drivers/dma/fsl-edma.c - third_party/linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * drivers/dma/fsl-edma.c
  *
  * Copyright 2013-2014 Freescale Semiconductor, Inc.
  *
  * Driver for the Freescale eDMA engine with flexible channel multiplexing
  * capability for DMA request sources. The eDMA block can be found on some
  * Vybrid and Layerscape SoCs.
  */

 #include <linux/module.h>
 #include <linux/interrupt.h>
 #include <linux/clk.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/of_address.h>
 #include <linux/of_irq.h>
 #include <linux/of_dma.h>
 #include <linux/dma-mapping.h>

 #include "fsl-edma-common.h"

 static void fsl_edma_synchronize(struct dma_chan *chan)
 {
 	struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);

 	vchan_synchronize(&fsl_chan->vchan);
 }

 static irqreturn_t fsl_edma_tx_handler(int irq, void *dev_id)
 {
 	struct fsl_edma_engine *fsl_edma = dev_id;
 	unsigned int intr, ch;
 	struct edma_regs *regs = &fsl_edma->regs;
 	struct fsl_edma_chan *fsl_chan;

 	intr = edma_readl(fsl_edma, regs->intl);
 	if (!intr)
 		return IRQ_NONE;

 	for (ch = 0; ch < fsl_edma->n_chans; ch++) {
 		if (intr & (0x1 << ch)) {
 			edma_writeb(fsl_edma, EDMA_CINT_CINT(ch), regs->cint);

 			fsl_chan = &fsl_edma->chans[ch];

 			spin_lock(&fsl_chan->vchan.lock);

 			if (!fsl_chan->edesc) {
 				/* terminate_all called before */
 				spin_unlock(&fsl_chan->vchan.lock);
 				continue;
 			}

 			if (!fsl_chan->edesc->iscyclic) {
 				list_del(&fsl_chan->edesc->vdesc.node);
 				vchan_cookie_complete(&fsl_chan->edesc->vdesc);
 				fsl_chan->edesc = NULL;
 				fsl_chan->status = DMA_COMPLETE;
 				fsl_chan->idle = true;
 			} else {
 				vchan_cyclic_callback(&fsl_chan->edesc->vdesc);
 			}

 			if (!fsl_chan->edesc)
 				fsl_edma_xfer_desc(fsl_chan);

 			spin_unlock(&fsl_chan->vchan.lock);
 		}
 	}
 	return IRQ_HANDLED;
 }

 static irqreturn_t fsl_edma_err_handler(int irq, void *dev_id)
 {
 	struct fsl_edma_engine *fsl_edma = dev_id;
 	unsigned int err, ch;
 	struct edma_regs *regs = &fsl_edma->regs;

 	err = edma_readl(fsl_edma, regs->errl);
 	if (!err)
 		return IRQ_NONE;

 	for (ch = 0; ch < fsl_edma->n_chans; ch++) {
 		if (err & (0x1 << ch)) {
 			fsl_edma_disable_request(&fsl_edma->chans[ch]);
 			edma_writeb(fsl_edma, EDMA_CERR_CERR(ch), regs->cerr);
 			fsl_edma->chans[ch].status = DMA_ERROR;
 			fsl_edma->chans[ch].idle = true;
 		}
 	}
 	return IRQ_HANDLED;
 }

 static irqreturn_t fsl_edma_irq_handler(int irq, void *dev_id)
 {
 	if (fsl_edma_tx_handler(irq, dev_id) == IRQ_HANDLED)
 		return IRQ_HANDLED;

 	return fsl_edma_err_handler(irq, dev_id);
 }

 static struct dma_chan *fsl_edma_xlate(struct of_phandle_args *dma_spec,
 		struct of_dma *ofdma)
 {
 	struct fsl_edma_engine *fsl_edma = ofdma->of_dma_data;
 	struct dma_chan *chan, *_chan;
 	struct fsl_edma_chan *fsl_chan;
 	u32 dmamux_nr = fsl_edma->drvdata->dmamuxs;
 	unsigned long chans_per_mux = fsl_edma->n_chans / dmamux_nr;

 	if (dma_spec->args_count != 2)
 		return NULL;

 	mutex_lock(&fsl_edma->fsl_edma_mutex);
 	list_for_each_entry_safe(chan, _chan, &fsl_edma->dma_dev.channels, device_node) {
 		if (chan->client_count)
 			continue;
 		if ((chan->chan_id / chans_per_mux) == dma_spec->args[0]) {
 			chan = dma_get_slave_channel(chan);
 			if (chan) {
 				chan->device->privatecnt++;
 				fsl_chan = to_fsl_edma_chan(chan);
 				fsl_chan->slave_id = dma_spec->args[1];
 				fsl_edma_chan_mux(fsl_chan, fsl_chan->slave_id,
 						true);
 				mutex_unlock(&fsl_edma->fsl_edma_mutex);
 				return chan;
 			}
 		}
 	}
 	mutex_unlock(&fsl_edma->fsl_edma_mutex);
 	return NULL;
 }

 static int
 fsl_edma_irq_init(struct platform_device *pdev, struct fsl_edma_engine *fsl_edma)
 {
 	int ret;

