drivers/dma/milbeaut-hdmac.c - linux/kernel/git/paulmck/linux-rcu - Git at Google

 // SPDX-License-Identifier: GPL-2.0
 //
 // Copyright (C) 2019 Linaro Ltd.
 // Copyright (C) 2019 Socionext Inc.

 #include <linux/bits.h>
 #include <linux/clk.h>
 #include <linux/dma-mapping.h>
 #include <linux/interrupt.h>
 #include <linux/iopoll.h>
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/of_dma.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/types.h>
 #include <linux/bitfield.h>

 #include "virt-dma.h"

 #define MLB_HDMAC_DMACR		0x0	/* global */
 #define MLB_HDMAC_DE		BIT(31)
 #define MLB_HDMAC_DS		BIT(30)
 #define MLB_HDMAC_PR		BIT(28)
 #define MLB_HDMAC_DH		GENMASK(27, 24)

 #define MLB_HDMAC_CH_STRIDE	0x10

 #define MLB_HDMAC_DMACA		0x0	/* channel */
 #define MLB_HDMAC_EB		BIT(31)
 #define MLB_HDMAC_PB		BIT(30)
 #define MLB_HDMAC_ST		BIT(29)
 #define MLB_HDMAC_IS		GENMASK(28, 24)
 #define MLB_HDMAC_BT		GENMASK(23, 20)
 #define MLB_HDMAC_BC		GENMASK(19, 16)
 #define MLB_HDMAC_TC		GENMASK(15, 0)
 #define MLB_HDMAC_DMACB		0x4
 #define MLB_HDMAC_TT		GENMASK(31, 30)
 #define MLB_HDMAC_MS		GENMASK(29, 28)
 #define MLB_HDMAC_TW		GENMASK(27, 26)
 #define MLB_HDMAC_FS		BIT(25)
 #define MLB_HDMAC_FD		BIT(24)
 #define MLB_HDMAC_RC		BIT(23)
 #define MLB_HDMAC_RS		BIT(22)
 #define MLB_HDMAC_RD		BIT(21)
 #define MLB_HDMAC_EI		BIT(20)
 #define MLB_HDMAC_CI		BIT(19)
 #define HDMAC_PAUSE		0x7
 #define MLB_HDMAC_SS		GENMASK(18, 16)
 #define MLB_HDMAC_SP		GENMASK(15, 12)
 #define MLB_HDMAC_DP		GENMASK(11, 8)
 #define MLB_HDMAC_DMACSA	0x8
 #define MLB_HDMAC_DMACDA	0xc

 #define MLB_HDMAC_BUSWIDTHS		(BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) | \
 					BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) | \
 					BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))

 struct milbeaut_hdmac_desc {
 	struct virt_dma_desc vd;
 	struct scatterlist *sgl;
 	unsigned int sg_len;
 	unsigned int sg_cur;
 	enum dma_transfer_direction dir;
 };

 struct milbeaut_hdmac_chan {
 	struct virt_dma_chan vc;
 	struct milbeaut_hdmac_device *mdev;
 	struct milbeaut_hdmac_desc *md;
 	void __iomem *reg_ch_base;
 	unsigned int slave_id;
 	struct dma_slave_config	cfg;
 };

 struct milbeaut_hdmac_device {
 	struct dma_device ddev;
 	struct clk *clk;
 	void __iomem *reg_base;
 	struct milbeaut_hdmac_chan channels[];
 };

 static struct milbeaut_hdmac_chan *
 to_milbeaut_hdmac_chan(struct virt_dma_chan *vc)
 {
 	return container_of(vc, struct milbeaut_hdmac_chan, vc);
 }

 static struct milbeaut_hdmac_desc *
 to_milbeaut_hdmac_desc(struct virt_dma_desc *vd)
 {
 	return container_of(vd, struct milbeaut_hdmac_desc, vd);
 }

 /* mc->vc.lock must be held by caller */
 static struct milbeaut_hdmac_desc *
 milbeaut_hdmac_next_desc(struct milbeaut_hdmac_chan *mc)
 {
 	struct virt_dma_desc *vd;

 	vd = vchan_next_desc(&mc->vc);
 	if (!vd) {
 		mc->md = NULL;
 		return NULL;
 	}

 	list_del(&vd->node);

 	mc->md = to_milbeaut_hdmac_desc(vd);

 	return mc->md;
 }

 /* mc->vc.lock must be held by caller */
 static void milbeaut_chan_start(struct milbeaut_hdmac_chan *mc,
 				struct milbeaut_hdmac_desc *md)
 {
 	struct scatterlist *sg;
 	u32 cb, ca, src_addr, dest_addr, len;
 	u32 width, burst;

 	sg = &md->sgl[md->sg_cur];
 	len = sg_dma_len(sg);

