diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
new file mode 100644
index 0000000..1b1a794
--- /dev/null
+++ b/drivers/misc/fastrpc.c
@@ -0,0 +1,1561 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (c) 2011-2018, The Linux Foundation. All rights reserved.
+// Copyright (c) 2018, Linaro Limited
+
+#include <linux/completion.h>
+#include <linux/device.h>
+#include <linux/dma-buf.h>
+#include <linux/dma-mapping.h>
+#include <linux/idr.h>
+#include <linux/list.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/of_address.h>
+#include <linux/of.h>
+#include <linux/sort.h>
+#include <linux/of_platform.h>
+#include <linux/rpmsg.h>
+#include <linux/scatterlist.h>
+#include <linux/slab.h>
+#include <uapi/misc/fastrpc.h>
+
+#define ADSP_DOMAIN_ID (0)
+#define MDSP_DOMAIN_ID (1)
+#define SDSP_DOMAIN_ID (2)
+#define CDSP_DOMAIN_ID (3)
+#define FASTRPC_DEV_MAX		4 /* adsp, mdsp, slpi, cdsp*/
+#define FASTRPC_MAX_SESSIONS	9 /*8 compute, 1 cpz*/
+#define FASTRPC_ALIGN		128
+#define FASTRPC_MAX_FDLIST	16
+#define FASTRPC_MAX_CRCLIST	64
+#define FASTRPC_PHYS(p)	((p) & 0xffffffff)
+#define FASTRPC_CTX_MAX (256)
+#define FASTRPC_INIT_HANDLE	1
+#define FASTRPC_CTXID_MASK (0xFF0)
+#define INIT_FILELEN_MAX (64 * 1024 * 1024)
+#define FASTRPC_DEVICE_NAME	"fastrpc"
+
+/* Retrives number of input buffers from the scalars parameter */
+#define REMOTE_SCALARS_INBUFS(sc)	(((sc) >> 16) & 0x0ff)
+
+/* Retrives number of output buffers from the scalars parameter */
+#define REMOTE_SCALARS_OUTBUFS(sc)	(((sc) >> 8) & 0x0ff)
+
+/* Retrives number of input handles from the scalars parameter */
+#define REMOTE_SCALARS_INHANDLES(sc)	(((sc) >> 4) & 0x0f)
+
+/* Retrives number of output handles from the scalars parameter */
+#define REMOTE_SCALARS_OUTHANDLES(sc)	((sc) & 0x0f)
+
+#define REMOTE_SCALARS_LENGTH(sc)	(REMOTE_SCALARS_INBUFS(sc) +   \
+					 REMOTE_SCALARS_OUTBUFS(sc) +  \
+					 REMOTE_SCALARS_INHANDLES(sc)+ \
+					 REMOTE_SCALARS_OUTHANDLES(sc))
+#define FASTRPC_BUILD_SCALARS(attr, method, in, out, oin, oout)  \
+				(((attr & 0x07) << 29) |		\
+				((method & 0x1f) << 24) |	\
+				((in & 0xff) << 16) |		\
+				((out & 0xff) <<  8) |		\
+				((oin & 0x0f) <<  4) |		\
+				(oout & 0x0f))
+
+#define FASTRPC_SCALARS(method, in, out) \
+		FASTRPC_BUILD_SCALARS(0, method, in, out, 0, 0)
+
+#define FASTRPC_CREATE_PROCESS_NARGS	6
+/* Remote Method id table */
+#define FASTRPC_RMID_INIT_ATTACH	0
+#define FASTRPC_RMID_INIT_RELEASE	1
+#define FASTRPC_RMID_INIT_CREATE	6
+#define FASTRPC_RMID_INIT_CREATE_ATTR	7
+#define FASTRPC_RMID_INIT_CREATE_STATIC	8
+
+#define miscdev_to_cctx(d) container_of(d, struct fastrpc_channel_ctx, miscdev)
+
+static const char *domains[FASTRPC_DEV_MAX] = { "adsp", "mdsp",
+						"sdsp", "cdsp"};
+struct fastrpc_phy_page {
+	u64 addr;		/* physical address */
+	u64 size;		/* size of contiguous region */
+};
+
+struct fastrpc_invoke_buf {
+	u32 num;		/* number of contiguous regions */
+	u32 pgidx;		/* index to start of contiguous region */
+};
+
+struct fastrpc_remote_arg {
+	u64 pv;
+	u64 len;
+};
+
+struct fastrpc_msg {
+	int pid;		/* process group id */
+	int tid;		/* thread id */
+	u64 ctx;		/* invoke caller context */
+	u32 handle;	/* handle to invoke */
+	u32 sc;		/* scalars structure describing the data */
+	u64 addr;		/* physical address */
+	u64 size;		/* size of contiguous region */
+};
+
+struct fastrpc_invoke_rsp {
+	u64 ctx;		/* invoke caller context */
+	int retval;		/* invoke return value */
+};
+
+struct fastrpc_buf_overlap {
+	u64 start;
+	u64 end;
+	int raix;
+	u64 mstart;
+	u64 mend;
+	u64 offset;
+};
+
+struct fastrpc_buf {
+	struct fastrpc_user *fl;
+	struct dma_buf *dmabuf;
+	struct device *dev;
+	void *virt;
+	u64 phys;
+	u64 size;
+	/* Lock for dma buf attachments */
+	struct mutex lock;
+	struct list_head attachments;
+};
+
+struct fastrpc_dma_buf_attachment {
+	struct device *dev;
+	struct sg_table sgt;
+	struct list_head node;
+};
+
+struct fastrpc_map {
+	struct list_head node;
+	struct fastrpc_user *fl;
+	int fd;
+	struct dma_buf *buf;
+	struct sg_table *table;
+	struct dma_buf_attachment *attach;
+	u64 phys;
+	u64 size;
+	void *va;
+	u64 len;
+	struct kref refcount;
+};
+
+struct fastrpc_invoke_ctx {
+	int nscalars;
+	int nbufs;
+	int retval;
+	int pid;
+	int tgid;
+	u32 sc;
+	u32 *crc;
+	u64 ctxid;
+	u64 msg_sz;
+	struct kref refcount;
+	struct list_head node; /* list of ctxs */
+	struct completion work;
+	struct work_struct put_work;
+	struct fastrpc_msg msg;
+	struct fastrpc_user *fl;
+	struct fastrpc_remote_arg *rpra;
+	struct fastrpc_map **maps;
+	struct fastrpc_buf *buf;
+	struct fastrpc_invoke_args *args;
+	struct fastrpc_buf_overlap *olaps;
+	struct fastrpc_channel_ctx *cctx;
+};
+
+struct fastrpc_session_ctx {
