[v5,3/5] misc: fastrpc: Add support for context Invoke method

diff --git a/drivers/misc/fastrpc.c b/drivers/misc/fastrpc.c
index c86c7babf403..8fdbc86da949 100644
--- a/drivers/misc/fastrpc.c
+++ b/drivers/misc/fastrpc.c
@@ -2,7 +2,9 @@ 
 // 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>
@@ -14,6 +16,7 @@ 
 #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)
@@ -21,14 +24,118 @@ 
 #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_CTXID_MASK (0xFF0)
 #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))
+/* Limit max scalars to 255, it needs revisit in future */
+#define MAX_REMOTE_SCALARS	0xff
+#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 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 {
+	struct fastrpc_user *fl;
+	struct device *dev;
+	void *virt;
+	u64 phys;
+	u64 size;
+};
+
+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 list_head node; /* list of ctxs */
+	struct completion 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_session_ctx {
 	struct device *dev;
@@ -55,6 +162,7 @@  struct fastrpc_user {
 
 	struct fastrpc_channel_ctx *cctx;
 	struct fastrpc_session_ctx *sctx;
+	struct fastrpc_buf *init_mem;
 
 	int tgid;
 	int pd;
@@ -64,6 +172,508 @@  struct fastrpc_user {
 	struct mutex mutex;
 };
 
+static void fastrpc_free_map(struct kref *ref)
+{
+	struct fastrpc_map *map;
+
+	map = container_of(ref, struct fastrpc_map, refcount);
+
+	list_del(&map->node);
+
+	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)
+{
+	struct fastrpc_user *fl;
+
+	if (map) {
+		fl = map->fl;
+		mutex_lock(&fl->mutex);
+		kref_put(&map->refcount, fastrpc_free_map);
+		mutex_unlock(&fl->mutex);
+	}
+}
+
+static int fastrpc_map_get(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) {
+			kref_get(&map->refcount);
+			*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;
+
+	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)
+		return -ENOMEM;
+
+	if (fl->sctx && fl->sctx->sid)
+		buf->phys += ((u64)fl->sctx->sid << 32);
+
+	*obuf = buf;
+
+	return 0;
+}
+
+static void fastrpc_context_free(struct fastrpc_invoke_ctx *ctx)
+{
+	struct fastrpc_channel_ctx *cctx = ctx->fl->cctx;
+	struct fastrpc_user *user = ctx->fl;
+	int scalars = REMOTE_SCALARS_LENGTH(ctx->sc);
+	int i;
+
+	spin_lock(&user->lock);
+	list_del(&ctx->node);
+	spin_unlock(&user->lock);
+
+	for (i = 0; i < scalars; i++)
+		fastrpc_map_put(ctx->maps[i]);
+
+	if (ctx->buf)
+		fastrpc_buf_free(ctx->buf);
+
+	spin_lock(&cctx->lock);
+	idr_remove(&cctx->ctx_idr, ctx->ctxid >> 4);
+	spin_unlock(&cctx->lock);
+
+	kfree(ctx->maps);
+	kfree(ctx);
+}
+
+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;
+	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->args = args;
+	}
+
+	ctx->sc = sc;
+	ctx->retval = -1;
+	ctx->pid = current->pid;
+	ctx->tgid = user->tgid;
+	init_completion(&ctx->work);
+
+	spin_lock(&user->lock);
+	list_add_tail(&ctx->node, &user->pending);
+	spin_unlock(&user->lock);
+
+	spin_lock(&cctx->lock);
+	ret = idr_alloc_cyclic(&cctx->ctx_idr, ctx, 1,
+			       FASTRPC_CTX_MAX, GFP_ATOMIC);
+	if (ret < 0) {
+		spin_unlock(&cctx->lock);
+		goto err_idr;
+	}
+	ctx->ctxid = ret << 4;
+	spin_unlock(&cctx->lock);
+
+	return ctx;
+err_idr:
+	spin_lock(&user->lock);
+	list_del(&ctx->node);
+	spin_unlock(&user->lock);
+	kfree(ctx->maps);
+	kfree(ctx);
+
+	return ERR_PTR(ret);
+}
+
+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_get(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 (!map->buf) {
+		err = -EINVAL;
+		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) {
+			size = ALIGN(size, FASTRPC_ALIGN);
+			size += ctx->args[i].length;
+		}
+	}
+
+	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) {
+		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, err = 0;
+	u64 rlen, pkt_size;
+	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);
+	fastrpc_create_maps(ctx);
+	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 (i = 0; i < ctx->nbufs; ++i) {
+		u64 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;
+
+		pages[i].size = roundup(len, PAGE_SIZE);
+
+		if (ctx->maps[i]) {
+			rpra[i].pv = (u64) ctx->args[i].ptr;
+			pages[i].addr = ctx->maps[i]->phys;
+		} else {
+			rlen -= ALIGN(args, FASTRPC_ALIGN) - args;
+			args = ALIGN(args, FASTRPC_ALIGN);
+			if (rlen < len)
+				goto bail;
+
+			rpra[i].pv = args;
+			pages[i].addr = ctx->buf->phys + (pkt_size - rlen);
+			pages[i].addr = pages[i].addr &	PAGE_MASK;
+			args = args + len;
+			rlen -= len;
+		}
+
+		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) {
+		fastrpc_buf_free(ctx->buf);
+		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 (ctx->maps[i]) {
+			fastrpc_map_put(ctx->maps[i]);
+			ctx->maps[i] = NULL;
+			continue;
+		}
+
+		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);
+
+	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;
+
+	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;
+	}
+	/* 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;
+
+	/* populate all the output buffers with results */
+	err = fastrpc_put_args(ctx, kernel);
+	if (err)
+		goto bail;
+
+	/* We are done with this compute, release it now! */
+bail:
+	if (ctx)
+		fastrpc_context_free(ctx);
+
+	if (err)
+		dev_dbg(fl->sctx->dev, "Error: Invoke Failed %d\n", err);
+
+	return err;
+}
+
 static struct fastrpc_session_ctx *fastrpc_session_alloc(
 					struct fastrpc_channel_ctx *cctx)
 {
@@ -95,11 +705,22 @@  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;
 
