Queue: Add policies to queues

Policies give a convenient place to hook into the queue operations
and notify something that there is new space free in the queue or
new units added.

Signed-off-by: Anton Staaf <robotboy@chromium.org>

BRANCH=None
BUG=None
TEST=make buildall -j

Change-Id: I94b2aa94b8e8d07911191bc19a39fa827623b117
Reviewed-on: https://chromium-review.googlesource.com/271791
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-by: Anton Staaf <robotboy@chromium.org>
Commit-Queue: Anton Staaf <robotboy@chromium.org>
Trybot-Ready: Anton Staaf <robotboy@chromium.org>
Tested-by: Anton Staaf <robotboy@chromium.org>

1 files changed, 20 insertions, 0 deletions

diff --git a/common/queue.c b/common/queue.c
index 70b4bd40d0..6e5e9e65ad 100644
--- a/common/queue.c
+++ b/common/queue.c
@@ -7,9 +7,21 @@
 #include "queue.h"
 #include "util.h"
 
+static void queue_action_null(struct queue_policy const *policy, size_t count)
+{
+}
+
+struct queue_policy const queue_policy_null = {
+	.add    = queue_action_null,
+	.remove = queue_action_null,
+};
+
 void queue_init(struct queue const *q)
 {
 	ASSERT(POWER_OF_TWO(q->buffer_units));
+	ASSERT(q->policy);
+	ASSERT(q->policy->add);
+	ASSERT(q->policy->remove);
 
 	q->state->head = 0;
 	q->state->tail = 0;
@@ -44,6 +56,8 @@ size_t queue_add_unit(struct queue const *q, void const *src)
 
 	q->state->tail += 1;
 
+	q->policy->add(q->policy, 1);
+
 	return 1;
 }
 
@@ -74,6 +88,8 @@ size_t queue_add_memcpy(struct queue const *q,
 
 	q->state->tail += transfer;
 
+	q->policy->add(q->policy, transfer);
+
 	return transfer;
 }
 
@@ -111,6 +127,8 @@ size_t queue_remove_unit(struct queue const *q, void *dest)
 
 	q->state->head += 1;
 
+	q->policy->remove(q->policy, 1);
+
 	return 1;
 }
 
@@ -133,6 +151,8 @@ size_t queue_remove_memcpy(struct queue const *q,
 
 	q->state->head += transfer;
 
+	q->policy->remove(q->policy, transfer);
+
 	return transfer;
 }