+	struct device *dev;
+	int sid;
+	bool used;
+	bool valid;
+};
+
+struct fastrpc_channel_ctx {
+	int domain_id;
+	int sesscount;
+	struct rpmsg_device *rpdev;
+	struct fastrpc_session_ctx session[FASTRPC_MAX_SESSIONS];
+	spinlock_t lock;
+	struct idr ctx_idr;
+	struct list_head users;
+	struct miscdevice miscdev;
+	struct kref refcount;
+};
+
+struct fastrpc_user {
+	struct list_head user;
+	struct list_head maps;
+	struct list_head pending;
+
+	struct fastrpc_channel_ctx *cctx;
+	struct fastrpc_session_ctx *sctx;
+	struct fastrpc_buf *init_mem;
+
+	int tgid;
+	int pd;
+	/* Lock for lists */
+	spinlock_t lock;
+	/* lock for allocations */
+	struct mutex mutex;
+};
+
+static void fastrpc_free_map(struct kref *ref)
+{
+	struct fastrpc_map *map;
+
+	map = container_of(ref, struct fastrpc_map, refcount);
+
+	if (map->table) {
+		dma_buf_unmap_attachment(map->attach, map->table,
+					 DMA_BIDIRECTIONAL);
+		dma_buf_detach(map->buf, map->attach);
+		dma_buf_put(map->buf);
+	}
+
+	kfree(map);
+}
+
+static void fastrpc_map_put(struct fastrpc_map *map)
+{
+	if (map)
+		kref_put(&map->refcount, fastrpc_free_map);
+}
+
+static void fastrpc_map_get(struct fastrpc_map *map)
+{
+	if (map)
+		kref_get(&map->refcount);
+}
+
+static int fastrpc_map_find(struct fastrpc_user *fl, int fd,
+			    struct fastrpc_map **ppmap)
+{
+	struct fastrpc_map *map = NULL;
+
+	mutex_lock(&fl->mutex);
+	list_for_each_entry(map, &fl->maps, node) {
+		if (map->fd == fd) {
+			fastrpc_map_get(map);
+			*ppmap = map;
+			mutex_unlock(&fl->mutex);
+			return 0;
+		}
+	}
+	mutex_unlock(&fl->mutex);
+
+	return -ENOENT;
+}
+
+static void fastrpc_buf_free(struct fastrpc_buf *buf)
+{
+	dma_free_coherent(buf->dev, buf->size, buf->virt,
+			  FASTRPC_PHYS(buf->phys));
+	kfree(buf);
+}
+
+static int fastrpc_buf_alloc(struct fastrpc_user *fl, struct device *dev,
+			     u64 size, struct fastrpc_buf **obuf)
+{
+	struct fastrpc_buf *buf;
+
+	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&buf->attachments);
+	mutex_init(&buf->lock);
+
+	buf->fl = fl;
+	buf->virt = NULL;
+	buf->phys = 0;
+	buf->size = size;
+	buf->dev = dev;
+
+	buf->virt = dma_alloc_coherent(dev, buf->size, (dma_addr_t *)&buf->phys,
+				       GFP_KERNEL);
+	if (!buf->virt) {
+		mutex_destroy(&buf->lock);
+		kfree(buf);
+		return -ENOMEM;
+	}
+
+	if (fl->sctx && fl->sctx->sid)
+		buf->phys += ((u64)fl->sctx->sid << 32);
+
+	*obuf = buf;
+
+	return 0;
+}
+
+static void fastrpc_channel_ctx_free(struct kref *ref)
+{
+	struct fastrpc_channel_ctx *cctx;
+
+	cctx = container_of(ref, struct fastrpc_channel_ctx, refcount);
+
+	kfree(cctx);
+}
+
+static void fastrpc_channel_ctx_get(struct fastrpc_channel_ctx *cctx)
+{
+	kref_get(&cctx->refcount);
+}
+
+static void fastrpc_channel_ctx_put(struct fastrpc_channel_ctx *cctx)
+{
+	kref_put(&cctx->refcount, fastrpc_channel_ctx_free);
+}
+
+static void fastrpc_context_free(struct kref *ref)
+{
+	struct fastrpc_invoke_ctx *ctx;
+	struct fastrpc_channel_ctx *cctx;
+	unsigned long flags;
+	int i;
+
+	ctx = container_of(ref, struct fastrpc_invoke_ctx, refcount);
+	cctx = ctx->cctx;
+
+	for (i = 0; i < ctx->nscalars; i++)
+		fastrpc_map_put(ctx->maps[i]);
+
+	if (ctx->buf)
+		fastrpc_buf_free(ctx->buf);
+
+	spin_lock_irqsave(&cctx->lock, flags);
+	idr_remove(&cctx->ctx_idr, ctx->ctxid >> 4);
+	spin_unlock_irqrestore(&cctx->lock, flags);
+
+	kfree(ctx->maps);
+	kfree(ctx->olaps);
+	kfree(ctx);
+
+	fastrpc_channel_ctx_put(cctx);
+}
+
+static void fastrpc_context_get(struct fastrpc_invoke_ctx *ctx)
+{
+	kref_get(&ctx->refcount);
+}
+
+static void fastrpc_context_put(struct fastrpc_invoke_ctx *ctx)
+{
+	kref_put(&ctx->refcount, fastrpc_context_free);
+}
+
+static void fastrpc_context_put_wq(struct work_struct *work)
+{
+	struct fastrpc_invoke_ctx *ctx =
+			container_of(work, struct fastrpc_invoke_ctx, put_work);
+
+	fastrpc_context_put(ctx);
+}
+
+#define CMP(aa, bb) ((aa) == (bb) ? 0 : (aa) < (bb) ? -1 : 1)
+static int olaps_cmp(const void *a, const void *b)
+{
+	struct fastrpc_buf_overlap *pa = (struct fastrpc_buf_overlap *)a;
+	struct fastrpc_buf_overlap *pb = (struct fastrpc_buf_overlap *)b;
+	/* sort with lowest starting buffer first */
+	int st = CMP(pa->start, pb->start);
+	/* sort with highest ending buffer first */
+	int ed = CMP(pb->end, pa->end);
+
+	return st == 0 ? ed : st;
+}
+
+static void fastrpc_get_buff_overlaps(struct fastrpc_invoke_ctx *ctx)
+{
+	u64 max_end = 0;
+	int i;
+
+	for (i = 0; i < ctx->nbufs; ++i) {
+		ctx->olaps[i].start = ctx->args[i].ptr;
+		ctx->olaps[i].end = ctx->olaps[i].start + ctx->args[i].length;
+		ctx->olaps[i].raix = i;
+	}
+
+	sort(ctx->olaps, ctx->nbufs, sizeof(*ctx->olaps), olaps_cmp, NULL);
+
+	for (i = 0; i < ctx->nbufs; ++i) {
