[PATCH 08/10] qmi: Implement QMI service request rate limiting in 'can_write_data'.

Determine if we need to rate-limit QMI services requests to a
transport-specific minimum request period. If so, return true so that
the queue can be retried again later.
---
 drivers/qmimodem/qmi.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/qmimodem/qmi.c b/drivers/qmimodem/qmi.c
index 00086578da10..591129c252e3 100644
--- a/drivers/qmimodem/qmi.c
+++ b/drivers/qmimodem/qmi.c
@@ -665,8 +665,23 @@ static bool can_write_data(struct l_io *io, void *user_data)
 {
 	struct qmi_transport *transport = user_data;
 	struct qmi_request *req;
+	const uint64_t now = l_time_now();
+	uint64_t delta = 0;
 	int r;
 
+	/*
+	 * Determine if we need to rate-limit commands to a
+	 * transport-specific minimum request period. If so,
+	 * return true so that the queue can be retried again
+	 * later.
+	 */
+	if (transport->last_req_sent_time_us != 0) {
+		delta = l_time_diff(now, transport->last_req_sent_time_us);
+
+		if (delta < transport->min_req_period_us)
+			return true;
+	}
+
 	req = l_queue_pop_head(transport->req_queue);
 	if (!req)
 		return false;
@@ -677,6 +692,8 @@ static bool can_write_data(struct l_io *io, void *user_data)
 		return false;
 	}
 
+	transport->last_req_sent_time_us = now;
+
 	if (l_queue_length(transport->req_queue) > 0)
 		return true;
 
-- 
2.45.0