dmaengine: add Qualcomm Technologies HIDMA channel driver

This patch adds support for hidma engine. The driver consists of two
logical blocks. The DMA engine interface and the low-level interface.
The hardware only supports memcpy/memset and this driver only support
memcpy interface. HW and driver doesn't support slave interface.
Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/qcom/Kconfig

@@ -17,3 +17,13 @@ config QCOM_HIDMA_MGMT
 	  start managing the channels. In a virtualized environment,
 	  the guest OS would run QCOM_HIDMA channel driver and the
 	  host would run the QCOM_HIDMA_MGMT management driver.
+
+config QCOM_HIDMA
+	tristate "Qualcomm Technologies HIDMA Channel support"
+	select DMA_ENGINE
+	help
+	  Enable support for the Qualcomm Technologies HIDMA controller.
+	  The HIDMA controller supports optimized buffer copies
+	  (user to kernel, kernel to kernel, etc.).  It only supports
+	  memcpy interface. The core is not intended for general
+	  purpose slave DMA.

drivers/dma/qcom/hidma.c

+/*
+ * Qualcomm Technologies HIDMA DMA engine interface
+ *
+ * Copyright (c) 2015, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+/*
+ * Copyright (C) Freescale Semicondutor, Inc. 2007, 2008.
+ * Copyright (C) Semihalf 2009
+ * Copyright (C) Ilya Yanok, Emcraft Systems 2010
+ * Copyright (C) Alexander Popov, Promcontroller 2014
+ *
+ * Written by Piotr Ziecik <kosmo@semihalf.com>. Hardware description
+ * (defines, structures and comments) was taken from MPC5121 DMA driver
+ * written by Hongjun Chen <hong-jun.chen@freescale.com>.
+ *
+ * Approved as OSADL project by a majority of OSADL members and funded
+ * by OSADL membership fees in 2009;  for details see www.osadl.org.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option)
+ * any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * The full GNU General Public License is included in this distribution in the
+ * file called COPYING.
+ */
+
+/* Linux Foundation elects GPLv2 license only. */
+
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/list.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/of_dma.h>
+#include <linux/property.h>
+#include <linux/delay.h>
+#include <linux/acpi.h>
+#include <linux/irq.h>
+#include <linux/atomic.h>
+#include <linux/pm_runtime.h>
+
+#include "../dmaengine.h"
+#include "hidma.h"
+
+/*
+ * Default idle time is 2 seconds. This parameter can
+ * be overridden by changing the following
+ * /sys/bus/platform/devices/QCOM8061:<xy>/power/autosuspend_delay_ms
+ * during kernel boot.
+ */
+#define HIDMA_AUTOSUSPEND_TIMEOUT		2000
+#define HIDMA_ERR_INFO_SW			0xFF
+#define HIDMA_ERR_CODE_UNEXPECTED_TERMINATE	0x0
+#define HIDMA_NR_DEFAULT_DESC			10
+
+static inline struct hidma_dev *to_hidma_dev(struct dma_device *dmadev)
+{
+	return container_of(dmadev, struct hidma_dev, ddev);
+}
+
+static inline
+struct hidma_dev *to_hidma_dev_from_lldev(struct hidma_lldev **_lldevp)
+{
+	return container_of(_lldevp, struct hidma_dev, lldev);
+}
+
+static inline struct hidma_chan *to_hidma_chan(struct dma_chan *dmach)
+{
+	return container_of(dmach, struct hidma_chan, chan);
+}
+
+static inline