+		/* Falling inside previous range */
+		if (ctx->olaps[i].start < max_end) {
+			ctx->olaps[i].mstart = max_end;
+			ctx->olaps[i].mend = ctx->olaps[i].end;
+			ctx->olaps[i].offset = max_end - ctx->olaps[i].start;
+
+			if (ctx->olaps[i].end > max_end) {
+				max_end = ctx->olaps[i].end;
+			} else {
+				ctx->olaps[i].mend = 0;
+				ctx->olaps[i].mstart = 0;
+			}
+
+		} else  {
+			ctx->olaps[i].mend = ctx->olaps[i].end;
+			ctx->olaps[i].mstart = ctx->olaps[i].start;
+			ctx->olaps[i].offset = 0;
+			max_end = ctx->olaps[i].end;
+		}
+	}
+}
+
+static struct fastrpc_invoke_ctx *fastrpc_context_alloc(
+			struct fastrpc_user *user, u32 kernel, u32 sc,
+			struct fastrpc_invoke_args *args)
+{
+	struct fastrpc_channel_ctx *cctx = user->cctx;
+	struct fastrpc_invoke_ctx *ctx = NULL;
+	unsigned long flags;
+	int ret;
+
+	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
+	if (!ctx)
+		return ERR_PTR(-ENOMEM);
+
+	INIT_LIST_HEAD(&ctx->node);
+	ctx->fl = user;
+	ctx->nscalars = REMOTE_SCALARS_LENGTH(sc);
+	ctx->nbufs = REMOTE_SCALARS_INBUFS(sc) +
+		     REMOTE_SCALARS_OUTBUFS(sc);
+
+	if (ctx->nscalars) {
+		ctx->maps = kcalloc(ctx->nscalars,
+				    sizeof(*ctx->maps), GFP_KERNEL);
+		if (!ctx->maps) {
+			kfree(ctx);
+			return ERR_PTR(-ENOMEM);
+		}
+		ctx->olaps = kcalloc(ctx->nscalars,
+				    sizeof(*ctx->olaps), GFP_KERNEL);
+		if (!ctx->olaps) {
+			kfree(ctx->maps);
+			kfree(ctx);
+			return ERR_PTR(-ENOMEM);
+		}
+		ctx->args = args;
+		fastrpc_get_buff_overlaps(ctx);
+	}
+
+	/* Released in fastrpc_context_put() */
+	fastrpc_channel_ctx_get(cctx);
+
+	ctx->sc = sc;
+	ctx->retval = -1;
+	ctx->pid = current->pid;
+	ctx->tgid = user->tgid;
+	ctx->cctx = cctx;
+	init_completion(&ctx->work);
+	INIT_WORK(&ctx->put_work, fastrpc_context_put_wq);
+
+	spin_lock(&user->lock);
+	list_add_tail(&ctx->node, &user->pending);
+	spin_unlock(&user->lock);
+
+	spin_lock_irqsave(&cctx->lock, flags);
+	ret = idr_alloc_cyclic(&cctx->ctx_idr, ctx, 1,
+			       FASTRPC_CTX_MAX, GFP_ATOMIC);
+	if (ret < 0) {
+		spin_unlock_irqrestore(&cctx->lock, flags);
+		goto err_idr;
+	}
+	ctx->ctxid = ret << 4;
+	spin_unlock_irqrestore(&cctx->lock, flags);
+
+	kref_init(&ctx->refcount);
+
+	return ctx;
+err_idr:
+	spin_lock(&user->lock);
+	list_del(&ctx->node);
+	spin_unlock(&user->lock);
+	fastrpc_channel_ctx_put(cctx);
+	kfree(ctx->maps);
+	kfree(ctx->olaps);
+	kfree(ctx);
+
+	return ERR_PTR(ret);
+}
+
+static struct sg_table *
+fastrpc_map_dma_buf(struct dma_buf_attachment *attachment,
+		    enum dma_data_direction dir)
+{
+	struct fastrpc_dma_buf_attachment *a = attachment->priv;
+	struct sg_table *table;
+
+	table = &a->sgt;
+
+	if (!dma_map_sg(attachment->dev, table->sgl, table->nents, dir))
+		return ERR_PTR(-ENOMEM);
+
+	return table;
+}
+
+static void fastrpc_unmap_dma_buf(struct dma_buf_attachment *attach,
+				  struct sg_table *table,
+				  enum dma_data_direction dir)
+{
+	dma_unmap_sg(attach->dev, table->sgl, table->nents, dir);
+}
+
+static void fastrpc_release(struct dma_buf *dmabuf)
+{
+	struct fastrpc_buf *buffer = dmabuf->priv;
+
+	fastrpc_buf_free(buffer);
+}
+
+static int fastrpc_dma_buf_attach(struct dma_buf *dmabuf,
+				  struct dma_buf_attachment *attachment)
+{
+	struct fastrpc_dma_buf_attachment *a;
+	struct fastrpc_buf *buffer = dmabuf->priv;
+	int ret;
+
+	a = kzalloc(sizeof(*a), GFP_KERNEL);
+	if (!a)
+		return -ENOMEM;
+
+	ret = dma_get_sgtable(buffer->dev, &a->sgt, buffer->virt,
+			      FASTRPC_PHYS(buffer->phys), buffer->size);
+	if (ret < 0) {
+		dev_err(buffer->dev, "failed to get scatterlist from DMA API\n");
+		kfree(a);
+		return -EINVAL;
+	}
+
+	a->dev = attachment->dev;
+	INIT_LIST_HEAD(&a->node);
+	attachment->priv = a;
+
+	mutex_lock(&buffer->lock);
+	list_add(&a->node, &buffer->attachments);
+	mutex_unlock(&buffer->lock);
+
+	return 0;
+}
+
+static void fastrpc_dma_buf_detatch(struct dma_buf *dmabuf,
+				    struct dma_buf_attachment *attachment)
+{
+	struct fastrpc_dma_buf_attachment *a = attachment->priv;
+	struct fastrpc_buf *buffer = dmabuf->priv;
+
+	mutex_lock(&buffer->lock);
+	list_del(&a->node);
+	mutex_unlock(&buffer->lock);
+	sg_free_table(&a->sgt);
+	kfree(a);
+}
+
+static void *fastrpc_kmap(struct dma_buf *dmabuf, unsigned long pgnum)
+{
+	struct fastrpc_buf *buf = dmabuf->priv;
+
+	return buf->virt ? buf->virt + pgnum * PAGE_SIZE : NULL;
+}
+
+static void *fastrpc_vmap(struct dma_buf *dmabuf)
+{
+	struct fastrpc_buf *buf = dmabuf->priv;
+
+	return buf->virt;
+}
+
+static int fastrpc_mmap(struct dma_buf *dmabuf,
+			struct vm_area_struct *vma)
+{
+	struct fastrpc_buf *buf = dmabuf->priv;
+	size_t size = vma->vm_end - vma->vm_start;
+
+	return dma_mmap_coherent(buf->dev, vma, buf->virt,