 	cb = MLB_HDMAC_CI | MLB_HDMAC_EI;
 	if (md->dir == DMA_MEM_TO_DEV) {
 		cb |= MLB_HDMAC_FD;
 		width = mc->cfg.dst_addr_width;
 		burst = mc->cfg.dst_maxburst;
 		src_addr = sg_dma_address(sg);
 		dest_addr = mc->cfg.dst_addr;
 	} else {
 		cb |= MLB_HDMAC_FS;
 		width = mc->cfg.src_addr_width;
 		burst = mc->cfg.src_maxburst;
 		src_addr = mc->cfg.src_addr;
 		dest_addr = sg_dma_address(sg);
 	}
 	cb |= FIELD_PREP(MLB_HDMAC_TW, (width >> 1));
 	cb |= FIELD_PREP(MLB_HDMAC_MS, 2);

 	writel_relaxed(MLB_HDMAC_DE, mc->mdev->reg_base + MLB_HDMAC_DMACR);
 	writel_relaxed(src_addr, mc->reg_ch_base + MLB_HDMAC_DMACSA);
 	writel_relaxed(dest_addr, mc->reg_ch_base + MLB_HDMAC_DMACDA);
 	writel_relaxed(cb, mc->reg_ch_base + MLB_HDMAC_DMACB);

 	ca = FIELD_PREP(MLB_HDMAC_IS, mc->slave_id);
 	if (burst == 16)
 		ca |= FIELD_PREP(MLB_HDMAC_BT, 0xf);
 	else if (burst == 8)
 		ca |= FIELD_PREP(MLB_HDMAC_BT, 0xd);
 	else if (burst == 4)
 		ca |= FIELD_PREP(MLB_HDMAC_BT, 0xb);
 	burst *= width;
 	ca |= FIELD_PREP(MLB_HDMAC_TC, (len / burst - 1));
 	writel_relaxed(ca, mc->reg_ch_base + MLB_HDMAC_DMACA);
 	ca |= MLB_HDMAC_EB;
 	writel_relaxed(ca, mc->reg_ch_base + MLB_HDMAC_DMACA);
 }

 /* mc->vc.lock must be held by caller */
 static void milbeaut_hdmac_start(struct milbeaut_hdmac_chan *mc)
 {
 	struct milbeaut_hdmac_desc *md;

 	md = milbeaut_hdmac_next_desc(mc);
 	if (md)
 		milbeaut_chan_start(mc, md);
 }

 static irqreturn_t milbeaut_hdmac_interrupt(int irq, void *dev_id)
 {
 	struct milbeaut_hdmac_chan *mc = dev_id;
 	struct milbeaut_hdmac_desc *md;
 	u32 val;

 	spin_lock(&mc->vc.lock);

 	/* Ack and Disable irqs */
 	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACB);
 	val &= ~(FIELD_PREP(MLB_HDMAC_SS, HDMAC_PAUSE));
 	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACB);
 	val &= ~MLB_HDMAC_EI;
 	val &= ~MLB_HDMAC_CI;
 	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACB);

 	md = mc->md;
 	if (!md)
 		goto out;

 	md->sg_cur++;

 	if (md->sg_cur >= md->sg_len) {
 		vchan_cookie_complete(&md->vd);
 		md = milbeaut_hdmac_next_desc(mc);
 		if (!md)
 			goto out;
 	}

 	milbeaut_chan_start(mc, md);

 out:
 	spin_unlock(&mc->vc.lock);
 	return IRQ_HANDLED;
 }

 static void milbeaut_hdmac_free_chan_resources(struct dma_chan *chan)
 {
 	vchan_free_chan_resources(to_virt_chan(chan));
 }

 static int
 milbeaut_hdmac_chan_config(struct dma_chan *chan, struct dma_slave_config *cfg)
 {
 	struct virt_dma_chan *vc = to_virt_chan(chan);
 	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);

 	spin_lock(&mc->vc.lock);
 	mc->cfg = *cfg;
 	spin_unlock(&mc->vc.lock);

 	return 0;
 }

 static int milbeaut_hdmac_chan_pause(struct dma_chan *chan)
 {
 	struct virt_dma_chan *vc = to_virt_chan(chan);
 	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
 	u32 val;

 	spin_lock(&mc->vc.lock);
 	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
 	val |= MLB_HDMAC_PB;
 	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);
 	spin_unlock(&mc->vc.lock);

 	return 0;
 }

 static int milbeaut_hdmac_chan_resume(struct dma_chan *chan)
 {
 	struct virt_dma_chan *vc = to_virt_chan(chan);
 	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
 	u32 val;

 	spin_lock(&mc->vc.lock);
 	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
 	val &= ~MLB_HDMAC_PB;
 	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);
 	spin_unlock(&mc->vc.lock);

 	return 0;
 }

 static struct dma_async_tx_descriptor *
 milbeaut_hdmac_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
 			     unsigned int sg_len,
 			     enum dma_transfer_direction direction,
 			     unsigned long flags, void *context)
 {
 	struct virt_dma_chan *vc = to_virt_chan(chan);
 	struct milbeaut_hdmac_desc *md;
 	int i;

 	if (!is_slave_direction(direction))
 		return NULL;

 	md = kzalloc(sizeof(*md), GFP_NOWAIT);
 	if (!md)
 		return NULL;

 	md->sgl = kcalloc(sg_len, sizeof(*sgl), GFP_NOWAIT);
 	if (!md->sgl) {
 		kfree(md);
 		return NULL;
 	}

 	for (i = 0; i < sg_len; i++)
 		md->sgl[i] = sgl[i];

 	md->sg_len = sg_len;
 	md->dir = direction;

 	return vchan_tx_prep(vc, &md->vd, flags);
 }

 static int milbeaut_hdmac_terminate_all(struct dma_chan *chan)
 {
 	struct virt_dma_chan *vc = to_virt_chan(chan);
 	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
 	unsigned long flags;
 	u32 val;

