dma_memcpy = imxdma_prep_dma_memcpy;
	imxdma->dma_device.device_control = imxdma_control;
	imxdma->dma_device.device_issue_pending = imxdma_issue_pending;

	platform_set_drvdata(pdev, imxdma);

	imxdma->dma_device.copy_align = 2; /* 2^2 = 4 bytes alignment */
	imxdma->dma_device.dev->dma_parms = &imxdma->dma_parms;
	dma_set_max_seg_size(imxdma->dma_device.dev, 0xffffff);

	ret = dma_async_device_register(&imxdma->dma_device);
	if (ret) {
		dev_err(&pdev->dev, "unable to register\n");
		goto err_init;
	}

	return 0;

err_init:
	while (--i >= 0) {
		struct imxdma_channel *imxdmac = &imxdma->channel[i];
		imx_dma_free(imxdmac->imxdma_channel);
	}

	kfree(imxdma);
	return ret;
}

static int __exit imxdma_remove(struct platform_device *pdev)
{
	struct imxdma_engine *imxdma = platform_get_drvdata(pdev);
	int i;

        dma_async_device_unregister(&imxdma->dma_device);

	for (i = 0; i < MAX_DMA_CHANNELS; i++) {
		struct imxdma_channel *imxdmac = &imxdma->channel[i];

		 imx_dma_free(imxdmac->imxdma_channel);
	}

        kfree(imxdma);

        return 0;
}

static struct platform_driver imxdma_driver = {
	.driver		= {
		.name	= "imx-dma",
	},
	.remove		= __exit_p(imxdma_remove),
};

static int __init imxdma_module_init(void)
{
	return platform_driver_probe(&imxdma_driver, imxdma_probe);
}
subsys_initcall(imxdma_module_init);

MODULE_AUTHOR("Sascha Hauer, Pengutronix <s.hauer@pengutronix.de>");
MODULE_DESCRIPTION("i.MX dma driver");
MODULE_LICENSE("GPL");