+				 FASTRPC_PHYS(buf->phys), size);
+}
+
+static const struct dma_buf_ops fastrpc_dma_buf_ops = {
+	.attach = fastrpc_dma_buf_attach,
+	.detach = fastrpc_dma_buf_detatch,
+	.map_dma_buf = fastrpc_map_dma_buf,
+	.unmap_dma_buf = fastrpc_unmap_dma_buf,
+	.mmap = fastrpc_mmap,
+	.map = fastrpc_kmap,
+	.vmap = fastrpc_vmap,
+	.release = fastrpc_release,
+};
+
+static int fastrpc_map_create(struct fastrpc_user *fl, int fd,
+			      u64 len, struct fastrpc_map **ppmap)
+{
+	struct fastrpc_session_ctx *sess = fl->sctx;
+	struct fastrpc_map *map = NULL;
+	int err = 0;
+
+	if (!fastrpc_map_find(fl, fd, ppmap))
+		return 0;
+
+	map = kzalloc(sizeof(*map), GFP_KERNEL);
+	if (!map)
+		return -ENOMEM;
+
+	INIT_LIST_HEAD(&map->node);
+	map->fl = fl;
+	map->fd = fd;
+	map->buf = dma_buf_get(fd);
+	if (IS_ERR(map->buf)) {
+		err = PTR_ERR(map->buf);
+		goto get_err;
+	}
+
+	map->attach = dma_buf_attach(map->buf, sess->dev);
+	if (IS_ERR(map->attach)) {
+		dev_err(sess->dev, "Failed to attach dmabuf\n");
+		err = PTR_ERR(map->attach);
+		goto attach_err;
+	}
+
+	map->table = dma_buf_map_attachment(map->attach, DMA_BIDIRECTIONAL);
+	if (IS_ERR(map->table)) {
+		err = PTR_ERR(map->table);
+		goto map_err;
+	}
+
+	map->phys = sg_dma_address(map->table->sgl);
+	map->phys += ((u64)fl->sctx->sid << 32);
+	map->size = len;
+	map->va = sg_virt(map->table->sgl);
+	map->len = len;
+	kref_init(&map->refcount);
+
+	spin_lock(&fl->lock);
+	list_add_tail(&map->node, &fl->maps);
+	spin_unlock(&fl->lock);
+	*ppmap = map;
+
+	return 0;
+
+map_err:
+	dma_buf_detach(map->buf, map->attach);
+attach_err:
+	dma_buf_put(map->buf);
+get_err:
+	kfree(map);
+
+	return err;
+}
+
+/*
+ * Fastrpc payload buffer with metadata looks like:
+ *
+ * >>>>>>  START of METADATA <<<<<<<<<
+ * +---------------------------------+
+ * |           Arguments             |
+ * | type:(struct fastrpc_remote_arg)|
+ * |             (0 - N)             |
+ * +---------------------------------+
+ * |         Invoke Buffer list      |
+ * | type:(struct fastrpc_invoke_buf)|
+ * |           (0 - N)               |
+ * +---------------------------------+
+ * |         Page info list          |
+ * | type:(struct fastrpc_phy_page)  |
+ * |             (0 - N)             |
+ * +---------------------------------+
+ * |         Optional info           |
+ * |(can be specific to SoC/Firmware)|
+ * +---------------------------------+
+ * >>>>>>>>  END of METADATA <<<<<<<<<
+ * +---------------------------------+
+ * |         Inline ARGS             |
+ * |            (0-N)                |
+ * +---------------------------------+
+ */
+
+static int fastrpc_get_meta_size(struct fastrpc_invoke_ctx *ctx)
+{
+	int size = 0;
+
+	size = (sizeof(struct fastrpc_remote_arg) +
+		sizeof(struct fastrpc_invoke_buf) +
+		sizeof(struct fastrpc_phy_page)) * ctx->nscalars +
+		sizeof(u64) * FASTRPC_MAX_FDLIST +
+		sizeof(u32) * FASTRPC_MAX_CRCLIST;
+
+	return size;
+}
+
+static u64 fastrpc_get_payload_size(struct fastrpc_invoke_ctx *ctx, int metalen)
+{
+	u64 size = 0;
+	int i;
+
+	size = ALIGN(metalen, FASTRPC_ALIGN);
+	for (i = 0; i < ctx->nscalars; i++) {
+		if (ctx->args[i].fd == 0 || ctx->args[i].fd == -1) {
+
+			if (ctx->olaps[i].offset == 0)
+				size = ALIGN(size, FASTRPC_ALIGN);
+
+			size += (ctx->olaps[i].mend - ctx->olaps[i].mstart);
+		}
+	}
+
+	return size;
+}
+
+static int fastrpc_create_maps(struct fastrpc_invoke_ctx *ctx)
+{
+	struct device *dev = ctx->fl->sctx->dev;
+	int i, err;
+
+	for (i = 0; i < ctx->nscalars; ++i) {
+		/* Make sure reserved field is set to 0 */
+		if (ctx->args[i].reserved)
+			return -EINVAL;
+
+		if (ctx->args[i].fd == 0 || ctx->args[i].fd == -1 ||
+		    ctx->args[i].length == 0)
+			continue;
+
+		err = fastrpc_map_create(ctx->fl, ctx->args[i].fd,
+					 ctx->args[i].length, &ctx->maps[i]);
+		if (err) {
+			dev_err(dev, "Error Creating map %d\n", err);
+			return -EINVAL;
+		}
+
+	}
+	return 0;
+}
+
+static int fastrpc_get_args(u32 kernel, struct fastrpc_invoke_ctx *ctx)
+{
+	struct device *dev = ctx->fl->sctx->dev;
+	struct fastrpc_remote_arg *rpra;
+	struct fastrpc_invoke_buf *list;
+	struct fastrpc_phy_page *pages;
+	int inbufs, i, oix, err = 0;
+	u64 len, rlen, pkt_size;
+	u64 pg_start, pg_end;
+	uintptr_t args;
+	int metalen;
+
+	inbufs = REMOTE_SCALARS_INBUFS(ctx->sc);
+	metalen = fastrpc_get_meta_size(ctx);
+	pkt_size = fastrpc_get_payload_size(ctx, metalen);
+
+	err = fastrpc_create_maps(ctx);
+	if (err)
+		return err;
+
+	ctx->msg_sz = pkt_size;
+
+	err = fastrpc_buf_alloc(ctx->fl, dev, pkt_size, &ctx->buf);
+	if (err)
+		return err;
+
+	rpra = ctx->buf->virt;
+	list = ctx->buf->virt + ctx->nscalars * sizeof(*rpra);
+	pages = ctx->buf->virt + ctx->nscalars * (sizeof(*list) +
+		sizeof(*rpra));