 	spin_lock(&cctx->lock);
 	list_del(&fl->user);
 	spin_unlock(&cctx->lock);
 
+	if (fl->init_mem)
+		fastrpc_buf_free(fl->init_mem);
+
+	list_for_each_entry_safe(ctx, n, &fl->pending, node)
+		fastrpc_context_free(ctx);
+
+	list_for_each_entry_safe(map, m, &fl->maps, node)
+		fastrpc_map_put(map);
+
 	fastrpc_session_free(fl->cctx, fl->sctx);
 
 	mutex_destroy(&fl->mutex);
@@ -134,9 +755,69 @@  static int fastrpc_device_open(struct inode *inode, struct file *filp)
 	return 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 = REMOTE_SCALARS_LENGTH(inv.sc);
+
+	if (nscalars > MAX_REMOTE_SCALARS)
+		return -EINVAL;
+
+	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;
+		}
+
+		/* Make sure reserved field is set to 0 */
+		if (args->reserved) {
+			kfree(args);
+			return -EINVAL;
+		}
+	}
+
+	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;
+	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)
@@ -260,9 +941,25 @@  static int fastrpc_rpmsg_probe(struct rpmsg_device *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;
+
+	spin_lock(&cctx->lock);
+	list_for_each_entry(user, &cctx->users, user)
+		fastrpc_notify_users(user);
+	spin_unlock(&cctx->lock);
 
 	misc_deregister(&cctx->miscdev);
 	of_platform_depopulate(&rpdev->dev);
@@ -272,6 +969,29 @@  static void fastrpc_rpmsg_remove(struct rpmsg_device *rpdev)
 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);
+
 	return 0;
 }
 
diff --git a/include/uapi/misc/fastrpc.h b/include/uapi/misc/fastrpc.h
new file mode 100644
index 000000000000..a69ef33dc37e
--- /dev/null
+++ b/include/uapi/misc/fastrpc.h
@@ -0,0 +1,23 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef __QCOM_FASTRPC_H__
+#define __QCOM_FASTRPC_H__
+
+#include <linux/types.h>
+
+#define FASTRPC_IOCTL_INVOKE		_IOWR('R', 3, struct fastrpc_invoke)
+
+struct fastrpc_invoke_args {
+	__u64 ptr;
+	__u64 length;
+	__s32 fd;
+	__u32 reserved;
+};
+
+struct fastrpc_invoke {
+	__u32 handle;
+	__u32 sc;
+	__u64 args;
+};
+
+#endif /* __QCOM_FASTRPC_H__ */