cyclic: make clients embed a struct cyclic_info in their own data structure

There are of course not a whole lot of examples in-tree yet, but
before they appear, let's make this API change: Instead of separately
allocating a 'struct cyclic_info', make the users embed such an
instance in their own structure, and make the convention that the
callback simply receives the 'struct cyclic_info *', from which the
clients can get their own data using the container_of() macro.

This has a number of advantages.

First, it means cyclic_register() simply cannot fail, simplifying the
code. The necessary storage will simply be allocated automatically
when the client's own structure is allocated (often via
uclass_priv_auto or similar).

Second, code for which CONFIG_CYCLIC is just an option can more easily
be written without #ifdefs, if we just provide an empty struct
cyclic_info {}. For example, the nested CONFIG_IS_ENABLED()s in
https://lore.kernel.org/u-boot/20240316201416.211480-1-marek.vasut+renesas@mailbox.org/
are mostly due to the existence of the 'struct cyclic_info *' member
being guarded by #ifdef CONFIG_CYCLIC.

And we do probably want to avoid the extra memory overhead of that
member when !CONFIG_CYCLIC. But that is automatic if, instead of a
'struct cyclic_info *', one simply embeds a 'struct cyclic_info',
which will have size 0 when !CONFIG_CYCLIC. Also, the no-op
cyclic_register() function can just unconditionally be called, and the
compiler will see that (1) the callback is referenced, so not emit a
warning for a maybe-unused function and (2) see that it can actually
never be reached, so not emit any code for it.

Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Rasmus Villemoes <rasmus.villemoes@prevas.dk>

1 files changed, 5 insertions, 17 deletions

diff --git a/common/cyclic.c b/common/cyclic.c
index c62e7fa7d1..ec38fad677 100644
--- a/common/cyclic.c
+++ b/common/cyclic.c
@@ -26,34 +26,22 @@ struct hlist_head *cyclic_get_list(void)
 	return (struct hlist_head *)&gd->cyclic_list;
 }
 
-struct cyclic_info *cyclic_register(cyclic_func_t func, uint64_t delay_us,
-				    const char *name, void *ctx)
+void cyclic_register(struct cyclic_info *cyclic, cyclic_func_t func,
+		     uint64_t delay_us, const char *name)
 {
-	struct cyclic_info *cyclic;
-
-	cyclic = calloc(1, sizeof(struct cyclic_info));
-	if (!cyclic) {
-		pr_debug("Memory allocation error\n");
-		return NULL;
-	}
+	memset(cyclic, 0, sizeof(*cyclic));
 
 	/* Store values in struct */
 	cyclic->func = func;
-	cyclic->ctx = ctx;
 	cyclic->name = name;
 	cyclic->delay_us = delay_us;
 	cyclic->start_time_us = timer_get_us();
 	hlist_add_head(&cyclic->list, cyclic_get_list());
-
-	return cyclic;
 }
 
-int cyclic_unregister(struct cyclic_info *cyclic)
+void cyclic_unregister(struct cyclic_info *cyclic)
 {
 	hlist_del(&cyclic->list);
-	free(cyclic);
-
-	return 0;
 }
 
 void cyclic_run(void)
@@ -76,7 +64,7 @@ void cyclic_run(void)
 		if (time_after_eq64(now, cyclic->next_call)) {
 			/* Call cyclic function and account it's cpu-time */
 			cyclic->next_call = now + cyclic->delay_us;
-			cyclic->func(cyclic->ctx);
+			cyclic->func(cyclic);
 			cyclic->run_cnt++;
 			cpu_time = timer_get_us() - now;
 			cyclic->cpu_time_us += cpu_time;