+struct hidma_desc *to_hidma_desc(struct dma_async_tx_descriptor *t)
+{
+	return container_of(t, struct hidma_desc, desc);
+}
+
+static void hidma_free(struct hidma_dev *dmadev)
+{
+	INIT_LIST_HEAD(&dmadev->ddev.channels);
+}
+
+static unsigned int nr_desc_prm;
+module_param(nr_desc_prm, uint, 0644);
+MODULE_PARM_DESC(nr_desc_prm, "number of descriptors (default: 0)");
+
+
+/* process completed descriptors */
+static void hidma_process_completed(struct hidma_chan *mchan)
+{
+	struct dma_device *ddev = mchan->chan.device;
+	struct hidma_dev *mdma = to_hidma_dev(ddev);
+	struct dma_async_tx_descriptor *desc;
+	dma_cookie_t last_cookie;
+	struct hidma_desc *mdesc;
+	unsigned long irqflags;
+	struct list_head list;
+
+	INIT_LIST_HEAD(&list);
+
+	/* Get all completed descriptors */
+	spin_lock_irqsave(&mchan->lock, irqflags);
+	list_splice_tail_init(&mchan->completed, &list);
+	spin_unlock_irqrestore(&mchan->lock, irqflags);
+
+	/* Execute callbacks and run dependencies */
+	list_for_each_entry(mdesc, &list, node) {
+		enum dma_status llstat;
+
+		desc = &mdesc->desc;
+
+		spin_lock_irqsave(&mchan->lock, irqflags);
+		dma_cookie_complete(desc);
+		spin_unlock_irqrestore(&mchan->lock, irqflags);
+
+		llstat = hidma_ll_status(mdma->lldev, mdesc->tre_ch);
+		if (desc->callback && (llstat == DMA_COMPLETE))
+			desc->callback(desc->callback_param);
+
+		last_cookie = desc->cookie;
+		dma_run_dependencies(desc);
+	}
+
+	/* Free descriptors */
+	spin_lock_irqsave(&mchan->lock, irqflags);
+	list_splice_tail_init(&list, &mchan->free);
+	spin_unlock_irqrestore(&mchan->lock, irqflags);
+
+}
+
+/*
+ * Called once for each submitted descriptor.
+ * PM is locked once for each descriptor that is currently
+ * in execution.
+ */
+static void hidma_callback(void *data)
+{
+	struct hidma_desc *mdesc = data;
+	struct hidma_chan *mchan = to_hidma_chan(mdesc->desc.chan);
+	struct dma_device *ddev = mchan->chan.device;
+	struct hidma_dev *dmadev = to_hidma_dev(ddev);
+	unsigned long irqflags;
+	bool queued = false;
+
+	spin_lock_irqsave(&mchan->lock, irqflags);
+	if (mdesc->node.next) {
+		/* Delete from the active list, add to completed list */
+		list_move_tail(&mdesc->node, &mchan->completed);
+		queued = true;
+
+		/* calculate the next running descriptor */
+		mchan->running = list_first_entry(&mchan->active,
+						  struct hidma_desc, node);
+	}
+	spin_unlock_irqrestore(&mchan->lock, irqflags);
+
+	hidma_process_completed(mchan);
+
+	if (queued) {
+		pm_runtime_mark_last_busy(dmadev->ddev.dev);
+		pm_runtime_put_autosuspend(dmadev->ddev.dev);
+	}
+}
+
+static int hidma_chan_init(struct hidma_dev *dmadev, u32 dma_sig)
+{
+	struct hidma_chan *mchan;
+	struct dma_device *ddev;
+
+	mchan = devm_kzalloc(dmadev->ddev.dev, sizeof(*mchan), GFP_KERNEL);
+	if (!mchan)
+		return -ENOMEM;
+
+	ddev = &dmadev->ddev;
+	mchan->dma_sig = dma_sig;
+	mchan->dmadev = dmadev;
+	mchan->chan.device = ddev;
+	dma_cookie_init(&mchan->chan);
+
+	INIT_LIST_HEAD(&mchan->free);
+	INIT_LIST_HEAD(&mchan->prepared);
+	INIT_LIST_HEAD(&mchan->active);
+	INIT_LIST_HEAD(&mchan->completed);
+
+	spin_lock_init(&mchan->lock);