 	LIST_HEAD(head);

 	spin_lock_irqsave(&vc->lock, flags);

 	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
 	val &= ~MLB_HDMAC_EB; /* disable the channel */
 	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);

 	if (mc->md) {
 		vchan_terminate_vdesc(&mc->md->vd);
 		mc->md = NULL;
 	}

 	vchan_get_all_descriptors(vc, &head);

 	spin_unlock_irqrestore(&vc->lock, flags);

 	vchan_dma_desc_free_list(vc, &head);

 	return 0;
 }

 static void milbeaut_hdmac_synchronize(struct dma_chan *chan)
 {
 	vchan_synchronize(to_virt_chan(chan));
 }

 static enum dma_status milbeaut_hdmac_tx_status(struct dma_chan *chan,
 						dma_cookie_t cookie,
 						struct dma_tx_state *txstate)
 {
 	struct virt_dma_chan *vc;
 	struct virt_dma_desc *vd;
 	struct milbeaut_hdmac_chan *mc;
 	struct milbeaut_hdmac_desc *md = NULL;
 	enum dma_status stat;
 	unsigned long flags;
 	int i;

 	stat = dma_cookie_status(chan, cookie, txstate);
 	/* Return immediately if we do not need to compute the residue. */
 	if (stat == DMA_COMPLETE || !txstate)
 		return stat;

 	vc = to_virt_chan(chan);

 	spin_lock_irqsave(&vc->lock, flags);

 	mc = to_milbeaut_hdmac_chan(vc);

 	/* residue from the on-flight chunk */
 	if (mc->md && mc->md->vd.tx.cookie == cookie) {
 		struct scatterlist *sg;
 		u32 done;

 		md = mc->md;
 		sg = &md->sgl[md->sg_cur];

 		if (md->dir == DMA_DEV_TO_MEM)
 			done = readl_relaxed(mc->reg_ch_base
 					     + MLB_HDMAC_DMACDA);
 		else
 			done = readl_relaxed(mc->reg_ch_base
 					     + MLB_HDMAC_DMACSA);
 		done -= sg_dma_address(sg);

 		txstate->residue = -done;
 	}

 	if (!md) {
 		vd = vchan_find_desc(vc, cookie);
 		if (vd)
 			md = to_milbeaut_hdmac_desc(vd);
 	}

 	if (md) {
 		/* residue from the queued chunks */
 		for (i = md->sg_cur; i < md->sg_len; i++)
 			txstate->residue += sg_dma_len(&md->sgl[i]);
 	}

 	spin_unlock_irqrestore(&vc->lock, flags);

 	return stat;
 }

 static void milbeaut_hdmac_issue_pending(struct dma_chan *chan)
 {
 	struct virt_dma_chan *vc = to_virt_chan(chan);
 	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
 	unsigned long flags;

 	spin_lock_irqsave(&vc->lock, flags);

 	if (vchan_issue_pending(vc) && !mc->md)
 		milbeaut_hdmac_start(mc);

 	spin_unlock_irqrestore(&vc->lock, flags);
 }

 static void milbeaut_hdmac_desc_free(struct virt_dma_desc *vd)
 {
 	struct milbeaut_hdmac_desc *md = to_milbeaut_hdmac_desc(vd);

 	kfree(md->sgl);
 	kfree(md);
 }

 static struct dma_chan *
 milbeaut_hdmac_xlate(struct of_phandle_args *dma_spec, struct of_dma *of_dma)
 {
 	struct milbeaut_hdmac_device *mdev = of_dma->of_dma_data;
 	struct milbeaut_hdmac_chan *mc;
 	struct virt_dma_chan *vc;
 	struct dma_chan *chan;

 	if (dma_spec->args_count != 1)
 		return NULL;

 	chan = dma_get_any_slave_channel(&mdev->ddev);
 	if (!chan)
 		return NULL;

 	vc = to_virt_chan(chan);
 	mc = to_milbeaut_hdmac_chan(vc);
 	mc->slave_id = dma_spec->args[0];

 	return chan;
 }

 static int milbeaut_hdmac_chan_init(struct platform_device *pdev,
 				    struct milbeaut_hdmac_device *mdev,
 				    int chan_id)
 {
 	struct device *dev = &pdev->dev;
 	struct milbeaut_hdmac_chan *mc = &mdev->channels[chan_id];
 	char *irq_name;
 	int irq, ret;

 	irq = platform_get_irq(pdev, chan_id);
 	if (irq < 0)
 		return irq;