+	args = (uintptr_t)ctx->buf->virt + metalen;
+	rlen = pkt_size - metalen;
+	ctx->rpra = rpra;
+
+	for (oix = 0; oix < ctx->nbufs; ++oix) {
+		int mlen;
+
+		i = ctx->olaps[oix].raix;
+		len = ctx->args[i].length;
+
+		rpra[i].pv = 0;
+		rpra[i].len = len;
+		list[i].num = len ? 1 : 0;
+		list[i].pgidx = i;
+
+		if (!len)
+			continue;
+
+		if (ctx->maps[i]) {
+			struct vm_area_struct *vma = NULL;
+
+			rpra[i].pv = (u64) ctx->args[i].ptr;
+			pages[i].addr = ctx->maps[i]->phys;
+
+			vma = find_vma(current->mm, ctx->args[i].ptr);
+			if (vma)
+				pages[i].addr += ctx->args[i].ptr -
+						 vma->vm_start;
+
+			pg_start = (ctx->args[i].ptr & PAGE_MASK) >> PAGE_SHIFT;
+			pg_end = ((ctx->args[i].ptr + len - 1) & PAGE_MASK) >>
+				  PAGE_SHIFT;
+			pages[i].size = (pg_end - pg_start + 1) * PAGE_SIZE;
+
+		} else {
+
+			if (ctx->olaps[oix].offset == 0) {
+				rlen -= ALIGN(args, FASTRPC_ALIGN) - args;
+				args = ALIGN(args, FASTRPC_ALIGN);
+			}
+
+			mlen = ctx->olaps[oix].mend - ctx->olaps[oix].mstart;
+
+			if (rlen < mlen)
+				goto bail;
+
+			rpra[i].pv = args - ctx->olaps[oix].offset;
+			pages[i].addr = ctx->buf->phys -
+					ctx->olaps[oix].offset +
+					(pkt_size - rlen);
+			pages[i].addr = pages[i].addr &	PAGE_MASK;
+
+			pg_start = (args & PAGE_MASK) >> PAGE_SHIFT;
+			pg_end = ((args + len - 1) & PAGE_MASK) >> PAGE_SHIFT;
+			pages[i].size = (pg_end - pg_start + 1) * PAGE_SIZE;
+			args = args + mlen;
+			rlen -= mlen;
+		}
+
+		if (i < inbufs && !ctx->maps[i]) {
+			void *dst = (void *)(uintptr_t)rpra[i].pv;
+			void *src = (void *)(uintptr_t)ctx->args[i].ptr;
+
+			if (!kernel) {
+				if (copy_from_user(dst, (void __user *)src,
+						   len)) {
+					err = -EFAULT;
+					goto bail;
+				}
+			} else {
+				memcpy(dst, src, len);
+			}
+		}
+	}
+
+	for (i = ctx->nbufs; i < ctx->nscalars; ++i) {
+		rpra[i].pv = (u64) ctx->args[i].ptr;
+		rpra[i].len = ctx->args[i].length;
+		list[i].num = ctx->args[i].length ? 1 : 0;
+		list[i].pgidx = i;
+		pages[i].addr = ctx->maps[i]->phys;
+		pages[i].size = ctx->maps[i]->size;
+	}
+
+bail:
+	if (err)
+		dev_err(dev, "Error: get invoke args failed:%d\n", err);
+
+	return err;
+}
+
+static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
+			    u32 kernel)
+{
+	struct fastrpc_remote_arg *rpra = ctx->rpra;
+	int i, inbufs;
+
+	inbufs = REMOTE_SCALARS_INBUFS(ctx->sc);
+
+	for (i = inbufs; i < ctx->nbufs; ++i) {
+		void *src = (void *)(uintptr_t)rpra[i].pv;
+		void *dst = (void *)(uintptr_t)ctx->args[i].ptr;
+		u64 len = rpra[i].len;
+
+		if (!kernel) {
+			if (copy_to_user((void __user *)dst, src, len))
+				return -EFAULT;
+		} else {
+			memcpy(dst, src, len);
+		}
+	}
+
+	return 0;
+}
+
+static int fastrpc_invoke_send(struct fastrpc_session_ctx *sctx,
+			       struct fastrpc_invoke_ctx *ctx,
+			       u32 kernel, uint32_t handle)
+{
+	struct fastrpc_channel_ctx *cctx;
+	struct fastrpc_user *fl = ctx->fl;
+	struct fastrpc_msg *msg = &ctx->msg;
+
+	cctx = fl->cctx;
+	msg->pid = fl->tgid;
+	msg->tid = current->pid;
+
+	if (kernel)
+		msg->pid = 0;
+
+	msg->ctx = ctx->ctxid | fl->pd;
+	msg->handle = handle;
+	msg->sc = ctx->sc;
+	msg->addr = ctx->buf ? ctx->buf->phys : 0;
+	msg->size = roundup(ctx->msg_sz, PAGE_SIZE);
+	fastrpc_context_get(ctx);
+
+	return rpmsg_send(cctx->rpdev->ept, (void *)msg, sizeof(*msg));
+}
+
+static int fastrpc_internal_invoke(struct fastrpc_user *fl,  u32 kernel,
+				   u32 handle, u32 sc,
+				   struct fastrpc_invoke_args *args)
+{
+	struct fastrpc_invoke_ctx *ctx = NULL;
+	int err = 0;
+
+	if (!fl->sctx)
+		return -EINVAL;
+
+	if (!fl->cctx->rpdev)
+		return -EPIPE;
+
+	ctx = fastrpc_context_alloc(fl, kernel, sc, args);
+	if (IS_ERR(ctx))
+		return PTR_ERR(ctx);
+
+	if (ctx->nscalars) {
+		err = fastrpc_get_args(kernel, ctx);
+		if (err)
+			goto bail;
+	}
+
+	/* make sure that all CPU memory writes are seen by DSP */
+	dma_wmb();
+	/* Send invoke buffer to remote dsp */
+	err = fastrpc_invoke_send(fl->sctx, ctx, kernel, handle);
+	if (err)
+		goto bail;
+
+	/* Wait for remote dsp to respond or time out */
+	err = wait_for_completion_interruptible(&ctx->work);
+	if (err)
+		goto bail;
+
+	/* Check the response from remote dsp */
+	err = ctx->retval;
+	if (err)
+		goto bail;
+
+	if (ctx->nscalars) {
+		/* make sure that all memory writes by DSP are seen by CPU */
+		dma_rmb();
+		/* populate all the output buffers with results */
+		err = fastrpc_put_args(ctx, kernel);
+		if (err)
+			goto bail;
+	}
+
+bail:
+	/* We are done with this compute context, remove it from pending list */
+	spin_lock(&fl->lock);
+	list_del(&ctx->node);
+	spin_unlock(&fl->lock);
+	fastrpc_context_put(ctx);
+
+	if (err)
+		dev_dbg(fl->sctx->dev, "Error: Invoke Failed %d\n", err);