+	list_add_tail(&mchan->chan.device_node, &ddev->channels);
+	dmadev->ddev.chancnt++;
+	return 0;
+}
+
+static void hidma_issue_task(unsigned long arg)
+{
+	struct hidma_dev *dmadev = (struct hidma_dev *)arg;
+
+	pm_runtime_get_sync(dmadev->ddev.dev);
+	hidma_ll_start(dmadev->lldev);
+}
+
+static void hidma_issue_pending(struct dma_chan *dmach)
+{
+	struct hidma_chan *mchan = to_hidma_chan(dmach);
+	struct hidma_dev *dmadev = mchan->dmadev;
+	unsigned long flags;
+	int status;
+
+	spin_lock_irqsave(&mchan->lock, flags);
+	if (!mchan->running) {
+		struct hidma_desc *desc = list_first_entry(&mchan->active,
+							   struct hidma_desc,
+							   node);
+		mchan->running = desc;
+	}
+	spin_unlock_irqrestore(&mchan->lock, flags);
+
+	/* PM will be released in hidma_callback function. */
+	status = pm_runtime_get(dmadev->ddev.dev);
+	if (status < 0)
+		tasklet_schedule(&dmadev->task);
+	else
+		hidma_ll_start(dmadev->lldev);
+}
+
+static enum dma_status hidma_tx_status(struct dma_chan *dmach,
+				       dma_cookie_t cookie,
+				       struct dma_tx_state *txstate)
+{
+	struct hidma_chan *mchan = to_hidma_chan(dmach);
+	enum dma_status ret;
+
+	ret = dma_cookie_status(dmach, cookie, txstate);
+	if (ret == DMA_COMPLETE)
+		return ret;
+
+	if (mchan->paused && (ret == DMA_IN_PROGRESS)) {
+		unsigned long flags;
+		dma_cookie_t runcookie;
+
+		spin_lock_irqsave(&mchan->lock, flags);
+		if (mchan->running)
+			runcookie = mchan->running->desc.cookie;
+		else
+			runcookie = -EINVAL;
+
+		if (runcookie == cookie)
+			ret = DMA_PAUSED;
+
+		spin_unlock_irqrestore(&mchan->lock, flags);
+	}
+
+	return ret;
+}
+
+/*
+ * Submit descriptor to hardware.
+ * Lock the PM for each descriptor we are sending.
+ */
+static dma_cookie_t hidma_tx_submit(struct dma_async_tx_descriptor *txd)
+{
+	struct hidma_chan *mchan = to_hidma_chan(txd->chan);
+	struct hidma_dev *dmadev = mchan->dmadev;
+	struct hidma_desc *mdesc;
+	unsigned long irqflags;
+	dma_cookie_t cookie;
+
+	pm_runtime_get_sync(dmadev->ddev.dev);
+	if (!hidma_ll_isenabled(dmadev->lldev)) {
+		pm_runtime_mark_last_busy(dmadev->ddev.dev);
+		pm_runtime_put_autosuspend(dmadev->ddev.dev);
+		return -ENODEV;
+	}
+
+	mdesc = container_of(txd, struct hidma_desc, desc);
+	spin_lock_irqsave(&mchan->lock, irqflags);
+
+	/* Move descriptor to active */
+	list_move_tail(&mdesc->node, &mchan->active);
+
+	/* Update cookie */
+	cookie = dma_cookie_assign(txd);
+
+	hidma_ll_queue_request(dmadev->lldev, mdesc->tre_ch);
+	spin_unlock_irqrestore(&mchan->lock, irqflags);
+
+	return cookie;
+}
+
+static int hidma_alloc_chan_resources(struct dma_chan *dmach)
+{
+	struct hidma_chan *mchan = to_hidma_chan(dmach);
+	struct hidma_dev *dmadev = mchan->dmadev;
+	struct hidma_desc *mdesc, *tmp;
+	unsigned long irqflags;
+	LIST_HEAD(descs);
+	unsigned int i;
+	int rc = 0;
+
+	if (mchan->allocated)
+		return 0;
+
+	/* Alloc descriptors for this channel */
+	for (i = 0; i < dmadev->nr_descriptors; i++) {
+		mdesc = kzalloc(sizeof(struct hidma_desc), GFP_NOWAIT);
+		if (!mdesc) {
+			rc = -ENOMEM;
+			break;
+		}
+		dma_async_tx_descriptor_init(&mdesc->desc, dmach);
+		mdesc->desc.tx_submit = hidma_tx_submit;