 	fsl_edma->txirq = platform_get_irq_byname(pdev, "edma-tx");
 	if (fsl_edma->txirq < 0)
 		return fsl_edma->txirq;

 	fsl_edma->errirq = platform_get_irq_byname(pdev, "edma-err");
 	if (fsl_edma->errirq < 0)
 		return fsl_edma->errirq;

 	if (fsl_edma->txirq == fsl_edma->errirq) {
 		ret = devm_request_irq(&pdev->dev, fsl_edma->txirq,
 				fsl_edma_irq_handler, 0, "eDMA", fsl_edma);
 		if (ret) {
 			dev_err(&pdev->dev, "Can't register eDMA IRQ.\n");
 			return ret;
 		}
 	} else {
 		ret = devm_request_irq(&pdev->dev, fsl_edma->txirq,
 				fsl_edma_tx_handler, 0, "eDMA tx", fsl_edma);
 		if (ret) {
 			dev_err(&pdev->dev, "Can't register eDMA tx IRQ.\n");
 			return ret;
 		}

 		ret = devm_request_irq(&pdev->dev, fsl_edma->errirq,
 				fsl_edma_err_handler, 0, "eDMA err", fsl_edma);
 		if (ret) {
 			dev_err(&pdev->dev, "Can't register eDMA err IRQ.\n");
 			return ret;
 		}
 	}

 	return 0;
 }

 static int
 fsl_edma2_irq_init(struct platform_device *pdev,
 		   struct fsl_edma_engine *fsl_edma)
 {
 	int i, ret, irq;
 	int count;

 	count = platform_irq_count(pdev);
 	dev_dbg(&pdev->dev, "%s Found %d interrupts\r\n", __func__, count);
 	if (count <= 2) {
 		dev_err(&pdev->dev, "Interrupts in DTS not correct.\n");
 		return -EINVAL;
 	}
 	/*
 	 * 16 channel independent interrupts + 1 error interrupt on i.mx7ulp.
 	 * 2 channel share one interrupt, for example, ch0/ch16, ch1/ch17...
 	 * For now, just simply request irq without IRQF_SHARED flag, since 16
 	 * channels are enough on i.mx7ulp whose M4 domain own some peripherals.
 	 */
 	for (i = 0; i < count; i++) {
 		irq = platform_get_irq(pdev, i);
 		if (irq < 0)
 			return -ENXIO;

 		sprintf(fsl_edma->chans[i].chan_name, "eDMA2-CH%02d", i);

 		/* The last IRQ is for eDMA err */
 		if (i == count - 1)
 			ret = devm_request_irq(&pdev->dev, irq,
 						fsl_edma_err_handler,
 						0, "eDMA2-ERR", fsl_edma);
 		else
 			ret = devm_request_irq(&pdev->dev, irq,
 						fsl_edma_tx_handler, 0,
 						fsl_edma->chans[i].chan_name,
 						fsl_edma);
 		if (ret)
 			return ret;
 	}

 	return 0;
 }

 static void fsl_edma_irq_exit(
 		struct platform_device *pdev, struct fsl_edma_engine *fsl_edma)
 {
 	if (fsl_edma->txirq == fsl_edma->errirq) {
 		devm_free_irq(&pdev->dev, fsl_edma->txirq, fsl_edma);
 	} else {
 		devm_free_irq(&pdev->dev, fsl_edma->txirq, fsl_edma);
 		devm_free_irq(&pdev->dev, fsl_edma->errirq, fsl_edma);
 	}
 }

 static void fsl_disable_clocks(struct fsl_edma_engine *fsl_edma, int nr_clocks)
 {
 	int i;

 	for (i = 0; i < nr_clocks; i++)
 		clk_disable_unprepare(fsl_edma->muxclk[i]);
 }

 static struct fsl_edma_drvdata vf610_data = {
 	.version = v1,
 	.dmamuxs = DMAMUX_NR,
 	.setup_irq = fsl_edma_irq_init,
 };

 static struct fsl_edma_drvdata ls1028a_data = {
 	.version = v1,
 	.dmamuxs = DMAMUX_NR,
 	.mux_swap = true,
 	.setup_irq = fsl_edma_irq_init,
 };

 static struct fsl_edma_drvdata imx7ulp_data = {
 	.version = v3,
 	.dmamuxs = 1,
 	.has_dmaclk = true,
 	.setup_irq = fsl_edma2_irq_init,
 };

 static const struct of_device_id fsl_edma_dt_ids[] = {
 	{ .compatible = "fsl,vf610-edma", .data = &vf610_data},
 	{ .compatible = "fsl,ls1028a-edma", .data = &ls1028a_data},
 	{ .compatible = "fsl,imx7ulp-edma", .data = &imx7ulp_data},
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, fsl_edma_dt_ids);

 static int fsl_edma_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *of_id =
 			of_match_device(fsl_edma_dt_ids, &pdev->dev);
 	struct device_node *np = pdev->dev.of_node;
 	struct fsl_edma_engine *fsl_edma;
 	const struct fsl_edma_drvdata *drvdata = NULL;
 	struct fsl_edma_chan *fsl_chan;
 	struct edma_regs *regs;
 	int len, chans;
 	int ret, i;