+
+	return err;
+}
+
+static int fastrpc_init_create_process(struct fastrpc_user *fl,
+					char __user *argp)
+{
+	struct fastrpc_init_create init;
+	struct fastrpc_invoke_args *args;
+	struct fastrpc_phy_page pages[1];
+	struct fastrpc_map *map = NULL;
+	struct fastrpc_buf *imem = NULL;
+	int memlen;
+	int err;
+	struct {
+		int pgid;
+		u32 namelen;
+		u32 filelen;
+		u32 pageslen;
+		u32 attrs;
+		u32 siglen;
+	} inbuf;
+	u32 sc;
+
+	args = kcalloc(FASTRPC_CREATE_PROCESS_NARGS, sizeof(*args), GFP_KERNEL);
+	if (!args)
+		return -ENOMEM;
+
+	if (copy_from_user(&init, argp, sizeof(init))) {
+		err = -EFAULT;
+		goto err;
+	}
+
+	if (init.filelen > INIT_FILELEN_MAX) {
+		err = -EINVAL;
+		goto err;
+	}
+
+	inbuf.pgid = fl->tgid;
+	inbuf.namelen = strlen(current->comm) + 1;
+	inbuf.filelen = init.filelen;
+	inbuf.pageslen = 1;
+	inbuf.attrs = init.attrs;
+	inbuf.siglen = init.siglen;
+	fl->pd = 1;
+
+	if (init.filelen && init.filefd) {
+		err = fastrpc_map_create(fl, init.filefd, init.filelen, &map);
+		if (err)
+			goto err;
+	}
+
+	memlen = ALIGN(max(INIT_FILELEN_MAX, (int)init.filelen * 4),
+		       1024 * 1024);
+	err = fastrpc_buf_alloc(fl, fl->sctx->dev, memlen,
+				&imem);
+	if (err)
+		goto err_alloc;
+
+	fl->init_mem = imem;
+	args[0].ptr = (u64)(uintptr_t)&inbuf;
+	args[0].length = sizeof(inbuf);
+	args[0].fd = -1;
+
+	args[1].ptr = (u64)(uintptr_t)current->comm;
+	args[1].length = inbuf.namelen;
+	args[1].fd = -1;
+
+	args[2].ptr = (u64) init.file;
+	args[2].length = inbuf.filelen;
+	args[2].fd = init.filefd;
+
+	pages[0].addr = imem->phys;
+	pages[0].size = imem->size;
+
+	args[3].ptr = (u64)(uintptr_t) pages;
+	args[3].length = 1 * sizeof(*pages);
+	args[3].fd = -1;
+
+	args[4].ptr = (u64)(uintptr_t)&inbuf.attrs;
+	args[4].length = sizeof(inbuf.attrs);
+	args[4].fd = -1;
+
+	args[5].ptr = (u64)(uintptr_t) &inbuf.siglen;
+	args[5].length = sizeof(inbuf.siglen);
+	args[5].fd = -1;
+
+	sc = FASTRPC_SCALARS(FASTRPC_RMID_INIT_CREATE, 4, 0);
+	if (init.attrs)
+		sc = FASTRPC_SCALARS(FASTRPC_RMID_INIT_CREATE_ATTR, 6, 0);
+
+	err = fastrpc_internal_invoke(fl, true, FASTRPC_INIT_HANDLE,
+				      sc, args);
+	if (err)
+		goto err_invoke;
+
+	kfree(args);
+
+	return 0;
+
+err_invoke:
+	fl->init_mem = NULL;
+	fastrpc_buf_free(imem);
+err_alloc:
+	if (map) {
+		spin_lock(&fl->lock);
+		list_del(&map->node);
+		spin_unlock(&fl->lock);
+		fastrpc_map_put(map);
+	}
+err:
+	kfree(args);
+
+	return err;
+}
+
+static struct fastrpc_session_ctx *fastrpc_session_alloc(
+					struct fastrpc_channel_ctx *cctx)
+{
+	struct fastrpc_session_ctx *session = NULL;
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&cctx->lock, flags);
+	for (i = 0; i < cctx->sesscount; i++) {
+		if (!cctx->session[i].used && cctx->session[i].valid) {
+			cctx->session[i].used = true;
+			session = &cctx->session[i];
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&cctx->lock, flags);
+
+	return session;
+}
+
+static void fastrpc_session_free(struct fastrpc_channel_ctx *cctx,
+				 struct fastrpc_session_ctx *session)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&cctx->lock, flags);
+	session->used = false;
+	spin_unlock_irqrestore(&cctx->lock, flags);
+}
+
+static int fastrpc_release_current_dsp_process(struct fastrpc_user *fl)
+{
+	struct fastrpc_invoke_args args[1];
+	int tgid = 0;
+	u32 sc;
+
+	tgid = fl->tgid;
+	args[0].ptr = (u64)(uintptr_t) &tgid;
+	args[0].length = sizeof(tgid);
+	args[0].fd = -1;
+	args[0].reserved = 0;
+	sc = FASTRPC_SCALARS(FASTRPC_RMID_INIT_RELEASE, 1, 0);
+
+	return fastrpc_internal_invoke(fl, true, FASTRPC_INIT_HANDLE,
+				       sc, &args[0]);
+}
+
+static int fastrpc_device_release(struct inode *inode, struct file *file)
+{
+	struct fastrpc_user *fl = (struct fastrpc_user *)file->private_data;
+	struct fastrpc_channel_ctx *cctx = fl->cctx;
+	struct fastrpc_invoke_ctx *ctx, *n;
+	struct fastrpc_map *map, *m;
+	unsigned long flags;
+
+	fastrpc_release_current_dsp_process(fl);
+
+	spin_lock_irqsave(&cctx->lock, flags);
+	list_del(&fl->user);
+	spin_unlock_irqrestore(&cctx->lock, flags);
+
+	if (fl->init_mem)
+		fastrpc_buf_free(fl->init_mem);
+
+	list_for_each_entry_safe(ctx, n, &fl->pending, node) {
+		list_del(&ctx->node);
+		fastrpc_context_put(ctx);
+	}
+
+	list_for_each_entry_safe(map, m, &fl->maps, node) {
+		list_del(&map->node);
+		fastrpc_map_put(map);
+	}
+
+	fastrpc_session_free(cctx, fl->sctx);
+	fastrpc_channel_ctx_put(cctx);
+
+	mutex_destroy(&fl->mutex);
+	kfree(fl);
+	file->private_data = NULL;
+
+	return 0;
+}
+
+static int fastrpc_device_open(struct inode *inode, struct file *filp)
+{
+	struct fastrpc_channel_ctx *cctx = miscdev_to_cctx(filp->private_data);
+	struct fastrpc_user *fl = NULL;
+	unsigned long flags;