+
+		rc = hidma_ll_request(dmadev->lldev, mchan->dma_sig,
+				      "DMA engine", hidma_callback, mdesc,
+				      &mdesc->tre_ch);
+		if (rc) {
+			dev_err(dmach->device->dev,
+				"channel alloc failed at %u\n", i);
+			kfree(mdesc);
+			break;
+		}
+		list_add_tail(&mdesc->node, &descs);
+	}
+
+	if (rc) {
+		/* return the allocated descriptors */
+		list_for_each_entry_safe(mdesc, tmp, &descs, node) {
+			hidma_ll_free(dmadev->lldev, mdesc->tre_ch);
+			kfree(mdesc);
+		}
+		return rc;
+	}
+
+	spin_lock_irqsave(&mchan->lock, irqflags);
+	list_splice_tail_init(&descs, &mchan->free);
+	mchan->allocated = true;
+	spin_unlock_irqrestore(&mchan->lock, irqflags);
+	return 1;
+}
+
+static struct dma_async_tx_descriptor *
+hidma_prep_dma_memcpy(struct dma_chan *dmach, dma_addr_t dest, dma_addr_t src,
+		size_t len, unsigned long flags)
+{
+	struct hidma_chan *mchan = to_hidma_chan(dmach);
+	struct hidma_desc *mdesc = NULL;
+	struct hidma_dev *mdma = mchan->dmadev;
+	unsigned long irqflags;
+
+	/* Get free descriptor */
+	spin_lock_irqsave(&mchan->lock, irqflags);
+	if (!list_empty(&mchan->free)) {
+		mdesc = list_first_entry(&mchan->free, struct hidma_desc, node);
+		list_del(&mdesc->node);
+	}
+	spin_unlock_irqrestore(&mchan->lock, irqflags);
+
+	if (!mdesc)
+		return NULL;
+
+	hidma_ll_set_transfer_params(mdma->lldev, mdesc->tre_ch,
+				     src, dest, len, flags);
+
+	/* Place descriptor in prepared list */
+	spin_lock_irqsave(&mchan->lock, irqflags);
+	list_add_tail(&mdesc->node, &mchan->prepared);
+	spin_unlock_irqrestore(&mchan->lock, irqflags);
+
+	return &mdesc->desc;
+}
+
+static int hidma_terminate_channel(struct dma_chan *chan)
+{
+	struct hidma_chan *mchan = to_hidma_chan(chan);
+	struct hidma_dev *dmadev = to_hidma_dev(mchan->chan.device);
+	struct hidma_desc *tmp, *mdesc;
+	unsigned long irqflags;
+	LIST_HEAD(list);
+	int rc;
+
+	pm_runtime_get_sync(dmadev->ddev.dev);
+	/* give completed requests a chance to finish */
+	hidma_process_completed(mchan);
+
+	spin_lock_irqsave(&mchan->lock, irqflags);
+	list_splice_init(&mchan->active, &list);
+	list_splice_init(&mchan->prepared, &list);
+	list_splice_init(&mchan->completed, &list);
+	spin_unlock_irqrestore(&mchan->lock, irqflags);
+
+	/* this suspends the existing transfer */
+	rc = hidma_ll_pause(dmadev->lldev);
+	if (rc) {
+		dev_err(dmadev->ddev.dev, "channel did not pause\n");
+		goto out;
+	}
+
+	/* return all user requests */
+	list_for_each_entry_safe(mdesc, tmp, &list, node) {
+		struct dma_async_tx_descriptor *txd = &mdesc->desc;
+		dma_async_tx_callback callback = mdesc->desc.callback;
+		void *param = mdesc->desc.callback_param;
+
+		dma_descriptor_unmap(txd);
+
+		if (callback)
+			callback(param);
+
+		dma_run_dependencies(txd);
+
+		/* move myself to free_list */
+		list_move(&mdesc->node, &mchan->free);
+	}
+
+	rc = hidma_ll_resume(dmadev->lldev);
+out:
+	pm_runtime_mark_last_busy(dmadev->ddev.dev);
+	pm_runtime_put_autosuspend(dmadev->ddev.dev);
+	return rc;
+}
+
+static int hidma_terminate_all(struct dma_chan *chan)
+{
+	struct hidma_chan *mchan = to_hidma_chan(chan);
+	struct hidma_dev *dmadev = to_hidma_dev(mchan->chan.device);
