dm: core: Don't allow uclass use before ready
At present it is possible to call uclass_get() before driver model is
inited. In fact this happens on x86 boards which use Intel FSPv1, since
mrccache_get_region() tries to get the SPI flash device very early
during init.
This has always been undefined behaviour. Previously it generally worked,
i.e. returned an error code without crashing, because gd->uclass_root_s
is zeroed and the uclass can be added despite driver model not being
ready, due to the way lists are implemented. With the change to use a
gd->uclass_root pointer, this no-longer works. For example, it causes a
hang on minnowmax.
Fix this by adding a check that driver model is ready when uclass_get() is
called. This function is called in the process of locating any device, so
it is a good place to add the check.
This fixes booting on minnowmax.
Signed-off-by: Simon Glass <sjg@chromium.org>
Fixes: 8a715530bb1 ("dm: core: Allow the uclass list to move")
diff --git a/drivers/core/uclass.c b/drivers/core/uclass.c
index 117d35a..3146dfd 100644
--- a/drivers/core/uclass.c
+++ b/drivers/core/uclass.c
@@ -146,6 +146,9 @@
{
struct uclass *uc;
+ /* Immediately fail if driver model is not set up */
+ if (!gd->uclass_root)
+ return -EDEADLK;
*ucp = NULL;
uc = uclass_find(id);
if (!uc) {
diff --git a/include/dm/uclass.h b/include/dm/uclass.h
index 2778818..da0c1bf 100644
--- a/include/dm/uclass.h
+++ b/include/dm/uclass.h
@@ -159,7 +159,8 @@
*
* @key: ID to look up
* @ucp: Returns pointer to uclass (there is only one per ID)
- * @return 0 if OK, -ve on error
+ * @return 0 if OK, -EDEADLK if driver model is not yet inited, other -ve on
+ * other error
*/
int uclass_get(enum uclass_id key, struct uclass **ucp);
diff --git a/test/dm/core.c b/test/dm/core.c
index 48e66b7..c9a7606 100644
--- a/test/dm/core.c
+++ b/test/dm/core.c
@@ -994,6 +994,7 @@
memset(&gd->uclass_root, '\0', sizeof(gd->uclass_root));
ut_asserteq_ptr(NULL, uclass_find(UCLASS_TEST));
+ ut_asserteq(-EDEADLK, uclass_get(UCLASS_TEST, &uc));
return 0;
}