 	irq_name = devm_kasprintf(dev, GFP_KERNEL, "milbeaut-hdmac-%d",
 				  chan_id);
 	if (!irq_name)
 		return -ENOMEM;

 	ret = devm_request_irq(dev, irq, milbeaut_hdmac_interrupt,
 			       IRQF_SHARED, irq_name, mc);
 	if (ret)
 		return ret;

 	mc->mdev = mdev;
 	mc->reg_ch_base = mdev->reg_base + MLB_HDMAC_CH_STRIDE * (chan_id + 1);
 	mc->vc.desc_free = milbeaut_hdmac_desc_free;
 	vchan_init(&mc->vc, &mdev->ddev);

 	return 0;
 }

 static int milbeaut_hdmac_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
 	struct milbeaut_hdmac_device *mdev;
 	struct dma_device *ddev;
 	int nr_chans, ret, i;

 	nr_chans = platform_irq_count(pdev);
 	if (nr_chans < 0)
 		return nr_chans;

 	ret = dma_set_mask(dev, DMA_BIT_MASK(32));
 	if (ret)
 		return ret;

 	mdev = devm_kzalloc(dev, struct_size(mdev, channels, nr_chans),
 			    GFP_KERNEL);
 	if (!mdev)
 		return -ENOMEM;

 	mdev->reg_base = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(mdev->reg_base))
 		return PTR_ERR(mdev->reg_base);

 	mdev->clk = devm_clk_get(dev, NULL);
 	if (IS_ERR(mdev->clk)) {
 		dev_err(dev, "failed to get clock\n");
 		return PTR_ERR(mdev->clk);
 	}

 	ret = clk_prepare_enable(mdev->clk);
 	if (ret)
 		return ret;

 	ddev = &mdev->ddev;
 	ddev->dev = dev;
 	dma_cap_set(DMA_SLAVE, ddev->cap_mask);
 	dma_cap_set(DMA_PRIVATE, ddev->cap_mask);
 	ddev->src_addr_widths = MLB_HDMAC_BUSWIDTHS;
 	ddev->dst_addr_widths = MLB_HDMAC_BUSWIDTHS;
 	ddev->directions = BIT(DMA_MEM_TO_DEV) | BIT(DMA_DEV_TO_MEM);
 	ddev->device_free_chan_resources = milbeaut_hdmac_free_chan_resources;
 	ddev->device_config = milbeaut_hdmac_chan_config;
 	ddev->device_pause = milbeaut_hdmac_chan_pause;
 	ddev->device_resume = milbeaut_hdmac_chan_resume;
 	ddev->device_prep_slave_sg = milbeaut_hdmac_prep_slave_sg;
 	ddev->device_terminate_all = milbeaut_hdmac_terminate_all;
 	ddev->device_synchronize = milbeaut_hdmac_synchronize;
 	ddev->device_tx_status = milbeaut_hdmac_tx_status;
 	ddev->device_issue_pending = milbeaut_hdmac_issue_pending;
 	INIT_LIST_HEAD(&ddev->channels);

 	for (i = 0; i < nr_chans; i++) {
 		ret = milbeaut_hdmac_chan_init(pdev, mdev, i);
 		if (ret)
 			goto disable_clk;
 	}

 	ret = dma_async_device_register(ddev);
 	if (ret)
 		goto disable_clk;

 	ret = of_dma_controller_register(dev->of_node,
 					 milbeaut_hdmac_xlate, mdev);
 	if (ret)
 		goto unregister_dmac;

 	platform_set_drvdata(pdev, mdev);

 	return 0;

 unregister_dmac:
 	dma_async_device_unregister(ddev);
 disable_clk:
 	clk_disable_unprepare(mdev->clk);

 	return ret;
 }

 static int milbeaut_hdmac_remove(struct platform_device *pdev)
 {
 	struct milbeaut_hdmac_device *mdev = platform_get_drvdata(pdev);
 	struct dma_chan *chan;
 	int ret;

 	/*
 	 * Before reaching here, almost all descriptors have been freed by the
 	 * ->device_free_chan_resources() hook. However, each channel might
 	 * be still holding one descriptor that was on-flight at that moment.
 	 * Terminate it to make sure this hardware is no longer running. Then,
 	 * free the channel resources once again to avoid memory leak.
 	 */
 	list_for_each_entry(chan, &mdev->ddev.channels, device_node) {
 		ret = dmaengine_terminate_sync(chan);
 		if (ret)
 			return ret;
 		milbeaut_hdmac_free_chan_resources(chan);
 	}

 	of_dma_controller_free(pdev->dev.of_node);
 	dma_async_device_unregister(&mdev->ddev);
 	clk_disable_unprepare(mdev->clk);

 	return 0;
 }

 static const struct of_device_id milbeaut_hdmac_match[] = {
 	{ .compatible = "socionext,milbeaut-m10v-hdmac" },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, milbeaut_hdmac_match);

 static struct platform_driver milbeaut_hdmac_driver = {
 	.probe = milbeaut_hdmac_probe,
 	.remove = milbeaut_hdmac_remove,
 	.driver = {
 		.name = "milbeaut-m10v-hdmac",
 		.of_match_table = milbeaut_hdmac_match,
 	},
 };
 module_platform_driver(milbeaut_hdmac_driver);

 MODULE_DESCRIPTION("Milbeaut HDMAC DmaEngine driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0
	//
	// Copyright (C) 2019 Linaro Ltd.
	// Copyright (C) 2019 Socionext Inc.