+
+	fl = kzalloc(sizeof(*fl), GFP_KERNEL);
+	if (!fl)
+		return -ENOMEM;
+
+	/* Released in fastrpc_device_release() */
+	fastrpc_channel_ctx_get(cctx);
+
+	filp->private_data = fl;
+	spin_lock_init(&fl->lock);
+	mutex_init(&fl->mutex);
+	INIT_LIST_HEAD(&fl->pending);
+	INIT_LIST_HEAD(&fl->maps);
+	INIT_LIST_HEAD(&fl->user);
+	fl->tgid = current->tgid;
+	fl->cctx = cctx;
+
+	fl->sctx = fastrpc_session_alloc(cctx);
+	if (!fl->sctx) {
+		dev_err(&cctx->rpdev->dev, "No session available\n");
+		mutex_destroy(&fl->mutex);
+		kfree(fl);
+
+		return -EBUSY;
+	}
+
+	spin_lock_irqsave(&cctx->lock, flags);
+	list_add_tail(&fl->user, &cctx->users);
+	spin_unlock_irqrestore(&cctx->lock, flags);
+
+	return 0;
+}
+
+static int fastrpc_dmabuf_alloc(struct fastrpc_user *fl, char __user *argp)
+{
+	struct fastrpc_alloc_dma_buf bp;
+	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
+	struct fastrpc_buf *buf = NULL;
+	int err;
+
+	if (copy_from_user(&bp, argp, sizeof(bp)))
+		return -EFAULT;
+
+	err = fastrpc_buf_alloc(fl, fl->sctx->dev, bp.size, &buf);
+	if (err)
+		return err;
+	exp_info.ops = &fastrpc_dma_buf_ops;
+	exp_info.size = bp.size;
+	exp_info.flags = O_RDWR;
+	exp_info.priv = buf;
+	buf->dmabuf = dma_buf_export(&exp_info);
+	if (IS_ERR(buf->dmabuf)) {
+		err = PTR_ERR(buf->dmabuf);
+		fastrpc_buf_free(buf);
+		return err;
+	}
+
+	bp.fd = dma_buf_fd(buf->dmabuf, O_ACCMODE);
+	if (bp.fd < 0) {
+		dma_buf_put(buf->dmabuf);
+		return -EINVAL;
+	}
+
+	if (copy_to_user(argp, &bp, sizeof(bp))) {
+		dma_buf_put(buf->dmabuf);
+		return -EFAULT;
+	}
+
+	return 0;
+}
+
+static int fastrpc_init_attach(struct fastrpc_user *fl)
+{
+	struct fastrpc_invoke_args args[1];
+	int tgid = fl->tgid;
+	u32 sc;
+
+	args[0].ptr = (u64)(uintptr_t) &tgid;
+	args[0].length = sizeof(tgid);
+	args[0].fd = -1;
+	args[0].reserved = 0;
+	sc = FASTRPC_SCALARS(FASTRPC_RMID_INIT_ATTACH, 1, 0);
+	fl->pd = 0;
+
+	return fastrpc_internal_invoke(fl, true, FASTRPC_INIT_HANDLE,
+				       sc, &args[0]);
+}
+
+static int fastrpc_invoke(struct fastrpc_user *fl, char __user *argp)
+{
+	struct fastrpc_invoke_args *args = NULL;
+	struct fastrpc_invoke inv;
+	u32 nscalars;
+	int err;
+
+	if (copy_from_user(&inv, argp, sizeof(inv)))
+		return -EFAULT;
+
+	/* nscalars is truncated here to max supported value */
+	nscalars = REMOTE_SCALARS_LENGTH(inv.sc);
+	if (nscalars) {
+		args = kcalloc(nscalars, sizeof(*args), GFP_KERNEL);
+		if (!args)
+			return -ENOMEM;
+
+		if (copy_from_user(args, (void __user *)(uintptr_t)inv.args,
+				   nscalars * sizeof(*args))) {
+			kfree(args);
+			return -EFAULT;
+		}
+	}
+
+	err = fastrpc_internal_invoke(fl, false, inv.handle, inv.sc, args);
+	kfree(args);
+
+	return err;
+}
+
+static long fastrpc_device_ioctl(struct file *file, unsigned int cmd,
+				 unsigned long arg)
+{
+	struct fastrpc_user *fl = (struct fastrpc_user *)file->private_data;
+	char __user *argp = (char __user *)arg;
+	int err;
+
+	switch (cmd) {
+	case FASTRPC_IOCTL_INVOKE:
+		err = fastrpc_invoke(fl, argp);
+		break;
+	case FASTRPC_IOCTL_INIT_ATTACH:
+		err = fastrpc_init_attach(fl);
+		break;
+	case FASTRPC_IOCTL_INIT_CREATE:
+		err = fastrpc_init_create_process(fl, argp);
+		break;
+	case FASTRPC_IOCTL_ALLOC_DMA_BUFF:
+		err = fastrpc_dmabuf_alloc(fl, argp);
+		break;
+	default:
+		err = -ENOTTY;
+		break;
+	}
+
+	return err;
+}
+
+static const struct file_operations fastrpc_fops = {
+	.open = fastrpc_device_open,
+	.release = fastrpc_device_release,
+	.unlocked_ioctl = fastrpc_device_ioctl,
+	.compat_ioctl = fastrpc_device_ioctl,
+};
+
+static int fastrpc_cb_probe(struct platform_device *pdev)
+{
+	struct fastrpc_channel_ctx *cctx;
+	struct fastrpc_session_ctx *sess;
+	struct device *dev = &pdev->dev;
+	int i, sessions = 0;
+	unsigned long flags;
+	int rc;
+
+	cctx = dev_get_drvdata(dev->parent);
+	if (!cctx)
+		return -EINVAL;
+
+	of_property_read_u32(dev->of_node, "qcom,nsessions", &sessions);
+
+	spin_lock_irqsave(&cctx->lock, flags);
+	sess = &cctx->session[cctx->sesscount];
+	sess->used = false;
+	sess->valid = true;
+	sess->dev = dev;
+	dev_set_drvdata(dev, sess);
+
+	if (of_property_read_u32(dev->of_node, "reg", &sess->sid))
+		dev_info(dev, "FastRPC Session ID not specified in DT\n");
+
+	if (sessions > 0) {
+		struct fastrpc_session_ctx *dup_sess;
+
+		for (i = 1; i < sessions; i++) {
+			if (cctx->sesscount++ >= FASTRPC_MAX_SESSIONS)
+				break;
+			dup_sess = &cctx->session[cctx->sesscount];
+			memcpy(dup_sess, sess, sizeof(*dup_sess));
+		}
+	}
+	cctx->sesscount++;
+	spin_unlock_irqrestore(&cctx->lock, flags);
+	rc = dma_set_mask(dev, DMA_BIT_MASK(32));
+	if (rc) {
+		dev_err(dev, "32-bit DMA enable failed\n");
+		return rc;
+	}
+
+	return 0;
+}
+