+	int rc;
+
+	rc = hidma_terminate_channel(chan);
+	if (rc)
+		return rc;
+
+	/* reinitialize the hardware */
+	pm_runtime_get_sync(dmadev->ddev.dev);
+	rc = hidma_ll_setup(dmadev->lldev);
+	pm_runtime_mark_last_busy(dmadev->ddev.dev);
+	pm_runtime_put_autosuspend(dmadev->ddev.dev);
+	return rc;
+}
+
+static void hidma_free_chan_resources(struct dma_chan *dmach)
+{
+	struct hidma_chan *mchan = to_hidma_chan(dmach);
+	struct hidma_dev *mdma = mchan->dmadev;
+	struct hidma_desc *mdesc, *tmp;
+	unsigned long irqflags;
+	LIST_HEAD(descs);
+
+	/* terminate running transactions and free descriptors */
+	hidma_terminate_channel(dmach);
+
+	spin_lock_irqsave(&mchan->lock, irqflags);
+
+	/* Move data */
+	list_splice_tail_init(&mchan->free, &descs);
+
+	/* Free descriptors */
+	list_for_each_entry_safe(mdesc, tmp, &descs, node) {
+		hidma_ll_free(mdma->lldev, mdesc->tre_ch);
+		list_del(&mdesc->node);
+		kfree(mdesc);
+	}
+
+	mchan->allocated = 0;
+	spin_unlock_irqrestore(&mchan->lock, irqflags);
+}
+
+static int hidma_pause(struct dma_chan *chan)
+{
+	struct hidma_chan *mchan;
+	struct hidma_dev *dmadev;
+
+	mchan = to_hidma_chan(chan);
+	dmadev = to_hidma_dev(mchan->chan.device);
+	if (!mchan->paused) {
+		pm_runtime_get_sync(dmadev->ddev.dev);
+		if (hidma_ll_pause(dmadev->lldev))
+			dev_warn(dmadev->ddev.dev, "channel did not stop\n");
+		mchan->paused = true;
+		pm_runtime_mark_last_busy(dmadev->ddev.dev);
+		pm_runtime_put_autosuspend(dmadev->ddev.dev);
+	}
+	return 0;
+}
+
+static int hidma_resume(struct dma_chan *chan)
+{
+	struct hidma_chan *mchan;
+	struct hidma_dev *dmadev;
+	int rc = 0;
+
+	mchan = to_hidma_chan(chan);
+	dmadev = to_hidma_dev(mchan->chan.device);
+	if (mchan->paused) {
+		pm_runtime_get_sync(dmadev->ddev.dev);
+		rc = hidma_ll_resume(dmadev->lldev);
+		if (!rc)
+			mchan->paused = false;
+		else
+			dev_err(dmadev->ddev.dev,
+				"failed to resume the channel");
+		pm_runtime_mark_last_busy(dmadev->ddev.dev);
+		pm_runtime_put_autosuspend(dmadev->ddev.dev);
+	}
+	return rc;
+}
+
+static irqreturn_t hidma_chirq_handler(int chirq, void *arg)
+{
+	struct hidma_lldev *lldev = arg;
+
+	/*
+	 * All interrupts are request driven.
+	 * HW doesn't send an interrupt by itself.
+	 */
+	return hidma_ll_inthandler(chirq, lldev);
+}
+
+static int hidma_probe(struct platform_device *pdev)
+{
+	struct hidma_dev *dmadev;
+	struct resource *trca_resource;
+	struct resource *evca_resource;
+	int chirq;
+	void __iomem *evca;
+	void __iomem *trca;
+	int rc;
+
+	pm_runtime_set_autosuspend_delay(&pdev->dev, HIDMA_AUTOSUSPEND_TIMEOUT);
+	pm_runtime_use_autosuspend(&pdev->dev);
+	pm_runtime_set_active(&pdev->dev);
+	pm_runtime_enable(&pdev->dev);
+
+	trca_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	trca = devm_ioremap_resource(&pdev->dev, trca_resource);
+	if (IS_ERR(trca)) {
+		rc = -ENOMEM;
+		goto bailout;
+	}
+
+	evca_resource = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	evca = devm_ioremap_resource(&pdev->dev, evca_resource);
+	if (IS_ERR(evca)) {
+		rc = -ENOMEM;
+		goto bailout;
+	}
+
+	/*
+	 * This driver only handles the channel IRQs.