	#include <linux/bits.h>
	#include <linux/clk.h>
	#include <linux/dma-mapping.h>
	#include <linux/interrupt.h>
	#include <linux/iopoll.h>
	#include <linux/list.h>
	#include <linux/module.h>
	#include <linux/of_dma.h>
	#include <linux/platform_device.h>
	#include <linux/slab.h>
	#include <linux/types.h>
	#include <linux/bitfield.h>

	#include "virt-dma.h"

	#define MLB_HDMAC_DMACR 0x0 /* global */
	#define MLB_HDMAC_DE BIT(31)
	#define MLB_HDMAC_DS BIT(30)
	#define MLB_HDMAC_PR BIT(28)
	#define MLB_HDMAC_DH GENMASK(27, 24)

	#define MLB_HDMAC_CH_STRIDE 0x10

	#define MLB_HDMAC_DMACA 0x0 /* channel */
	#define MLB_HDMAC_EB BIT(31)
	#define MLB_HDMAC_PB BIT(30)
	#define MLB_HDMAC_ST BIT(29)
	#define MLB_HDMAC_IS GENMASK(28, 24)
	#define MLB_HDMAC_BT GENMASK(23, 20)
	#define MLB_HDMAC_BC GENMASK(19, 16)
	#define MLB_HDMAC_TC GENMASK(15, 0)
	#define MLB_HDMAC_DMACB 0x4
	#define MLB_HDMAC_TT GENMASK(31, 30)
	#define MLB_HDMAC_MS GENMASK(29, 28)
	#define MLB_HDMAC_TW GENMASK(27, 26)
	#define MLB_HDMAC_FS BIT(25)
	#define MLB_HDMAC_FD BIT(24)
	#define MLB_HDMAC_RC BIT(23)
	#define MLB_HDMAC_RS BIT(22)
	#define MLB_HDMAC_RD BIT(21)
	#define MLB_HDMAC_EI BIT(20)
	#define MLB_HDMAC_CI BIT(19)
	#define HDMAC_PAUSE 0x7
	#define MLB_HDMAC_SS GENMASK(18, 16)
	#define MLB_HDMAC_SP GENMASK(15, 12)
	#define MLB_HDMAC_DP GENMASK(11, 8)
	#define MLB_HDMAC_DMACSA 0x8
	#define MLB_HDMAC_DMACDA 0xc

	#define MLB_HDMAC_BUSWIDTHS (BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) \| \
	BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) \| \
	BIT(DMA_SLAVE_BUSWIDTH_4_BYTES))

	struct milbeaut_hdmac_desc {
	struct virt_dma_desc vd;
	struct scatterlist *sgl;
	unsigned int sg_len;
	unsigned int sg_cur;
	enum dma_transfer_direction dir;
	};

	struct milbeaut_hdmac_chan {
	struct virt_dma_chan vc;
	struct milbeaut_hdmac_device *mdev;
	struct milbeaut_hdmac_desc *md;
	void __iomem *reg_ch_base;
	unsigned int slave_id;
	struct dma_slave_config cfg;
	};

	struct milbeaut_hdmac_device {
	struct dma_device ddev;
	struct clk *clk;
	void __iomem *reg_base;
	struct milbeaut_hdmac_chan channels[];
	};

	static struct milbeaut_hdmac_chan *
	to_milbeaut_hdmac_chan(struct virt_dma_chan *vc)
	{
	return container_of(vc, struct milbeaut_hdmac_chan, vc);
	}

	static struct milbeaut_hdmac_desc *
	to_milbeaut_hdmac_desc(struct virt_dma_desc *vd)
	{
	return container_of(vd, struct milbeaut_hdmac_desc, vd);
	}

	/* mc->vc.lock must be held by caller */
	static struct milbeaut_hdmac_desc *
	milbeaut_hdmac_next_desc(struct milbeaut_hdmac_chan *mc)
	{
	struct virt_dma_desc *vd;

	vd = vchan_next_desc(&mc->vc);
	if (!vd) {
	mc->md = NULL;
	return NULL;
	}

	list_del(&vd->node);

	mc->md = to_milbeaut_hdmac_desc(vd);

	return mc->md;
	}

	/* mc->vc.lock must be held by caller */
	static void milbeaut_chan_start(struct milbeaut_hdmac_chan *mc,
	struct milbeaut_hdmac_desc *md)
	{
	struct scatterlist *sg;
	u32 cb, ca, src_addr, dest_addr, len;
	u32 width, burst;

	sg = &md->sgl[md->sg_cur];
	len = sg_dma_len(sg);