 	if (of_id)
 		drvdata = of_id->data;
 	if (!drvdata) {
 		dev_err(&pdev->dev, "unable to find driver data\n");
 		return -EINVAL;
 	}

 	ret = of_property_read_u32(np, "dma-channels", &chans);
 	if (ret) {
 		dev_err(&pdev->dev, "Can't get dma-channels.\n");
 		return ret;
 	}

 	len = sizeof(*fsl_edma) + sizeof(*fsl_chan) * chans;
 	fsl_edma = devm_kzalloc(&pdev->dev, len, GFP_KERNEL);
 	if (!fsl_edma)
 		return -ENOMEM;

 	fsl_edma->drvdata = drvdata;
 	fsl_edma->n_chans = chans;
 	mutex_init(&fsl_edma->fsl_edma_mutex);

 	fsl_edma->membase = devm_platform_ioremap_resource(pdev, 0);
 	if (IS_ERR(fsl_edma->membase))
 		return PTR_ERR(fsl_edma->membase);

 	fsl_edma_setup_regs(fsl_edma);
 	regs = &fsl_edma->regs;

 	if (drvdata->has_dmaclk) {
 		fsl_edma->dmaclk = devm_clk_get(&pdev->dev, "dma");
 		if (IS_ERR(fsl_edma->dmaclk)) {
 			dev_err(&pdev->dev, "Missing DMA block clock.\n");
 			return PTR_ERR(fsl_edma->dmaclk);
 		}

 		ret = clk_prepare_enable(fsl_edma->dmaclk);
 		if (ret) {
 			dev_err(&pdev->dev, "DMA clk block failed.\n");
 			return ret;
 		}
 	}

 	for (i = 0; i < fsl_edma->drvdata->dmamuxs; i++) {
 		char clkname[32];

 		fsl_edma->muxbase[i] = devm_platform_ioremap_resource(pdev,
 								      1 + i);
 		if (IS_ERR(fsl_edma->muxbase[i])) {
 			/* on error: disable all previously enabled clks */
 			fsl_disable_clocks(fsl_edma, i);
 			return PTR_ERR(fsl_edma->muxbase[i]);
 		}

 		sprintf(clkname, "dmamux%d", i);
 		fsl_edma->muxclk[i] = devm_clk_get(&pdev->dev, clkname);
 		if (IS_ERR(fsl_edma->muxclk[i])) {
 			dev_err(&pdev->dev, "Missing DMAMUX block clock.\n");
 			/* on error: disable all previously enabled clks */
 			fsl_disable_clocks(fsl_edma, i);
 			return PTR_ERR(fsl_edma->muxclk[i]);
 		}

 		ret = clk_prepare_enable(fsl_edma->muxclk[i]);
 		if (ret)
 			/* on error: disable all previously enabled clks */
 			fsl_disable_clocks(fsl_edma, i);

 	}

 	fsl_edma->big_endian = of_property_read_bool(np, "big-endian");

 	INIT_LIST_HEAD(&fsl_edma->dma_dev.channels);
 	for (i = 0; i < fsl_edma->n_chans; i++) {
 		struct fsl_edma_chan *fsl_chan = &fsl_edma->chans[i];

 		fsl_chan->edma = fsl_edma;
 		fsl_chan->pm_state = RUNNING;
 		fsl_chan->slave_id = 0;
 		fsl_chan->idle = true;
 		fsl_chan->dma_dir = DMA_NONE;
 		fsl_chan->vchan.desc_free = fsl_edma_free_desc;
 		vchan_init(&fsl_chan->vchan, &fsl_edma->dma_dev);

 		edma_writew(fsl_edma, 0x0, &regs->tcd[i].csr);
 		fsl_edma_chan_mux(fsl_chan, 0, false);
 	}

 	edma_writel(fsl_edma, ~0, regs->intl);
 	ret = fsl_edma->drvdata->setup_irq(pdev, fsl_edma);
 	if (ret)
 		return ret;

 	dma_cap_set(DMA_PRIVATE, fsl_edma->dma_dev.cap_mask);
 	dma_cap_set(DMA_SLAVE, fsl_edma->dma_dev.cap_mask);
 	dma_cap_set(DMA_CYCLIC, fsl_edma->dma_dev.cap_mask);
 	dma_cap_set(DMA_MEMCPY, fsl_edma->dma_dev.cap_mask);

 	fsl_edma->dma_dev.dev = &pdev->dev;
 	fsl_edma->dma_dev.device_alloc_chan_resources
 		= fsl_edma_alloc_chan_resources;
 	fsl_edma->dma_dev.device_free_chan_resources
 		= fsl_edma_free_chan_resources;
 	fsl_edma->dma_dev.device_tx_status = fsl_edma_tx_status;
 	fsl_edma->dma_dev.device_prep_slave_sg = fsl_edma_prep_slave_sg;
 	fsl_edma->dma_dev.device_prep_dma_cyclic = fsl_edma_prep_dma_cyclic;
 	fsl_edma->dma_dev.device_prep_dma_memcpy = fsl_edma_prep_memcpy;
 	fsl_edma->dma_dev.device_config = fsl_edma_slave_config;
 	fsl_edma->dma_dev.device_pause = fsl_edma_pause;
 	fsl_edma->dma_dev.device_resume = fsl_edma_resume;
 	fsl_edma->dma_dev.device_terminate_all = fsl_edma_terminate_all;
 	fsl_edma->dma_dev.device_synchronize = fsl_edma_synchronize;
 	fsl_edma->dma_dev.device_issue_pending = fsl_edma_issue_pending;

 	fsl_edma->dma_dev.src_addr_widths = FSL_EDMA_BUSWIDTHS;
 	fsl_edma->dma_dev.dst_addr_widths = FSL_EDMA_BUSWIDTHS;
 	fsl_edma->dma_dev.directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV);

 	fsl_edma->dma_dev.copy_align = DMAENGINE_ALIGN_32_BYTES;
 	/* Per worst case 'nbytes = 1' take CITER as the max_seg_size */
 	dma_set_max_seg_size(fsl_edma->dma_dev.dev, 0x3fff);

 	platform_set_drvdata(pdev, fsl_edma);

 	ret = dma_async_device_register(&fsl_edma->dma_dev);
 	if (ret) {
 		dev_err(&pdev->dev,
 			"Can't register Freescale eDMA engine. (%d)\n", ret);
 		fsl_disable_clocks(fsl_edma, fsl_edma->drvdata->dmamuxs);
 		return ret;
 	}

 	ret = of_dma_controller_register(np, fsl_edma_xlate, fsl_edma);
 	if (ret) {
 		dev_err(&pdev->dev,
 			"Can't register Freescale eDMA of_dma. (%d)\n", ret);
 		dma_async_device_unregister(&fsl_edma->dma_dev);
 		fsl_disable_clocks(fsl_edma, fsl_edma->drvdata->dmamuxs);
 		return ret;
 	}

 	/* enable round robin arbitration */
 	edma_writel(fsl_edma, EDMA_CR_ERGA | EDMA_CR_ERCA, regs->cr);

 	return 0;
 }

 static int fsl_edma_remove(struct platform_device *pdev)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct fsl_edma_engine *fsl_edma = platform_get_drvdata(pdev);

 	fsl_edma_irq_exit(pdev, fsl_edma);
 	fsl_edma_cleanup_vchan(&fsl_edma->dma_dev);
 	of_dma_controller_free(np);
 	dma_async_device_unregister(&fsl_edma->dma_dev);
 	fsl_disable_clocks(fsl_edma, fsl_edma->drvdata->dmamuxs);

 	return 0;
 }

 static int fsl_edma_suspend_late(struct device *dev)
 {
 	struct fsl_edma_engine *fsl_edma = dev_get_drvdata(dev);
 	struct fsl_edma_chan *fsl_chan;
 	unsigned long flags;
 	int i;

 	for (i = 0; i < fsl_edma->n_chans; i++) {
 		fsl_chan = &fsl_edma->chans[i];
 		spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
 		/* Make sure chan is idle or will force disable. */
 		if (unlikely(!fsl_chan->idle)) {
 			dev_warn(dev, "WARN: There is non-idle channel.");
 			fsl_edma_disable_request(fsl_chan);
 			fsl_edma_chan_mux(fsl_chan, 0, false);
 		}

 		fsl_chan->pm_state = SUSPENDED;
 		spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
 	}

 	return 0;
 }

 static int fsl_edma_resume_early(struct device *dev)
 {
 	struct fsl_edma_engine *fsl_edma = dev_get_drvdata(dev);
 	struct fsl_edma_chan *fsl_chan;
 	struct edma_regs *regs = &fsl_edma->regs;
 	int i;

 	for (i = 0; i < fsl_edma->n_chans; i++) {
 		fsl_chan = &fsl_edma->chans[i];
 		fsl_chan->pm_state = RUNNING;
 		edma_writew(fsl_edma, 0x0, &regs->tcd[i].csr);
 		if (fsl_chan->slave_id != 0)
 			fsl_edma_chan_mux(fsl_chan, fsl_chan->slave_id, true);
 	}

 	edma_writel(fsl_edma, EDMA_CR_ERGA | EDMA_CR_ERCA, regs->cr);

 	return 0;
 }

 /*
  * eDMA provides the service to others, so it should be suspend late
  * and resume early. When eDMA suspend, all of the clients should stop
  * the DMA data transmission and let the channel idle.
  */
 static const struct dev_pm_ops fsl_edma_pm_ops = {
 	.suspend_late   = fsl_edma_suspend_late,
 	.resume_early   = fsl_edma_resume_early,
 };

 static struct platform_driver fsl_edma_driver = {
 	.driver		= {
 		.name	= "fsl-edma",
 		.of_match_table = fsl_edma_dt_ids,
 		.pm     = &fsl_edma_pm_ops,
 	},
 	.probe          = fsl_edma_probe,
 	.remove		= fsl_edma_remove,
 };

 static int __init fsl_edma_init(void)
 {
 	return platform_driver_register(&fsl_edma_driver);
 }
 subsys_initcall(fsl_edma_init);

 static void __exit fsl_edma_exit(void)
 {
 	platform_driver_unregister(&fsl_edma_driver);
 }
 module_exit(fsl_edma_exit);

 MODULE_ALIAS("platform:fsl-edma");
 MODULE_DESCRIPTION("Freescale eDMA engine driver");
 MODULE_LICENSE("GPL v2");
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* drivers/dma/fsl-edma.c
	*
	* Copyright 2013-2014 Freescale Semiconductor, Inc.
	*
	* Driver for the Freescale eDMA engine with flexible channel multiplexing
	* capability for DMA request sources. The eDMA block can be found on some
	* Vybrid and Layerscape SoCs.
	*/

	#include <linux/module.h>
	#include <linux/interrupt.h>
	#include <linux/clk.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/of_address.h>
	#include <linux/of_irq.h>
	#include <linux/of_dma.h>
	#include <linux/dma-mapping.h>

	#include "fsl-edma-common.h"

	static void fsl_edma_synchronize(struct dma_chan *chan)
	{
	struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);

	vchan_synchronize(&fsl_chan->vchan);
	}

	static irqreturn_t fsl_edma_tx_handler(int irq, void *dev_id)
	{
	struct fsl_edma_engine *fsl_edma = dev_id;
	unsigned int intr, ch;
	struct edma_regs *regs = &fsl_edma->regs;
	struct fsl_edma_chan *fsl_chan;

	intr = edma_readl(fsl_edma, regs->intl);
	if (!intr)
	return IRQ_NONE;

	for (ch = 0; ch < fsl_edma->n_chans; ch++) {
	if (intr & (0x1 << ch)) {
	edma_writeb(fsl_edma, EDMA_CINT_CINT(ch), regs->cint);

	fsl_chan = &fsl_edma->chans[ch];

	spin_lock(&fsl_chan->vchan.lock);

	if (!fsl_chan->edesc) {
	/* terminate_all called before */
	spin_unlock(&fsl_chan->vchan.lock);
	continue;
	}

	if (!fsl_chan->edesc->iscyclic) {
	list_del(&fsl_chan->edesc->vdesc.node);
	vchan_cookie_complete(&fsl_chan->edesc->vdesc);
	fsl_chan->edesc = NULL;
	fsl_chan->status = DMA_COMPLETE;
	fsl_chan->idle = true;
	} else {
	vchan_cyclic_callback(&fsl_chan->edesc->vdesc);
	}

	if (!fsl_chan->edesc)
	fsl_edma_xfer_desc(fsl_chan);

	spin_unlock(&fsl_chan->vchan.lock);
	}
	}
	return IRQ_HANDLED;
	}

	static irqreturn_t fsl_edma_err_handler(int irq, void *dev_id)
	{
	struct fsl_edma_engine *fsl_edma = dev_id;
	unsigned int err, ch;
	struct edma_regs *regs = &fsl_edma->regs;

	err = edma_readl(fsl_edma, regs->errl);
	if (!err)
	return IRQ_NONE;

	for (ch = 0; ch < fsl_edma->n_chans; ch++) {
	if (err & (0x1 << ch)) {
	fsl_edma_disable_request(&fsl_edma->chans[ch]);
	edma_writeb(fsl_edma, EDMA_CERR_CERR(ch), regs->cerr);
	fsl_edma->chans[ch].status = DMA_ERROR;
	fsl_edma->chans[ch].idle = true;
	}
	}
	return IRQ_HANDLED;
	}

	static irqreturn_t fsl_edma_irq_handler(int irq, void *dev_id)
	{
	if (fsl_edma_tx_handler(irq, dev_id) == IRQ_HANDLED)
	return IRQ_HANDLED;

	return fsl_edma_err_handler(irq, dev_id);
	}

	static struct dma_chan fsl_edma_xlate(struct of_phandle_args dma_spec,
	struct of_dma *ofdma)
	{
	struct fsl_edma_engine *fsl_edma = ofdma->of_dma_data;
	struct dma_chan chan, _chan;
	struct fsl_edma_chan *fsl_chan;
	u32 dmamux_nr = fsl_edma->drvdata->dmamuxs;
	unsigned long chans_per_mux = fsl_edma->n_chans / dmamux_nr;

	if (dma_spec->args_count != 2)
	return NULL;

	mutex_lock(&fsl_edma->fsl_edma_mutex);
	list_for_each_entry_safe(chan, _chan, &fsl_edma->dma_dev.channels, device_node) {
	if (chan->client_count)
	continue;
	if ((chan->chan_id / chans_per_mux) == dma_spec->args[0]) {
	chan = dma_get_slave_channel(chan);
	if (chan) {
	chan->device->privatecnt++;
	fsl_chan = to_fsl_edma_chan(chan);
	fsl_chan->slave_id = dma_spec->args[1];
	fsl_edma_chan_mux(fsl_chan, fsl_chan->slave_id,
	true);
	mutex_unlock(&fsl_edma->fsl_edma_mutex);
	return chan;
	}
	}
	}
	mutex_unlock(&fsl_edma->fsl_edma_mutex);
	return NULL;
	}

	static int
	fsl_edma_irq_init(struct platform_device pdev, struct fsl_edma_engine fsl_edma)
	{
	int ret;

	fsl_edma->txirq = platform_get_irq_byname(pdev, "edma-tx");
	if (fsl_edma->txirq < 0)
	return fsl_edma->txirq;

	fsl_edma->errirq = platform_get_irq_byname(pdev, "edma-err");
	if (fsl_edma->errirq < 0)
	return fsl_edma->errirq;

	if (fsl_edma->txirq == fsl_edma->errirq) {
	ret = devm_request_irq(&pdev->dev, fsl_edma->txirq,
	fsl_edma_irq_handler, 0, "eDMA", fsl_edma);
	if (ret) {
	dev_err(&pdev->dev, "Can't register eDMA IRQ.\n");
	return ret;
	}
	} else {
	ret = devm_request_irq(&pdev->dev, fsl_edma->txirq,
	fsl_edma_tx_handler, 0, "eDMA tx", fsl_edma);
	if (ret) {
	dev_err(&pdev->dev, "Can't register eDMA tx IRQ.\n");
	return ret;
	}

	ret = devm_request_irq(&pdev->dev, fsl_edma->errirq,
	fsl_edma_err_handler, 0, "eDMA err", fsl_edma);
	if (ret) {
	dev_err(&pdev->dev, "Can't register eDMA err IRQ.\n");
	return ret;
	}
	}

	return 0;
	}

	static int
	fsl_edma2_irq_init(struct platform_device *pdev,
	struct fsl_edma_engine *fsl_edma)
	{
	int i, ret, irq;
	int count;

	count = platform_irq_count(pdev);
	dev_dbg(&pdev->dev, "%s Found %d interrupts\r\n", __func__, count);
	if (count <= 2) {
	dev_err(&pdev->dev, "Interrupts in DTS not correct.\n");
	return -EINVAL;
	}
	/*
	* 16 channel independent interrupts + 1 error interrupt on i.mx7ulp.
	* 2 channel share one interrupt, for example, ch0/ch16, ch1/ch17...
	* For now, just simply request irq without IRQF_SHARED flag, since 16
	* channels are enough on i.mx7ulp whose M4 domain own some peripherals.
	*/
	for (i = 0; i < count; i++) {
	irq = platform_get_irq(pdev, i);
	if (irq < 0)
	return -ENXIO;

	sprintf(fsl_edma->chans[i].chan_name, "eDMA2-CH%02d", i);

	/* The last IRQ is for eDMA err */
	if (i == count - 1)
	ret = devm_request_irq(&pdev->dev, irq,
	fsl_edma_err_handler,
	0, "eDMA2-ERR", fsl_edma);
	else
	ret = devm_request_irq(&pdev->dev, irq,
	fsl_edma_tx_handler, 0,
	fsl_edma->chans[i].chan_name,
	fsl_edma);
	if (ret)
	return ret;
	}

	return 0;
	}

	static void fsl_edma_irq_exit(
	struct platform_device pdev, struct fsl_edma_engine fsl_edma)
	{
	if (fsl_edma->txirq == fsl_edma->errirq) {
	devm_free_irq(&pdev->dev, fsl_edma->txirq, fsl_edma);
	} else {
	devm_free_irq(&pdev->dev, fsl_edma->txirq, fsl_edma);
	devm_free_irq(&pdev->dev, fsl_edma->errirq, fsl_edma);
	}
	}

	static void fsl_disable_clocks(struct fsl_edma_engine *fsl_edma, int nr_clocks)
	{
	int i;

	for (i = 0; i < nr_clocks; i++)
	clk_disable_unprepare(fsl_edma->muxclk[i]);
	}

	static struct fsl_edma_drvdata vf610_data = {
	.version = v1,
	.dmamuxs = DMAMUX_NR,
	.setup_irq = fsl_edma_irq_init,
	};

	static struct fsl_edma_drvdata ls1028a_data = {
	.version = v1,
	.dmamuxs = DMAMUX_NR,
	.mux_swap = true,
	.setup_irq = fsl_edma_irq_init,
	};

	static struct fsl_edma_drvdata imx7ulp_data = {
	.version = v3,
	.dmamuxs = 1,
	.has_dmaclk = true,
	.setup_irq = fsl_edma2_irq_init,
	};

	static const struct of_device_id fsl_edma_dt_ids[] = {
	{ .compatible = "fsl,vf610-edma", .data = &vf610_data},
	{ .compatible = "fsl,ls1028a-edma", .data = &ls1028a_data},
	{ .compatible = "fsl,imx7ulp-edma", .data = &imx7ulp_data},
	{ /* sentinel */ }
	};
	MODULE_DEVICE_TABLE(of, fsl_edma_dt_ids);

	static int fsl_edma_probe(struct platform_device *pdev)
	{
	const struct of_device_id *of_id =
	of_match_device(fsl_edma_dt_ids, &pdev->dev);
	struct device_node *np = pdev->dev.of_node;
	struct fsl_edma_engine *fsl_edma;
	const struct fsl_edma_drvdata *drvdata = NULL;
	struct fsl_edma_chan *fsl_chan;
	struct edma_regs *regs;
	int len, chans;
	int ret, i;

	if (of_id)
	drvdata = of_id->data;
	if (!drvdata) {
	dev_err(&pdev->dev, "unable to find driver data\n");
	return -EINVAL;
	}

	ret = of_property_read_u32(np, "dma-channels", &chans);
	if (ret) {
	dev_err(&pdev->dev, "Can't get dma-channels.\n");
	return ret;
	}

	len = sizeof(fsl_edma) + sizeof(fsl_chan) * chans;
	fsl_edma = devm_kzalloc(&pdev->dev, len, GFP_KERNEL);
	if (!fsl_edma)
	return -ENOMEM;

	fsl_edma->drvdata = drvdata;
	fsl_edma->n_chans = chans;
	mutex_init(&fsl_edma->fsl_edma_mutex);

	fsl_edma->membase = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(fsl_edma->membase))
	return PTR_ERR(fsl_edma->membase);

	fsl_edma_setup_regs(fsl_edma);
	regs = &fsl_edma->regs;

	if (drvdata->has_dmaclk) {
	fsl_edma->dmaclk = devm_clk_get(&pdev->dev, "dma");
	if (IS_ERR(fsl_edma->dmaclk)) {
	dev_err(&pdev->dev, "Missing DMA block clock.\n");
	return PTR_ERR(fsl_edma->dmaclk);
	}

	ret = clk_prepare_enable(fsl_edma->dmaclk);
	if (ret) {
	dev_err(&pdev->dev, "DMA clk block failed.\n");
	return ret;
	}
	}

	for (i = 0; i < fsl_edma->drvdata->dmamuxs; i++) {
	char clkname[32];

	fsl_edma->muxbase[i] = devm_platform_ioremap_resource(pdev,
	1 + i);
	if (IS_ERR(fsl_edma->muxbase[i])) {
	/* on error: disable all previously enabled clks */
	fsl_disable_clocks(fsl_edma, i);
	return PTR_ERR(fsl_edma->muxbase[i]);
	}

	sprintf(clkname, "dmamux%d", i);
	fsl_edma->muxclk[i] = devm_clk_get(&pdev->dev, clkname);
	if (IS_ERR(fsl_edma->muxclk[i])) {
	dev_err(&pdev->dev, "Missing DMAMUX block clock.\n");
	/* on error: disable all previously enabled clks */
	fsl_disable_clocks(fsl_edma, i);
	return PTR_ERR(fsl_edma->muxclk[i]);
	}

	ret = clk_prepare_enable(fsl_edma->muxclk[i]);
	if (ret)
	/* on error: disable all previously enabled clks */
	fsl_disable_clocks(fsl_edma, i);

	}

	fsl_edma->big_endian = of_property_read_bool(np, "big-endian");

	INIT_LIST_HEAD(&fsl_edma->dma_dev.channels);
	for (i = 0; i < fsl_edma->n_chans; i++) {
	struct fsl_edma_chan *fsl_chan = &fsl_edma->chans[i];

	fsl_chan->edma = fsl_edma;
	fsl_chan->pm_state = RUNNING;
	fsl_chan->slave_id = 0;
	fsl_chan->idle = true;
	fsl_chan->dma_dir = DMA_NONE;
	fsl_chan->vchan.desc_free = fsl_edma_free_desc;
	vchan_init(&fsl_chan->vchan, &fsl_edma->dma_dev);

	edma_writew(fsl_edma, 0x0, &regs->tcd[i].csr);
	fsl_edma_chan_mux(fsl_chan, 0, false);
	}

	edma_writel(fsl_edma, ~0, regs->intl);
	ret = fsl_edma->drvdata->setup_irq(pdev, fsl_edma);
	if (ret)
	return ret;

	dma_cap_set(DMA_PRIVATE, fsl_edma->dma_dev.cap_mask);
	dma_cap_set(DMA_SLAVE, fsl_edma->dma_dev.cap_mask);
	dma_cap_set(DMA_CYCLIC, fsl_edma->dma_dev.cap_mask);
	dma_cap_set(DMA_MEMCPY, fsl_edma->dma_dev.cap_mask);

	fsl_edma->dma_dev.dev = &pdev->dev;
	fsl_edma->dma_dev.device_alloc_chan_resources
	= fsl_edma_alloc_chan_resources;
	fsl_edma->dma_dev.device_free_chan_resources
	= fsl_edma_free_chan_resources;
	fsl_edma->dma_dev.device_tx_status = fsl_edma_tx_status;
	fsl_edma->dma_dev.device_prep_slave_sg = fsl_edma_prep_slave_sg;
	fsl_edma->dma_dev.device_prep_dma_cyclic = fsl_edma_prep_dma_cyclic;
	fsl_edma->dma_dev.device_prep_dma_memcpy = fsl_edma_prep_memcpy;
	fsl_edma->dma_dev.device_config = fsl_edma_slave_config;
	fsl_edma->dma_dev.device_pause = fsl_edma_pause;
	fsl_edma->dma_dev.device_resume = fsl_edma_resume;
	fsl_edma->dma_dev.device_terminate_all = fsl_edma_terminate_all;
	fsl_edma->dma_dev.device_synchronize = fsl_edma_synchronize;
	fsl_edma->dma_dev.device_issue_pending = fsl_edma_issue_pending;

	fsl_edma->dma_dev.src_addr_widths = FSL_EDMA_BUSWIDTHS;
	fsl_edma->dma_dev.dst_addr_widths = FSL_EDMA_BUSWIDTHS;
	fsl_edma->dma_dev.directions = BIT(DMA_DEV_TO_MEM) \| BIT(DMA_MEM_TO_DEV);

	fsl_edma->dma_dev.copy_align = DMAENGINE_ALIGN_32_BYTES;
	/* Per worst case 'nbytes = 1' take CITER as the max_seg_size */
	dma_set_max_seg_size(fsl_edma->dma_dev.dev, 0x3fff);

	platform_set_drvdata(pdev, fsl_edma);

	ret = dma_async_device_register(&fsl_edma->dma_dev);
	if (ret) {
	dev_err(&pdev->dev,
	"Can't register Freescale eDMA engine. (%d)\n", ret);
	fsl_disable_clocks(fsl_edma, fsl_edma->drvdata->dmamuxs);
	return ret;
	}

	ret = of_dma_controller_register(np, fsl_edma_xlate, fsl_edma);
	if (ret) {
	dev_err(&pdev->dev,
	"Can't register Freescale eDMA of_dma. (%d)\n", ret);
	dma_async_device_unregister(&fsl_edma->dma_dev);
	fsl_disable_clocks(fsl_edma, fsl_edma->drvdata->dmamuxs);
	return ret;
	}

	/* enable round robin arbitration */
	edma_writel(fsl_edma, EDMA_CR_ERGA \| EDMA_CR_ERCA, regs->cr);

	return 0;
	}

	static int fsl_edma_remove(struct platform_device *pdev)
	{
	struct device_node *np = pdev->dev.of_node;
	struct fsl_edma_engine *fsl_edma = platform_get_drvdata(pdev);

	fsl_edma_irq_exit(pdev, fsl_edma);
	fsl_edma_cleanup_vchan(&fsl_edma->dma_dev);
	of_dma_controller_free(np);
	dma_async_device_unregister(&fsl_edma->dma_dev);
	fsl_disable_clocks(fsl_edma, fsl_edma->drvdata->dmamuxs);

	return 0;
	}

	static int fsl_edma_suspend_late(struct device *dev)
	{
	struct fsl_edma_engine *fsl_edma = dev_get_drvdata(dev);
	struct fsl_edma_chan *fsl_chan;
	unsigned long flags;
	int i;

	for (i = 0; i < fsl_edma->n_chans; i++) {
	fsl_chan = &fsl_edma->chans[i];
	spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
	/* Make sure chan is idle or will force disable. */
	if (unlikely(!fsl_chan->idle)) {
	dev_warn(dev, "WARN: There is non-idle channel.");
	fsl_edma_disable_request(fsl_chan);
	fsl_edma_chan_mux(fsl_chan, 0, false);
	}

	fsl_chan->pm_state = SUSPENDED;
	spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags);
	}

	return 0;
	}

	static int fsl_edma_resume_early(struct device *dev)
	{
	struct fsl_edma_engine *fsl_edma = dev_get_drvdata(dev);
	struct fsl_edma_chan *fsl_chan;
	struct edma_regs *regs = &fsl_edma->regs;
	int i;

	for (i = 0; i < fsl_edma->n_chans; i++) {
	fsl_chan = &fsl_edma->chans[i];
	fsl_chan->pm_state = RUNNING;
	edma_writew(fsl_edma, 0x0, &regs->tcd[i].csr);
	if (fsl_chan->slave_id != 0)
	fsl_edma_chan_mux(fsl_chan, fsl_chan->slave_id, true);
	}

	edma_writel(fsl_edma, EDMA_CR_ERGA \| EDMA_CR_ERCA, regs->cr);

	return 0;
	}

	/*
	* eDMA provides the service to others, so it should be suspend late
	* and resume early. When eDMA suspend, all of the clients should stop
	* the DMA data transmission and let the channel idle.
	*/
	static const struct dev_pm_ops fsl_edma_pm_ops = {
	.suspend_late = fsl_edma_suspend_late,
	.resume_early = fsl_edma_resume_early,
	};

	static struct platform_driver fsl_edma_driver = {
	.driver = {
	.name = "fsl-edma",
	.of_match_table = fsl_edma_dt_ids,
	.pm = &fsl_edma_pm_ops,
	},
	.probe = fsl_edma_probe,
	.remove = fsl_edma_remove,
	};

	static int __init fsl_edma_init(void)
	{
	return platform_driver_register(&fsl_edma_driver);
	}
	subsys_initcall(fsl_edma_init);

	static void __exit fsl_edma_exit(void)
	{
	platform_driver_unregister(&fsl_edma_driver);
	}
	module_exit(fsl_edma_exit);

	MODULE_ALIAS("platform:fsl-edma");
	MODULE_DESCRIPTION("Freescale eDMA engine driver");
	MODULE_LICENSE("GPL v2");