remoteproc: simplify unregister/free interfaces

Simplify the unregister/free interfaces, and make them easier
to understand and use, by moving to a symmetric and consistent
alloc() -> register() -> unregister() -> free() flow.

To create and register an rproc instance, one needed to invoke
rproc_alloc() followed by rproc_register().

To unregister and free an rproc instance, one now needs to invoke
rproc_unregister() followed by rproc_free().

Cc: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Ohad Ben-Cohen <ohad@wizery.com>

1 files changed, 8 insertions, 13 deletions

diff --git a/Documentation/remoteproc.txt b/Documentation/remoteproc.txt
index 70a048cd3fa3..ad6ded4bca5c 100644
--- a/Documentation/remoteproc.txt
+++ b/Documentation/remoteproc.txt
@@ -120,14 +120,14 @@ int dummy_rproc_example(struct rproc *my_rproc)
       On success, the new rproc is returned, and on failure, NULL.
 
       Note: _never_ directly deallocate @rproc, even if it was not registered
-      yet. Instead, if you just need to unroll rproc_alloc(), use rproc_free().
+      yet. Instead, when you need to unroll rproc_alloc(), use rproc_free().
 
   void rproc_free(struct rproc *rproc)
     - Free an rproc handle that was allocated by rproc_alloc.
-      This function should _only_ be used if @rproc was only allocated,
-      but not registered yet.
-      If @rproc was already successfully registered (by calling
-      rproc_register()), then use rproc_unregister() instead.
+      This function essentially unrolls rproc_alloc(), by decrementing the
+      rproc's refcount. It doesn't directly free rproc; that would happen
+      only if there are no other references to rproc and its refcount now
+      dropped to zero.
 
   int rproc_register(struct rproc *rproc)
     - Register @rproc with the remoteproc framework, after it has been
@@ -143,19 +143,14 @@ int dummy_rproc_example(struct rproc *my_rproc)
       probed.
 
   int rproc_unregister(struct rproc *rproc)
-    - Unregister a remote processor, and decrement its refcount.
-      If its refcount drops to zero, then @rproc will be freed. If not,
-      it will be freed later once the last reference is dropped.
-
+    - Unroll rproc_register().
       This function should be called when the platform specific rproc
       implementation decides to remove the rproc device. it should
       _only_ be called if a previous invocation of rproc_register()
       has completed successfully.
 
-      After rproc_unregister() returns, @rproc is _not_ valid anymore and
-      it shouldn't be used. More specifically, don't call rproc_free()
-      or try to directly free @rproc after rproc_unregister() returns;
-      none of these are needed, and calling them is a bug.
+      After rproc_unregister() returns, @rproc is still valid, and its
+      last refcount should be decremented by calling rproc_free().
 
       Returns 0 on success and -EINVAL if @rproc isn't valid.