	cb = MLB_HDMAC_CI \| MLB_HDMAC_EI;
	if (md->dir == DMA_MEM_TO_DEV) {
	cb \|= MLB_HDMAC_FD;
	width = mc->cfg.dst_addr_width;
	burst = mc->cfg.dst_maxburst;
	src_addr = sg_dma_address(sg);
	dest_addr = mc->cfg.dst_addr;
	} else {
	cb \|= MLB_HDMAC_FS;
	width = mc->cfg.src_addr_width;
	burst = mc->cfg.src_maxburst;
	src_addr = mc->cfg.src_addr;
	dest_addr = sg_dma_address(sg);
	}
	cb \|= FIELD_PREP(MLB_HDMAC_TW, (width >> 1));
	cb \|= FIELD_PREP(MLB_HDMAC_MS, 2);

	writel_relaxed(MLB_HDMAC_DE, mc->mdev->reg_base + MLB_HDMAC_DMACR);
	writel_relaxed(src_addr, mc->reg_ch_base + MLB_HDMAC_DMACSA);
	writel_relaxed(dest_addr, mc->reg_ch_base + MLB_HDMAC_DMACDA);
	writel_relaxed(cb, mc->reg_ch_base + MLB_HDMAC_DMACB);

	ca = FIELD_PREP(MLB_HDMAC_IS, mc->slave_id);
	if (burst == 16)
	ca \|= FIELD_PREP(MLB_HDMAC_BT, 0xf);
	else if (burst == 8)
	ca \|= FIELD_PREP(MLB_HDMAC_BT, 0xd);
	else if (burst == 4)
	ca \|= FIELD_PREP(MLB_HDMAC_BT, 0xb);
	burst *= width;
	ca \|= FIELD_PREP(MLB_HDMAC_TC, (len / burst - 1));
	writel_relaxed(ca, mc->reg_ch_base + MLB_HDMAC_DMACA);
	ca \|= MLB_HDMAC_EB;
	writel_relaxed(ca, mc->reg_ch_base + MLB_HDMAC_DMACA);
	}

	/* mc->vc.lock must be held by caller */
	static void milbeaut_hdmac_start(struct milbeaut_hdmac_chan *mc)
	{
	struct milbeaut_hdmac_desc *md;

	md = milbeaut_hdmac_next_desc(mc);
	if (md)
	milbeaut_chan_start(mc, md);
	}

	static irqreturn_t milbeaut_hdmac_interrupt(int irq, void *dev_id)
	{
	struct milbeaut_hdmac_chan *mc = dev_id;
	struct milbeaut_hdmac_desc *md;
	u32 val;

	spin_lock(&mc->vc.lock);

	/* Ack and Disable irqs */
	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACB);
	val &= ~(FIELD_PREP(MLB_HDMAC_SS, HDMAC_PAUSE));
	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACB);
	val &= ~MLB_HDMAC_EI;
	val &= ~MLB_HDMAC_CI;
	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACB);

	md = mc->md;
	if (!md)
	goto out;

	md->sg_cur++;

	if (md->sg_cur >= md->sg_len) {
	vchan_cookie_complete(&md->vd);
	md = milbeaut_hdmac_next_desc(mc);
	if (!md)
	goto out;
	}

	milbeaut_chan_start(mc, md);

	out:
	spin_unlock(&mc->vc.lock);
	return IRQ_HANDLED;
	}

	static void milbeaut_hdmac_free_chan_resources(struct dma_chan *chan)
	{
	vchan_free_chan_resources(to_virt_chan(chan));
	}

	static int
	milbeaut_hdmac_chan_config(struct dma_chan chan, struct dma_slave_config cfg)
	{
	struct virt_dma_chan *vc = to_virt_chan(chan);
	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);

	spin_lock(&mc->vc.lock);
	mc->cfg = *cfg;
	spin_unlock(&mc->vc.lock);

	return 0;
	}

	static int milbeaut_hdmac_chan_pause(struct dma_chan *chan)
	{
	struct virt_dma_chan *vc = to_virt_chan(chan);
	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
	u32 val;

	spin_lock(&mc->vc.lock);
	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
	val \|= MLB_HDMAC_PB;
	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);
	spin_unlock(&mc->vc.lock);

	return 0;
	}

	static int milbeaut_hdmac_chan_resume(struct dma_chan *chan)
	{
	struct virt_dma_chan *vc = to_virt_chan(chan);
	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
	u32 val;

	spin_lock(&mc->vc.lock);
	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
	val &= ~MLB_HDMAC_PB;
	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);
	spin_unlock(&mc->vc.lock);

	return 0;
	}

	static struct dma_async_tx_descriptor *
	milbeaut_hdmac_prep_slave_sg(struct dma_chan chan, struct scatterlist sgl,
	unsigned int sg_len,
	enum dma_transfer_direction direction,
	unsigned long flags, void *context)
	{
	struct virt_dma_chan *vc = to_virt_chan(chan);
	struct milbeaut_hdmac_desc *md;
	int i;

	if (!is_slave_direction(direction))
	return NULL;

	md = kzalloc(sizeof(*md), GFP_NOWAIT);
	if (!md)
	return NULL;

	md->sgl = kcalloc(sg_len, sizeof(*sgl), GFP_NOWAIT);
	if (!md->sgl) {
	kfree(md);
	return NULL;
	}

	for (i = 0; i < sg_len; i++)
	md->sgl[i] = sgl[i];

	md->sg_len = sg_len;
	md->dir = direction;

	return vchan_tx_prep(vc, &md->vd, flags);
	}

	static int milbeaut_hdmac_terminate_all(struct dma_chan *chan)
	{
	struct virt_dma_chan *vc = to_virt_chan(chan);
	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
	unsigned long flags;
	u32 val;