+static int fastrpc_cb_remove(struct platform_device *pdev)
+{
+	struct fastrpc_channel_ctx *cctx = dev_get_drvdata(pdev->dev.parent);
+	struct fastrpc_session_ctx *sess = dev_get_drvdata(&pdev->dev);
+	unsigned long flags;
+	int i;
+
+	spin_lock_irqsave(&cctx->lock, flags);
+	for (i = 1; i < FASTRPC_MAX_SESSIONS; i++) {
+		if (cctx->session[i].sid == sess->sid) {
+			cctx->session[i].valid = false;
+			cctx->sesscount--;
+		}
+	}
+	spin_unlock_irqrestore(&cctx->lock, flags);
+
+	return 0;
+}
+
+static const struct of_device_id fastrpc_match_table[] = {
+	{ .compatible = "qcom,fastrpc-compute-cb", },
+	{}
+};
+
+static struct platform_driver fastrpc_cb_driver = {
+	.probe = fastrpc_cb_probe,
+	.remove = fastrpc_cb_remove,
+	.driver = {
+		.name = "qcom,fastrpc-cb",
+		.of_match_table = fastrpc_match_table,
+		.suppress_bind_attrs = true,
+	},
+};
+
+static int fastrpc_rpmsg_probe(struct rpmsg_device *rpdev)
+{
+	struct device *rdev = &rpdev->dev;
+	struct fastrpc_channel_ctx *data;
+	int i, err, domain_id = -1;
+	const char *domain;
+
+	err = of_property_read_string(rdev->of_node, "label", &domain);
+	if (err) {
+		dev_info(rdev, "FastRPC Domain not specified in DT\n");
+		return err;
+	}
+
+	for (i = 0; i <= CDSP_DOMAIN_ID; i++) {
+		if (!strcmp(domains[i], domain)) {
+			domain_id = i;
+			break;
+		}
+	}
+
+	if (domain_id < 0) {
+		dev_info(rdev, "FastRPC Invalid Domain ID %d\n", domain_id);
+		return -EINVAL;
+	}
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	data->miscdev.minor = MISC_DYNAMIC_MINOR;
+	data->miscdev.name = kasprintf(GFP_KERNEL, "fastrpc-%s",
+				domains[domain_id]);
+	data->miscdev.fops = &fastrpc_fops;
+	err = misc_register(&data->miscdev);
+	if (err)
+		return err;
+
+	kref_init(&data->refcount);
+
+	dev_set_drvdata(&rpdev->dev, data);
+	dma_set_mask_and_coherent(rdev, DMA_BIT_MASK(32));
+	INIT_LIST_HEAD(&data->users);
+	spin_lock_init(&data->lock);
+	idr_init(&data->ctx_idr);
+	data->domain_id = domain_id;
+	data->rpdev = rpdev;
+
+	return of_platform_populate(rdev->of_node, NULL, NULL, rdev);
+}
+
+static void fastrpc_notify_users(struct fastrpc_user *user)
+{
+	struct fastrpc_invoke_ctx *ctx;
+
+	spin_lock(&user->lock);
+	list_for_each_entry(ctx, &user->pending, node)
+		complete(&ctx->work);
+	spin_unlock(&user->lock);
+}
+
+static void fastrpc_rpmsg_remove(struct rpmsg_device *rpdev)
+{
+	struct fastrpc_channel_ctx *cctx = dev_get_drvdata(&rpdev->dev);
+	struct fastrpc_user *user;
+	unsigned long flags;
+
+	spin_lock_irqsave(&cctx->lock, flags);
+	list_for_each_entry(user, &cctx->users, user)
+		fastrpc_notify_users(user);
+	spin_unlock_irqrestore(&cctx->lock, flags);
+
+	misc_deregister(&cctx->miscdev);
+	of_platform_depopulate(&rpdev->dev);
+
+	cctx->rpdev = NULL;
+	fastrpc_channel_ctx_put(cctx);
+}
+
+static int fastrpc_rpmsg_callback(struct rpmsg_device *rpdev, void *data,
+				  int len, void *priv, u32 addr)
+{
+	struct fastrpc_channel_ctx *cctx = dev_get_drvdata(&rpdev->dev);
+	struct fastrpc_invoke_rsp *rsp = data;
+	struct fastrpc_invoke_ctx *ctx;
+	unsigned long flags;
+	unsigned long ctxid;
+
+	if (len < sizeof(*rsp))
+		return -EINVAL;
+
+	ctxid = ((rsp->ctx & FASTRPC_CTXID_MASK) >> 4);
+
+	spin_lock_irqsave(&cctx->lock, flags);
+	ctx = idr_find(&cctx->ctx_idr, ctxid);
+	spin_unlock_irqrestore(&cctx->lock, flags);
+
+	if (!ctx) {
+		dev_err(&rpdev->dev, "No context ID matches response\n");
+		return -ENOENT;
+	}
+
+	ctx->retval = rsp->retval;
+	complete(&ctx->work);
+
+	/*
+	 * The DMA buffer associated with the context cannot be freed in
+	 * interrupt context so schedule it through a worker thread to
+	 * avoid a kernel BUG.
+	 */
+	schedule_work(&ctx->put_work);
+
+	return 0;
+}
+
+static const struct of_device_id fastrpc_rpmsg_of_match[] = {
+	{ .compatible = "qcom,fastrpc" },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, fastrpc_rpmsg_of_match);
+
+static struct rpmsg_driver fastrpc_driver = {
+	.probe = fastrpc_rpmsg_probe,
+	.remove = fastrpc_rpmsg_remove,
+	.callback = fastrpc_rpmsg_callback,
+	.drv = {
+		.name = "qcom,fastrpc",
+		.of_match_table = fastrpc_rpmsg_of_match,
+	},
+};
+
+static int fastrpc_init(void)
+{
+	int ret;
+
+	ret = platform_driver_register(&fastrpc_cb_driver);
+	if (ret < 0) {
+		pr_err("fastrpc: failed to register cb driver\n");
+		return ret;
+	}
+
+	ret = register_rpmsg_driver(&fastrpc_driver);
+	if (ret < 0) {
+		pr_err("fastrpc: failed to register rpmsg driver\n");
+		platform_driver_unregister(&fastrpc_cb_driver);
+		return ret;
+	}
+
+	return 0;
+}
+module_init(fastrpc_init);
+
+static void fastrpc_exit(void)
+{
+	platform_driver_unregister(&fastrpc_cb_driver);
+	unregister_rpmsg_driver(&fastrpc_driver);
+}
+module_exit(fastrpc_exit);
+
+MODULE_LICENSE("GPL v2");