misc: fastrpc: Add fdlist implementation

Add fdlist implementation to support dma handles. fdlist is populated by
DSP if any map is no longer used and it is freed during put_args.

Signed-off-by: Vamsi Krishna Gattupalli <quic_vgattupa@quicinc.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220214161002.6831-11-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/fastrpc.c

@@ -320,15 +320,15 @@ static void fastrpc_map_get(struct fastrpc_map *map)
 		kref_get(&map->refcount);
 }
 
-static int fastrpc_map_find(struct fastrpc_user *fl, int fd,
+
+static int fastrpc_map_lookup(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;
@@ -339,6 +339,17 @@ static int fastrpc_map_find(struct fastrpc_user *fl, int fd,
 	return -ENOENT;
 }
 
+static int fastrpc_map_find(struct fastrpc_user *fl, int fd,
+			    struct fastrpc_map **ppmap)
+{
+	int ret = fastrpc_map_lookup(fl, fd, ppmap);
+
+	if (!ret)
+		fastrpc_map_get(*ppmap);
+
+	return ret;
+}
+
 static void fastrpc_buf_free(struct fastrpc_buf *buf)
 {
 	dma_free_coherent(buf->dev, buf->size, buf->virt,
@@ -411,7 +422,7 @@ static void fastrpc_context_free(struct kref *ref)
 	ctx = container_of(ref, struct fastrpc_invoke_ctx, refcount);
 	cctx = ctx->cctx;
 
-	for (i = 0; i < ctx->nscalars; i++)
+	for (i = 0; i < ctx->nbufs; i++)
 		fastrpc_map_put(ctx->maps[i]);
 
 	if (ctx->buf)
@@ -969,9 +980,19 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
 			    u32 kernel)
 {
 	struct fastrpc_remote_arg *rpra = ctx->rpra;
-	int i, inbufs;
+	struct fastrpc_user *fl = ctx->fl;
+	struct fastrpc_map *mmap = NULL;
+	struct fastrpc_invoke_buf *list;
+	struct fastrpc_phy_page *pages;
+	u64 *fdlist;
+	int i, inbufs, outbufs, handles;
 
 	inbufs = REMOTE_SCALARS_INBUFS(ctx->sc);
+	outbufs = REMOTE_SCALARS_OUTBUFS(ctx->sc);
+	handles = REMOTE_SCALARS_INHANDLES(ctx->sc) + REMOTE_SCALARS_OUTHANDLES(ctx->sc);
+	list = fastrpc_invoke_buf_start(rpra, ctx->nscalars);
+	pages = fastrpc_phy_page_start(list, ctx->nscalars);
+	fdlist = (uint64_t *)(pages + inbufs + outbufs + handles);
 
 	for (i = inbufs; i < ctx->nbufs; ++i) {
 		if (!ctx->maps[i]) {
@@ -988,6 +1009,13 @@ static int fastrpc_put_args(struct fastrpc_invoke_ctx *ctx,
 		}
 	}
 
+	for (i = 0; i < FASTRPC_MAX_FDLIST; i++) {
+		if (!fdlist[i])
+			break;
+		if (!fastrpc_map_lookup(fl, (int)fdlist[i], &mmap))
+			fastrpc_map_put(mmap);
+	}
+
 	return 0;
 }