	LIST_HEAD(head);

	spin_lock_irqsave(&vc->lock, flags);

	val = readl_relaxed(mc->reg_ch_base + MLB_HDMAC_DMACA);
	val &= ~MLB_HDMAC_EB; /* disable the channel */
	writel_relaxed(val, mc->reg_ch_base + MLB_HDMAC_DMACA);

	if (mc->md) {
	vchan_terminate_vdesc(&mc->md->vd);
	mc->md = NULL;
	}

	vchan_get_all_descriptors(vc, &head);

	spin_unlock_irqrestore(&vc->lock, flags);

	vchan_dma_desc_free_list(vc, &head);

	return 0;
	}

	static void milbeaut_hdmac_synchronize(struct dma_chan *chan)
	{
	vchan_synchronize(to_virt_chan(chan));
	}

	static enum dma_status milbeaut_hdmac_tx_status(struct dma_chan *chan,
	dma_cookie_t cookie,
	struct dma_tx_state *txstate)
	{
	struct virt_dma_chan *vc;
	struct virt_dma_desc *vd;
	struct milbeaut_hdmac_chan *mc;
	struct milbeaut_hdmac_desc *md = NULL;
	enum dma_status stat;
	unsigned long flags;
	int i;

	stat = dma_cookie_status(chan, cookie, txstate);
	/* Return immediately if we do not need to compute the residue. */
	if (stat == DMA_COMPLETE \|\| !txstate)
	return stat;

	vc = to_virt_chan(chan);

	spin_lock_irqsave(&vc->lock, flags);

	mc = to_milbeaut_hdmac_chan(vc);

	/* residue from the on-flight chunk */
	if (mc->md && mc->md->vd.tx.cookie == cookie) {
	struct scatterlist *sg;
	u32 done;

	md = mc->md;
	sg = &md->sgl[md->sg_cur];

	if (md->dir == DMA_DEV_TO_MEM)
	done = readl_relaxed(mc->reg_ch_base
	+ MLB_HDMAC_DMACDA);
	else
	done = readl_relaxed(mc->reg_ch_base
	+ MLB_HDMAC_DMACSA);
	done -= sg_dma_address(sg);

	txstate->residue = -done;
	}

	if (!md) {
	vd = vchan_find_desc(vc, cookie);
	if (vd)
	md = to_milbeaut_hdmac_desc(vd);
	}

	if (md) {
	/* residue from the queued chunks */
	for (i = md->sg_cur; i < md->sg_len; i++)
	txstate->residue += sg_dma_len(&md->sgl[i]);
	}

	spin_unlock_irqrestore(&vc->lock, flags);

	return stat;
	}

	static void milbeaut_hdmac_issue_pending(struct dma_chan *chan)
	{
	struct virt_dma_chan *vc = to_virt_chan(chan);
	struct milbeaut_hdmac_chan *mc = to_milbeaut_hdmac_chan(vc);
	unsigned long flags;

	spin_lock_irqsave(&vc->lock, flags);

	if (vchan_issue_pending(vc) && !mc->md)
	milbeaut_hdmac_start(mc);

	spin_unlock_irqrestore(&vc->lock, flags);
	}

	static void milbeaut_hdmac_desc_free(struct virt_dma_desc *vd)
	{
	struct milbeaut_hdmac_desc *md = to_milbeaut_hdmac_desc(vd);

	kfree(md->sgl);
	kfree(md);
	}

	static struct dma_chan *
	milbeaut_hdmac_xlate(struct of_phandle_args dma_spec, struct of_dma of_dma)
	{
	struct milbeaut_hdmac_device *mdev = of_dma->of_dma_data;
	struct milbeaut_hdmac_chan *mc;
	struct virt_dma_chan *vc;
	struct dma_chan *chan;

	if (dma_spec->args_count != 1)
	return NULL;

	chan = dma_get_any_slave_channel(&mdev->ddev);
	if (!chan)
	return NULL;

	vc = to_virt_chan(chan);
	mc = to_milbeaut_hdmac_chan(vc);
	mc->slave_id = dma_spec->args[0];

	return chan;
	}

	static int milbeaut_hdmac_chan_init(struct platform_device *pdev,
	struct milbeaut_hdmac_device *mdev,
	int chan_id)
	{
	struct device *dev = &pdev->dev;
	struct milbeaut_hdmac_chan *mc = &mdev->channels[chan_id];
	char *irq_name;
	int irq, ret;

	irq = platform_get_irq(pdev, chan_id);
	if (irq < 0)
	return irq;

	irq_name = devm_kasprintf(dev, GFP_KERNEL, "milbeaut-hdmac-%d",
	chan_id);
	if (!irq_name)
	return -ENOMEM;

