platform/surface: aggregator: Add control packet allocation caching

Surface Serial Hub communication is, in its core, packet based. Each
sequenced packet requires to be acknowledged, via an ACK-type control
packet. In case invalid data has been received by the driver, a NAK-type
(not-acknowledge/negative acknowledge) control packet is sent,
triggering retransmission.

Control packets are therefore a core communication primitive and used
frequently enough (with every sequenced packet transmission sent by the
embedded controller, including events and request responses) that it may
warrant caching their allocations to reduce possible memory
fragmentation.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Link: https://lore.kernel.org/r/20201221183959.1186143-3-luzmaximilian@gmail.com
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 26 insertions, 1 deletions

diff --git a/drivers/platform/surface/aggregator/core.c b/drivers/platform/surface/aggregator/core.c
index 18e0e9e34e7b..60d312f71436 100644
--- a/drivers/platform/surface/aggregator/core.c
+++ b/drivers/platform/surface/aggregator/core.c
@@ -780,7 +780,32 @@ static struct serdev_device_driver ssam_serial_hub = {
 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
 	},
 };
-module_serdev_device_driver(ssam_serial_hub);
+
+
+/* -- Module setup. --------------------------------------------------------- */
+
+static int __init ssam_core_init(void)
+{
+	int status;
+
+	status = ssh_ctrl_packet_cache_init();
+	if (status)
+		return status;
+
+	status = serdev_device_driver_register(&ssam_serial_hub);
+	if (status)
+		ssh_ctrl_packet_cache_destroy();
+
+	return status;
+}
+module_init(ssam_core_init);
+
+static void __exit ssam_core_exit(void)
+{
+	serdev_device_driver_unregister(&ssam_serial_hub);
+	ssh_ctrl_packet_cache_destroy();
+}
+module_exit(ssam_core_exit);
 
 MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
 MODULE_DESCRIPTION("Subsystem and Surface Serial Hub driver for Surface System Aggregator Module");