+	 * Common IRQ is handled by the management driver.
+	 */
+	chirq = platform_get_irq(pdev, 0);
+	if (chirq < 0) {
+		rc = -ENODEV;
+		goto bailout;
+	}
+
+	dmadev = devm_kzalloc(&pdev->dev, sizeof(*dmadev), GFP_KERNEL);
+	if (!dmadev) {
+		rc = -ENOMEM;
+		goto bailout;
+	}
+
+	INIT_LIST_HEAD(&dmadev->ddev.channels);
+	spin_lock_init(&dmadev->lock);
+	dmadev->ddev.dev = &pdev->dev;
+	pm_runtime_get_sync(dmadev->ddev.dev);
+
+	dma_cap_set(DMA_MEMCPY, dmadev->ddev.cap_mask);
+	if (WARN_ON(!pdev->dev.dma_mask)) {
+		rc = -ENXIO;
+		goto dmafree;
+	}
+
+	dmadev->dev_evca = evca;
+	dmadev->evca_resource = evca_resource;
+	dmadev->dev_trca = trca;
+	dmadev->trca_resource = trca_resource;
+	dmadev->ddev.device_prep_dma_memcpy = hidma_prep_dma_memcpy;
+	dmadev->ddev.device_alloc_chan_resources = hidma_alloc_chan_resources;
+	dmadev->ddev.device_free_chan_resources = hidma_free_chan_resources;
+	dmadev->ddev.device_tx_status = hidma_tx_status;
+	dmadev->ddev.device_issue_pending = hidma_issue_pending;
+	dmadev->ddev.device_pause = hidma_pause;
+	dmadev->ddev.device_resume = hidma_resume;
+	dmadev->ddev.device_terminate_all = hidma_terminate_all;
+	dmadev->ddev.copy_align = 8;
+
+	device_property_read_u32(&pdev->dev, "desc-count",
+				 &dmadev->nr_descriptors);
+
+	if (!dmadev->nr_descriptors && nr_desc_prm)
+		dmadev->nr_descriptors = nr_desc_prm;
+
+	if (!dmadev->nr_descriptors)
+		dmadev->nr_descriptors = HIDMA_NR_DEFAULT_DESC;
+
+	dmadev->chidx = readl(dmadev->dev_trca + 0x28);
+
+	/* Set DMA mask to 64 bits. */
+	rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
+	if (rc) {
+		dev_warn(&pdev->dev, "unable to set coherent mask to 64");
+		rc = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
+		if (rc)
+			goto dmafree;
+	}
+
+	dmadev->lldev = hidma_ll_init(dmadev->ddev.dev,
+				      dmadev->nr_descriptors, dmadev->dev_trca,
+				      dmadev->dev_evca, dmadev->chidx);
+	if (!dmadev->lldev) {
+		rc = -EPROBE_DEFER;
+		goto dmafree;
+	}
+
+	rc = devm_request_irq(&pdev->dev, chirq, hidma_chirq_handler, 0,
+			      "qcom-hidma", dmadev->lldev);
+	if (rc)
+		goto uninit;
+
+	INIT_LIST_HEAD(&dmadev->ddev.channels);
+	rc = hidma_chan_init(dmadev, 0);
+	if (rc)
+		goto uninit;
+
+	rc = dma_async_device_register(&dmadev->ddev);
+	if (rc)
+		goto uninit;
+
+	dmadev->irq = chirq;
+	tasklet_init(&dmadev->task, hidma_issue_task, (unsigned long)dmadev);
+	dev_info(&pdev->dev, "HI-DMA engine driver registration complete\n");
+	platform_set_drvdata(pdev, dmadev);
+	pm_runtime_mark_last_busy(dmadev->ddev.dev);
+	pm_runtime_put_autosuspend(dmadev->ddev.dev);
+	return 0;
+
+uninit:
+	hidma_ll_uninit(dmadev->lldev);
+dmafree:
+	if (dmadev)
+		hidma_free(dmadev);
+bailout:
+	pm_runtime_put_sync(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+	return rc;
+}
+
+static int hidma_remove(struct platform_device *pdev)
+{
+	struct hidma_dev *dmadev = platform_get_drvdata(pdev);
+
+	pm_runtime_get_sync(dmadev->ddev.dev);
+	dma_async_device_unregister(&dmadev->ddev);
+	devm_free_irq(dmadev->ddev.dev, dmadev->irq, dmadev->lldev);
+	hidma_ll_uninit(dmadev->lldev);
+	hidma_free(dmadev);
+
+	dev_info(&pdev->dev, "HI-DMA engine removed\n");
+	pm_runtime_put_sync_suspend(&pdev->dev);
+	pm_runtime_disable(&pdev->dev);
+
+	return 0;
+}
+
+#if IS_ENABLED(CONFIG_ACPI)
+static const struct acpi_device_id hidma_acpi_ids[] = {
+	{"QCOM8061"},
+	{},
+};
+#endif
+
+static const struct of_device_id hidma_match[] = {
+	{.compatible = "qcom,hidma-1.0",},
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, hidma_match);
+
+static struct platform_driver hidma_driver = {
+	.probe = hidma_probe,
+	.remove = hidma_remove,
+	.driver = {
+		   .name = "hidma",
+		   .of_match_table = hidma_match,
+		   .acpi_match_table = ACPI_PTR(hidma_acpi_ids),
+	},
+};
+
+module_platform_driver(hidma_driver);
+MODULE_LICENSE("GPL v2");

drivers/dma/qcom/hidma.h

+/*
+ * Qualcomm Technologies HIDMA data structures
+ *
+ * Copyright (c) 2014, The Linux Foundation. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef QCOM_HIDMA_H
+#define QCOM_HIDMA_H
+
+#include <linux/kfifo.h>
+#include <linux/interrupt.h>
+#include <linux/dmaengine.h>
+
+#define TRE_SIZE			32 /* each TRE is 32 bytes  */
+#define TRE_CFG_IDX			0
+#define TRE_LEN_IDX			1
+#define TRE_SRC_LOW_IDX		2
+#define TRE_SRC_HI_IDX			3
+#define TRE_DEST_LOW_IDX		4
+#define TRE_DEST_HI_IDX		5
+
+struct hidma_tx_status {
+	u8 err_info;			/* error record in this transfer    */
+	u8 err_code;			/* completion code		    */
+};
+
+struct hidma_tre {
+	atomic_t allocated;		/* if this channel is allocated	    */
+	bool queued;			/* flag whether this is pending     */
+	u16 status;			/* status			    */
+	u32 chidx;			/* index of the tre		    */
+	u32 dma_sig;			/* signature of the tre		    */
+	const char *dev_name;		/* name of the device		    */
+	void (*callback)(void *data);	/* requester callback		    */
+	void *data;			/* Data associated with this channel*/
+	struct hidma_lldev *lldev;	/* lldma device pointer		    */
+	u32 tre_local[TRE_SIZE / sizeof(u32) + 1]; /* TRE local copy        */
+	u32 tre_index;			/* the offset where this was written*/
+	u32 int_flags;			/* interrupt flags		    */
+};
+
+struct hidma_lldev {
+	bool initialized;		/* initialized flag               */
+	u8 trch_state;			/* trch_state of the device	  */
+	u8 evch_state;			/* evch_state of the device	  */
+	u8 chidx;			/* channel index in the core	  */
+	u32 nr_tres;			/* max number of configs          */
+	spinlock_t lock;		/* reentrancy                     */
+	struct hidma_tre *trepool;	/* trepool of user configs */
+	struct device *dev;		/* device			  */
+	void __iomem *trca;		/* Transfer Channel address       */
+	void __iomem *evca;		/* Event Channel address          */
+	struct hidma_tre
+		**pending_tre_list;	/* Pointers to pending TREs	  */
+	struct hidma_tx_status
+		*tx_status_list;	/* Pointers to pending TREs status*/
+	s32 pending_tre_count;		/* Number of TREs pending	  */
+
+	void *tre_ring;			/* TRE ring			  */
+	dma_addr_t tre_ring_handle;	/* TRE ring to be shared with HW  */
+	u32 tre_ring_size;		/* Byte size of the ring	  */
+	u32 tre_processed_off;		/* last processed TRE		  */
+
+	void *evre_ring;		/* EVRE ring			   */
+	dma_addr_t evre_ring_handle;	/* EVRE ring to be shared with HW  */
+	u32 evre_ring_size;		/* Byte size of the ring	   */
+	u32 evre_processed_off;		/* last processed EVRE		   */
+
+	u32 tre_write_offset;           /* TRE write location              */
+	struct tasklet_struct task;	/* task delivering notifications   */
+	DECLARE_KFIFO_PTR(handoff_fifo,
+		struct hidma_tre *);    /* pending TREs FIFO               */
+};
+
+struct hidma_desc {
+	struct dma_async_tx_descriptor	desc;
+	/* link list node for this channel*/
+	struct list_head		node;
+	u32				tre_ch;
+};
+
+struct hidma_chan {
+	bool				paused;
+	bool				allocated;
+	char				dbg_name[16];
+	u32				dma_sig;
+
+	/*
+	 * active descriptor on this channel
+	 * It is used by the DMA complete notification to
+	 * locate the descriptor that initiated the transfer.
+	 */
+	struct dentry			*debugfs;
+	struct dentry			*stats;
+	struct hidma_dev		*dmadev;
+	struct hidma_desc		*running;
+
+	struct dma_chan			chan;
+	struct list_head		free;
+	struct list_head		prepared;
+	struct list_head		active;
+	struct list_head		completed;
+
+	/* Lock for this structure */
+	spinlock_t			lock;
+};
+
+struct hidma_dev {
+	int				irq;
+	int				chidx;
+	u32				nr_descriptors;
+
+	struct hidma_lldev		*lldev;
+	void				__iomem *dev_trca;
+	struct resource			*trca_resource;
+	void				__iomem *dev_evca;
+	struct resource			*evca_resource;
+
+	/* used to protect the pending channel list*/
+	spinlock_t			lock;
+	struct dma_device		ddev;
+
+	struct dentry			*debugfs;
+	struct dentry			*stats;
+
+	/* Task delivering issue_pending */
+	struct tasklet_struct		task;
+};
+
+int hidma_ll_request(struct hidma_lldev *llhndl, u32 dev_id,
+			const char *dev_name,
+			void (*callback)(void *data), void *data, u32 *tre_ch);
+
+void hidma_ll_free(struct hidma_lldev *llhndl, u32 tre_ch);
+enum dma_status hidma_ll_status(struct hidma_lldev *llhndl, u32 tre_ch);
+bool hidma_ll_isenabled(struct hidma_lldev *llhndl);
+void hidma_ll_queue_request(struct hidma_lldev *llhndl, u32 tre_ch);
+void hidma_ll_start(struct hidma_lldev *llhndl);
+int hidma_ll_pause(struct hidma_lldev *llhndl);
+int hidma_ll_resume(struct hidma_lldev *llhndl);
+void hidma_ll_set_transfer_params(struct hidma_lldev *llhndl, u32 tre_ch,
+	dma_addr_t src, dma_addr_t dest, u32 len, u32 flags);
+int hidma_ll_setup(struct hidma_lldev *lldev);
+struct hidma_lldev *hidma_ll_init(struct device *dev, u32 max_channels,
+			void __iomem *trca, void __iomem *evca,
+			u8 chidx);
+int hidma_ll_uninit(struct hidma_lldev *llhndl);
+irqreturn_t hidma_ll_inthandler(int irq, void *arg);
+void hidma_cleanup_pending_tre(struct hidma_lldev *llhndl, u8 err_info,
+				u8 err_code);
+#endif