	ret = devm_request_irq(dev, irq, milbeaut_hdmac_interrupt,
	IRQF_SHARED, irq_name, mc);
	if (ret)
	return ret;

	mc->mdev = mdev;
	mc->reg_ch_base = mdev->reg_base + MLB_HDMAC_CH_STRIDE * (chan_id + 1);
	mc->vc.desc_free = milbeaut_hdmac_desc_free;
	vchan_init(&mc->vc, &mdev->ddev);

	return 0;
	}

	static int milbeaut_hdmac_probe(struct platform_device *pdev)
	{
	struct device *dev = &pdev->dev;
	struct milbeaut_hdmac_device *mdev;
	struct dma_device *ddev;
	int nr_chans, ret, i;

	nr_chans = platform_irq_count(pdev);
	if (nr_chans < 0)
	return nr_chans;

	ret = dma_set_mask(dev, DMA_BIT_MASK(32));
	if (ret)
	return ret;

	mdev = devm_kzalloc(dev, struct_size(mdev, channels, nr_chans),
	GFP_KERNEL);
	if (!mdev)
	return -ENOMEM;

	mdev->reg_base = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(mdev->reg_base))
	return PTR_ERR(mdev->reg_base);

	mdev->clk = devm_clk_get(dev, NULL);
	if (IS_ERR(mdev->clk)) {
	dev_err(dev, "failed to get clock\n");
	return PTR_ERR(mdev->clk);
	}

	ret = clk_prepare_enable(mdev->clk);
	if (ret)
	return ret;

	ddev = &mdev->ddev;
	ddev->dev = dev;
	dma_cap_set(DMA_SLAVE, ddev->cap_mask);
	dma_cap_set(DMA_PRIVATE, ddev->cap_mask);
	ddev->src_addr_widths = MLB_HDMAC_BUSWIDTHS;
	ddev->dst_addr_widths = MLB_HDMAC_BUSWIDTHS;
	ddev->directions = BIT(DMA_MEM_TO_DEV) \| BIT(DMA_DEV_TO_MEM);
	ddev->device_free_chan_resources = milbeaut_hdmac_free_chan_resources;
	ddev->device_config = milbeaut_hdmac_chan_config;
	ddev->device_pause = milbeaut_hdmac_chan_pause;
	ddev->device_resume = milbeaut_hdmac_chan_resume;
	ddev->device_prep_slave_sg = milbeaut_hdmac_prep_slave_sg;
	ddev->device_terminate_all = milbeaut_hdmac_terminate_all;
	ddev->device_synchronize = milbeaut_hdmac_synchronize;
	ddev->device_tx_status = milbeaut_hdmac_tx_status;
	ddev->device_issue_pending = milbeaut_hdmac_issue_pending;
	INIT_LIST_HEAD(&ddev->channels);

	for (i = 0; i < nr_chans; i++) {
	ret = milbeaut_hdmac_chan_init(pdev, mdev, i);
	if (ret)
	goto disable_clk;
	}

	ret = dma_async_device_register(ddev);
	if (ret)
	goto disable_clk;

	ret = of_dma_controller_register(dev->of_node,
	milbeaut_hdmac_xlate, mdev);
	if (ret)
	goto unregister_dmac;

	platform_set_drvdata(pdev, mdev);

	return 0;

	unregister_dmac:
	dma_async_device_unregister(ddev);
	disable_clk:
	clk_disable_unprepare(mdev->clk);

	return ret;
	}

	static int milbeaut_hdmac_remove(struct platform_device *pdev)
	{
	struct milbeaut_hdmac_device *mdev = platform_get_drvdata(pdev);
	struct dma_chan *chan;
	int ret;

	/*
	* Before reaching here, almost all descriptors have been freed by the
	* ->device_free_chan_resources() hook. However, each channel might
	* be still holding one descriptor that was on-flight at that moment.
	* Terminate it to make sure this hardware is no longer running. Then,
	* free the channel resources once again to avoid memory leak.
	*/
	list_for_each_entry(chan, &mdev->ddev.channels, device_node) {
	ret = dmaengine_terminate_sync(chan);
	if (ret)
	return ret;
	milbeaut_hdmac_free_chan_resources(chan);
	}

	of_dma_controller_free(pdev->dev.of_node);
	dma_async_device_unregister(&mdev->ddev);
	clk_disable_unprepare(mdev->clk);

	return 0;
	}

	static const struct of_device_id milbeaut_hdmac_match[] = {
	{ .compatible = "socionext,milbeaut-m10v-hdmac" },
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, milbeaut_hdmac_match);

	static struct platform_driver milbeaut_hdmac_driver = {
	.probe = milbeaut_hdmac_probe,
	.remove = milbeaut_hdmac_remove,
	.driver = {
	.name = "milbeaut-m10v-hdmac",
	.of_match_table = milbeaut_hdmac_match,
	},
	};
	module_platform_driver(milbeaut_hdmac_driver);

	MODULE_DESCRIPTION("Milbeaut HDMAC DmaEngine driver");
	MODULE_LICENSE("GPL v2");