firewire: cdev: implement new event to notify response subaction with time stamp

The callback function now receives an argument for time stamps relevant
to asynchronous transaction. This commit implements a new event to
notify response subaction with the time stamps for user space.

Link: https://lore.kernel.org/r/20230529113406.986289-10-o-takashi@sakamocchi.jp
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>

Author: takaswie

drivers/firewire/core-cdev.c

@@ -172,6 +172,7 @@ struct outbound_transaction_event {
 	struct outbound_transaction_resource r;
 	union {
 		struct fw_cdev_event_response without_tstamp;
+		struct fw_cdev_event_response2 with_tstamp;
 	} rsp;
 };
 
@@ -538,41 +539,64 @@ static void release_transaction(struct client *client,
 {
 }
 
-static void complete_transaction(struct fw_card *card, int rcode,
-				 void *payload, size_t length, void *data)
+static void complete_transaction(struct fw_card *card, int rcode, u32 request_tstamp,
+				 u32 response_tstamp, void *payload, size_t length, void *data)
 {
 	struct outbound_transaction_event *e = data;
-	struct fw_cdev_event_response *rsp = &e->rsp.without_tstamp;
 	struct client *client = e->client;
 	unsigned long flags;
 
-	if (length < rsp->length)
-		rsp->length = length;
-	if (rcode == RCODE_COMPLETE)
-		memcpy(rsp->data, payload, rsp->length);
-
 	spin_lock_irqsave(&client->lock, flags);
 	idr_remove(&client->resource_idr, e->r.resource.handle);
 	if (client->in_shutdown)
 		wake_up(&client->tx_flush_wait);
 	spin_unlock_irqrestore(&client->lock, flags);
 
-	rsp->type = FW_CDEV_EVENT_RESPONSE;
-	rsp->rcode = rcode;
+	switch (e->rsp.without_tstamp.type) {
+	case FW_CDEV_EVENT_RESPONSE:
+	{
+		struct fw_cdev_event_response *rsp = &e->rsp.without_tstamp;
+
+		if (length < rsp->length)
+			rsp->length = length;
+		if (rcode == RCODE_COMPLETE)
+			memcpy(rsp->data, payload, rsp->length);
+
+		rsp->rcode = rcode;
+
+		// In the case that sizeof(*rsp) doesn't align with the position of the
+		// data, and the read is short, preserve an extra copy of the data
+		// to stay compatible with a pre-2.6.27 bug.  Since the bug is harmless
+		// for short reads and some apps depended on it, this is both safe
+		// and prudent for compatibility.
+		if (rsp->length <= sizeof(*rsp) - offsetof(typeof(*rsp), data))
+			queue_event(client, &e->event, rsp, sizeof(*rsp), rsp->data, rsp->length);
+		else
+			queue_event(client, &e->event, rsp, sizeof(*rsp) + rsp->length, NULL, 0);
 
-	/*
-	 * In the case that sizeof(*rsp) doesn't align with the position of the
-	 * data, and the read is short, preserve an extra copy of the data
-	 * to stay compatible with a pre-2.6.27 bug.  Since the bug is harmless
-	 * for short reads and some apps depended on it, this is both safe
-	 * and prudent for compatibility.
-	 */
-	if (rsp->length <= sizeof(*rsp) - offsetof(typeof(*rsp), data))
-		queue_event(client, &e->event, rsp, sizeof(*rsp),
-			    rsp->data, rsp->length);
-	else
-		queue_event(client, &e->event, rsp, sizeof(*rsp) + rsp->length,
-			    NULL, 0);
+		break;
+	}
+	case FW_CDEV_EVENT_RESPONSE2:
+	{
+		struct fw_cdev_event_response2 *rsp = &e->rsp.with_tstamp;
+
+		if (length < rsp->length)
+			rsp->length = length;
+		if (rcode == RCODE_COMPLETE)
+			memcpy(rsp->data, payload, rsp->length);
+
+		rsp->rcode = rcode;
+		rsp->request_tstamp = request_tstamp;
+		rsp->response_tstamp = response_tstamp;
+
+		queue_event(client, &e->event, rsp, sizeof(*rsp) + rsp->length, NULL, 0);
+
+		break;
+	default:
+		WARN_ON(1);
+		break;
+	}
+	}
 
 	/* Drop the idr's reference */
 	client_put(client);
@@ -583,7 +607,6 @@ static int init_request(struct client *client,
 			int destination_id, int speed)
 {
 	struct outbound_transaction_event *e;
-	struct fw_cdev_event_response *rsp;
 	void *payload;
 	int ret;
 
@@ -600,10 +623,21 @@ static int init_request(struct client *client,
 		return -ENOMEM;
 	e->client = client;
 
-	rsp = &e->rsp.without_tstamp;
-	rsp->length = request->length;
-	rsp->closure = request->closure;
-	payload = rsp->data;
+	if (client->version < FW_CDEV_VERSION_EVENT_ASYNC_TSTAMP) {
+		struct fw_cdev_event_response *rsp = &e->rsp.without_tstamp;
+
+		rsp->type = FW_CDEV_EVENT_RESPONSE;
+		rsp->length = request->length;
+		rsp->closure = request->closure;
+		payload = rsp->data;
+	} else {
+		struct fw_cdev_event_response2 *rsp = &e->rsp.with_tstamp;
+
+		rsp->type = FW_CDEV_EVENT_RESPONSE2;
+		rsp->length = request->length;
+		rsp->closure = request->closure;
+		payload = rsp->data;
+	}
 
 	if (request->data && copy_from_user(payload, u64_to_uptr(request->data), request->length)) {
 		ret = -EFAULT;
@@ -615,9 +649,9 @@ static int init_request(struct client *client,
 	if (ret < 0)
 		goto failed;
 
-	fw_send_request(client->device->card, &e->r.transaction, request->tcode, destination_id,
-			request->generation, speed, request->offset, payload, request->length,
-			complete_transaction, e);
+	fw_send_request_with_tstamp(client->device->card, &e->r.transaction, request->tcode,
+				    destination_id, request->generation, speed, request->offset,
+				    payload, request->length, complete_transaction, e);
 	return 0;
 
  failed: